document_title: Chevrolet Silverado

question_text: what size engine is in a 2000 chevy silverado

question_tokens: what size engine is in a 2000 chevy silverado

text: Chevrolet Silverado

text: History[edit]

text: Although General Motors introduced its first pickup truck in 1930, the term "Silverado" was a designation used only to detail the trim for the Chevrolet C/K pickup trucks, Suburbans, and Tahoes from 1975 through 1999.[1] GMC used a few variations of the "Sierra" name (e.g. Sierra, Sierra Classic, and High Sierra); however, Chevrolet still uses the CK and the CC in their current model codes.

text: The Chevrolet Silverado and GMC Sierra trucks have been essentially the same for their entire history. However, there are some trim and add-on option variations. Early models included variations in the engine and equipment, but the present differences are slight. The 1999 model year redesign included different grilles and interior trim, and certain features (e.g. Quadrasteer) were included at different times on the two trucks. The GMC Sierra has a luxury package known as "Denali" which adds tons of creature comfort features and design changes. Chevrolet's equivalent to the Denali trim level is the High Country Silverado which was introduced in the 2014 model year.

text: First generation (1999-2007)[edit]

text:
First generation

Overview

Also called
Chevrolet C/K (South Korea)

Production
June 1998-2007

Designer
Ken Sohocki (1994)[2]

Body and chassis

Platform
GM GMT800 platform

Powertrain

Engine
Vortec 4300 (4.3 L) V6
Vortec 4800 (4.8 L) V8
Vortec 5300 (5.3 L) V8
Vortec 6000 (6.0 L) V8

Transmission
4-speed 4L60-E automatic
4-speed 4L65-E automatic
4-speed 4L80-E automatic
5-speed NV3500 manual

Dimensions

Wheelbase
119 in (3,023 mm)
133 in (3,378 mm)
143.5 in (3,645 mm)

Length
203 in (5,156 mm)
227 in (5,766 mm)
246 in (6,248 mm)
Hybrid: 230.2 in (5,847 mm)

Width
78.5 in (1,994 mm)

Height
74 in (1,880 mm)
77 in (1,956 mm)
Hybrid 2WD: 71.2 in (1,808 mm)
Hybrid 4WD: 73.9 in (1,877 mm)

text: The GMT800 Silverado/Sierra 1500 and 2500 (non Heavy Duty) (light pickup trucks) were released in August 1998 as 1999 models. The "classic" light-duty GMT400 C/K trucks were continued in production for that first year alongside the new models, and the Heavy-Duty GMT400 pickups (alongside the GMT400 SUVs) were continued through 2000, with the new GMT800 Silverado/Sierra HD (Heavy Duty) being introduced. A small refresh for 2003 models was introduced in 2002, bringing slight design changes and an upgrade to the audio and HVAC controls. The latter 2006 and 2007 GMT800 production units used the name Classic to denote the difference between the first and second generation trucks.

text: Light duty[edit]

text: There are a number of models of light-duty Silverados and Sierras, including the half-ton, SS, and Hybrid.

text: The light-duty trucks use the 1500 name. They are available in three cab lengths, 2-door standard/regular cab, 4-door extended cab, and front-hinged 4-door crew cab. Three cargo beds are available: a 69.2 in (1,758 mm) short box, 78.7 in (1,999 mm) standard box, and a 97.6 in (2,479 mm) long box. The short box is only available with the extended or crew cab, and is the only option on the latter.

text: For the first year, only the regular cab and an extended cab were available, along with the Vortec 4300 V6, Vortec 4800 V8, and the Vortec 5300 V8. In 2000, a driver's side door option became available for the extended cab, giving it four doors, and the crew-cab body was added to the lineup. Output on the 5.3 L engine also increased to 285 hp (213 kW) and 325 lb·ft (441 N·m).

text: The 6.0 L Vortec 6000 V8 was standard on the 2500 and was added for the 2001 Heavy Duty models, rated at 300 hp (224 kW), with the GMC Sierra 1500 C3 getting an uprated 25 hp (19 kW) version of this engine. The Silverado Z71 got an optional lighter composite box, with a suspension package for towing, but lacked the high-output engine. The C3 became the Denali for 2002, and Quadrasteer was added.

text: GM introduced a reworked version of the Silverado (but not the Sierra) in 2003, with a new front end and a slightly updated rear end. In 2006 the Silverado received another facelift, similar to the HD version introduced in 2005 HD models. In addition to that, Chevrolet has deleted the "Chevrolet" badge off the tailgate that was used from 1998-2005. Its SUV counterparts retained the use of the pre-facelift sheetmetal.

text: The Insurance Institute for Highway Safety (IIHS) gave the Silverado an overall "marginal" score on the frontal offset crash test for poor structural integrity and poor dummy control, although no injuries were recorded on the dummy's body regions.[3]

text: 2001 GMC Sierra C3/Denali[edit]

text: GMC created an upscale version of its Sierra 1500 in 2000 called the Sierra C3. It used all-wheel drive with a 3.73 final drive gear ratio and included the 6.0 L Vortec 6000 LQ4 V8 rated at 325 hp (242 kW) at 5000 rpm and 370 lb•ft (502 N·m) of torque at 4000 rpm coupled to a 4L60E-HD four speed automatic transmission along with other upscale equipment. For 2002, the name was changed to Sierra Denali, but the specifications remained essentially the same except for the addition of Quadrasteer and GM changed from the 4L60E-HD to the 4L65E in conjunction with a 4.10 final drive gear ratio.

text: The Denali is rated for towing 9,100 pounds (4,100 kg) and hauling 1,595 pounds (723 kg) in the cargo box.

text: The Sierra Denali was initially equipped with Delphi's Quadrasteer system as standard equipment. It was a 4-wheel steering system that greatly reduced the truck's turning radius and improved lane changing while towing. General Motors dropped Quadrasteer from the Sierra Denali after the 2004 model year and its entire lineup after 2005 due to poor sales of this expensive option.[4]

text: For the '07 model year, the Sierra Denali shares the same billet grille from the other Denali models, and also has the same dash as the '07 SUV's. The '07 Sierra Denali was initially the only half ton pickup that had a 6.2 liter with 403 hp (301 kW) and 417 lb·ft (565 N·m) of torque coupled to a six speed transmission. This truck is also an optional all wheel drive vehicle and goes 0-60 mph in 6.3 seconds.

text: Chevrolet Silverado SS[edit]

text: Launched in early 2003, the Silverado SS is a high-performance pickup truck built by Chevrolet. It is based on the 1500 Silverado with upgrades in drive train and both exterior and interior appearance. It was equipped standard with the 6.0 liter Vortec High-Output V8 rated at 345 hp (257 kW) at 5200 rpm and 380 lb·ft (515 N·m) of torque at 4000 rpm coupled to a 4L65E four speed automatic transmission. This was the same engine used for the second generation Cadillac Escalade. Chevrolet and GMC advertised this engine as the Vortec High Output and later as the "VortecMAX", while Cadillac calls it the "HO 6000". The SS debuted in 2003 with a standard All Wheel Drive setup with a 4.10 final drive gear ratio and 4 wheel disc brakes. In 2005, in an attempt to increase sales, a 2-wheel drive version became available (the 2WD SS also lost its rear disc brakes in favor of drums, as did the rest of the 1/2-ton GMT800s). 2005 was also the first year the sun roof was available in the SS line up. In 2006, the AWD variant was dropped and the rear wheel drive was the only driveline layout available. In a further effort to reduce cost, you could also get cloth interior and/ or bench seat. The Silverado SS also comes with the Z60 performance suspension and 20 inch aluminum wheels. All the SS trucks in both 2 wheel drive and AWD used the torsion bar style front suspension for better handling. It should also be noted the SS themed trucks were only available from the factory in Black Onyx, Victory Red, and Arrival Blue Metallic from 2003 to 2004. In 2005 Arrival Blue Metallic was dropped from the color choice and replaced with Silver Birch Metallic...

text: Intimidator SS[edit]

text: In 2006, Chevrolet released a special edition Silverado SS under the name "Intimidator SS" (licensed by Dale Earnhardt Inc.) to honor the late Dale Earnhardt. The truck came with several minor appearance upgrades (rear spoiler, embroidered headrests, Intimidator custom badging), but was essentially just a regular Silverado SS. Of the 1,033 scheduled trucks, only 933 were made (the remaining 100 were sold as 2007 Silverado SS "classic" bodystyle trucks before the 2007.5 MY changeover. These trucks were only available in Black Onyx exterior but could be ordered with cloth or leather interior. Also features[5]-

text: Vortec High Output/Vortec Max[edit]

text: The Vortec High Output option was first introduced in 2004 to a limited market (mainly consisting of Texas and several surrounding areas); it was available nationwide for MY 2005. It was available for both the Chevy and GMC 1500 series trucks. This special edition package (under option code B4V) included several options previously not found on the standard 1500 model, most notably the LQ9 6.0 L V-8 engine (the same used for the Silverado SS, the 2005-2006 GMC Denalis and the Cadillac Escalade). The LQ9 motor was rated at 345 hp (257 kW) at 5200 rpm and 380 lb·ft (515 N·m) of torque at 4000 rpm, which was the same specifications shared in the SS models. The B4V package could only be ordered on extended cab standard box 2WD trucks. They were all built at the Canadian assembly plant and were equipped with the Z60 High Performance suspension package, in addition to the M32 = 4L65E transmission, GT4 = 3.73 rear gear, and G80 Gov Lock as standard equipment. The 2004 models were equipped with the standard 10 bolt 8.625 rear end. The 2005 models were upgraded with the larger 14 bolt 9.5 rear end under RPO option AXN. The package also included one style of the newly introduced GM 20 inch wheels installed from the factory. This marked the first time the LQ9 engine was available for a two-wheel drive application. Unlike the previous years with the SS Package, you could order the interior combination in anything from basic cloth to fully loaded. There were also more exterior color options available with this package.

text: In 2006, the Vortec Max trailering package became available. The Vortec Max package was added to the option list with an array of similar features and new badges, and at its core retained the LQ9/4L65-E powertrain. However, the Vortec Max package differed from the Performance edition in that it also came with a variant of the Z85 Handling/Trailering suspension, as well as 17-inch wheels and tires under the option code NHT on 4x4 models versus the Z60 High Performance Suspension and 20-inch wheel and tire package of the regular B4V 2 wheel drive Performance Edition. This was because the Vortec Max package was intended for max trailer towing, while the Performance Edition was intended more for customers who wanted the Silverado SS mechanicals without the visuals of the SS. It was also made available (in addition to the extended cab) in the light duty 4 door crew cab models. For the first time it was also available in 2 wheel drive or 4 wheel drive on both the Silverados and Sierras, with or without the Z71 package.

text: The newest Vortec Max performance package introduced in 2006 on the GMT900 includes a 10,800 pounds towing capacity.[6]

text: Hybrid[edit]

text: GM launched a hybrid version of the Silverado/Sierra in 2004, becoming the first ever GM hybrid passenger vehicle. Known within GM as the Parallel Hybrid Truck or PHT it is not actually a parallel hybrid by the current definition, but a type of micro hybrid design. The electric motor housed within the transmission flywheel housing, serves only to provide engine cranking/starting, battery charging, and powering accessories. The engine automatically shuts down as the truck comes to a stop and uses 42 Volt electric power to the starter/generator unit to restart the engine as the brake pedal is released. Besides the typical 12 V automotive battery the PHT uses three additional 12 V valve regulated lead acid (VRLA) batteries mounted under the rear seat to store and provide power. The truck uses a 5.3 L Vortec 5300 V8 for primary propulsion power. These trucks were also purchased back from customers for more than what they were worth in the late 2000s.

text: The PHT features four 120 volt 20 amp AC outlets, two in the bed and two inside the cab under the rear seat. These are particularly interesting to the building/construction contractor market, since they often require AC power when on the job. Additionally, the extra reserves of power for the accessories make this truck well-suited to that market, where trucks often sit at idle for hours at a time.

text: Availability was extremely limited at first, with commercial buyers getting the first allotment. Later in 2005, the truck was offered at retail in Alaska, California, Florida, Nevada, Oregon, Washington and Canada. For 2006-07 the truck was generally available to retail buyers throughout North America. The Parallel Hybrid Truck was discontinued for the 2008 model year with the release of the GMT900 truck line. Starting in 2009, General Motors offers a second generation Chevrolet Silverado and GMC Sierra equipped with a Two-Mode Hybrid powertrain and 4-speed CVT.[7]

text: Heavy duty[edit]

text:
GMT800 Heavy Duty

Overview

Production
2000–2007

Body and chassis

Platform
GM GMT880 platform

Powertrain

Engine
6.0 L Vortec 6000 V8
8.1 L Vortec 8100 V8
6.6 L Duramax V8

Transmission
4-speed 4L80-E automatic
5-speed Allison 1000 automatic (2000–2005)
6-speed Allison 1000 automatic (2005–2007)
5-speed NV4500 manual (2000–2007 6.0)
6-speed ZF S6-650 manual (2000–2006 6.6 and 8.1)

Dimensions

Wheelbase
133 in (3,378 mm)
143.5 in (3,645 mm)
157.5 in (4,000 mm)
167 in (4,242 mm)
153 in (3,886 mm)

Length
222.1 in (5,641 mm)
227.7 in (5,784 mm)
246.6 in (6,264 mm)
237.2 in (6,025 mm)
256.1 in (6,505 mm)

Width
SRW: 79.7 in (2,024 mm)
DRW: 96.1 in (2,441 mm)

Height
76.0-77.4 in (1,930-1,966 mm)

text: The HD variant is a heavy-duty light truck. It is a strengthened version of the Silverado/Sierra light-duty, and is available in the 1500HD, 2500HD, and 3500HD models. The 2500, introduced in 2000, offers a Vortec 6000 V8 with 300 hp (224 kW) at 5200 rpm and 360 lb·ft (488 N·m) of torque at 4000 rpm with a Hydra-Matic 4L80E four-speed automatic transmission. The 2500HD also offers either the LB7 Duramax V8 with 300 hp (224 kW) at 3100 rpm and 520 lb·ft (705 N·m) of torque at 1800 rpm, the LLY Duramax V8 with 310 hp (231 kW) @ 3000RPM and 605 lb·ft (820 N·m) @ 1600RPM, and the LBZ Duramax V8 with 360 hp (268 kW) @ 3200RPM and 650 lb·ft (881 N·m) @ 1600RPM. Also available is the Vortec 8100 V8 with 340 hp (254 kW) at 4200 rpm and 455 lb·ft (617 N·m) of torque at 3200 rpm.

text: The 2500HD has an available five-speed (six-speed for 2006-2007 models) Allison 1000 transmission with the Vortec 8100 and Duramax 6.6. The Silverado 3500 offers the same engine/transmission features that the 2500HD does, however it is usually equipped with "dually" twin wheels at the rear and has a stronger suspension. The HD models are primarily used for towing and high-weight cargo. The Chevrolet Silverado 2500HD came in at #2 in a 2016 study by iSeeCars.com ranking the top 10 longest-lasting vehicles. The Silverado 2500HD had 5.7% of vehicles over 200,000 miles, according to the iSeeCars study.[8]

text: Towing capacity for the 1500HD is rated at 10,300 pounds (4,700 kg) and can haul 3,129 pounds (1,419 kg) in the bed depending on options. Towing capacity for the 2500HD is rated at 16,100 pounds (7,300 kg) with the gasoline 8.1L V8 with 3.73:1 rear and can haul 3,964 pounds (1,798 kg) in the bed depending on options. Towing capacity for the 3500HD is rated at 16,700 pounds (7,600 kg) and can haul 5,753 pounds (2,610 kg) in the bed depending on options. The addition of 4 wheel drive tends to reduce the towing and carrying capacity by 200 to 400 lb (181 kg), depending upon year and model. Other factors, such as options, can also affect these numbers.

text: Engines[edit]

text:
Model
Year
Engine
Power
Torque

1500
1998–2003
4.3 L Vortec 4300 V6
200 hp (149 kW) @ 4600 RPM
260 lb·ft (353 N·m) @ 2800 RPM

2004–2006
195 hp (145 kW) @ 4600 RPM
260 lb·ft (353 N·m) @ 2800 RPM

1999
4.8 L Vortec 4800 V8
255 hp (190 kW) @ 5200 RPM
285 lb·ft (386 N·m) @ 4000 RPM

2000-2003
270 hp (201 kW) @ 5200 RPM
285 lb·ft (386 N·m) @ 4000 RPM

2004-2007
285 hp (213 kW) @ 5200 RPM
295 lb·ft (400 N·m) @ 4000 RPM

1999
5.3 L Vortec 5300 V8
270 hp (201 kW) @ 5200 RPM
315 lb·ft (427 N·m) @ 4000 RPM

2000–2003
285 hp (213 kW) @ 5200 RPM
325 lb·ft (441 N·m) @ 4000 RPM

2004–2007
295 hp (220 kW) @ 5200 RPM
335 lb·ft (454 N·m) @ 4000 RPM

2005-2007
310 hp (231 kW) @ 5200 RPM
335 lb-ft (454 N-m) @ 4000 RPM

1500HD/2500HD/3500HD
2000-2006
6.0 L Vortec 6000 V8
300 hp (224 kW) @ 4400 RPM
360 lb·ft (488 N·m) @ 4000 RPM

2000–2004
8.1 L Vortec 8100 V8
340 hp (254 kW) @ 4200 RPM
455 lb·ft (617 N·m) @ 3200 RPM

2004–2006
330 hp (246 kW) @ 4200 RPM
450 lb·ft (610 N·m) @ 3200 RPM

2001–2002 w/ LQY
270 hp (201 kW) @ 3600 RPM
400 lb·ft (542 N·m) @ 1600 RPM

2001–2002 w/ LQQ
210 hp (157 kW) @ 3600 RPM
325 lb·ft (441 N·m) @ 1200 RPM

2002–2005 w/ LRW
325 hp (242 kW) @ 4000 RPM
450 lb·ft (610 N·m) @ 2800 RPM

2002–2006 w/ LRZ
295 hp (220 kW) @ 3600 RPM
440 lb·ft (597 N·m) @ 3200 RPM

2002–2006 w/ LQR
225 hp (168 kW) @ 3600 RPM
350 lb·ft (475 N·m) @ 1200 RPM

2000–2004
6.6 L Duramax (LB7/LLY) V8
300 hp (224 kW) @ 3100 RPM
520 lb·ft (705 N·m) @ 1800 RPM

2005-2006 w/ MTX
300 hp (224 kW) @ 3000 RPM
520 lb·ft (705 N·m) @ 1800 RPM

2005-2006 w/ ATX
310 hp (231 kW) @ 3000 RPM
605 lb·ft (820 N·m) @ 1600 RPM

2006-2007
6.6 L Duramax (LBZ) V8
360 hp (268 kW) @ 3200 RPM
650 lb·ft (881 N·m) @ 1600 RPM

GMC Sierra C3
2000-2001
6.0 L Vortec 6000 V8
325 hp (242 kW) @ 5000 RPM
370 lb·ft (502 N·m) @ 4000 RPM

GMC Sierra Denali
2002–2004

2004–2006
6.0 L Vortec 6000 V8
345 hp (257 kW) @ 5200 RPM
380 lb·ft (515 N·m) @ 4000 RPM

Chevrolet Silverado SS
2002–2006

Chevrolet Silverado Vortec High Output
2003–2005

Chevrolet Silverado VortecMAX
2005-2006

text:
1999–2002 Chevrolet Silverado 2500 regular cab

2003–2007 Chevrolet Silverado 3500 crew cab

The Allison 1000 attached to the 6.6L Duramax Diesel

2004 Silverado 2500 HD

2009 Chevrolet Silverado Single Cab in Chile

tag: ul

text: Second generation (2006–2014)[edit]

text:
Second generation

Overview

Also called
Chevrolet Platform/Shakebody
GMC Dump Truck
VIA VTRUX
GMC Sierra
Chevrolet/GMC C/K

Production
2006–2014

Body and chassis

Platform
GM GMT900 platform:
GMT901 (Chevrolet Silverado)
GMT902 (GMC Sierra)

Powertrain

Engine
4.3 L V6 195 hp (145 kW)[9][10]
4.8 L V8 295 hp (220 kW)[9]
5.3 L V8 315 hp (235 kW)[9]
6.0 L V8 360 hp (268 kW)[9]
6.2 L V8 403 hp (301 kW)[9]

Transmission
4-speed 4L60-E automatic[9][10]
4-speed "2-Mode Hybrid transmission" 2ML70 (Hybrid)[10][11]
6-speed 6L80 automatic[9][10][12]

Dimensions

Wheelbase
Regular: 119 in (3,023 mm)
Extended & Crew: 143.5 in (3,645 mm)

Length
Regular: 205.6 in (5,222 mm)
Extended & Crew: 230.2 in (5,847 mm)
Hybrid: 229.9 in (5,839 mm)

Width
Regular & Extended: 79.9 in (2,029 mm)
Crew: 80 in (2,032 mm)

Height
Regular & Extended: 73.9 in (1,877 mm)
Crew: 73.8 in (1,875 mm)
Hybrid 4WD: 73.7 in (1,872 mm)

text: The all-new GMT900 generation of the Silverado/Sierra arrived in the last quarter of 2006 as a 2007 model. It features a redesigned exterior, interior, frame, and suspension as well as a power increases on certain engines. It takes styling cues from the 2007 GMT900 SUVs and the Chevrolet Colorado pickups. Like the GMT900 SUVs, these pickups also have greatly improved aerodynamics over their predecessors like steeply raked windshields and tighter panel gaps which improve fuel economy. The GMT800 models were continued through 2007 badged as "Classic", just as the GMT400 models continued for two years after the GMT800's introduction.

text: The new Silverado earned the North American Truck of the Year award for 2007 and was Motor Trend magazine's Truck of the Year for 2007. Like its predecessors, the new Silverado offers buyers a choice of two door regular cabs, four door extended cabs (with rear doors that now open 170 degrees similar to the Nissan Titan) and four door crew cabs with the rear doors opening in the same direction as the front doors. GM also offers the trucks in the traditional two and four wheel drive configurations.

text: The Generation III small block V8 engines offered in the GMT 800 trucks were replaced in the GMT 900 series by the Generation IV small block V8 engine family, featuring upgrades such as increased power and Active Fuel Management on the 5.3 L and 6.0 L V8s. A new high performance 6.2 liter V8 (with 403 hp (301 kW) and 417 lb·ft (565 N·m) of torque) was introduced with the 2007 Cadillac Escalade and 2007 GMC Denali line, and is now available on the Silverado LTZ trim line. After skipping the 2008 model year, with 2007 being the last for the GMT800 hybrid line, a two-mode hybrid model was introduced in late 2008 as a 2009 model. General Motors discontinued the Silverado Hybrid due to poor sales along with the GMC Sierra Hybrid, Chevy Avalanche, Chevy Tahoe Hybrid, GMC Yukon Hybrid, Cadillac Escalade Hybrid, and Cadillac Escalade EXT after the 2013 model year even though it was the one of the two first hybrid pickup trucks ever manufactured.[13] Available in either two- or four-wheel-drive, the Sierra 1500 Hybrid is powered by a 6.0-liter V8. It's joined by two 60-kilowatt electric motors supplied by a nickel–metal hydride battery pack under the rear seat. On its own, the V8 is rated at 332 horsepower and 367 pound-feet of torque. GM engineers say that combined output with the electric motors is 379 hp. The unique transmission houses the electric motors along with three different planetary gear sets and four traditional clutches.[14]

text: There were two dash options offered in this model Silverado and Sierra: a luxury-inspired dash that closely mimics the dash in their GMT900 SUVs, and a more traditional upright dash to make room for a passenger seat in place of a center console.

text: As of 2008, General Motors full-size trucks were no longer sold in United States and Canada with manual transmissions; they were only offered in Mexico in the Silverado 1500 V6 engine and Silverado 3500.[15]

text: All Silverado & Sierra 1/2-ton models received a revised bumper and shortened front fascia midway through the 2009 model year and a full mid-cycle refresh followed with all 2010 models, including new interior door panels (which moved the handle forward and added an additional cup holder) and a six-speed automatic transmission on regular and extended cab models with 5.3L or larger V8's was also made standard. Two new exterior colors were added: Taupe Gray Metallic and Sheer Silver Metallic.

text:
2007 GMC Sierra Denali

Chevrolet Silverado Hybrid

2009 GMC Sierra Hybrid

2012 Chevrolet Silverado 1500 LTZ extended cab

2013 GMC Sierra Denali Crew Cab

text:
GMT900 Heavy Duty

Overview

Production
2006–2014

Body and chassis

Platform
GM GMT910 platform:
GMT911 (Chevrolet Silverado)
GMT912 (GMC Sierra)

Powertrain

Engine

6.0 L V8 360 hp (268 kW)[9]
6.6 L Duramax diesel V8 397 hp (296 kW)[9]

Transmission
6-speed 6L90 automatic[9][10]
6-speed Allison 1000 automatic[9]

Dimensions

Wheelbase
Varies greatly

Length
Varies greatly

Width
80 in (2,032 mm)
95.9 in (2,436 mm) (Towing mirrors)

Height
76 in (1,930 mm)

text: The 8.1 L big-block V8 is no longer offered on the Heavy Duty models, and no replacement has been announced. The 6L90 6-speed automatic transmission is standard in all Heavy Duty models. The Allison 1000 transmission is paired with the optional Duramax V8 diesel.

text: As of 2011 the GMC and Chevrolet heavy Duty's have being upgraded with a new fully boxed high strength steel frame from front to rear improving stiffness by 92% with bigger rear springs, larger engine and transmission mounts and new hydraulic body mounts to improve the ride.The front suspension incorporates new upper and lower control arms and new torsion bars tailored to one of five different gross axle weight ratings. Upper control arms are constructed from forged steel that is both stronger and lighter than the previous arms, while the new lower arms are cast iron to maximize load capacity. Using a unique torsion bar for each gross weight rating allows for better control over vehicle height, resulting in improved handling and better alignment for reduced tire wear. These improvements allow for up to a 6,000 pound front axle weight rating, allowing all 4wd trucks to accommodate a snow plow. Additional front suspension enhancements come from new urethane bump stops, two per side. The upper shock mount has been changed from a single stem mount to a two-bolt design to eliminate the possibility of squeaks and thumps. The rear suspension design uses asymmetrical leaf springs that are wider and capable of greater load handling. The design features 3-inch wide leaves, with front and rear spring sections of different lengths to reduce the twisting that can result in axle hop and loss of traction. The 2500HD use a two-stage design with a rating of 6,200 lbs, and 3500HD models have a three-stage design with 7,050 lb and 9,375 lb ratings on single and dual-wheel models respectively

text:
2012 Chevrolet Silverado 2500HD crew cab

2012 GMC Sierra Denali HD

2008 GMC Sierra 3500HD SLT crew cab

2012 Chevrolet Silverado 3500HD crew cab

text: Engines[edit]

text:
Model
Year
Engine
Power
Torque

1500
2007-2013
4.3 L Vortec 4300 V6
195 hp (145 kW) @ 4600 RPM
260 lb·ft (353 N·m) @ 2800 RPM

2007-2008
4.8 L Vortec 4800 V8
295 hp (220 kW) @ 5600 RPM
305 lb·ft (414 N·m) @ 4800 RPM

2009
295 hp (220 kW) @ 5600 RPM
305 lb·ft (414 N·m) @ 4600 RPM

2010-2013
302 hp (225 kW) @ 5600 RPM
305 lb·ft (414 N·m) @ 4600 RPM

2007-2009
5.3 L Vortec 5300 V8
315 hp (235 kW) @ 5200 RPM
338 lb·ft (458 N·m) @ 4400 RPM

2010-2013
315 hp (235 kW) @ 5300 RPM
335 lb·ft (454 N·m) @ 4400 RPM

2007-2008
6.0 L Vortec 6000 V8
367 hp (274 kW) @ 5500 RPM
375 lb·ft (508 N·m) @ 4300 RPM

2009
367 hp (274 kW) @ 5600 RPM
375 lb·ft (508 N·m) @ 4300 RPM

2009-2013
6.2 L Vortec 6200 V8
403 hp (301 kW) @ 5700 RPM
417 lb·ft (565 N·m) @ 4300 RPM

2500HD/3500HD
2007-2008
6.0 L Vortec 6000 V8
353 hp (263 kW) @ 5400 RPM
373 lb·ft (506 N·m) @ 4400 RPM

2009-2014
360 hp (268 kW) @ 5400 RPM
380 lb·ft (515 N·m) @ 4200 RPM

2007-2010
6.6 L Duramax V8
365 hp (272 kW) @ 3200 RPM
660 lb·ft (895 N·m) @ 1600 RPM

2011-2014
397 hp (296 kW) @ 3000 RPM
765 lb·ft (1,037 N·m) @ 1600 RPM

Silverado XFE
2009
6.0 L Vortec 6000 V8
332 hp (248 kW) @ 5100 RPM
367 lb·ft (498 N·m) @ 4100 RPM

Silverado Hybrid
2009-2013

text: Production location switch[edit]

text: For the 2011 model year of the Silverado/Sierra, the production of crew cab models partially shipped from Silao, Mexico to Flint, Michigan.[16]

text: Safety[edit]

text: The Silverado comes standard with four-wheel ABS. StabiliTrak and side curtain airbags are optional on certain trim levels.

text: 2007 NHTSA crash test:[17]

text:
Frontal Driver:
Frontal Passenger:
Side Driver:
Side Rear Passenger:
Rollover:

text: The IIHS gave the Silverado a "Good" score in their frontal crash test, however 2007-09 models equipped with or without optional side curtain airbags received a "Poor" rating in the side impact test.[3] For 2010 models the side structure was strengthened, side torso air bags were added, and side airbags became standard, with the upgrades the IIHS side impact overall rating improved to "Acceptable", while the overall side structure rating is improved from "Poor" to "Acceptable".[18] The crew cab variant of the 2011-13 Silverado is also rated "Marginal" in the IIHS roof strength test.[19]

text: Electric version[edit]

text: In 2011 developer of the Chevrolet Volt and former vice chairman Bob Lutz joined VIA Motors in developing electric versions of the Chevrolet Silverado/GMC Sierra called VIA VTrux.

text: 2013 VIA VTRUX

text: Third generation (2013–present)[edit]

text:
Third generation

Overview

Also called
GMC Sierra
VIA Vtrux Truck

Production
2013–present (1500) 2014-present (2500 and 3500)

Designer
Kevin O'Donnell (2010)[20]

Body and chassis

Platform
GMT K2XX

Powertrain

Engine

LV3 EcoTec3 4.3 L V6 285 hp (213 kW)[21]
L83 EcoTec3 5.3 L V8 355 hp (265 kW)[21]
L8B EcoTec3 5.3 L V8 355 hp (265 kW)[22]
L86 EcoTec3 6.2 L V8 420 hp (313 kW)[21]
LY6 Vortec 6000 6.0 L V8 360 hp (268 kW)
LML Duramax 6.6 L V8 397 hp (296 kW)

Transmission
6-speed 6L80 automatic[21]
8-speed 8L90 automatic

Dimensions

Wheelbase
Regular 6'6": 119 in (3,023 mm)
Regular 8': 133 in (3,378 mm)
Double 6'6" & Crew 5'5": 143.5 in (3,645 mm)
Crew 6'6": 153 in (3,886 mm)

Length
Regular 6'6": 205.6 in (5,222 mm)
Regular 8': 224.4 in (5,700 mm)
Double & Crew 5'5": 230 in (5,842 mm)
Crew 6'6": 239.6 in (6,086 mm)

Width
80 in (2,032 mm)

Height
73.5 in (1,867 mm) – 74.2 in (1,885 mm)

text: On December 13, 2012, the redesigned 2014 Chevrolet Silverado, along with the related 2014 GMC Sierra were introduced in Detroit, Michigan at the North American International Auto Show. GM dropped the 900 platform and changed to K2XX. The third generation Silverado 1500 has three gas engine options: 4.3 L EcoTec3 V6, 5.3 L EcoTec3 V8, or 6.2 L EcoTec3 V8. Chevrolet's MyLink touch-screen multimedia interface system will be available on most models. It will have A2DP stereo streaming technologies, Bluetooth hands-free telephone, USB hookups, and an input for an Apple iPod or iPhone. When connected via the USB port, an iPhone 4/4S, iPhone 5/iPhone 5S, iPhone 6, or iPhone 6 Plus will be able to stream music from Pandora Radio. A Bose premium audio system, as well as a Bose surround sound audio system will be available on most models. OnStar will be standard on all models.

text: Underneath, the Silverado rides on a fully boxed high strength steel frame with hydroforming technology; truck cab's frame is built with high strength steel as well. The third generation Silverado uses aluminum on the hood, for the engine block and for the control arms in order to save mass. The truck's bed is made of roll-formed steel instead of stamped steel used by other manufacturers in order to save weight and gain strength. The third generation Silverado introduced the upmarket High Country edition which includes saddle brown leather interior, which is Chevrolet's first entry into the luxury market. A revised front end features styling cues from the 1980s-era Chevrolet C-Series Trucks, and, on Z-71 models, a Z-71 badge was added to the front grille. The first production Silverado completed assembly on April 29, 2013. The Silverado 1500 went on sale in May 2013 as a 2014 model, with the Silverado HD Series being available in early 2014 for the 2015 model year. On January 10, 2014 a recall was issued for 370,000 Silverado and Sierra pickups due to a fire risk.[23]

text: A rebadged version of the Silverado called the Chevrolet Cheyenne is sold in Mexico.

text: The American model version of the 2014 Chevrolet Silverado 1500/2500/3500HD and the 2015 Chevrolet Silverado High Country was introduced to the Philippines market by Chevrolet Motorama Show late November 2014 as a MY2015, along with the MY2015 Chevrolet Suburban, 2015 Chevrolet Tahoe, 2015 Chevrolet Impala, 2015 Chevrolet Express Van, 2015 Chevrolet Trax and 2015 Chevrolet Colorado.

text: On January 14, 2014, The Silverado, along with the Chevrolet Corvette Stingray, received the 2014 North American International Auto Show's Car and Truck of the Year awards.[24]

text: For the 2015 model year, the 6.2L Ecotec3 was paired with the new 8-speed 8L90 transmission, offering a wider ratio spread with more closely spaced gears, quicker shifts, and improved acceleration and fuel economy.[25]

text: Special Editions[edit]

text: Chevrolet[edit]

text: For that year, Chevrolet introduced Special Edition for the Silverado truck series. They are in the following series of Rally Edition 1 and 2, Midnight Edition, Custom Sport Edition, Custom Sport Plus Edition, Black Out Edition, and Texas Longhorns Edition.[26]

text:
Rally Edition 1

Rally Edition 2

Black Out Edition

Texas Longhorns Edition

text: For 2016, the Chevrolet Silverado 1500 and GMC Sierra 1500 received its first mid-cycle refresh. The refreshed Silverado and Sierra received a new grille, new headlights and new front fascia, with design influences from the 2015 Chevrolet Colorado, as well as all new LED tail lights on the 2016 Silverado LTZ, HIGH COUNTRY, 2016 GMC Sierra SLT and DENALI trim levels while the 2016 Chevy Silverado LT trim levels and below still have the pre-facelifted taillights along with the 2016 GMC Sierra SLE trim levels and below. On October 1, 2015, HD Radio was added to the Silverado, Sierra, and their HD level models. The Silverado/Silverado HD will add HD Radio to their 8-inch MyLink system as a standard on the LT and LTZ trims, while the Sierra/Sierra HD will include the feature in its IntelliLink system as a standard on all its trims and for the 2017 model year the Chevy Silverado received CarPlay in the IntelliLink system and the Silverado 2500 and 3500 models received a new front hood with vents.[27]

text: Special editions[edit]

text: GMC[edit]

text: In 2016, GMC announced they introduced the Sierra All Terrain X, which is equipped with a 5.3-liter V8 engine with performance exhaust, bumping output up from 355 to 365 horsepower. On the exterior, the Sierra All Terrain X features back 18 inch rims fitted with Goodyear Wrangler DuraTrac MT tires, black bed-mounted sport bar, LED off-road lights, and blacked-out accents.[28]

text: Chevrolet[edit]

text: For that year, Chevrolet has added and dropped some of the Special Editions for the Silverado truck series. They are in the following series of Rally Edition 1 and 2, Midnight HD Edition, Midnight Edition, Custom Sport HD Edition, Realtree Edition, Custom Sport HD Edition, Black Out Edition, and Special Ops Edition.[29]

text:
Custom Sport HD Edition

Black Out Edition

text: Engines[edit]

text:
Model
Year
Engine
Power
Torque

1500
2014-
4.3 L LV3 GM EcoTec3 4300 V6
285 hp (213 kW) @ 5300 RPM
305 lb·ft (414 N·m) @ 3900 RPM

2014-
5.3 L L83 GM EcoTec3 5300 V8
355 hp (265 kW) @ 5600 RPM
383 lb·ft (519 N·m) @ 4100 RPM

2016-
5.3 L L8B GM EcoTec3 5300 V8
355 hp (265 kW) @ 5600 RPM
383 lb·ft (519 N·m) @ 4100 RPM

2014-
6.2 L L86 GM EcoTec3 6200 V8
420 hp (313 kW) @ 5600 RPM
460 lb·ft (624 N·m) @ 4100 RPM

2500HD/3500HD
2015-
6.0 L LY6 Vortec 6000 V8
360 hp (268 kW) @ 5400 RPM
380 lb·ft (515 N·m) @ 4400 RPM

2015-2016
6.6 L LML Duramax V8
397 hp (296 kW) @ 3200 RPM
765 lb·ft (1,037 N·m) @ 1600 RPM

2017
6.6 L L5P Duramax V8
445 hp (332 kW) @ 2800 RPM
910 lb·ft (1,234 N·m) @ 1600 RPM

text: Military applications[edit]

text:
LSSV

Overview

Manufacturer
General Motors, AM General

Model years
2001–present

Body and chassis

Body style
2-door SUV
4-door SUV
2-door pickup
4-door pickup

Platform
GM GMT880 platform

Powertrain

Engine
6.6 L Duramax V8

Transmission
4-speed 4L80-E automatic
5-speed Allison 1000 automatic

Dimensions

Width
79.9 in (2.03 m)

Height
74.5 in (1.89 m)

text: When production of the CUCV II ended in 2000, GM redesigned it to coincide with civilian truck offerings. The CUCV nomenclature was changed to Light Service Support Vehicle in 2001. In 2005, LSSV production switched to AM General, a unit of MacAndrews and Forbes Holdings. The LSSV is a GM-built Chevrolet Silverado 1500, Chevrolet Silverado 2500 HD, Chevrolet Tahoe, or Chevrolet Suburban that is powered by a Duramax 6.6 liter turbo diesel engine. The various Silverados, Tahoes, and Suburbans that are used provide numerous platforms for different kinds of vehicles. As GM has redesigned its civilian trucks and SUVs from 2001–present, LSSVs have also been updated cosmetically.[30]

text: The Militarization of standard GM trucks/SUVs to become LSSVs includes exterior changes such as CARC paint (Forest Green, Desert Sand, or 3-color Camouflage), blackout lights, military bumpers, a brush guard, a NATO slave receptacle/NATO trailer receptacle, a pintle hook and tow shackles. The electrical system is changed to the 24/12 volt military standard. The dashboard has additional controls and dataplates. The truck also can be equipped with weapon supports in the cab, cargo tie down hooks, folding troop seats, pioneer tools, winches, and other military accessories.[30]

text: The Enhanced Mobility Package (EMP) option adds enhanced suspension, 4-wheel anti-lock brakes, a locking differential, on/off-road beadlock tires, a tire pressure monitoring system and other upgrades. About 2,000 LSSV units were sold to U.S. and international military and law enforcement organizations.[30]

text: Variants[edit]

text:
Cargo/Troop Carrier Pickup (2-door, Extended Cab, or 4-door Silverado)
Cargo/Command Vehicle (4-door Tahoe)
Cargo/Trooprier/Command Vehicle/Ambulance (4-door Suburban)

text: Awards[edit]

text:
1999 - Motor Trend magazine's Truck of the Year
2001 - Motor Trend magazine's Truck of the Year (Heavy Duty Model)
2001 - Car and Driver magazine's Best Pickup Truck
2002 - Car and Driver magazine's Best Pickup Truck
2003 - Car and Driver magazine's Best Pickup Truck
2007 - North American Truck of the Year
2007 - Motor Trend magazine's Truck of the Year
2007 - ICOTY International Truck of the Year[31]
2007 - Truckin' magazine's Truck of the Year
2011 - Heavy Duty model won Motor Trend magazine's Truck of the Year[32]

text: Motorsport[edit]

text: Chevrolet is represented in the NASCAR Camping World Truck Series by the Silverado.[33] As of the 2016 season, 19 full-time teams use the Silverado.[34] Xpress Motorsports won the 2002 and 2003 NASCAR Craftsman Truck Series. The Silverado is also the title sponsor for the Chevrolet Silverado 250 Truck Series race at Canadian Tire Motorsport Park.[35]

text: The truck also won the Primm 300 off-road race in 2004, 2005 and 2006.

text: World markets[edit]

text: As of 2015, the Chevrolet Silverado is sold in the United States, Canada, Mexico, Venezuela, Chile, and the Middle East. And the GMC Sierra is sold in the United States, Canada, Mexico, and the Middle East (except Israel and Iran).

text: GM has also announced plans to introduce the Silverado, along with the smaller Colorado, to China.

text: There is a small gray market for both the Chevrolet Silverado and GMC Sierra trucks in some parts of the world, mostly in Scandinavian countries and Germany.

text: Gray import gallery[edit]

text: Chevrolet Silverado in Asker, Norway in front of McDonalds

text: Yearly American sales[edit]

text:
Calendar Year
Chevrolet Silverado
GMC Sierra
Total

1998[36]
538,254
160,555
698,809

1999
636,150
208,693
844,843

2000[37]
642,119
188,907
831,026

2001[38]
716,051
210,154
926,205

2002
652,646
202,045
854,691

2003[39]
684,302
196,689
880,991

2004[40]
680,768
213,756
894,524

2005
705,982
229,488
935,468

2006[41]
636,069
210,736
846,805

2007
618,259
208,243
826,500

2008[42]
465,065
168,544
633,609

2009[43]
316,554
111,842
428,396

2010[43]
370,135
129,794
499,929

2011[44]
415,130
149,170
564,300

2012[45]
418,312
157,185
575,497

2013[46]
480,414
184,389
664,803

2014[47]
529,755
211,833
741,588

2015[48]
600,544
224,139
824,683

2016[49]
574,876
221,680
796,556

text: Special use Silverados and Sierras[edit]

text:
Tow truck in Honolulu, Hawaii.

Spill response vehicle used after Hurricane Sandy, Staten Island, New York

Firetruck in Nebraska

Humpty Dumpty delivery van in Montreal

Dump truck in Milwaukee, Wisconsin

Ambulance in Uppsala, Sweden

Landing an airplane in Airdrie, Alberta

Race car

Drying a race track

Railway vehicle

Taxi in Saint Thomas, U.S. Virgin Islands

Beach patrol in Santa Monica, California

Hearse in Indianola, Mississippi

Chevrolet Cheyenne in use as a police car in Tijuana, Mexico


document_title: Silent Witness

question_text: who played sam ryan's son in silent witness

question_tokens: who played sam ryan 's son in silent witness

root

text: Silent Witness

text: Background[edit]

text: The original series was based on Professor Helen Whitwell, a forensic pathologist based in Sheffield, whom McCrery had known while serving as a police officer. The programme originally followed the activities of pathologist Sam Ryan, played by Amanda Burton. However, Burton's character departed early in the eighth series.

tag: p

text: There had been a succession of regular supporting characters, changing almost every series, but Dr. Leo Dalton (William Gaminara) and Dr. Harry Cunningham (Tom Ward), who were introduced in the sixth series, remained in the series and continued as lead characters following Ryan's departure, with Dalton replacing her as professor.

text: A new character, Dr Nikki Alexander (Emilia Fox), was introduced to the team in the eighth series. While working as a forensic anthropologist, she appropriates facilities and software in the pathology department to analyse an Iron Age find, with the belated, bemused and begrudging approval of Dalton. Dr. Alexander is able to assist in a set of cases being investigated by the team, as it turns out she had "worked in forensic pathology in Johannesburg for six months" and is Home Office certified to practise. She is of such assistance that she overcomes Leo's reluctance and, with Harry's support, is offered and accepts a position on the team.

text: During the fifteenth series, Dr. Cunningham leaves to accept a position in New York City. Subsequently, he is replaced by forensics expert Jack Hodgson (David Caves), and his assistant Clarissa Mullery (Liz Carr). During the sixteenth series, Dr. Dalton is killed in an explosion. At the start of the seventeenth series, his replacement, Dr. Thomas Chamberlain (Richard Lintern), is introduced to the team.

text: Although the show focuses heavily on areas of pathology, the police also have a heavy presence in each case. During latter series of the show, detectives and investigators tend to differ from episode to episode, with guest artists appearing in these roles. However, during the early years of the show, several characters appeared regularly to investigate each case.

text: The first three series were set in Cambridge. This changed to London from the start of the fourth series, following Sam as she took up an academic position. Each series is typically made up of a series of two-part stories. The first nine series typically featured eight episodes (four two-part stories), increased to ten episodes (five two-part stories) from the tenth series onwards.

text: In 1998, writer John Milne received an Edgar Award from the Mystery Writers of America for the second series episode "Blood, Sweat and Tears". In the United States, the series airs during 'Mystery Monday' on BBC America.

text: The series airs in Norway under the name "Tause vitner" on the Norwegian Broadcasting Corporation NRK[7] and in Sweden on TV4 under the name "Tyst vittne".[8] Both the Norwegian and Swedish titles are direct translations. The show is also broadcast in the Netherlands by public broadcaster KRO, Belgium on VRT channel Canvas and in Finland on the Finnish Broadcasting Company Yle using the name "Hiljainen todistaja", which is also a direct translation of the original title.[9]

text: The theme music featured in the series is entitled "Silencium", and is performed by John Harle. The arrangement, for Chamber Orchestra and soprano saxophone solo, was first performed as part of the Canterbury Festival on 22 October 2011.[10] The vocal section is performed by Sarah Leonard.[11]

text: The incidental music used in the series is written by BAFTA nominated composer Sheridan Tongue.

text: In August 2012, the series came under criticism for being "unduly gruesome". Controversy was specifically found in the fifteenth series episode, Redhill, written by Ed Whitmore. According to complaints, the episode was "too violent". The BBC responded with the following:

text: "As programme makers we take our responsibility to the audience extremely seriously and try to make sure we strike the right balance between compelling drama without being unnecessarily graphic. Towards the end of the first episode, we had established that DI Bridges and Officer Kessler had previously worked together and that he was the one very much in control. The final scene was not an attempt to gratuitously shock the audience; it was rooted in character and research, showing just what DI Bridges was prepared to do for her colleague for the sake of her family, as well as the brutality that Kessler was capable of.

text: We acknowledge that certain scenes may have been challenging, but we filmed and presented them in such a way as to make sure that although as a viewer the implication was there, it was never actually shown.[12]

text: Silent Witness is now in its fifteenth series, and we believe the general tone and content is widely recognised by its regular audience. It’s fair to say the show is known for tackling challenging stories and exploring adult themes and we don’t feel the content of these episodes would have gone beyond viewers' expectations. As well as scheduling the series after the watershed, we made sure the content was widely publicised and gave a warning before both episodes."[13]

text: Episodes[edit]

text: Characters[edit]

text: Main[edit]

text:
Actor
Character
Series

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

Amanda Burton
Professor Sam Ryan
Main
Absent

William Gaminara
Professor Leo Dalton
Absent
Main
Absent
Guest

Tom Ward
Dr. Harry Cunningham
Absent
Main
Absent

Emilia Fox
Dr. Nikki Alexander
Absent
Main

David Caves
Jack Hodgson
Absent
Main

Liz Carr
Clarissa Mullery
Absent
Main

Richard Lintern
Dr. Thomas Chamberlain
Absent
Main

tag: table

text: Main characters[edit]

text:
Professor Sam Ryan (Amanda Burton) – Series 1–8. Sam originally lived and worked in Cambridge, but moved to London at the end of series three after she was offered the job of professor at a university. Sam departed in the first episode of series eight, "A Time To Heal". Sam returned home to Ireland after a member of her family was implicated in a murder.
Professor Leo Dalton (William Gaminara) – Series 6–16. Leo first appeared in the episode "The Fall Out", where he was nothing more than a simple doctor. However, he was promoted to professor after former professor Sam Ryan left. In the episode "Ghosts", both his wife, Theresa, and his daughter, Cassie, are killed in a car accident. He began a relationship with fellow professor Janet Mander in "Death's Door", but ended their relationship in the episode "Domestic". Leo often took a strong opinion on cases and became emotionally involved. He died in the series 16 finale "Greater Love", when he sacrificed himself to save many others from a terrorist bomb explosion. He briefly appeared in a flashback in the last episode of series 20.
Dr. Harry Cunningham (Tom Ward) – Series 6–15. Harry started out life as a junior doctor, who worked as an apprentice alongside Sam and Leo. However, he soon qualified as a pathologist, and has worked on equal footing with the team for a number of years. Harry was single, and lived alone, but has had several romantic relationships, including an ongoing 'will they-won't they' relationship with his colleague Nikki. Harry left the team to accept a professorship in New York at the end of series 15. As this was decided after filming was completed, and the stories were reordered, with "And Then I Fell in Love" airing last, where it was originally scheduled as the second episode, his departure was never on screen.
Dr. Nikki Alexander (Emilia Fox) – since Series 8. Originally appearing in the episode "Nowhere Fast", Nikki was originally assigned to the Lyell Centre to defuse the tension between Harry and Leo after Sam's departure. However, Nikki soon became a permanent fixture within the team, and although she features more prominently in the series, holds a lower rank in pathology than Leo. Despite her native home being South Africa, Nikki regards the United Kingdom as her second home, as the reason for her departure from the country lies solely in the hands of her father, Victor, as explained in the episode "Double Dare". Nikki often flirted with colleague Harry, and even invited him to stay at her house after his flat blew up in an explosion. Nikki and Harry were in an ongoing 'will they-won't they' relationship until he left in Series 15. As well as this, she developed a close relationship with Leo and looked up to him as a father figure.
Jack Hodgson (David Caves) – since Series 16. Before his arrival at the Lyell Centre, Jack was a forensic scientist for the police, working on regular murder investigations. However, when he is called out to the scene of a man's suspicious death in "Change", both Nikki and Leo spot his potential, and looking for a senior colleague to replace Harry, decide to offer Jack a job as the centre's forensic expert. Jack is close friends with colleague Clarissa Mullery, whom he invites to work with him at the Lyell Centre, much to Leo's surprise. In his spare time, Jack is a cage fighter, and splits his home life between forensic research and training for his next fight.
Clarissa Mullery (Liz Carr) – since Series 16. Clarissa is Jack's personal lab assistant, who first appears in the episode "Change", when Jack invites her to work at the Lyell Centre with him, much to Leo's surprise. She has a very cheeky side, first making a quip at Leo after he fails to recognise who she is on her first arrival. Clarissa had clearly worked for Jack for a long period before his appointment at the Lyell Centre; however, the exact period of time is unknown.
Dr. Thomas Chamberlain (Richard Lintern) – since Series 17. Thomas Chamberlain has taken over as head of the Lyell Centre from Leo who died at the end of series 16. He is an experienced forensic pathologist with a renowned reputation in toxicology and is described as charming, charismatic and socially shrewd. His first encounters with Jack, Nikki and Clarissa did not go well but they were gradually warmed to him. It is revealed in the last episode of his first series that his wife has left him just before he started working at the Lyell Centre, and has taken their daughter with her.

text: Other characters[edit]

text:
Dr. Trevor Stewart (William Armstrong) – Series 1–3. As well as being a pathologist in his own right, Trevor was Sam's business partner, owning half of the morgue and its facilities. Trevor decided to stay in Cambridge with his friends and family when Sam accepted the professorship position at a university in London and moved away at the end of series three.
Dr. Fred Dale (Sam Parks) – Series 1–3. Fred was Sam's main assistant during post mortems and on visits to crime scenes, often identifying DNA samples at the scene of the crime, and linking them to those responsible. He was also notable for not having many speaking lines, and regularly appearing without speaking. His fate at the end of series three was not revealed.
Professor Janet Mander (Jaye Griffiths) – Series 12–15. Janet is a psychological profiler who assists the police in cases of serial offences. She began a relationship with Leo in the episode "Safe", and they lived together as partners until Leo ended the relationship in "Redhill". She recurringly worked alongside the team to provide them with information in order to get an idea of the suspect they are looking for. Janet decided to move away from London after Leo ended their relationship.
Dr. Charlie Gibbs (Wunmi Mosaku) – Series 13. A junior doctor and lab technician, who was appointed to work with the team by Professor Dalton.
Dr. Zak Khan (Arsher Ali) – Series 14. A junior doctor who worked his forensic science apprenticeship with the team, to learn the ropes of the profession.[14]
Wyn Ryan (Ruth McCabe) – Series 1–3. Professor Ryan's sister, who, after coming over to visit her from her home in Ireland, ended up living with her on a permanent basis.
Ricky Ryan (Matthew Steer) – Series 1. Wyn's son and Sam's nephew, who regularly got into trouble and was expelled from school for very poor behaviour.
Rosemary Mason (Jane Hazlegrove) – Series 6–7. The main receptionist at the Lyell Centre, before the change in focus from university department to purely commercial pathology.

text: Police[edit]

text:
Superintendent Helen Farmer (Clare Higgins) – Series 1. A superintendent, and Tom Adams' boss and mentor, who accompanied him on investigating several cases during his time in the force.
Detective Chief Inspector Tom Adams (John McGlynn) – Series 1. An investigator with the Cambridgeshire police force, who had an affair with Kerry Cox, before her death.
Detective Constable Kerry Cox (Ruth Gemmell) – Series 1. A junior trainee detective who had an affair with Tom Adams, but was later killed in a freak accident in a hospital basement.
Detective Constable Marcia Evans (Janice Acquah) – Series 1. A fellow junior trainee detective for the Cambridgeshire police force, who resigned after Kerry Cox's death.
Superintendent Peter Ross (Mick Ford) – Series 2. A superintendent, and an ex-boyfriend of Sam's, who believed in a strong relationship between the police and the pathology lab.
Detective Chief Inspector Rachel Selway (Nicola Redmond) – Series 2. Tom Adams' replacement, following his resignation from the force. She joined the team alongside junior sergeant Tony Speed.
Detective Sergeant Tony Speed (Richard Huw) – Series 2. A junior sergeant, who joined the team alongside his superior officer, Rachel Selway. He knew Peter Ross from a previous posting.
Detective Chief Inspector Michael Connor (Nick Reding) – Series 3–4. A detective chief inspector, and old friend of Sam's, whom she met during her junior years at university.
Detective Sergeant Rob Bradley (Mark Letheren) – Series 3. A detective sergeant, who as Connor's junior officer, accompanied him with the investigating in the cases which he was assigned to.

text: Novels[edit]

text: During the early years of the show, series creator McCrery wrote and published a number of tie-in novels relating to the series, following Sam Ryan (Amanda Burton) and Trevor Stewart (William Armstrong), as well as former main character Superintendent Tom Adams (John McGlynn), and brand new character DS Stanley Sharman, with Burton generally appearing on the front cover of each novel. The fifth novel, due to be published in 2003, was placed on indefinite hold, and has never been released.

text:
Title
No.
Publication Date

"A Case for the Defence"
1
9 September 1996

Walking home from a night out, Sam stumbles upon the remains of a mutilated body on a footpath in the Northwick graveyard. Evidence suggests that the killing may be linked to a particularly ritualistic form of the black arts, but Sam is unconvinced as the murder bears an uncanny resemblance to another murder committed in the same town many years ago. When a second body is discovered, Sam's evidence is called into question, and is used to create the information that the police need to solve the case, before the killer strikes again. As Sam and Trevor uncover information surrounding the circumstances of the murders, elements that once seemed like coincidences soon appear to belong to a more horrific plan.

"Strange Screams of Death"
2
3 August 1998

Sam is tasked with investigating the circumstances surrounding the death of a woman whose body is discovered in a disused shed at a former American airbase on the outskirts of Cambridge. The post mortem reveals that she had been violently raped, before being tortured, and viciously murdered. When a second body is discovered in similar circumstances, Sam finds herself dealing with a serial killer, who has the hunger to slaughter again. Can her profile of information find the identity of the killer before it is too late? Meanwhile, as Tom Adams closes in on his prime suspect, Sam discovers that he may not be working alone, and a search is launched to find the accomplice of a dangerous criminal.

"The Spider's Web"
3
2 August 1999

Sam is asked to perform a second autopsy on a teenage boy who was killed in a tragic joyriding accident, when despite his parents' protests, the results of the autopsy seem clear—he died of multiple injuries consistent with a high-speed car crash. However, as Trevor performed the post mortem, Sam is reluctant to go up against her friend and colleague, in an attempt to find the answers that the family are looking for. However, reading Trevor's post mortem report prompts Sam to go ahead with the second autopsy, and her findings seem to suggest that the accident may have been no such thing. But neither Trevor nor Superintendent Tom Adams accept her findings, and believe that she is reading between the lines.

"Faceless Strangers"
4
3 September 2001

When the wife and beau of a local member of parliament is found dead in her own home, Superintendent Tom Adams calls upon Sam and the entire resources of the Cambridge Constabulary, in an attempt to further his career, and solve the case as quickly as possible. However, his investigation is halted by the discovery of the decomposed body of a homeless drug addict in the local underground toilet block. When Adams dimisses the death as an open and shut case, one of his juniors, DS Stanley Sharman, decides to enlist Sam's help, to discover the indentity of the dead woman – and discover just who is responsible for her death. Meanwhile, Adams is determined to crack his case.

"In Search of Evil[15]"
5
3 November 2003

When the body of elderly widow Violet Thorpe is discovered beneath the floor of her own cellar, Sam quickly establishes that she had been poisoned, and died more than a year prior to the discovery of her body. Meanwhile, the victim's contact with an old friend living in Brighton, appears to be a vital piece of evdidence in discovering who is responsible for her murder. When Sam and DS Stanley Sharman visit the address of the old friend in Brighton, they find themselves on a bizarre trail of a mentally deranged killer, who appears to be travelling up and down the country in search of lonely old ladies to kill, and Sam finds herself in a race to discover the identity of one of the country's most prolific serial killers.


document_title: Okinawa Island

question_text: where is okinawa japan located on a map

question_tokens: where is okinawa japan located on a map

text: Okinawa Island

text: History[edit]

text:
History of Ryukyu

Periods[show]

Prehistoric
pre–14,000 BC

Early Shell Mound
14,000–300 BC

Middle Shell Mound
300 BC–750 AD

Late Shell Mound
750–1187

Gusuku
1187–1314

Sanzan
1314–1429

First Shō Dynasty
1429–1469

Second Shō Dynasty
1469–1879

Invasion of Ryūkyū
1609

Ryūkyū Domain
1872–1879

Annexation of Ryūkyū
1879

Meiji
1879–1912

Taishō
1912–1926

Pre-World War 2
1926–1945

Militarism

Battle of Okinawa
1945

American Occupation
1945–1972

Koza riot
1970

Okinawa Prefecture
1972–present

Kagoshima Prefecture
1953–present

Topics[show]

Ryukyu Kingdom

1429–1879

Ryukyu independence movement

1945–present

v
t
e

text: The time when human beings first appeared in Okinawa remains unknown.

text: Early Okinawan history is defined by midden or shell heap culture, and is divided into Early, Middle, and Late Shell Mound periods. The Early Shell Mound period was a hunter-gatherer society, with wave-like opening Jomon pottery. In the latter part of this period, archaeological sites moved near the seashore, suggesting the engagement of people in fishing. In Okinawa, rice was not cultivated until the Middle Shell Mound period. Shell rings for arms made of shells obtained in the Sakishima Islands, namely Miyakojima and Yaeyama islands, were imported by Japan. In these islands, the presence of shell axes, 2500 years ago, suggests the influence of a southeastern-Pacific culture.[citation needed][7][8]

text: After the Late Shell Mound period, agriculture started about the 12th century, with the center moving from the seashore to higher places. This period is called the Gusuku period. Gusuku is the term used for the distinctive Ryukyuan form of castles or fortresses. Many gusukus and related cultural remains in the Ryukyu Islands have been listed by UNESCO as World Heritage Sites under the title Gusuku Sites and Related Properties of the Kingdom of Ryukyu. There are three perspectives regarding the nature of gusukus: 1) a holy place, 2) dwellings encircled by stones, 3) a castle of a leader of people. In this period, porcelain trade between Okinawa and other countries became busy, and Okinawa became an important relay point in eastern-Asian trade. Ryukyuan kings, such as Shunten and Eiso, were important rulers. An attempted Mongolian invasion in 1291 during the Eiso Dynasty ended in failure. Hiragana was imported from Japan by Ganjin in 1265. Noro, village priestesses of the Ryukyuan religion, appeared.

text: The Sanzan period began in 1314, when the kingdoms of Hokuzan and Nanzan declared independence from Chūzan. The three kingdoms competed with one another for recognition and trade with Ming China. King Satto, leading Chūzan, was very successful, establishing relations with Korea and Southeast Asia as well as China. The Hongwu Emperor sent 36 families from Fujian in 1392 at the request of the Ryukyuan King. Their job was to manage maritime dealings in the kingdom. Many Ryukyuan officials were descended from these Chinese immigrants, being born in China or having Chinese ancestors. They assisted the Ryukyuans in developing their technology and diplomatic relations. In 1407, however, a man named Hashi overthrew Satto's descendent, King Bunei, and installed his own father, Shishō, as king of Chūzan. After his father died, Hashi became king, and the Xuande Emperor of China gave him the surname "Shō" (Chinese: Shang).

text: In 1429, King Shō Hashi completed the unification of the three kingdoms and founded the Ryūkyū Kingdom with its capital at Shuri Castle. His descendants would conquer the Amami Islands. In 1469, King Shō Taikyū died, so the royal government chose a man named Kanemaru as the new king, who chose the name Shō En and established the Second Shō Dynasty. His son, Shō Shin would then conquer the Sakishima Islands and centralize the royal government, the military, and the noro priestesses.

text: In 1609, the Japanese domain of Satsuma launched an invasion of the Ryukyu Kingdom, ultimately capturing the king and his capital after a long struggle. Ryukyu was forced to cede the Amami Islands and become a vassal of Satsuma. The kingdom became both a tributary of China and a tributary of Japan. Because China would not make a formal trade agreement unless a country was a tributary state, the kingdom was a convenient loophole for Japanese trade with China. When Japan officially closed off trade with European nations except the Dutch, Nagasaki, Tsushima, and Kagoshima became the only Japanese trading ports offering connections with the outside world.

text: A number of Europeans visited Ryukyu starting in the late 18th century. The most important visits to Okinawa were from Captain Basil Chamberlain in 1816 and Commodore Matthew C. Perry in 1852. A Christian missionary, Bernard Jean Bettelheim, lived in the Gokoku-ji temple in Naha from 1846 to 1854.

text: In 1879, Japan annexed the entire Ryukyu archipelago.[9] The Meiji government then established Okinawa Prefecture. The monarchy in Shuri was abolished and the deposed king Shō Tai (1843–1901) was forced to relocate to Tokyo.

text: Hostility against Japan increased in the islands immediately after the annexation in part because of the systematic attempt on the part of Japan to eliminate Ryukyuan culture, including the language, religion, and cultural practices.

text: The island of Okinawa was the site of most of the ground warfare in the Battle of Okinawa during World War II, when U.S. Army and Marine Corps troops fought a long and bloody battle to capture Okinawa, so it could next be used as the major air force and troop base for the planned invasion of Japan. During this 82-day-long battle, about 95,000 Imperial Japanese Army troops and 12,510 Americans were killed. The Cornerstone of Peace at the Okinawa Prefecture Memorial Peace Park lists 149,193 persons of Okinawan origin - approximately one quarter of the civilian population - who either were killed or committed suicide during the Battle of Okinawa and the Pacific War.[10]

text: During the American military occupation of Japan (1945–52), which followed the Imperial Japanese surrender on September 2, 1945, in Tokyo Bay, the United States controlled Okinawa Island and the rest of the Ryukyu Islands. The Amami Islands were returned to Japanese control in 1953, but the rest remained in American military possession until June 17, 1972, with numerous U.S. Army, U.S. Marine Corps, and U.S. Air Force bases there.

text: Demographics[edit]

text: As of September, 2009, the Japanese government estimates the population at 1,384,762,[11] which includes American military personnel and their families. The Okinawan language, called Uchinaaguchi, is spoken mostly by the elderly.[12]

text: Whereas the northern half of Okinawa Island is sparsely populated, the south-central and southern parts of the island are markedly urbanized—particularly the city of Naha and the urban corridor stretching north from there to Okinawa City.

text: Geography[edit]

text: Okinawa is the fifth largest island in Japan (excluding the disputed islands north of Hokkaido). The island has an area of 1,201.03 square kilometers (463.72 sq mi). It is roughly 640 kilometres (400 mi) south of the rest of Japan. The island is connected to nearby islands by a land bridge: Yokatsu Peninsula (aka Katsuren Peninsula) is connected via the Mid-Sea Road to Henza Island, Miyagi Island, Ikei Island, and Hamahiga Island. Similarly, from the Motobu Peninsula on the northwestern side, all of Sesokojima, plus both of Yagaji Island and Kōri-jima are connected by bridges.

text: Geology[edit]

text: The southern end of the island consists of uplifted coral reef, whereas the northern half has proportionally more igneous rock. The easily eroded limestone of the south has many caves, the most famous of which is Gyokusendō in Nanjō. An 850 m-long stretch is open to tourists.

text: Fauna[edit]

text: In the forests of Yanbaru, there are a small number of Yanbaru kuina (also known as the Okinawa rail), a small flightless bird that is close to extinction.

text: The Indian mongoose was introduced to the island to prevent the native habu pit viper from attacking the birds. It did not succeed in eliminating the habu, but instead preyed on birds, increasing the threat to the Okinawa rail.

text: Climate[edit]

text: The island has an humid subtropical climate bordering on a tropical rainforest climate. The island supports a dense northern forest and a rainy season occurring in the late spring.

text: Food[edit]

text: There are many local pubs (izakaya) and cafes that serve Okinawan cuisine and dishes, such as goya champuru (bitter melon stir fry), fu champuru (wheat gluten chanpuru), and tonkatsu (tenderized, breaded, fried pork cutlet). Okinawan soba is the signature dish and consists of wheat noodles served hot in a soup, usually with pork (rib or pork belly). This contrasts with the mainland soba, which is buckwheat noodles. Rafute, which is braised pork belly, is another popular Okinawan dish. American presence on the island has also led to some creative dishes such as taco rice, which is now a common meal served in bentos, and common use of spam.

text: Economy[edit]

text: Among the prefectures of Japan, Okinawa has the youngest and fastest-growing population, but has the lowest employment rate and average income. The island economy is primarily driven by tourism and the US military presence, with efforts in recent years to diversify into other sectors.[13]

text: Tourism[edit]

text: Tourist attractions include Okinawa Churaumi Aquarium (at one time the world's largest aquarium), Century Beach, Pineapple Park, the Orion Beer Factory and Hiji Falls. In recent years, Okinawa has become an increasingly popular destination for tourists from China and Southeast Asia.[14]

text: U.S. military presence[edit]

text: There are 32 U.S. military bases[15] located on Okinawa Island. In total, these bases occupy approximately 25% of the island's area. The major bases are Futenma,[16] Kadena, Hansen, Torii, Schwab, Foster, and Kinser. The bases primarily exist to serve Japanese and U.S. strategic interests, but are unpopular with most local residents[17] despite recent efforts to move the bases out of core areas following incidents involving military personnel and resultant protests (including the 1995 Okinawa rape incident).[citation needed]

text: Economically, the bases have been of declining importance, especially after Okinawan sovereignty returned to Japan, recently accounting for 4 to 5% of the island economy, but the economic impact may be double edged, as the presence of the bases may be hampering investment (and tourism potential).[15][18] In 2012, an agreement was struck between the United States and Japan to reduce the number of U.S. military personnel on the island, moving 9,000 personnel to other locations and moving bases out of heavily populated Greater Naha, but 10,000 marines will remain on the island, along with other U.S. military units.[16][19] Attempts to completely close bases on the southern third of the island, where 90% of the population lives (all but about 120,000 people) have been impeded by both the U.S. desire that alternative locations be found where bases subject to closure could move to (e.g. Henoko Peninsula roughly mid-island), as well as by local Okinawan opposition to any suggested locations on the island (who demand no US troops at all anywhere on the island).[17] There exists also a smaller contingent of Japanese military bases on the island, to whom the local Okinawans also view as colonizers. Tokyo itself has a different view of the situation from that of local residents, who complain that despite being home to less than 1% of Japan's population and area, have to put up with the majority of Japan's U.S. military occupation.[20] In late December 2013, the governor of Okinawa, Hirokazu Nakaima, gave permission for land reclamation to begin for a new U.S. military base at Henoko reneging on previous promises, furthering the effort to consolidate American troop presence on the island, though away from urban Naha.[21] This resulted in his loss of the governorship.

text: Several former US military facilities in Okinawa have been re-developed as commercial areas, most notably the American Village in Chatan, Okinawa, which opened in 1998, and the Aeon Mall Okinawa Rycom in Kitanakagusuku, Okinawa, which opened in 2015.[14]

text: Transportation and logistics[edit]

text: Naha Airport is the main transportation hub for the Ryukyu Islands and has an increasingly large role in regional logistics. All Nippon Airways opened a cargo hub at the airport in 2009, providing overnight freight service between Japan and other Asian countries.[14]

text: Transportation[edit]

text: Naha Airport serves the island. There are multiple bus companies, such as Toyo Bus, Ryukyu Bus Kotsu, Naha Bus, and Okinawa Bus. There is also a monorail. The Okinawa Expressway is a toll road that runs from Naha to Nago, and has a speed limit of 80 km/h (49.7 mph), the highest on the island. There are also many ferries to many of the nearby islands, such as Ie Shima. Tomarin Port in Naha, has ferries to nearby islands like Aguni Island, Tokashiki Island, Zamami Island. Naha Cruise Terminal, Naha city also has a cruise terminal.

text: Film[edit]

text: Teahouse of the August Moon (1956), starring Marlon Brando and Glenn Ford, was based on the hit Broadway play. The storyline of the play and the film were set in Okinawa, but actual filming took place in mainland Japan near Nara and in a studio in California.[22]

text: Okinawa was the setting for the 1974 Japanese science fiction kaiju film Godzilla vs. Mechagodzilla, which featured a shisa dog as one of the monsters in the film; due to an awkward translation from Japanese to English, this monster is known in the film as King Caesar. Several scenes were filmed in the, at the time, recently discovered Gyokusendo caves.

text: Okinawa was also the setting for the 1986 film The Karate Kid, Part II, in which Mr. Miyagi (Pat Morita) returns home to Okinawa with his student Daniel LaRusso (Ralph Macchio). Although Okinawa was the setting for the film, only short scenes of the film were actually filmed in Okinawa.

text: Okinawa was the World War II fighting location in the 2016 Hacksaw Ridge movie detailing the true story of Desmond Doss, a conscientious objector played by Andrew Garfield.


document_title: History of gravitational theory

question_text: who came up with the theory of gravity

question_tokens: who came up with the theory of gravity

text: History of gravitational theory

text: Antiquity[edit]

text: Greece[edit]

text: In the 4th century BC, the Greek philosopher Aristotle believed that there is no effect or motion without a cause. The cause of the downward motion of heavy bodies, such as the element earth, was related to their nature, which caused them to move downward toward the center of the universe, which was their natural place. Conversely, light bodies such as the element fire, move by their nature upward toward the inner surface of the sphere of the Moon. Thus in Aristotle's system heavy bodies are not attracted to the Earth by an external force of gravity, but tend toward the center of the universe because of an inner gravitas or heaviness.[1][2]

text: In Book VII of his De Architectura, the Roman engineer and architect Vitruvius contends that gravity is not dependent on a substance's "weight" but rather on its "nature" (cf. specific gravity).

text: If the quicksilver is poured into a vessel, and a stone weighing one hundred pounds is laid upon it, the stone swims on the surface, and cannot depress the liquid, nor break through, nor separate it. If we remove the hundred pound weight, and put on a scruple of gold, it will not swim, but will sink to the bottom of its own accord. Hence, it is undeniable that the gravity of a substance depends not on the amount of its weight, but on its nature.[3]

text: India[edit]

text: Aryabhata first identified the force to explain why objects do not fall when the earth rotates,and developed a geocentric solar system of gravitation, with an eccentric elliptical model of the planets, where the planets spin on their axes and follow elliptical orbits,the Sun and the moon revolving around the earth in epicycles. Indian astronomer and mathematician Brahmagupta described gravity as an attractive force and used the term "gurutvākarṣaṇ" for gravity.[4][5][6]

text: Al Hamdānī and Al Biruni quote Brahmagupta saying

text: "Disregarding this, we say that the earth on all its sides is the same; all people on the earth stand upright, and all heavy things fall down to the earth by a law of nature, for it is the nature of the earth to attract and to keep things, as it is the nature of water to flow, that of fire to burn, and that of the wind to set in motion. If a thing wants to go deeper down than the earth, let it try. The earth is the only low thing, and seeds always return to it, in whatever direction you may throw them away, and never rise upwards from the earth."[7][8]

text: Modern era[edit]

text: This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2009) (Learn how and when to remove this template message)

text: During the 17th century, Galileo found that, counter to Aristotle's teachings, all objects accelerated equally when falling.

text: In the late 17th century, as a result of Robert Hooke's suggestion that there is a gravitational force which depends on the inverse square of the distance,[9] Isaac Newton was able to mathematically derive Kepler's three kinematic laws of planetary motion, including the elliptical orbits for the six then known planets and the Moon:

text: "I deduced that the forces which keep the planets in their orbs must be reciprocally as the squares of their distances from the centres about which they revolve, and thereby compared the force requisite to keep the moon in her orb with the force of gravity at the surface of the earth and found them to answer pretty nearly."

text: So Newton's original formula was:

text:
where the symbol

∝

{\displaystyle \propto }

 means "is proportional to".

text: To make this into an equal-sided formula or equation, there needed to be a multiplying factor or constant that would give the correct force of gravity no matter the value of the masses or distance between them. This gravitational constant was first measured in 1797 by Henry Cavendish.

text: In 1907 Albert Einstein, in what was described by him as "the happiest thought of my life", realized that an observer who is falling from the roof of a house experiences no gravitational field. In other words, gravitation was exactly equivalent to acceleration. Between 1911 and 1915 this idea, initially stated as the equivalence principle, was formally developed into Einstein's theory of general relativity.

text: Newton's theory of gravitation[edit]

text: In 1687, English mathematician Sir Isaac Newton published Principia, which hypothesizes the inverse-square law of universal gravitation. In his own words, "I deduced that the forces which keep the planets in their orbs must be reciprocally as the squares of their distances from the centers about which they revolve; and thereby compared the force requisite to keep the Moon in her orb with the force of gravity at the surface of the Earth; and found them answer pretty nearly."

text: Newton's theory enjoyed its greatest success when it was used to predict the existence of Neptune based on motions of Uranus that could not be accounted by the actions of the other planets. Calculations by John Couch Adams and Urbain Le Verrier both predicted the general position of the planet, and Le Verrier's calculations are what led Johann Gottfried Galle to the discovery of Neptune.

text: Years later, it was another discrepancy in a planet's orbit that showed Newton's theory to be inaccurate. By the end of the 19th century, it was known that the orbit of Mercury could not be accounted for entirely under Newtonian gravity, and all searches for another perturbing body (such as a planet orbiting the Sun even closer than Mercury) have been fruitless. This issue was resolved in 1915 by Albert Einstein's new general theory of relativity, which accounted for the discrepancy in Mercury's orbit.

text: Paul Dirac developed the hypothesis that gravitation should have slowly and steadily decreased over the course of the history of the universe.[10]

text: Although Newton's theory has been superseded, most modern non-relativistic gravitational calculations still use it because it is much easier to work with and is sufficiently accurate for most applications.

text: Mechanical explanations of gravitation[edit]

text: The mechanical theories or explanations of the gravitation are attempts to explain the law of gravity by aid of basic mechanical processes, such as pushes, and without the use of any action at a distance. These theories were developed from the 16th until the 19th century in connection with the aether theories.[11]

text: René Descartes (1644) and Christiaan Huygens (1690) used vortices to explain gravitation. Robert Hooke (1671) and James Challis (1869) assumed, that every body emits waves which lead to an attraction of other bodies. Nicolas Fatio de Duillier (1690) and Georges-Louis Le Sage (1748) proposed a corpuscular model, using some sort of screening or shadowing mechanism. Later a similar model was created by Hendrik Lorentz, who used electromagnetic radiation instead of the corpuscles. Isaac Newton (1675) and Bernhard Riemann (1853) argued that aether streams carry all bodies to each other. Newton (1717) and Leonhard Euler (1760) proposed a model, in which the aether loses density near the masses, leading to a net force directing to the bodies. Lord Kelvin (1871) proposed that every body pulsates, which might be an explanation of gravitation and the electric charges.

text: However, those models were overthrown because most of them lead to an unacceptable amount of drag, which is not observed. Other models are violating the energy conservation law and are incompatible with modern thermodynamics.[12]

text: General relativity[edit]

text: In general relativity, the effects of gravitation are ascribed to spacetime curvature instead of to a force. The starting point for general relativity is the equivalence principle, which equates free fall with inertial motion. The issue that this creates is that free-falling objects can accelerate with respect to each other. In Newtonian physics, no such acceleration can occur unless at least one of the objects is being operated on by a force (and therefore is not moving inertially).

text: To deal with this difficulty, Einstein proposed that spacetime is curved by matter, and that free-falling objects are moving along locally straight paths in curved spacetime. (This type of path is called a geodesic). More specifically, Einstein and Hilbert discovered the field equations of general relativity, which relate the presence of matter and the curvature of spacetime and are named after Einstein. The Einstein field equations are a set of 10 simultaneous, non-linear, differential equations. The solutions of the field equations are the components of the metric tensor of spacetime. A metric tensor describes the geometry of spacetime. The geodesic paths for a spacetime are calculated from the metric tensor.

text: Notable solutions of the Einstein field equations include:

text:
The Schwarzschild solution, which describes spacetime surrounding a spherically symmetric non-rotating uncharged massive object. For compact enough objects, this solution generated a black hole with a central singularity. For radial distances from the center which are much greater than the Schwarzschild radius, the accelerations predicted by the Schwarzschild solution are practically identical to those predicted by Newton's theory of gravity.
The Reissner–Nordström solution, in which the central object has an electrical charge. For charges with a geometrized length which are less than the geometrized length of the mass of the object, this solution produces black holes with an event horizon surrounding a Cauchy horizon.
The Kerr solution for rotating massive objects. This solution also produces black holes with multiple horizons.
The cosmological Robertson–Walker solution, which predicts the expansion of the universe.

text: General relativity has enjoyed much success because of the way its predictions of phenomena which are not called for by the older theory of gravity have been regularly confirmed. For example:

text:
General relativity accounts for the anomalous perihelion precession of the planet Mercury.
The prediction that time runs slower at lower potentials has been confirmed by the Pound–Rebka experiment, the Hafele–Keating experiment, and the GPS.
The prediction of the deflection of light was first confirmed by Arthur Eddington in 1919, and has more recently been strongly confirmed through the use of a quasar which passes behind the Sun as seen from the Earth. See also gravitational lensing.
The time delay of light passing close to a massive object was first identified by Irwin Shapiro in 1964 in interplanetary spacecraft signals.
Gravitational radiation has been indirectly confirmed through studies of binary pulsars. In 2016, the LIGO experiments directly detected gravitational radiation from two colliding black holes, making this the first direct observation of both the gravitational radiation as well as black holes.
The expansion of the universe (predicted by the Robertson–Walker metric) was confirmed by Edwin Hubble in 1929.

text: Gravity and quantum mechanics[edit]

text: Several decades after the discovery of general relativity it was realized that it cannot be the complete theory of gravity because it is incompatible with quantum mechanics.[13] Later it was understood that it is possible to describe gravity in the framework of quantum field theory like the other fundamental forces. In this framework the attractive force of gravity arises due to exchange of virtual gravitons, in the same way as the electromagnetic force arises from exchange of virtual photons.[14][15] This reproduces general relativity in the classical limit, but only at the linearized level and postulating that the conditions for the applicability of Ehrenfest theorem holds, which is not always the case. Besides, this approach fails at short distances of the order of the Planck length.[13]

text: It is notable that in general relativity, gravitational radiation, which under the rules of quantum mechanics must be composed of gravitons, is created only in situations where the curvature of spacetime is oscillating, such as is the case with co-orbiting objects. The amount of gravitational radiation emitted by the solar system is far too small to measure.

text: However, gravitational radiation has been observed both indirectly, as an energy loss over time in binary pulsar systems such as PSR 1913+16, and directly by the LIGO gravitational wave observatory, whose first detection (named GW150914) occurred on 14 September 2015[16] and matched theoretical predictions of signals due to the inward spiral and merger of a pair of black holes. It is believed that neutron star mergers (since detected in 2017)[17] and black hole formation may also create detectable amounts of gravitational radiation.