In the first equation above, g is referred to as the acceleration of gravity. Its value is 9.8 m/s2 on Earth. That is to say, the acceleration of gravity on the surface of the earth at sea level is 9.8 m/s2.
This results in Earth having a gravitational strength of 9.8 m/s² close to the surface (also known as 1 g), which naturally decreases the farther away one is from the surface. In addition, the force of gravity on Earth actually changes depending on where you're standing on it.
The acceleration of an object toward the ground caused by gravity alone, near the surface of Earth, is called "normal gravity," or 1g. This acceleration is equal to 32.2 ft/sec2 (9.8 m/sec2).
Changes due to location. The acceleration g varies by about 1/2 of 1 percent with position on Earth's surface, from about 9.78 metres per second per second at the Equator to approximately 9.83 metres per second per second at the poles.
The numerical value for the acceleration of gravity is most accurately known as 9.8 m/s/s. There are slight variations in this numerical value (to the second decimal place) that are dependent primarily upon on altitude.
This difference in surface gravity is due to a number of factors – mass, density, and radius being the foremost. Even though Mars has almost the same land surface area as Earth, it has only half the diameter and less density than Earth – possessing roughly 15% of Earth's volume and 11% of its mass.
Definition: Zero Gravity or Zero-G can simply be defined as the state or condition of weightlessness. It also refers to the state in which the net or an apparent effect of gravity (i.e. the gravitational force) is zero.
Throughout space, gravity actually is constant. It is the acceleration due to gravity that changes and that is what we are talking about when we say gravity is 9.81 meters per second squared.
Gravity is measured by the acceleration that it gives to freely falling objects. At Earth's surface the acceleration of gravity is about 9.8 metres (32 feet) per second per second.
Changes in speed are expressed in multiples of gravitational acceleration, or 'G'. Most of us can withstand up to 4-6G. Fighter pilots can manage up to about 9G for a second or two. But sustained G-forces of even 6G would be fatal.
10G is ten times the acceleration due to gravity, which would be 320 ft/sec/sec. In simple words, this would mean, starting from zero, you would increase your speed to 320 ft/sec by the end of the first second.
Indycar driver Kenny Bräck (SWE) survived a split-second deceleration of 214 g during a 220‑mph (354‑km/h) crash on lap 188 of the Chevy 500 at Texas Motor Speedway, USA, on 12 October 2003. This is according to data registered in Bräck's in-car “crash violence recording system”.
Although gravity never reaches zero, it gets close. The premise of Einstein's theory of general relativity can be used to explain gravity in space.
Contrary to popular belief, there's no such thing as zero gravity. Weightlessness and zero gravity are two different things. The earth's gravity keeps the moon in orbit. And astronauts are generally much closer to earth than the moon is, which means that the earth's pull on them has to be much stronger.
Zero gravity is another term referring to the phenomenon of weightlessness. Bodies in free fall and those in orbit experience this. For example, people aboard the International Space Station (one of the man-made satellites in orbit around the earth) all experience zero gravity when they are on board.
Out into space
Once at a steady cruising speed of about 16,150mph (26,000kph) in orbit, astronauts no more feel their speed than do passengers on a commercial airplane.
Earth's gravity comes from all its mass. All its mass makes a combined gravitational pull on all the mass in your body. That's what gives you weight. And if you were on a planet with less mass than Earth, you would weigh less than you do here.
Aerobatic competition is a little different in that there is more negative G's involved, as many as 8 negative and 10 positive. Kirby often says, “At 10 G's, it's hard to breathe and feels like a house is sitting on your chest.” That's a ton of pressure, literally!
One g is the force per unit mass due to gravity at the Earth's surface and is the standard gravity (symbol: gn), defined as 9.80665 metres per second squared, or equivalently 9.80665 newtons of force per kilogram of mass.
1G is the acceleration we feel due to the force of gravity. It's what keeps our feet firmly planted on the ground. Gravity is measured in metres per second squared, or m/s2. On Earth, the acceleration of gravity generally has a value of 9.806 m/s2 or 32.1740 f/s2.
Could a human live for a time on a planet with 10 times the gravity? Assuming you mean 10 times Earth's gravity, yes. That time, however, would be measured in seconds. Even very fit fighter pilots cannot sustain 10 g for more than a few seconds before losing consciousness.
Without a "thermal blanket," Mars can't retain any heat energy. On average, the temperature on Mars is about minus 80 degrees F (minus 60 degrees Celsius) according to NASA. In winter, near the poles, temperatures can get down to minus 195 degrees F (minus 125 degrees C).
The red planet once had a global ocean, rivers, and lakes. Then, the solar wind — charged particles from the Sun — stripped away the Martian atmosphere. As the planet's protective shield faded, all liquid water on the surface evaporated into space, merged with minerals, or fled underground to become water ice.
The Earth's gravitational field extends well into space it does not stop. However, it does weaken as one gets further from the center of the Earth. The Shuttle orbits about 125 mi above the surface, roughly the distance between Jackson and Nashville!