Gravity is everywhere. It keeps us anchored to the ground. The pull of the moon and sun creates the tides. Clouds of gas and dust called nebulae collapse to form stars and planets under its grip. Gravity even pulls on light, preventing it from leaving a massive star as it contracts into a black hole and disappears from view as in the example above.
The idea of gravity as a force traces its origin back to Isaac Newton and his apple tree. But the modern view of gravity bequeathed to us by the wispy-haired Einstein, sees gravity not as a force that holds things together so much as an object's influence on surrounding space.
A massive object like the Earth warps the fabric of space, similar to how a bowling ball placed on a trampoline creates a depression in the mat. A marble placed at the mat's edge will roll downslope and stop when it strikes the bowling ball. Albert Einstein showed in his General Relativity Theory that the gravity of massive bodies warps the fabric of space, called spacetime. Here the Earth orbits the sun by following the curvature the sun's gravity makes in spacetime. In the same way, the moon follows the curvature of space think of it as a depressed trampoline mat around the Earth and freefalls toward the planet.
It doesn't crash into us like the marble hitting the ball because it possesses enough forward speed or momentum to keep from falling downhill. Its average orbital velocity is 2, mph 3, kph , fast enough to remain in orbit while escaping the clutches of Earth. For fun, let's say the moon came to a sudden stop.
Were that to happen it would immediately begin falling toward the Earth just like the marble obediently following the curvature of the rubber mat on the trampoline. The impact would re-melt the planet with catastrophic consequences.
Speaking of which, the only reason you don't fall straight to the center of the Earth when you jump — the same way a "stopped" moon would plummet — is because the ground gets in the way. Remind me to kiss the blessed earth the next time I'm outside.
US Markets Loading H M S In the news. Dave Mosher. This is Earth. You've jumped here before. This is a normal vertical hop for a person on Earth. The bottom of your feet might break 1. On to the moon: the only place other than Earth where humans have dared to leap. Using the same force of a jump on Earth, you could rise about 10 feet off the ground and stay in the air for about 4 seconds.
Jupiter has more than times the mass as Earth, so its gravitational pull is stronger. Your jump is now Really pathetic. Let's try Mars — a planet bigger than the moon yet considerably smaller than Earth, with about a third of its gravity. You're like a Martian Michael Jordan and can jump roughly 3 feet off the ground and stay aloft for 2 seconds. Pluto may be a dwarf planet, but it's still pretty massive. How high could you go? A good hop would send you about 25 feet in the air and let you enjoy the view for a full seconds.
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Create a free Team What is Teams? Learn more. Will colonists on Mars have enhanced physical mobility relative to an Earth-normal environment? Ask Question.
Asked 8 years, 3 months ago. Active 1 year, 9 months ago. Viewed 10k times. Improve this question. Jerard Puckett 7, 2 2 gold badges 32 32 silver badges 78 78 bronze badges. James Jenkins James Jenkins By definitions, humans cannot have superhuman abilities, ever. I suggest you rephrase your question and ask how high and far one would get on Mars with the equivalent physical effort as on Earth.
Add a comment. Active Oldest Votes. We could assume the following; If you can jump 1 m high in Earth's gravity distance between feet and the ground when feet are stretched in the air , your initial velocity or linear momentum would have to be 4. Then again, that work you're quoting is fiction, and I'm making too much of it again Improve this answer. TildalWave TildalWave On earth, running has both feet leave the ground. With the runner making small jumps with each step.
On Mars one might expect the height of these small jumps to increase. At the point of impact and launch, the runner will have the most force pushing against the ground. At least some all of that is the runners ability to expend energy over time.
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