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What I mean, if Earth travels through space at 1,700 km/hour, when a spaceship or other object leaves its atmosphere, should it not stay behind? And if it is gravity that keeps it near Earth, should that speed not disintegrate them?

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    $\begingroup$ Can you explain why the speed of something (in empty space) should disintegrate that thing? Where do you read such a thing, can be useful too. $\endgroup$
    – Ng Ph
    Nov 26, 2021 at 13:45
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    $\begingroup$ Everything on Earth is traveling in the same direction and at the same speed as Earth. There is nothing in space that could make things stop. Space is mostly vacuum, unlike water in the ocean or road surface that make moving things stop due to friction. $\endgroup$
    – Naktibalda
    Nov 26, 2021 at 14:56
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    $\begingroup$ The Earth orbits the Sun at about $30\,\mathrm{km/s}$, which works out to about $110\,000\,\mathrm{km/hr}$. $\endgroup$
    – notovny
    Nov 26, 2021 at 16:41
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    $\begingroup$ When you're near the equator the Earth is rotating at 1674 km/hour, or about 1700 km/hour. Rhetorical question: When you jump up into the air at the equator, does the Earth suddenly start speeding away from you at 1700 km/hour? The answer is of course no. Linear momentum is a conserved quantity. $\endgroup$ Nov 26, 2021 at 17:45
  • $\begingroup$ Incorrect figure, false fact, and..... amusing conjecture based on the interaction of those two. Where to start, to correct this person... $\endgroup$ Nov 26, 2021 at 17:45

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We've already covered that this is the speed of rotation at the equator, it goes much faster around the Sun. But anything launched from the Earth is starting on the earth and in the same state of motion as the Earth. One of the first things you learn in physics class is that a body in motion will stay in uniform motion unless acted on by an external force; in the absence of something like friction or wind resistance it will just keep going. Gravity is a force, of course, pulling inward toward the earth, and that's why the space station orbits the planet instead of flying away in a state of uniform motion. It causes every part of the space station to accelerate by the same amount and in the same direction, so there are no stresses that would cause it to disintegrate. (Footnote: there are small differences due to gravity being central and proportional to 1/r2, so the acceleration of gravity is not quite the same at every point on the space station. But that's in the microgravity regime, very small. You need some extraordinary conditions, like being close to a neutron star, for those so-called tidal forces to be a threat.)

I might add that rocketeers usually like to launch their rockets in the direction of Earth's rotation (east) because the rocket gets a boost to its speed. The rotational speed actually does matter. It matters for those involved with artillery, too; you can look up the Eötvös effect.

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Short answer from someone who doesn't have a degree in physics and is bad at math.

While in space you are in a vacuum, since you are in a vacuum there is almost no resistance. When moving through the atmosphere there is air which provides resistance against the direction you are moving.

I say almost no resistance because at the height of the ISS there is still some resistance present therefore the ISS needs to boost itself once a while.

As for the leaving behind part. When in space you are almost always in orbit of something. This means that an object with an higher gravity is pulling you towards the object but since your speed is higher than the force pulling you you will stay in orbit around the object pulling.

please correct me if I'm wrong

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  • $\begingroup$ Feel also free to add numbers to clarify things $\endgroup$ Nov 26, 2021 at 15:20
  • $\begingroup$ In order to explain clearly, without disgusting someone with lots of physics and math, we do not need numbers. What we need most is to understand the reasoning the OP had to come to the issue asked. Unfortunately, the OP doesn't seem wanting to share this. Unsolvable problem, I would think. $\endgroup$
    – Ng Ph
    Nov 27, 2021 at 15:18

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