How do rockets accelerate in space?

[ursaminortaur]

All orbiting things will eventually fall out of the sky (ie the orbit will decay to the point where they hit the ground).

So when do you expect the moon to hit the earth? Or when will Uranus hit the sun.

If it weren't for the fact that the Sun becoming a red giant and swallowing the earth and moon would intervene then the moon would probably spiral in and break up to form a ring a couple of hundred billion years from now.

https://www.forbes.com/sites/quora/2018/06/13/will-the-moon-ever-stop-drifting-away-from-earth/

Right now, the Moon is moving away from the Earth at a rate of about four centimeters per year, due to the tidal interaction between the Earth and the Moon. At a basic level, the Moon’s gravity exerts a drag on the Earth that slows its rotation, and the Earth’s gravity exerts a pull on the Moon that expands its orbit. The two effects balance out, conserving angular momentum.
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Projecting forward, there will come a day about 50 billion years from now when the Moon’s orbit will reach its maximum size. At that point, one lunar orbit (one month) will take 47 days. Earth’s rotation period will also be 47 days, meaning that one side of the Earth will face the Moon at all times, just as one side of the Moon currently faces the Earth at all times. With the whole system synchronized, the Earth and Moon will no longer have any tidal effects on each other, and the Moon will stop moving away.

But not all tides will be gone at that point! The Sun will continue to exert tides on the Earth, slowing its rotation further. Now the effect will be reversed and the Earth will drag on the Moon, pulling it steadily closer. After a long time (perhaps a few hundred billion years), the Moon would spiral in so close that it would be torn up by Earth’s gravity, forming a ring.

[gryffron]

All orbiting things will eventually fall out of the sky (ie the orbit will decay to the point where they hit the ground).

Not always. See Lagrange points.

[johnhemming]

The reason I referred to Uranus was that as the Sun expands it should not get that far. Hence Uranus probably will not hit the Sun nor will most of the moon hit the earth. The point is a simple one. Orbiting and falling are different things. Comets are good examples of objects that have eliptical orbits where for part of the time they are moving away from the Sun.

https://en.wikipedia.org/wiki/Comet

[Watis]

All orbiting things will eventually fall out of the sky (ie the orbit will decay to the point where they hit the ground).

So when do you expect the moon to hit the earth? Or when will Uranus hit the sun.

The Moon will never hit the earth, since it is actually moving away. Hence, a time will come when there can be no more total solar eclipses.

Details here: https://www.bbc.co.uk/news/science-environment-12311119

Watis

[ursaminortaur]

All orbiting things will eventually fall out of the sky (ie the orbit will decay to the point where they hit the ground).

So when do you expect the moon to hit the earth? Or when will Uranus hit the sun.

The Moon will never hit the earth, since it is actually moving away. Hence, a time will come when there can be no more total solar eclipses.

Details here: https://www.bbc.co.uk/news/science-environment-12311119

Watis

See my previous reply as to why theoretically the Moon would eventually start spiralling in again after about 50 billion years if it weren't for the fact the Sun would become a red giant long before that.

[johnhemming]

Details here: https://www.bbc.co.uk/news/science-environment-12311119

The BBC often don't tell the whole story which you can find in this thread.