Why doesn't Earth speed away once we leave its gravitational pull?

Does your question presuppose that one can somehow not only leave the Solar System but attain absolute rest after leaving it?

What you do is what you do.But regardless of what you do, the Earth travels about 33,333 mph in order to get around the Sun within one year. Also the Earth is traveling at another high speed as the solar system travels through the Milky Way Galaxy as the the Milky Way Galaxy travels through space at some other speed.

So can you ever get left?

No, you’re always in the Earth’s gravitational pull. It just gets weaker and weaker the further you go. Also, due to inertia nothing is going to suddenly speed away. To accelerate away some new force would have to be applied to you or to the Earth.

The physics of it all is astoundingly stable. Well, until the sun goes nova then it’ll be a mess. But I don’t think our sun is big enough to go nova.

So the speed at which the galaxy is moving is like keeping this one big fish bowl where we can swim from point a to point b without the solar system leaving us in its dust?

It’s all kept in place by gravity. Gravity defines just about everything about us.

I love this video. I’m not sure how, but it seems to explain a lot of things to me.

I find astrophysics to be well explained here. ;-)

“So the speed at which the galaxy is moving is like keeping this one big fish bowl where we can swim from point a to point b without the solar system leaving us in its dust?”

This is fundamentally wrong. It’s not analogous to a fish bowl. The key is that there are no orbital mechanics in a fish bowl.

You don’t “swim” from a to b in outer space. All motion involves some sort of trajectory.

Satellites around the Earth stay in orbit around the Earth because they move sideways at high enough velocities.

I think that Newton’s Canonball is the best way of illustrating this. Saves me trying to explain it in words so much.

This concept of trajectories applies to all celestial bodies, and space travel between them. The Apollo missions to the Moon didn’t involve “swimming” in space from the Earth to the Moon, but rather first orbiting the Earth, and then thrusting prograde (using rockets to propel in the forward direction of the orbit) in order to change the craft’s orbit so that its highest point from the Earth would meet the Moon’s sphere of influence (where the Moon’s gravity becomes the dominant gravitational force). This is called a Trans-Lunar Injection.

“So can you ever get left?”

It’s matter of being so far away that something other than the sun (the black hole at the centre of the galaxy) will exert a greater gravitational influence than the sun. I’ve read this to be approximately 1 light year away, or about 6 trillion miles. Anything nearer and you’ll still be orbiting the sun. Farther out, and you’re orbiting the black hole in the middle of the galaxy. This would be the Sun’s Hill Sphere.

Ladies and Gentlemen, I think we have a winner.

You’ve been messing with us @Ltryptophan!

Because you start out the same velocity that the Earth starts out at and you maintain that vector.

Think of it this way. Let’s say you’re in a moving car going at 30 mph, and you throw a baseball out the window in front of you at 40 mph (ignore wind resistance). The baseball looks like it’s moving away from you at 40 mph, but if you’re on the sidewalk and you get hit with the baseball the baseball will be moving at 30 + 40 = 70 mph.

Same thing if you’re in a spacecraft.

Our solar system orbits around the center of our galaxy at 220 km/s:
http://en.wikipedia.org/wiki/Milky_Way

Our planet orbits around the Sun at 30 km/s:
http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Speeds.shtml

If you want to orbit around Earth, you have to go at least 7.8 km/s:
http://en.wikipedia.org/wiki/Low_Earth_orbit

If you go into space and orbit around Earth, you will still be in Earth’s gravity field so won’t drift off to infinity. Earth will pull you along within its gravity field at 30 km/s around the Sun.

If you get going >11 km/s, you will be able to escape Earth’s gravity field, but you will still be stuck in the Sun’s gravity field. You might drift around, depending on your speed and direction, but you won’t drift off to infinity. The Sun will pull you along within its gravity field at 220 km/s around the galaxy.

But if you have just escaped Earth’s gravity field, you will likely be traveling in an elliptical orbit around the Sun. Earth has its own elliptical orbit around the Sun, so your path and Earth’s path might be different. It might be a while before you come close to Earth again.