Is Space Really Empty and What Does That Mean for Propulsion?

[russ_watters]

. You cannot compress a vacuum but since that area is really not a vacuum. It should be compressible. By that I mean it is possible create a high pressure from a low pressure. I find it hard to believe that the area known as space is completely empty...

It isn't like we are guessing. Humans have sent thousands of objects into space and hundreds of people. We have a pretty good idea about what is out there. Yes, the vacuum of space is pretty empty. In our solar system it is on the order of 100 particles per cubic centimeter, which is sparse enough for a hydrogen atom to travel an average of 150,000 km without hitting another.

 

[CaptTrey]

I'm sure that someday the word vacuum will find a new place. As a mechanic. I never used and was not aware of the use of absolute pressure. As far as empty well, I believe that in time we will find that it is not necessarily true either. 100 particles Per cubic centimeter. Does not sound empty to me.And that is just the particles we are aware of. Until discoveries are actually made I am willing to accept things as they are being presented.
As I wrote previously, I do understand how a rocket engine( external combustion engine) works. Can anyone tell me though, how compressed air jets are used?

 

[Dale]

I do understand how a rocket engine( external combustion engine) works. Can anyone tell me though, how compressed air jets are used?

The same way a rocket engine works, just easier to turn on and off. In both cases you accelerate a gas one way and the rest of the rocket accelerates the other way in accordance with Newton's third law.

 

[russ_watters]

100 particles Per cubic centimeter. Does not sound empty to me.

At sea level, it is about 30000000000000000000, so yeah, 100 is pretty empty by comparison.

 

[russ_watters]

The same way a rocket engine works, just easier to turn on and off. In both cases you accelerate a gas one way and the rest of the rocket accelerates the other way in accordance with Newton's third law.

Also exactly like the recoil from a gun.

 

[Chestermiller]

As far as empty well, I believe that in time we will find that it is not necessarily true either. 100 particles Per cubic centimeter. Does not sound empty to me.And that is just the particles we are aware of.

This sounds an awful lot like a personal theory to me. What are the rules about threads with personal theories again? Aren't they supposed to be shut down?

In addition, I think we've beat this one to death. I'm closing the thread.

Chet