Objects in space will move forever unless they hit something?

Question

according to the laws of space because there is no air if you were to push somethignit woudl neer stop until it hit something, yet we are told that spaceships cannot do a lifelong journey or go to far because the lack of fuel. This makes no sense wouldnt the ship just need an initial burst for each direction it wished to travel?

Answer 1

It's not that there is no air it's that there is no friction to slow it down. What is being said about the space shuttle and the fuel issue is that there might not be enough to counter act the intial trust in one direction to make it change direction and come back.
It takes a lot of umph to get it up there in the first place so it has a lot of momentum and need just as much if not more to get it to stop and or reverse it's direction.

Answer 2

You're right. "An object in motion tends to stay in motion until acted upon by an outside force". An object in space would indeed travel in a straight line at a constant speed forever as long as it's not acted upon by any outside forces. So a spaceship would indeed only need an initial burst to reach distant planets, as long as the course did not take it into the path of any other objects, or gravitational pull from celestial bodies. However, the lack of fuel issue stems from the amount of fuel required to leave earth, land safely on another planet, break gravity on the other planet to leave, and land safely on earth. The spaceship needs so much fuel to just leave earth and land once, that it needs a second ship (booster rockets) to carry it all. We just can't get all that fuel off the planet yet.

Answer 3

Yes, very true, see if you take a spaceship and just give it one burst that's all that is needed for it to go forever.

V.Imp is the fuel for spaceships which is not chemical energy ( from fuels) but solar energy ( through solar panels)- which 2 have a limited life.

So techinically, a spaceship can go around forever and ever with nothing to stop it,.., but the panels, the quipment etc., does need energy - and when the eqipment fails - like solar panels or runs through it's life, you have a dead spaceship which will still continue to do the going-round thing ( orbiting) even though it might be as useless as a space rock. yes, only one initial burst of energy is required, and that is gotten by burning fuel rather than through solar panels,...cos the spaceships' heavy...hope u got the idea

Answer 4

Well, you've really got to have a little perspective here. Let's say you have enough feul to accellerate to a million meters per second or 1 x 10^6 meters per second. That's pretty darned fast. But the nearest stellar neighbor is 4 × 10^16 meters. We're still talking about a travel time of 1300 years and don't forget, if you used up all your feul getting up to that speed, you need to use the same amount of fuel to stop!

Now remember, the fastest spacecraft we've built is only going 7 x 10^4 meters per second, so we're talking a long wait time.

Don't even get me into relativistic effects. As you approach the speed of light, you have to expend more fuel to accellerate, but that's a topic we won't have to deal with for quite a while.

Answer 5

Yes, because of no resistance to the bodies in space. It follows Newton's first law of motion (also called law of inertia): A body will keep in continuous rest or motion unless an external force acts upon it.

Answer 6

Hmmm...good question...there is NO GRAVITY in space...plus air...how do "we' know for a fact that "spaceships" cannot travel a lifelong journey? This is new to me..what you say

Answer 7

I'm no astrophysicist, but I would assume it would need fuel to keep the crew alive since they would need oxygen and other necessaries. And, gravitational pull would probably cause it to go in unintended directions without rockets to propel it in the proper direction.

Answer 8

yes the spaceship would keep going much like the voyager probes are going on right now. But eventually they will fall into another gravitational field which might stop them or make them crash.

Answer 9

it will travel without a direction and can get attracted towards gravity of other nearby or passing objects.for e.g planets rotate aroung sun and don't travel elsewhere although they are suspended..I am not an expert or something but this is what i believe it would be.

Answer 10

You need lots of speed, and to get speed you need acceleration. And even in space in order to get acceleration, you need fuel. Remember F=ma. And dont forget that you need the same amount of fuel to DECELERATE once you get to your destination.