how come a spaceship cannot achieve very high but definite velocity even though there is no friction in space?

Question

there is no friction in outer space.....so even a small accelaration will increase the velocity...even if it is a little bit....it will still increase....so why cant we increase the velocity indefinitely???

Answer 1

If you are constantly accelerating then you are using energy so to increase the velocity indefinitely, you would need an infinite amount of fuel. BTW, some spacecraft *are* moving at very high speeds -- the Voyager probes, out beyond the edge of our solar system by now, are travelling at tens of thousands of miles per hour.

Answer 2

All space craft accelerate as much as they can before they run out of fuel. That definite speed is the speed they can reach with the available fuel on board. Space craft accelerate up to that speed in the first 10 or 20 minutes after launch, and the rocket uses up ALL its fuel in that time. After that the space craft coasts freely, with only occasional small bursts of rocket power from very small onboard maneuvering rockets that are not part of the launch rocket and themselves have a VERY limited fuel supply due to the launch rocket not being able to carry the added weight of the added fuel that would be needed to use those maneuvering rockets more.

Answer 3

Because Mr. Albert Einstein says it can't be done. Simply put, if you approach the speed of light the amount of energy needed to increase your speed would not be available because your mass would be so great it could not be accelerated any further. In a nutshell, as matter approaches the speed of light mass approaches infinity and time approaches zero. These are facts, accept them.

Answer 4

Increasing the velocity indefinitely requires a huge amount of fuel onboard the rocket.

Now your are trapped in an endless loop...

If you add more fuel to run the engine longer, it takes more fuel to power the rocket up off of the launch pad to Escape Velocity, and you need a bigger rocket to carry the fuel.

If you need a bigger rocket to carry the fuel, you will need more fuel to lift the rocket at launch and accelerate it to Escape Velocity.

But, if you need more fuel, you will need a bigger rocket to carry the extra fuel...

If you need a bigger rocket, you will need more fuel to launch the bigger rocket and accelerate it to Escape Velocity...

Answer 5

Because weird things start to happen when you start talking about velocities nearing the speed of light. Because of these 'weird' things, it turns out that you need an infinite amount of energy to accelerate something to the speed of light.

[Edit]
While these numbers are not correct, you can think of it this way...

A spaceship leaves from earth and accelerates to 99% of the speed of light and has 1000 gallons of fuel remaining. 100 pounds of fuel is burned and the ship accelerates to 99.1% of the speed of light.

Now since the ship is getting lighter as fuel is burned, and only 10% of the remaining fuel was used to increase speed from 99.1% to 99.2% of the speed of light, you would think that you have enough fuel to reach 100% of the speed of light with some fuel left over. But that only works if the equations for speed, mass, and acceleration are linear.

So another 100 pounds of fuel is burned, the ship only increases its speed to 99.15% of the speed of light. After another 300 pounds of fuel is burned, the speed increases to 99.2% of the speed of light. After the final 500 pounds of feul is burned, the final speed is only 99.25% of the speed of light.

This is where you suddenly realize that physics is no longer linear when dealing with things near the speed of light.

Answer 6

well as i understand it , even if we were to accelerate to the speed of light
it would still take 26,0000 years just to get to the center of the milky way
and Andromeda 2,5 million years , so
the vast distances is our limitation in space

Answer 7

As your velocity increases, so does your mass (exponentially). And you are neglecting gravity. Gravity, in layman's terms, pulls a mass inward toward its source. (Our sun's gravity extends well beyond Pluto and the various number of comets that orbit beyond that. And our galaxy exerts gravity upon our sun, so where would you go to escape gravity?) So as your mass increases, you experience more and more gravity. At least that is my knowledge and understanding as applied to the Theory of Relativity

Answer 8

You can, all you have to do is find a source of reaction mass that will last indefinitely. to accelerate you in one direction, you have to give something up with equal energy in the opposite direction.