What kind of thrust would be produced to reach the speed of light.?

Question

How big would the space-ship need to be and what affect would it have on the Earth?.

Answer 1

A lot of complicated and daft (funny!) answers but the short one is: you can't get an infinite thrust, you can't wait forever, so it is impossible to get right up to the speed of light in any real amount of time. Things can only travel at the speed of light if they have no mass (like particles of light).

Answer 2

Depends on the mass of the object that's to be pushed. Even though a spaceship is weightless in space, it still has mass. When you push on something, you create inertia, which works kind of like a temporary gravity. The more you accelerate, the more energy you'll need for the increasing speed. Once you achieved a given speed, the ships speed can remain constant without additional fuel needed. In other words, adrift.
Now to achieve light speed, that would be a most difficult task. If you take off and jump to light speed immediately, the amount of energy needed to accomplish this would have to be incredibly tremendous...probably like a nuclear blast. If the ship survives, the tremendous inertia generated would not only crush the astronauts flat, but would destroy the ship, unless it's made of diamond, or something much more harder.
A more gentler approach would be needed. A constant acceleration, keeping the astronauts feeling 1g would work, but it would take months to reach the speed of light. Also the increasing demand of more energy for the increasing speed would make it impossible with todays technology. Also the same amount of energy would be needed to slow down and stop.
It's a catch-22 situation. You can build a huge ship with a huge storage of energy, but now you have to push this huge amount of mass, and much more energy would be needed than what's on the ship. So for now...it's impossible.
Maybe there will be other ways to travel the universe, like worm holes, black holes, inter-dimensional shifts. These are interesting theories, but may bloom to something more conceivable.

Answer 3

The thrust has to accelerate the mass until it (theoretically) reaches the speed of light. So in Newtonian mechanics use F=ma. F would be the thrust in newtons, m the mass in kg and a the acceleration in ms^-2. You need to know the mass of your space-ship. Now you can see it would be a mater of how quickly you wish to accelerate. You would probably wish to think more in terms of how long you want to accelerate so use v= u+at where v is your final velocity i.e. the speed of light, u is your starting speed and assume this is 0, a is acceleration and t is the time you want to take - that's up to you as Captain of your spaceship. One final thing, we assume you have first got into outer space or at least escaped the Earth's gravitational pull.
However, Newtonian mechanics does not hold as you near the speed of light. The mass of your space-ship increases so your need more and more thrust. The maths predicts th mass increases to such a point that you can never reach the speed of light.

Answer 4

To accelerate an object of mass m from rest to a speed u, you need energy K given by this equation:

K = m x (c squared) x (1/(square root of (1 - (u squared)/(c
squared))) - 1)

(where c is the speed of light)
(strictly speaking, m is the "rest mass" of the object - its mass
as measured by an observer who is stationary relative to the
object.)

If u is very low compared to the speed of light, this equation gives almost exactly the same answer as K = (1/2) x m x (u squared), i.e. the well-known kinetic energy equation.

The first equation above gives infinity as the answer, if u is the speed of light. So it seems to be impossible to accelerate a finite mass to the speed of light - it seems that an infinite amount of energy would be required, and the universe doesn't contain an infinite amount of energy.

The first equation above also gives very high numbers as u approaches the speed of light. For example, the energy required to accelerate a 100g mass to 99% of the speed of light would be equal to the energy output over 1.5 years by a high-powered nuclear power station.

A small mass could be accelerated to close to the speed of light, by continuously directing a particle beam so that the particles collided with the rear of the mass. The particles would impart their momentum to the mass, and gradually accelerate it. Physicists already know how to accelerate particles to close to the speed of light - they do it all the time in places like CERN. However, arranging for a particle beam to shine continuously on a mass as the mass accelerated to near light speed, would be an engineering challenge. Hopefully it will be done some time in the future.

It may be impossible for a spaceship to accelerate itself to close to the speed of light, using its own fuel. The problem is that the spaceship would run out of fuel while still going fairly slowly compared to c.

Stars emit a lot of material that travels close to the speed of light. It may well be possible for suitably-designed spacecraft to be "blown" by this material and accelerated up to high speeds, but I'm not sure if you could get anwhere near c by this method. It would be good if you could, though - you could use the same technique to slow down, as you neared another star.

The fastest spacecraft so far lauched are Voyager 1 and Voyager 2. These are travelling at about 30 thousand miles per hour - fast enough to escape from the Sun's gravity - and are the first starships.

The great thing about accelerating a spaceship to close to the speed of light is that the journey time (for the crew) would be greatly reduced. During a journey of, say, 100 light years, the crew would only age by, say, six months (depending on the exact speed of the spacecraft). On returning home, the crew would find that they were 199 years younger than those they left behind.

Answer 5

You cant reach the speed of light so the question is meaningless.
Just for reference beau nidle is wrong, accelerating at 1g will never get you to the speed of light, as you get faster less and less of the energy will actually go into speeding you up so the effective efficiency of the will reduce. You would however get interesting relatavistic effects which would appear to compress the entire universe in the direction you are moving which would bring the destination closer! Don't even try and visualise it, relativity and quantum effects require maths not intuition.

Answer 6

I would think that once you are in space not a lot of thrust would be required as you only have to overcome inertia but it would take a long time to accelerate to the speed of light even if it was possible

Answer 7

Any size thrust will work, but it must be continuous. Eventually, any speed can be obtained.

Such a source of force is unimaginable. Even nuclear forces would require a ship nearly the size of a star. Such a huge mass would actually BECOME a star.

Answer 8

don't need thrust other than to leave the earth gravity, unless u want to transition to the speed of light rapidly. to attain light speed u simply need to continue to accelerate once in space

Answer 9

No material object, including spaceships, can reach the speed of light because it would require an infinite amount of energy (..all the energy in the universe)

Answer 10

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