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PHYSICS OF THE IMPOSSIBLE
Princeton physicist Freeman Dyson proposed that in the far future
we might find two neutron stars that are revolving around each other
at great speed. By traveling extremely close to one of these neutron
stars, we could whip around it and then be hurled into space at speeds
approaching a third the speed of light. In effect, we would be using
gravity to give us an additional boost to nearly the speed of light. On
paper this just might work.
Others have proposed that we whip around our own sun in order
to accelerate to near the speed of light. This method, in fact, was used
in Star Trek IV: The Voyage Home, when the crew of the Enterprise hijacked a Rlingon ship and then sped close to the Sun in order to break
the light barrier and go back in time. In the movie When Worlds Collide, when Earth is threatened by a collision with an asteroid, scientists
flee the Earth by creating a gigantic roller coaster. A rocket ship descends the roller coaster, gaining great velocity, and then whips
around the bottom of the roller coaster to blast off into space.
In fact, however, neither of these methods of using gravity to boost
our way into space will work. (Because of the conservation of energy,
in going down a roller coaster and coming back up, we wind up with
the same velocity as that with which we started, so there is no gain in
energy whatsoever. Likewise, by whipping around the stationary sun,
we wind up with the same velocity as that with which we originally
started.) The reason Dyson's method of using two neutron stars might
work is because the neutron stars are revolving so fast. A spacecraft
using the slingshot effect gains its energy from the motion of a planet
or star. If they are stationary, there is no slingshot effect at all.
Although Dyson's proposal could work, it does not help today's
Earth-bound scientists, because we would need a starship just to visit
rotating neutron stars.
RAIL GUNS TO THE HEAVENS
Yet another ingenious method for flinging objects into space at fantastic velocities is the rail gun, which Arthur C. Clarke and others have
PHYSICS OF THE IMPOSSIBLE
Princeton physicist Freeman Dyson proposed that in the far future
we might find two neutron stars that are revolving around each other
at great speed. By traveling extremely close to one of these neutron
stars, we could whip around it and then be hurled into space at speeds
approaching a third the speed of light. In effect, we would be using
gravity to give us an additional boost to nearly the speed of light. On
paper this just might work.
Others have proposed that we whip around our own sun in order
to accelerate to near the speed of light. This method, in fact, was used
in Star Trek IV: The Voyage Home, when the crew of the Enterprise hijacked a Rlingon ship and then sped close to the Sun in order to break
the light barrier and go back in time. In the movie When Worlds Collide, when Earth is threatened by a collision with an asteroid, scientists
flee the Earth by creating a gigantic roller coaster. A rocket ship descends the roller coaster, gaining great velocity, and then whips
around the bottom of the roller coaster to blast off into space.
In fact, however, neither of these methods of using gravity to boost
our way into space will work. (Because of the conservation of energy,
in going down a roller coaster and coming back up, we wind up with
the same velocity as that with which we started, so there is no gain in
energy whatsoever. Likewise, by whipping around the stationary sun,
we wind up with the same velocity as that with which we originally
started.) The reason Dyson's method of using two neutron stars might
work is because the neutron stars are revolving so fast. A spacecraft
using the slingshot effect gains its energy from the motion of a planet
or star. If they are stationary, there is no slingshot effect at all.
Although Dyson's proposal could work, it does not help today's
Earth-bound scientists, because we would need a starship just to visit
rotating neutron stars.
RAIL GUNS TO THE HEAVENS
Yet another ingenious method for flinging objects into space at fantastic velocities is the rail gun, which Arthur C. Clarke and others have