Our only hope to be able to travel between the stars is tu use
spaceships that are powered by a yet-to-be developed technology. If we can,
imagine two missions on these ships - one headed to a star in Ursa Minor,
and another to a star in nearly the opposite direction in the constellation Crux.
After a long acceleration phase, each ship could be moving away from Earth at
a speed of 60% the speed of light (v=0.6c).
Viewed from Earth, this is fine because neither speed exceeds c.
But if you
take the point of view of an astronaut on one of the ships,
it might seem that she would see the other ship moving away at 1.2c.
How can this be?
In your own words, please provide a concise definition of the following
terms, based on the readings you've done and what we have done in class
proper (or absolute) time
relativity of simultaneity
We've said in class, many times, that c is the "ultimate speed
limit." From what you've learned about relativity, prove it!
A thought question - if you are a photon, how long does it take you to
travel a distance of 1000 light years, in your reference frame?
For each of the following objects, compute the radius, in centimeters, of
the event horizon were they to become a black hole. Express your answer
using scientific notation (a x 10b).
You will need to consult some reference material (or the WWW) to find the
mass of the objects. Remember, the mass of the Sun is 2x1033
grams, and the event horizon for something the mass of the Sun has a radius
of 3 km.
The planet Saturn
The Empire State Building in New York City.
Mount Everest
Masahiro Tanaka (newly-signed pither for the New York Yankees)