--Answer below:
Things "rising" and "setting" give the appearance of something rising or setting. In reality objects like the Sun or Moon aren't physically rising from the horizon. Most of the motions we see in the sky are caused by the Earth's motion, both its rotation and orbital motion. So all of the "motions" described below are really apparent motions and not really an indication of how things are actually moving, but how they appear to move.
2. (5 points) How long does light take to travel to the Earth from the moon?
--Answer below:
As the Moon is 400,000 km from the Earth and the speed of light is 300,000 km's the time taken is about 1.3 seconds.
3. (5 points) How long does it take a starship traveling at half the speed of light to get to Alpha Centauri?
--Answer below:
The distance to the Alpha Centauri system is 4.4 light years, meaning that it takes light 4.4 years to get from here to there.
If you travel the same distance at 1/2 the speed of light, it takes (4.4/0.5) = 8.8 years.
4. (5 points) The New Horizons spacecraft, launched in 2006, is expected to arrive at Pluto in about ten years. How fast is it traveling?
--Answer below:
In January 2006, NASA launched the New Horizons probe on a mission to fly by Pluto. New Horizons is one of the fastest man-made objects ever launched, and is not scheduled to arrive at Pluto until July 2015. As of today, it takes about 9.5 years to travel from the Earth to Pluto. The distance from Earth to Pluto is not constant, but averages to 3.57 billion miles. The Space Shuttle orbits at 17,500 miles per hour. Therefore 205,000 hours or 8,500 days or 23 years 105 days.
5. (5 points) The Voyager spacecraft, launched in 1977, travels at about 120 kilometers per second. How far away is it now? Is it still in the solar system? How long would it take Voyager to get to Sirius?