ASTR 109 HOMEWORK #1 (Hamilton)
Solutions

a) Hand in a copy of the corrected conversion quiz. Full credit if they are all right.
b) Hand in a copy of the corrected multiply/divide quiz. Full credit if they are all right.

a) The fastest speed for a spaceship to travel is just below the speed of light at approximately 300,000 km/s.
b) At the speed of light it takes 1.27s to get to the Moon and 5.34 hours to get to Pluto.
c) Light from a galaxy in the Coma cluster that reaches us now left there 339 million years ago.
d) Driving at 100km/s it would take 5.32 months to reach the Moon and 6590 years to reach Pluto. Your car may be a factor of ~2 faster or slower than this.

a) The Sun forms on Sept. 1 at 8:00am, the Earth on Sept. 11 at 2:00am, and the Moon on Sept. 13 at 12:00pm.
b) The earliest life forms on Sept. 30 at 1:00pm, and complex life doesn't from until Dec. 14 at 11:00pm.
c) Dinosaurs only lasted for 3 days and 7 hours.
d) The human race has lasted only 21 minutes!

a) In order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune, Pluto.
b) The first four planets are made mostly of rock.
c) The next four planets are made mostly of gas (with some ices).
d) Pluto is made mostly of ice (with some rock). Pluto is a different type of object from the terrestrial planets and is very different from the gas giants. It could be called an ice planet, but there are a lot more icy objects of nearly Pluto's size out there! The major choices are to leave Pluto as the only icy planet, allow for multiple icy planets in the outer Solar System, or give them all a new classification: dwarf planets. All of these solutions have some backing.