Supernovae put out a huge quantity of high energy radiation and particles. A nearby supernova could produce enough radiation to be dangerous to life.
Water is a basic constituent of the solar system and occurs throughout it. Comets are nearly all water, as are some of the moons of the outer planets, but in the cold of the farther reaches of the solar system, the water is frozen. Mercury is too close to the Sun and any water it may have had quickly boiled away. Venus probably began with water but lost it due to its great heat. Mars lost much of its water because of its weak gravity, but retains some frozen into a permafrost.
Twinkling of starlight is due to turbulent cells of air in the upper atmosphere acting like lenses. You probably have seen the air shimmer above a hot pavement or a heat radiator, for instance. Different wavelengths of the light are affected by different amounts as the twinkling takes place, and so the color seems to change. If you were in space above the atmosphere the stars wouldn't appear to twinkle as you looked at them.
The nearest star is about 4 light years distant. The farthest object you can see without a telescope or binoculars is the Andromeda galaxy, located some 2 million light years away, which is visible in very dark skies as a faint, fuzzy patch of light in the constellation Andromeda. Most bright visible stars in the sky are several hundred light years away. You can always bet someone, but collecting is more difficult.
Copyright © 1998 John F. Hawley