Astonomy exam

problem with upper-main-sequence (high-luminosity) host stars

They are unlikely to live long enough for life to develop

stability of technological civilizations

The longer a civilization is able to send out a signal, the higher the chance another civilization has developed the technology to receive it

A civilization that loses its technological capabilities will no longer be able to send or receive signals, which would prevent humans from communicating with them.

Humans are only able to receive signals that have arrived at Earth during the time we have had radio telescopes.

physical basis for life chemistry on Earth

carbon

significance of the Miller-Urey experiment

It showed that complex organic molecules form naturally in a wide variety of circumstances

blue-green tint on Uranus and Neptune

Their atmospheres contain a significant amount of methane

Seasons on Uranus

84 times longer and more extreme than on Earth

thin planetary ring retain its shape

Small moons orbiting just inside and outside the rings shepherd the ring particles

Pluto reclassified as a dwarf planet

Pluto is too small to sweep away material in its orbit

evidence is there that Pluto and Charon are made of rock and ice

their densities    

evidence that Jupiter has a very hot interior

It emits 70% more energy at infrared wavelengths than it receives from the sun

Why is Jupiter more oblate than Earth

it rotates quickly, it has a liquid interior, it has a large diameter

Jovian planet are more oblate

they are all large, liquid, and rotate quickly

Ring formation

the rings are formed from collisions between moons and asteroids or comets