What does an astronomer do? What planets have been explored?

On Tue, 27 Apr 1999, you wrote:

> hi i'm liz and i am curious to know what an astronomer do and also
> history of the planets which have been explored.

Hi, Liz,

Astronomers are scientists who study objects in outer space. There are
two main types of astronomers - observers and theorists, although most
astronomers are a mix of both. Observers are astronomers who take
pictures of the sky through telescopes. These pictures may be taken in
ordinary visible light, or they may be pictures of radio waves, or of
x-rays, or any other type of light. Some observers even look for
high-energy particles called cosmic rays which come from deep space.
Observers then take these pictures (and whatever other information they
may collect) and try to determine what they saw, and what that tells us
about the universe.
Theorists are astronomers who try and explain what observers see,
and even predict objects that might exist that we have not or cannot see.
Theorists use mathematics and physics to explain how the universe works.
They often use giant, powerful computers to solve complicated math problems.
Theorists and observers work together to try and explain
everything from the dust that makes up meteors to the structure of the
entire universe. They try and explain how stars and galaxies are born,
live, and die.

As for the history of the planets, I suggest that you look at a
web page designed by students at the university of Arizona. The web
address is:
http://seds.lpl.arizona.edu/nineplanets/nineplanets/intro.html

Thanks for writing!

Sincerely,
Kurtis Williams

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