This is planetary radio. Hi again everyone and welcome back I'm Matt Kaplan. Remember flashlights with a button you could push and release to send messages to your

buddies? Could an extraterrestrial civilization be using a giant laser to do the same thing?

It's possible. Even we Earthlings have the technology within

our grasp. Dr. Paul Horowitz is watching for those flashes from afar, and he'll soon be doing so with the biggest telescope in the eastern

U.S.

He joins us on today's planetary radio.

Bruce Betts will return with another trivia contest and more fascinating space facts in What's Up.

First though, here's Emily,awala with questions and answers. A listener asked, I heard that it actually

rains diamonds on Neptune. Is that true? How?

We asked Laura Benedetti who published the Diamonds on Neptune story in

Science magazine to answer the question. Yes, it's probably true that diamonds reined on Neptune

at least early in its history and possibly still today. The atmospheres of both Uranus and Neptune

contain methane, a simple molecule containing carbon.

The conditions deep inside these planets are extreme, with very high pressures due to the

weight of over

from the gravitational energy of planetary formation.

In laboratory experiments, simulating these extreme conditions,

methane becomes unstable and breaks down and pure carbon is formed as diamond.

If the same reaction occurs in the atmospheres of Uranus and Neptune,

the resulting diamonds would drop like rain or hail

or maybe like grains of sand sinking to the ocean floor.

What other weird environments exist in our solar system?

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