Alien Astronomers Could Discern Earth's Features

New Scientist ^ | 12-21-2007 | Stephen Battersby

[blam]

Alien astronomers could discern Earth's features

14:58 21 December 2007
NewScientist.com news service
Stephen Battersby

Aliens spying on us from another star system might be able to discern continents and oceans on our planet, using technology barely more advanced than our own.

In imaginary form, these inquisitive extraterrestrials have been helping astronomers work out how much detail the next generation of space telescopes could reveal on Earth-like planets orbiting other stars.

Seeing any detail at all is a tough task. Even at the distance of the nearest stars, only a few light years away, terrestrial planets would appear so small that no planned telescope could see any detail directly. Even NASA's Terrestrial Planet Finder, a flotilla of large space telescopes that could be launched within a decade, would see Earth as a featureless point.

"In fact, Earth and the Moon would be in the same pixel," says team member Eric Ford of the University of Florida in Gainesville, US.

There is one trick, however, that astronomers might employ. As an alien Earth rotates, sunlight falls on different surface features such as forests, deserts and seas, and the total brightness of the planet should vary. By plotting that fluctuation in brightness over many days, a careful observer could sketch out those surface features.

That is, unless clouds spoil the view. Because clouds reflect so much light, chaotic weather patterns could make the brightness of a planet fluctuate unpredictably, perhaps enough to obscure those more subtle, regular variations due to continents and seas.

To find out, Ford and his colleagues calculated what a distant observer would see of the Earth, using satellite observations of weather around the globe. They discovered that in the long run, cloud cover mimics the pattern of surface features quite closely. Deserts have clear skies,

[Sunny Poipu]

Tinkle tinkle little star..

[Doc Savage]

DefEcating!

[steveo]

That's it boys...no more peeing outside.

Mrs. always sez 'way to go charm boy'...

[Zuben Elgenubi]

Aliens spying on us from another star system might be able to discern continents and oceans on our planet, using technology barely more advanced than our own.

I wonder what they think of all the tasering? Zapppa!!!!

[dayglored]

> DefEcating!

Yep... hey, it' not my sign... ;-)

[org.whodat]

Are they kidding? The people from K-PAX come here regular. They say the taste of the produce alone is worth the trip.

True, some people are just so behind times!

[americanophile]

I wonder if the glare from their telescopes could be contributing to global warming?

[seowulf]

If I moon them tonight, might this cause an interstellar incident?

No problem. Mooning will just make the planetary brightness vary a little more than usual.

[boop]

"That is, unless clouds spoil the view. Because clouds reflect so much light, chaotic weather patterns could make the brightness of a planet fluctuate unpredictably, perhaps enough to obscure those more subtle, regular variations due to continents and seas."

I know it's a little off topic, but was it only after we put satellites into orbit that we realized that the earth has visible clouds? Whenever I see a movie from the 50's or 60's set in space, they show earth bald like a globe.

[BenLurkin]

[BenLurkin]

They come here for the "produce"?

Not just that...

[HeartlandOfAmerica]

So surely they can see the Constellation Urion!

[reagan_fanatic]

Wow! That’s gotta be real!

[G8 Diplomat]

Alien Astronomers Could Discern Earth's Features

Dennis Kucinich sure can, otherwise he wouldn't be here.

[Picklezz]

The thread title got me to thinkin' Has anyone asked the "experts" (algore and co.) if it's possible that the UFO aliens (as opposed to the illegal aliens) could be the cause of the hole in the ozone. Is that hole letting something out that is interferring with their environment? Or in, that is making a "very rich genius" blubberman of algore.

What a bunch of phony baloney.

[BenLurkin]

http://www.youtube.com/watch?v=fkVlr21pRbY

[reagan_fanatic]

I love a good prank, and that’s got to be one of the funniest I’ve seen! LOL!!

[tbw2]

If you are curious about what aliens could actually learn about Earth via their version of SETI, read “SETI in Reverse”, available from Amazon.com
Admission: I am the author.

[Zuben Elgenubi]

OK, I’ll try it.