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Detecting alien life by looking for cities at night
November 7, 2011 10:00 PM   Subscribe

Detecting alien life by looking for cities at night (a world tour). [via]
posted by stbalbach (24 comments total) 9 users marked this as a favorite

 
From the first link:
A metropolis the size of Tokyo would be easily visible with existing telescopes about 50 astronomical units away. The closest star is 100 times farther than that, you would need a telescope with optics at least 100 times wider in diameter than the Hubble Space Telescope's. The next generation of ground and space telescopes could prove capable .."
From the second link: "The brightest spot on Earth: Las Vegas, NV. A beacon for humanity."
posted by stbalbach at 10:01 PM on November 7, 2011


But what if the alien societies all have strict light pollution laws because they are races of star watchers?
posted by Horselover Phattie at 10:08 PM on November 7, 2011 [9 favorites]


Convergent Evolution, Horselover. All technological sentients* will be jerks.


*excluding gas-borne and aquatic species
posted by clarknova at 10:22 PM on November 7, 2011


What if we've been mistaking Coruscant for a star all this time!?
posted by Brocktoon at 10:42 PM on November 7, 2011


The nerdiness of the dudes voice is strangely soothing...
posted by Jibuzaemon at 10:55 PM on November 7, 2011


What if it is a race of dolphin creatures that communicate primarily with sound?
posted by KokuRyu at 11:04 PM on November 7, 2011


The Obama administration says no ET.

Republicans at a loss for someone to blame.
posted by twoleftfeet at 11:11 PM on November 7, 2011


Hmm, that planet will be close to a nearby star, meaning that there is a very bright light source extremely close to it (relatively speaking from our viewpoint lightyears away). Also, half of the planet is covered with light from that star and therefore likely very bright. The only time that most of its dark side faces the earth is when it is close to that star, i.e. when star-planet-earth are more or less aligned (if they are arranged at right angles, half of the visible planet will be covered with "sun"light), but in that situation, the brightness from the star will make detection of those cities at night difficult.

I think they haven`t quite thought this through yet.
posted by sour cream at 11:19 PM on November 7, 2011


I think they haven`t quite thought this through yet.

I haven't RTFA, but I would assume they intend to use spectroscopy to filter out the sun by only looking in the band gaps? Perhaps mercury-sodium-vapour lamps, for example, have spectra that are not naturally occurring in stars of a certain age?

Or maybe not. I haven't read the article yet
posted by -harlequin- at 2:30 AM on November 8, 2011


Metafilter: Why do we even need articles? Can't we just speculate?
posted by victory_laser at 3:00 AM on November 8, 2011 [4 favorites]


How does the idea of building a giant shade into the orbit to block the starlight in order to better see the planet play into this?
posted by Anything at 3:14 AM on November 8, 2011


I choked up my coffee at "Las Vegas, beacon for humanity" I've been to Las Vegas, and yes I get beacon, but it ain't for humanity.
posted by the noob at 3:32 AM on November 8, 2011 [2 favorites]


Horselover. All technological sentients* will be jerks.

For a second there I thought this was a late-PKD reference of some kind, which was puzzling me a little in several ways....
posted by lodurr at 4:30 AM on November 8, 2011


Hmm, that planet will be close to a nearby star, meaning that there is a very bright light source extremely close to it (relatively speaking from our viewpoint lightyears away).

Should this still matter to a telescope in a vacuum?
posted by lodurr at 4:31 AM on November 8, 2011


Cities at Night (previously)
posted by crunchland at 4:38 AM on November 8, 2011


This is never going to detect those aliens who mate by stubbing there toes in the dark.
posted by orme at 6:00 AM on November 8, 2011 [1 favorite]


Won't work. They all see in the police band.
posted by jfuller at 6:05 AM on November 8, 2011


Because every little thing they do is magic.
posted by crunchland at 6:37 AM on November 8, 2011 [1 favorite]


sour cream: the article discusses that at least the types of lights that we use on Earth (incandescent and fluorescent) have different signatures than sunlight. I think they're counting on that to be able to distinguish at a distance as well.
posted by Inkoate at 7:05 AM on November 8, 2011


Metafilter: Why do we even need articles? Can't we just speculate?

On reading the article, it does indeed appear that I'm so brilliant that I don't actually need to bother reading the articles. :)
posted by -harlequin- at 11:17 AM on November 8, 2011


-harlequin-: "I'm so brilliant"

I'm blinded by what you did there.
posted by namewithoutwords at 12:44 PM on November 8, 2011


I'm blinded by what you did there.

Use spectroscopy to filter me out.
posted by -harlequin- at 1:05 PM on November 8, 2011


Also previously Cities at Night which shows how they made the images using stabilizers.
posted by stbalbach at 5:36 PM on November 13, 2011


(crunchland got it above)
posted by stbalbach at 5:37 PM on November 13, 2011


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