h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Here's an artist's conception of the system: http://www.nasa.gov/topics/universe/features/Gliese_581.html

How unlike NASA to do it so carelessly. If (as I read) the planet does not spin, the water will only appear on a belt round the planet, where the sun is in what would apear to be sunrise/sunset. Away from the sun would be permafrost, towards it desert.

The planet is tidally locked, but let's not spoil the illustration of a pretty Earth Two eh

Even Mars would have an intolerably hot climate with winds sweeping the dark side before they could lose their burden of heat if it always presented the same face to the sun.

The 'Goldilocks zone' model is predicated stellar ('solar') constant only (why did they call it 'Goldilocks' anyway?) acting on an Earth like planet with an Earth like diurnal period and doesn't take diurnal period

amendment to the above, post 24

...diurnal period... [...into consideration.]

To repost post 15 (because it's worth it)

>Isn't the Goldilocks zone somewhere in the vicinity of Ursa Major, Ursa Minor and Ursa Media?

Nice one, Icy!

...at any rate probably had something to do with little red riding hood turning into a giant pumpkin...

So it seems we are probably not alone . . . not that we will ever make contact

we want to contact, its just that aliens don't want to contact us and who could blame them

Apparently we've already sent a message back in 2008. The content of the message was chosen by a competition on Bebo (anybody remember when Bebo was the social networking site?). It'll reach the planet in 2029.

I was looking for that info, thanks Gnomon

we've been shouting as to where we are since the first radio, then TV signals. I hope we aren't contacted just yetwe've got enough immigration going on already

Ah, but as the mighty pTerry pointed out, it'll do wonders for social cohesion - who cares about black and white when we've got green to gang up on?

Though as Kurt Vonnegut and Douglas Adams pointed out repeatedly, there is no reason to expect we would get on well with each other. We could be mutually fatal without even trying -- as the Europeans were fatal to the Americans, with our germs more than our guns and steel.

http://www.pbs.org/gunsgermssteel/

As a matter of fact, planet Earth has been producing electromagnetic signals detectable over interstellar distances since Samuel F. B. Morse put his first commercial electrical telegraph system on line. Any electrical system of the character, including power transmission lines, produces secondary ELF wave noise between any two junctures where the lines bend.

http://www.radio-astronomy.org/node/56

ELF waves are notable for going through media which stop conventional radio, like water or earth or rock, as though those sheilding material were not there. On the other hand, given the Extremely Low Frequencies, rate of data transmission is correspondingly slow. (One bit per wave, maximum.)

Meanwhile, this lends itself to a simplified treatment on the Drake equation, if one takes the fraction of the entire geological history of the Earth over which we've been producing even accidental signals that can cross the interstellar void, dating that to Morse, and then take that fraction of all the sunlike stars in the Galaxy with conditions that allow of stable and orderly planetary systems, it works out to only two or three in the entire galaxy, and we may be the only one. On the other hand, if one dates that to the dawn of civilization, civilization at any level, the arithmetic works out to between 15 and 20 thousand. So there may be a distinct shortage of Klingons and Romulans, but on the other hand, Poul Andersons' Cynthians and Wodenites are probably out there.

The figures above don't include red dwarf stars, which are more numerous than the sunlike stars, and if anything, possibly even more likely to harbor life bearing worlds.

Fascinating my friend. You know so much. !!

Go well

Christiane
AR80
Sunday 10/10/2010 17.00 BMT