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Observatories on 5 continents to scan skies for extraterrestrial life

Suddenly, the prospects for finding planets that might have complex life and environments to support it appear to have brightened. Scientists well in the future may still conclude Earth is the only planet that harbors life, but discoveries in the last few years seem to increase the odds that we are not alone after all.
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This is whats most interests me...
 
Well, realistically they have increased from what - Totally unknown to incredibly small?

The only complex life we are able to detect is life complex enough to change it's planetary atmosphere, or life using radio frequencies.
They also have to be , either by pure coincidence, or for reasons yet to be found, in a volume of space we can observe in some detail.

Remember , we can see Mars. We have robots on the surface, probes in orbit and we still don't know if there is life there, because if there is, it does not photosynthesise in a big way and it surely doesn't broadcast RF.

I'm pro-SETI, but realistically, I reckon the chance of a radio-level technological civilisation existing or having once existed in the right (miniscule) area of spacetime for their transmissions to be reaching us exactly now, is very small. There may well be many civilisations out there, but "out there" is awfully big.
 
Soapy Sam said:
Well, realistically they have increased from what - Totally unknown to incredibly small?

The only complex life we are able to detect is life complex enough to change it's planetary atmosphere, or life using radio frequencies.
They also have to be , either by pure coincidence, or for reasons yet to be found, in a volume of space we can observe in some detail.

Remember , we can see Mars. We have robots on the surface, probes in orbit and we still don't know if there is life there, because if there is, it does not photosynthesise in a big way and it surely doesn't broadcast RF.

I'm pro-SETI, but realistically, I reckon the chance of a radio-level technological civilisation existing or having once existed in the right (miniscule) area of spacetime for their transmissions to be reaching us exactly now, is very small. There may well be many civilisations out there, but "out there" is awfully big.
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If there's some kind of Moore's law for telescopes, eventually we should be able to see planets the size of earth around other stars. That's when I think we might finally detect extraterrestrial life. An oxygen-rich atmosphere like ours is what I would hope to see. That would be a smoking gun for some kind of life, although it might not be intelligent.
 
;)SETI is a shot in the dark. It's fairly inexpensive and if it ever pays off it will be a world view changing event.To me it's worth it.
The same with ESP and other pseudo sciences as long as they aren't using my tax dollars. I would love to discover that ESP works. I don't expect it to but hope springs eternal.
 
Francois2807 said:
;)SETI is a shot in the dark. It's fairly inexpensive and if it ever pays off it will be a world view changing event.To me it's worth it.
The same with ESP and other pseudo sciences as long as they aren't using my tax dollars. I would love to discover that ESP works. I don't expect it to but hope springs eternal.
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wow, for me SETI and ESP are entirly different. SETI is scientific, but ESP is entirely fantasy.
 
Soapy Sam said:
(sorry for the edit)...I'm pro-SETI, but realistically, I reckon the chance of a radio-level technological civilisation existing or having once existed in the right (miniscule) area of spacetime for their transmissions to be reaching us exactly now, is very small. There may well be many civilisations out there, but "out there" is awfully big.
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Yeah, Kinda big. Really big. Perhaps beyond what we can see right now.
 
Puppycow said:
Kepler Observatory Seeks More Earths and Other Beings

Another fine article on current efforts to find life on other planets.
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Kepler is not attempting to find life on other planets, nor can it possibly do so.

Its purpose is more generally about finding extrasolar planets. It will answer several questions (is there a typical planetary system? etc.) and in particular will give us an idea of how many earth-like planets (by mass) there are, and to figure out how many of them are likely to be in the Habitable Zone (where liquid water is at least possible).
 
JoeTheJuggler said:
Kepler is not attempting to find life on other planets, nor can it possibly do so.
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Well, first you have to find the planets themselves before you can find the life on the planets (if it's there of course).

I like to think of it as all part of the effort to find extraterrestrial life. I'm not particularly interested in finding lifeless rocks orbiting other stars, and would be quite disappointed if that's all they turned out to be, but I am interested in finding extraterrestrial life, and finding those rocks is probably a prerequisite to finding extraterrestrial life. Baby steps.

:)
 
Soapy Sam said:
Well, realistically they have increased from what - Totally unknown to incredibly small?

The only complex life we are able to detect is life complex enough to change it's planetary atmosphere, or life using radio frequencies.
They also have to be , either by pure coincidence, or for reasons yet to be found, in a volume of space we can observe in some detail.

Remember , we can see Mars. We have robots on the surface, probes in orbit and we still don't know if there is life there, because if there is, it does not photosynthesise in a big way and it surely doesn't broadcast RF.

I'm pro-SETI, but realistically, I reckon the chance of a radio-level technological civilisation existing or having once existed in the right (miniscule) area of spacetime for their transmissions to be reaching us exactly now, is very small. There may well be many civilisations out there, but "out there" is awfully big.
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Soapy Sam speaks for me on these issues so I thought I'd just copy his post.

Puppycow said:
If there's some kind of Moore's law for telescopes, eventually we should be able to see planets the size of earth around other stars. That's when I think we might finally detect extraterrestrial life. An oxygen-rich atmosphere like ours is what I would hope to see. That would be a smoking gun for some kind of life, although it might not be intelligent.
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I don't think there is some kind of Moore's law for telescopes or if there is one it is an inverse Moore's law. To get more resolution telescopes need to increase in diameter which roughly means that the cost of improving resolution in telescopes goes up with the cube of the size. There are some technological tricks which make that not quite true, interferometry, adaptive optics, CCD's, and maybe some other stuff but mostly those technological break throughs are already in place. Interferometry might be an exception and gigantic space born networked space telescopes have at least been proposed. My guess is that I won't live to seem them in place but you might if you're ten or so years younger than me.

As an aside and a bit coincidentally I have visited two interferometry installations in the last two weeks. One was the CHARMA radio telescope installation out of Big Pine in the White Mountains and the other was the CHARA array on Mt. Wilson. In the case of CHARMA we were very lucky to get a bit of a personal tour. I learned that they actually do experiments where data from other radio telescope arrays can be combined to greatly increase the resolution of the observations, I took a picture of the super accurate maser clock that they use to synchronize the data from the remote installations. Pretty amazing. In the case of the CHARA array we had a pleasant tour guide who wasn't all that informed and the actual guts of the optical combining hardware are not open at all to the public.

sphenisc said:
The Kepler Orrery
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That is a totally cool link. I knew what an Orrery was but I couldn't imagine how it applied in this situation. I had a vision of some guy in a garage creating a giant machine with little styrofoam balls circling around.

Side note: My spell checker says that styrofoam should be capitalized. Screw him. I'm not going to capitalize it. Power to the man. Rebellion is good. I think for my next act of civil disobedience I might spell rumour like the Brits do.
 
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Soapy Sam said:
The only complex life we are able to detect is life complex enough to change it's planetary atmosphere,
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This is actually a VERY good test. I mean, humans think we can influence the atmosphere, but we're really pathetic--I mean, we can influence a few hundred of parts per million of a few trace gasses, maybe add a few new chemicals. The Oxygen Revolution, on the other hand, happened because single-celled organisms produced enough toxic waste to alter the way the planet works on a chemical level. The Earth, at equilibrium and without biology, would have very little oxygen in it--it's a relatively reactive gas, and would quickly combine with other chemicals (chemical weathering is largely this). So really, looking for unstable atmospheres (or atmospheres that appear to be in a dynamic equilibrium) is a good way to detect very simple life.
 
Soapy Sam said:
Well, realistically they have increased from what - Totally unknown to incredibly small?

The only complex life we are able to detect is life complex enough to change it's planetary atmosphere, or life using radio frequencies.
They also have to be , either by pure coincidence, or for reasons yet to be found, in a volume of space we can observe in some detail.

Remember , we can see Mars. We have robots on the surface, probes in orbit and we still don't know if there is life there, because if there is, it does not photosynthesise in a big way and it surely doesn't broadcast RF.

I'm pro-SETI, but realistically, I reckon the chance of a radio-level technological civilisation existing or having once existed in the right (miniscule) area of spacetime for their transmissions to be reaching us exactly now, is very small. There may well be many civilisations out there, but "out there" is awfully big.
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I'd agree I think there should be a general development of a gateway for how long radio civs last. I gateway I suspect is 150 or less years. Given the number of civilizations out there, I'm of doubt that radio would work. The new light arrays that are being developed do excite me though.
 
Yeah, the emission window is pretty short. We could be spending a lot of time searching for the cosmic equivalent of telegraph transmissions while the rest of the universe has cell phones.
 
Robrob said:
Yeah, the emission window is pretty short. We could be spending a lot of time searching for the cosmic equivalent of telegraph transmissions while the rest of the universe has cell phones.
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I've always wondered if we could test the idea of SETI by sending a probe out, just into our solar system, and getting it to "find" earth? Seems to me that any undirected RF emissions from an intelligent species would be pretty muddy and unidentifiable.
 
ApolloGnomon said:
I've always wondered if we could test the idea of SETI by sending a probe out, just into our solar system, and getting it to "find" earth? Seems to me that any undirected RF emissions from an intelligent species would be pretty muddy and unidentifiable.
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In a sense, this has been done. Voyager 1 has been operating for about 34 years and is now about 10 ^ 10 kms (.001 light year) from the earth. The Deep Space Network has been communicating with it for those 34 years in the s-band.

http://en.wikipedia.org/wiki/Voyager_1

Both Voyagers are so far away from Earth that only the largest DSN antennas — 230 feet in diameter — can send commands to the spacecraft. To do that, they use a 20 kilowatt S-Band transmitter. That's about one-half to one-quarter of the power transmitted by an ordinary commercial AM or FM radio station on Earth.
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Source: http://www.spacetoday.org/SolSys/DeepSpaceNetwork/DeepSpaceNetwork.html
Note that a 230 foot antenna has a lot of gain (is very directional) so it takes much less transmitted power to communicate with Voyager than it would with a less directional antenna.

In an earlier discussion about the chances of success for SETI I posted this table:
Code: 
-------------+--------------+-----------+--------+--------+-----------+
Source       | Frequency    | Bandwidth | Tsys   | EIRP   | Detection |
             | Range        |    (Br)   |(Kelvin)|        | Range (R) |
-------------+--------------+-----------+--------+--------+-----------+
AM Radio     | 530-1605 kHz |  10   kHz | 68E6   | 100 KW |  0.007 AU |
-------------+--------------+-----------+--------+--------+-----------+
FM Radio     |  88-108  MHz | 150   kHz |  430   |   5 MW |    5.4 AU |
-------------+--------------+-----------+--------+--------+-----------+
UHF TV       | 470-806  MHz |   6   MHz |  50  ? |   5 MW |    2.5 AU |
Picture      |              |           |        |        |           |
-------------+--------------+-----------+--------+--------+-----------+
UHF TV       | 470-806  MHz |   0.1  Hz |  50  ? |   5 MW |    0.3 LY |
Carrier      |              |           |        |        |           |
-------------+--------------+-----------+--------+--------+-----------+
WSR-88D      |   2.8    GHz |  0.63 MHz |  40    |  32 GW |   0.01 LY |
Weather Radar|              |           |        |        |           |
-------------+--------------+-----------+--------+--------+-----------+
Arecibo      |   2.380  GHz |  0.1   Hz |  40    |  22 TW |    720 LY |
S-Band (CW)  |              |           |        |        |           |
-------------+--------------+-----------+--------+--------+-----------+
Arecibo      |   2.380  GHz |  0.1   Hz |  40    |   1 TW |    150 LY |
S-Band (CW)  |              |           |        |        |           |
-------------+--------------+-----------+--------+--------+-----------+
Arecibo      |   2.380  GHz |  0.1   Hz |  40    |   1 GW |      5 LY |
S-Band (CW)  |              |           |        |        |           |
-------------+--------------+-----------+--------+--------+-----------+
Pioneer 10   |   2.295  GHz |  1.0   Hz |  40    | 1.6 kW |    120 AU |
Carrier      |              |           |        |        |           |
-------------+--------------+-----------+--------+--------+-----------
AU = astronomical unit (avg. distance of earth to sun), LY = light year

The purpose of this table is to provide an estimate of how far away a purpose built transmitter could be detected from Earth given assumptions about transmitter power and frequency range. Note that the transmitter power is given in EIRP (Equivalent isotropically radiated power) so that the actual transmitter power might be much less given the use of a high gain antenna.

Source: http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html

One thing that the table suggests is that the idea that some sentient civilization has been tuning in to old episodes of I love Lucy is probably wrong. Without a huge high gain antenna routine earth communication type transmissions just don't have enough power to be detected even by a receiver on the nearest star. But extraterrestrial civilizations might not routinely make broadcasts with huge high gain antennas and then if they happen to they would need to point them very precisely in Earth's direction for them to be detected on earth at significant distances.

My own take away from all this is that communication with a sentient civilization with radio band electromagnetic waves probably is limited to about 150 light years. Communication via optical lasers might have a longer range but then one needs to assume a sentient population with the technology and will to build a large laser and the inclination to point it at us for awhile. My sense of it was that the detection of optical lasers might be feasible at as far as 1000 light years. But the farther away you go some combination of more power and more directionality is required.
 
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davefoc said:
Side note: My spell checker says that styrofoam should be capitalized. Screw him. I'm not going to capitalize it. Power to the man. Rebellion is good. I think for my next act of civil disobedience I might spell rumour like the Brits do.
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Styrofoam is a registered trademark of the Dow Chemical Company.

Don't tell Geo.
 
davefoc said:
Side note: My spell checker says that styrofoam should be capitalized. Screw him. I'm not going to capitalize it. Power to the man. Rebellion is good. I think for my next act of civil disobedience I might spell rumour like the Brits do.
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1. And the Aussies, and the Kiwis, and the South Africans, and some Canadians.

2. Capitalise.

:p
 
Architect said:
1. And the Aussies, and the Kiwis, and the South Africans, and some Canadians.

2. Capitalise.

:p
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Hey! All Canadians! Well.... the ones in Canada. The ones in the U.K. might spell armour, colour, centre, valour, etc in the american style, but only to irritate. :)

A nice little NASA exoplanet site out of JPL in Pasadena, Calif. summariZes the current missions...

http://planetquest.jpl.nasa.gov/


ETA Canadians spell muskeg in the canadian style- unlike the UK musquaigh... LOL [Algonquian, "grassy bog"]
 
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