ET first contact 'within 20 years' sez senior SETI astronomer.

[shecky]

http://www.newscientist.com/news/news.jsp?id=ns99996189

If intelligent life exists elsewhere in our galaxy, advances in computer processing power and radio telescope technology will ensure we detect their transmissions within two decades. That is the bold prediction from a leading light at the Search for Extraterrestrial Intelligence Institute in Mountain View, California.

Seth Shostak, the SETI Institute's senior astronomer, based his prediction on accepted assumptions about the likelihood of alien civilisations existing, combined with projected increases in computing power.

[Number Six]

I'm skeptical of this. I bet that 20 years from now we still won't be sure if there is life (detectable by transmissions that is...of course there could be life like on Earth 500 years ago and the only way to know would be to go and check).

I'd like to turn this around and ask this question...how close would a planet with technology like ours have to be to Earth to detect life on Earth? Or, with this new technology the guy says we'll have in 20 years, how far would a planet then have to be away from Earth to detect us? I don't know the answer to those questions but I'd like to.

[Benguin]

Yes, or it could be tomorrow ... I'm not sure of any prediction to unknown discovery!

I suppose they are just playing a poker hand for next year's funding. Best of luck to them, I'm all in favour of their work.

[Hellbound]

Originally posted by Number Six
I'd like to turn this around and ask this question...how close would a planet with technology like ours have to be to Earth to detect life on Earth? Or, with this new technology the guy says we'll have in 20 years, how far would a planet then have to be away from Earth to detect us? I don't know the answer to those questions but I'd like to.

All depends. There are several factors involved:

1. Age of the radio signal. Radio waves travel at light-speed, so there is a limited detection radius from any source. There might be a radio-producing intellignet civilization 100 light years away, that started broadcasting 80 years ago. We won't know for 20 more years.

2. Strength of radio signal. Of course, a stronger signal can be easily detected from a greater distance. However, newer equipment and algorithms mean we can seperate signal from noise more effectively and extend the range at which we find weak signals. I'm pretty sure it's a fairly large distance, though. Not sure on this one.

3. Direction of signal. Most radio is broadcast unidirectionally, but it can be directionally aimed as well. In fact, a directional signal would be the best way to make contact. When searching, you can get a stronger, more easily detectable signal for the same power as opposed to broadcast; if you're communicating with a known planet, you simply ttrack that planet/system instead of broadcasting all over.

I'm sure there are other factors, as well, but these are the big ones. I'm heard estimates before that put our detection radius as something in the 100 to 200 light year range for signals similar to commercial TV or radio; I could be completely off on this estimate, though, as it is purely from memory.

[drkitten]

Originally posted by Huntsman


I'm sure there are other factors, as well, but these are the big ones. I'm heard estimates before that put our detection radius as something in the 100 to 200 light year range for signals similar to commercial TV or radio; I could be completely off on this estimate, though, as it is purely from memory.

Based on this number, I can get a back-of-the-envelope calculation to support his claim. Assume, first, that Moore's law (computers double in capacity every 18 months) continues to hold, and second, that an increase in computing power produces a corresponding increase in detection ability, due to our ability to find the signal in the noise. Twenty years gives us thirteen doublings of computing power, so computers will be about 8,000 times better than they are now and we'll have 8,000 times the detection radius. 8000 times the current detection radius of 100 light years is 800,000 light years, which is more than the size of the Milky Way. So a radio source anywhere in the Milky Way (of the appropriate age) would be detectable.

Of course, these are two highly dubious assumptions --- but it's hard to make any uncontroversial assumptions about future technology.

[Frostbite]

There has been this unexplained signal:

http://antwrp.gsfc.nasa.gov/apod/ap040307.html

A google search for "SETI signals" also pops up a couple interesting articles.