I cant understand the signals from a woman standing next to me in a bar !

stuart mackie, london,

There is zillions and zillions of intelligent life out there ...thats why we do not hear from them....

COLIN, PORTLAND, DORSET

Duh !!

COLIN, PORTLAND, DORSET

Stephen Jay Gould's conjecture: It is possible, perhaps likely or near-certain, that wherever life evolves, it evolves to a point where it has consumed ALL its life-supporting resources and then begins a process of self-destruction resulting in "Vivicide" - the death of ALL life - on that planet.

For an example of this priniciple in action, just... Do I have to complete this sentence? No, you are reading this in a newspaper, so you know what's going on around you already. Not too good, is it?

Remember this: We took millions of years to evolve to where we COULD send or detect communication with exoplanets, but it only took 150 years after discovering oil to USE IT ALL UP! It's less than 100 years since we gained the ability to send or receive such signals but we're just about to to hit the BIG global warming tipping point - and America's policies are NOT helping us. Why should any other planet have better "luck" than us? There is really NO compelling reason that they should, is there?

Tim, Winnipeg, Canada

Since SETI is only searching for radio frequencies, how likely is it that we are going to find ET tuned into Radio 1? Perhaps they have developed enough to listen to internet radio, still we might be able to hack an ancient interplanetary WIFI connection - oh silly me that's microwaves. I wonder if I can submit a propsal for reasearch funding into intergalactic smoke signals - that is if they haven't banned smoking of course.

Rich Smee, Cardiff, Cardiff

Looking at the Drake equation, it is easy to see that altering even a single parameter can have dramatic effects on the resulting figure. So the location of any life forms outside of our world can easily change the equation to a far more positive result, and that having been said, a case can be made for this from the information on this page:

http://www.xenotechresearch.com/marsgal2.htm

The claims that so many rare or odd events had to happen for life to exist on Earth are simply untrue- nature has, built within itself, the propensity to create organic compounds just from the laws of physics.

Most people seem to suffer from a strange sense of uniqueness or self-importance, but the truth is almost always completely different from our expectations. We are surely not unique; life must be very common through all of space, although in many cases it may be no more than bacteria or sea urchins.

Intelligence is the most important thing to find.

Charles Shults, Orlando, Florida

Todd, if you're implying that scientists do not "work" for a living then that's disgraceful. If you had any idea about the theoretical and practical skills needed to find an exo-planet, you wouldn't say such naive things. Also, such experiments aid research in other areas of cosmology.

You also seem to be uable to appreciate just how many planets there are out there. I advise first learning astrophysics, then elementary probability theory, and then get a pen and paper and do your own calculations, before you spout off anti-intellectualism on this website.

I wonder if anybody else is sick and tired of scientists being treated with scorn? We live in a society where armchair hypocrites are prepared to use technology to post their comments, but also one where spiritualist and mysticism books outsell science books by 3 to 1. It makes me furious.

Dave Jones, Liverpool, UK,

Why is it that, if signals containing encoded information were detected coming from outer space, the scientific community would jump to ascribe it to extraterrestrial intelligence; and yet when we see information clearly encoded in our DNA, it is deemed 'unscientific' to infer an intelligent designer? This double-standard is, to say the least, puzzling.

Stephen Morris, Shrewsbury, UK

If there is life "out there”, we will never be able to communicate with them in any meaningful manner because messages will take years to arrive, each way, and that's for the closest ones. Since most of the stars in our galaxy are thousands to tens of thousands of light years away, messages would take many life times to reach their targets.

In addition, the processes that make life on Earth possible are so very numerous, that even the vast numbers of possible planets in the Universe does not seem sufficient for the odds. It is highly likely we are the only attraction, with no supporting players. But who am I to spoil the party? Let those with the grant money scan the heavens anyway, just for the fun of it (sure beats working for a living).

Todd, New Egypt, New Jersey

If ET finds us let's hope we don't turn out to be like the US Plains Indians, and his friends the Europeans.

Ferdinand Bull, Lectoure, France

It seems far more likely that there are Aliens out there than that there are not. The time frame in which they might use radio as a means of communication however is likely to be tiny, relatively speaking, so SETI seems unlikely to succeed. We need to get out there ourselves and make some interstallar noise by terraforming Mars and sending near-light speed probes with (expensive) new engine technology to nearby stars. That would attract someone's attention, perhaps. Of course, that might be catastrophic for our survival...

Dave B, Manchester, UK

how can the universe be 100 billion light years across if the maximum velocity of anything is light speed, and the universe is estimated to be between 11.2 and 20 billion years old.

colin, alicante,

We could never disprove the idea that there is intelligent life elsewhere in the Universe. On the other hand, there is not a scrap of evidence that there is any such life. The logical thing is not to believe in extraterrestrial intelligent life, but to be prepared to be proved wrong.

Frank Upton, Solihull,

Using the anthropic principle, the answer is no. Should be interesting.

Ben, York,

Its maddening to think that the signal is arriving NOW as I write this; but it might take till 2030 to find it. We could find it tomorrow if we just knew the precise spot to look. It is a single point in the sky.

Sentinent, Rockford, Minn

4 light-years is approximately 40 million million kilometres (not miles, as stated). Looking forward to watching the programme!

Chris Miller, Naphill, Bucks