Sad news for the spaceflight and SETI communities this week:
The death of billionaire technologist, philanthropist and private-spaceflight entrepreneur Paul Allen has hit hard for people from many different walks of life.
Allen passed away yesterday (Oct. 15) at the age of 65 from complications of non-Hodgkin lymphoma. Though he was best known for co-founding Microsoft, Allen was also an important figure in both the spaceflight and search for extraterrestrial intelligence (SETI) communities.
Most notably, Allen helped bankroll the SETI-focused Allen Telescope Array, a 42-dish network in Northern California, to the tune of $30 million dollars. He was also a major investor in Scaled Composites SpaceShipOne project whose legacy lives on in Virgin Galactic’s SpaceShipTwo program, and more recently he founded Stratolaunch Systems featuring a competing air-to-orbit launch system aiming to be operational by 2020.
Understandably, one thing that’s been mostly missing from the coverage so far is any speculation as to the fate of Paul Allen’s estate, estimated to be around $26 billion. I have no doubt that many of the organizations and charities Allen contributed to during his life are holding their breath while awaiting news of his final instructions, especially given that he never married or had children of his own. Will the SETI community be remembered in his will? Beyond the fact that he pledged to leave more than half of his accumulated fortune to charitable causes, we have very little nothing to go on, so only time will tell.
The simplest [message] would be a constant blast in all directions, but in a narrow range of frequencies, similar to early radio broadcasts – like a constant hum that would tell a listener it is artificial.
As Messerschmitt explains, broadcasting a continuous omni-directional signal would take colossal amounts of energy, which would be beyond the means of all but the most advanced alien civilizations. Therefore, he argues they would likely adopt a more practical method:
[I]nstead of a constant, narrow-band signal, he argues that ET would beep out short bursts in a wider range of frequencies – a broadband signal. This would take less energy to transmit, and could encode information.
And therein lies the problem, says Seth Shostak of the SETI Institute:
“The problem is that… encoding a message; means that any signal would vary quickly. To see such variations – to get the information in the signal – requires having enough sensitivity to see changes in a 10th or 100th of a millionth of a second. That requires antennas with collecting areas maybe 10,000 times larger than necessary to detect a steady signal.” No such antennas currently exist that would pick up the variations more than a few light years away.
Messerschmitt does provide one possible solution — to adapt SETI@Home to look for this type of burst broadband signal as well as the existing narrowband search, which sounds eminently sensible and doable, given how the rapid increase in CPU processing power has greatly improved the detection capabilities of the program.
“There is every reason to believe that Mars and other planets are inhabited. Why should the earth be the only planet supporting human life? It is not singular in any other respect.”
While he was wrong about Mars, the rest of the observation seems obvious to us today, but at the time he made it, we had barely even discovered that the Milky Way was just one of billions of similar galaxies in the Universe, and it would be another 70 years before we detected planets outside our own solar system.
He also had something to say about the possibility of communicating with aliens:
“But if intelligent creatures do exist, as we may assume they do elsewhere in the universe, I should not expect them to try to communicate with the Earth by wireless [radio]. Light rays, the direction of which can be controlled much more easily, would more probably be the first method attempted.”
Whether or not he is correct is still open to question. There is good reason to believe that aliens seeking to make contact across deep space would use radio waves, since at the right frequency they can cut through the clutter of cosmic dust and gases in the way, but it is interesting to note that there has recently been renewed interest in optical SETI and the possibility that an alien civilization might send out rapid pulses of light as their preferred means of communication.
Time will tell which method is correct–and least that’s the hope.
Astronomers in Australia recently detected a short, 5 millisecond, burst of radio waves from outer space, whose original is as yet, unclear. The most interesting part, from an scientific perspective, is that it was the first time astronomers have ever detected such a burst of radio waves in real time. Previously it’s always been after the fact, when the data from an observation run was analyzed.
However, in this case, there is substantial reason to believe that it’s not a response to SETI. According to data on this event gathered from 12 telescopes around the world the [fast radio burst] originated 5.5 billion light years from Earth. That means that the event which caused the signal happened about 900 million years before our solar system began to form.
Even if it were found to be a communication from an intelligent alien species, by the time we could get a signal back to the source our sun would have burned out.
Such discoveries are important, even if they do turn out to be the result of natural causes. They will help to eliminate false positives, and more important, they tell us more about the Universe we live in.
The Vox website has just published an excellent guide detailing the five steps we need to take if we’re going to find life on other planets:
Find a star
Find a planet
Find the right kind of planet
Analyze the planet’s atmosphere
Search for biosignatures
The good news is that we’re already on step three, the bad news is that steps four and five are the most difficult and will likely not be possible until the next generation of telescopes is online.
Of course, there is one additional step to take if we’re going to find intelligent life:
6. Search for signs of intelligent agency
If, when analyzing a planet’s atmosphere, we find traces of pollutants that have no natural explanation, it could be indicative of some form of intelligence living there. Alternatively, if the planet is close enough, our largest radio telescopes can be trained upon it on the off-chance we might overhear something interesting.
It’s a long shot, but since we’re not going anywhere soon, our only realistic hope of finding intelligent alien life in the near future is to continue searching from afar.