The Search for Super-civilizations in the Cosmos

The WISE Telescope

In 1964, Russian scientist Nikolai Kardashev suggested that in the long history of the universe, which began billions of years before the origin of our Sun and Earth, really advanced civilizations might have developed.  Such civilizations might learn to control the total power of their stars -- and, ultimately, the total power of their galaxies. 

Now, Jason Wright and Roger Griffith, a pair of scientists at Penn State University, have actually searched for this last kind of super-civilization.  If such advanced beings have actually colonized and exploited the billions of stars within a galaxy, these civilizations could produce tremendous amounts of waste heat.  

Just like your car and your computer produce waste heat while they are operating, so the thought is that large-scale civilizations will generate an unnatural amount of heat, beyond the heat that all objects give off.

A recent satellite called the Widefield Infrared Survey Explorer (WISE) has been collecting information on sources of heat energy around the sky.  Wright and Griffith have looked at the output of 100,000 galaxies, to see if anyone of them might betray signs that the heat they produce is not natural, but comes from a super-civilization.

Although they did not find any obvious and definitive evidence, they did note some galaxies whose infrared energy was unusual in some ways.  These are worth investigating further. 

Of course no one really knows whether intelligent creatures can ever evolve to a level of technology where they take over an entire galaxy.  So finding one by this method is a long shot. (But I asked Geoff Marcy, the world's leading planet hunter, and he pointed out that just about all our searches for intelligence in the universe so far have been "long shots" -- no one can be sure today what method will pay off.  So Marcy feels we should explore as many different methods as possible.)

I also asked Jill Tarter, the U.S. leader of the search for extra-terrestrial intelligence using radio waves, and she also was excited about our adding more techniques to our SETI arsenal.  She told me she was adding the unusual galaxies from the WISE survey to the list of places where they would point radio telescopes, just in case there were any intelligent radio signals to be found.

Indeed, the SETI institute organized a Google hangout about this survey, and included Jill Tarter and Freeman Dyson, who first suggested ways that an advanced civilization might betray itself with infrared waves.  You can hang out and see what they said at: https://plus.google.com/events/cs8lq28m1ebd2bnukspml93njc8  

Third Closest Star to the Sun is Not A Star At All

The third closest star system has recently been found and it turns out to be a pair of faint "brown dwarfs" -- failed stars that just don't have what it takes to be a full-fledged sun. The new system -- known as Luhman 16, after its discoverer -- is 6.6 light years away. This means that light traveling from there to us would take a bit more than six and a half years to cross the distance between us. (The nearest star system is about 4.4 light years away, and the second nearest is 6 light years from us.)

I heard about this system from Dr. Gibor Basri, one of the discoverers of brown dwarfs, who gave a talk in the Silicon Valley Astronomy Lecture Series, which I have the privilege of organizing and moderating. Brown dwarfs were first named as part of her thesis by Jill Tarter, now the leading scientist searching for signs of extra-terrestrial intelligence, but then a graduate student getting her PhD at Berkeley. They are globes of hot gas that just don't have enough material to sustain the vast release of nuclear energy which powers ordinary stars.

It's the same in space as in Hollywood -- not everyone has what it takes to be a star. Just as many actors with ambitions to be in the movies wind up waiting on tables in Los Angeles, not every ball of hot material in space gets to be an on-going star. Some just glow briefly, especially with heat-rays (infra-red), but then slowly fade away. In fact, it was with the WISE infra-red telescope that astronomer Kevin Luhman discovered the brown dwarf system which now joins our list of intimate neighbors in space. (Its other name is WISE 1049-5319, which is a code that tells astronomers its location in the sky.)

In the picture with this article, you can see a later image of the system, taken with the giant Gemini telescope in Chile, that allowed astronomers to see that there were actually TWO brown dwarfs in the same star system, orbiting each other. We estimate they take about 25 years to go around. Interestingly, the Luhman 16 system is not only our third closest neighbor, but now appears to be the closest neighbor of our closest neighbor, the Alpha Centauri system. In other words, if you lived in the triple star system we call Alpha Centauri, and someone asked you, what's your closest neighbor in space, you would say Luhman 16. (Until recently, we thought WE were their closest neighbor, just like they were ours. But the brown dwarfs, which lie in the same rough direction as Alpha Centauri, but beyond them, now take our place as their closest neighbor.)

It's remarkable that something this close was just discovered. But that is a testament to how faint these failed stars really are. We are therefore able to find only the closer ones and many others that are further away remain undiscovered. The first brown dwarf was only found in 1995; today hundreds are known (thanks mostly to the WISE telescope.)

Dr. Basri's talk was videotaped and will eventually be up on our new YouTube Channel for the Silicon Valley Astronomy Lectures. You can go there now and see many other talks by noted astronomers: http://www.youtube.com/SVAstronomyLectures/