Megawatt-Class Lasers from Earth Could Attract Alien Astronomers, Says New Study
A new study , published in the Astrophysical Journal , suggests that if a 1- to 2-megawatt (MW) laser were focused through a 30- to 45-m telescope and aimed out into space, the combination would produce a beam of infrared radiation strong enough to stand out from the Sun’s energy and attract attention from as far as 20,000 light-years away. Such a signal could be detectable by extraterrestrial astronomers performing a cursory survey of our section of our Milky Way Galaxy — especially if those astronomers live in nearby planetary systems, such as around Proxima Centauri and TRAPPIST-1.
“If we were to successfully close a handshake and start to communicate, we could flash a message, at a data rate of about a few hundred bits per second, which would get there in just a few years,” said lead author James Clark , a graduate student in the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology (MIT).
“The notion of such an alien-attracting beacon may seem far-fetched, but the feat can be realized with a combination of technologies that exist now and that could be developed in the near term (MW-class lasers, telescopes tens of meters in size).”
Clark and MIT’s Dr. Kerri Cahoy analyzed combinations of lasers and telescopes of various wattage and size, and found that a 2-MW laser, pointed through a 30-m telescope, could produce a signal strong enough to be easily detectable by alien astronomers on Proxima b , a Earth-mass exoplanet that orbits our closest star, 4.23 light-years away.
Similarly, a 1-MW laser, directed through a 45-m telescope, would generate a clear signal in any survey conducted by astronomers within the TRAPPIST-1 planetary system , a system of seven temperate terrestrial planets located 38.8 light-years from Earth.
Either setup could produce a generally detectable signal from up to 20,000 light-years away.
Both scenarios would require laser and telescope technology that has either already been developed, or is within practical reach.
Could E.T. be phoning?
Should we be?
There is a tremendous amount of space out there. Plenty of room for E.T. to evolve. Trouble is, there is so much space that the universe could be full of E.T. life and none of us would have a single clue of each other's existence.
The observable universe is ~90 billion light years in diameter. Image a sphere of that size (if possible). How many E.T.s could exist in such an expanse with no chance of ever seeing each other? Then consider the size of the actual universe (beyond observable) which might be hundreds of times larger.
Funny thing, with an observable universe that has been expanding for 13.7+ billion years we might just be late comers. Countless E.T. species could have come and gone billions of years ago. They may have lived in a time where their galaxies were close enough to each other to communicate (or even travel to). The advanced technology from our perspective (our future) might seem trivial to ancient E.T.
The whole party may have taken place billions of years in the past and now the universe has grown too big to ever get together again.
They might exist but be out of reach forever.
I am sure that is true as well as those that are still evolving. But I am also pretty convinced that there are still far more that can see this and at least know they are not alone.
I wish we knew ... something. The lack of evidence is frustrating.
Extremely.
Depressing even.
But we've hardly started looking, though. So much space, so many frequencies, so few resources committed to the search.
True. And our ability to explore is expanding at an exponential pace.
If they haven't passed beyond the cosmic event horizon, then we might someday be able to detect them in ancient light from billions of light years away. If we figure out what to look for and how, that is. They may be long gone, but some of their signals might still be heading our way.
Certainly. But the party is over thought is another hypothesis for why we have not detected extraterrestrial life.