Since humans started looking up at the stars, it seems that our species has wondered about the possibility of alien civilizations. As science has advanced, as well as our ability to search the cosmos along with it, we have pursued the question with limitless zeal, but have yet to find an answer. Now, the search for alien civilizations has entered uncharted new territory. Last week, new research was published in the journal Astrobioloy that indicates that more planets than ever before believed could harbor advanced alien civilizations in the Milky Way alone.
The study was co-authored by Woodruff Sullivan and Adam Frank, and it investigated recent discoveries of “potentially habitable” exoplanets, looking into the odds of whether advanced alien civilizations could exist on them or could have existed in the past, reports the Huffington Post.
“What we showed was the ‘floor’ on the probability for a civilization to form on any randomly chosen planet. If we are the only civilization in cosmic history, then that what we calculated is the actual probability nature has set. But if the actual probability is higher than that floor, then civilizations have happened before.”
According to Adam Frank, the potential number of planets orbiting their respective stars within the so-called “Goldilocks zone” or even a habitable distance is mind-boggling. In fact, according to the researcher, even if the odds had one alien civilization existing for every 100 billion of those planets, we’re talking trillions of alien civilizations over the history of the universe.
“Even if you are pretty pessimistic and think that you’d have to search through 100 billion (habitable zone) planets before you found one where a civilization developed, then there have still been a trillion civilizations over cosmic history! When I think about that, my mind reels — even if there is just a one in a 100 billion chance of evolution creating exo-civilizations, the universe still has made so many of them that we are swamped by histories other than our own.”
Astronomer Frank Drake, who could be considered the modern father of the search for alien civilizations, created what came to be known as the “Drake equation” in 1961. The equation was used to calculate the estimated number of planets that could be home to advanced alien civilizations. Drake also founded SETI (or the “Search for Extraterrestrial Intelligence”).
Frank and Sullivan created an updated equation, which expanded upon the Drake equation. The Drake equation can be used to calculate the estimated number of alien civilizations in the Milky Way. Sullivan and Frank’s version goes beyond that number to estimate the number of advanced alien civilization that could have existed in our home galaxy for the entire history of the known universe.
The pair also significantly simplified the Drake equation. Instead of the complex beauty of the Drake equation, the duo’s equation is fairly straightforward: A = Nast * fbt.
When attempting to figure out the probability of alien civilizations, scientists consider a slew of variables.
- How quickly stars with planets that could harbor intelligent life form.
- How many of those stars that have planetary systems.
- Whether those planets have environments possibly capable of sustaining life.
- How many of those planets develop life.
- How many of those planets’ life is intelligent.
- How many of those life forms could create technology.
In their study, the Sullivan and Frank note that modern advances in the study of exoplanets has provided “strong constraints” on the terms in the Drake equation. Therefore, the pair made some changes to the equation that has been the basis of the estimation of alien civilizations in the universe for decades.
“We set a firm lower bound on the probability that one or more technological species have evolved anywhere and at any time in the history of the observable universe.”
The pair of scientists also addressed “the cosmic frequency of technological species,” otherwise known as advanced alien civilizations.
“The universe is more than 13 billion years old. That means that even if there have been 1,000 civilizations in our own galaxy, if they live only as long as we have been around — roughly 10,000 years — then all of them are likely already extinct. And others won’t evolve until we are long gone.”
When it comes to humans finding an advanced alien civilization, Sullivan says that such an alien civilization would likely need to meet one primary criteria.
“For us to have much chance in finding another ‘contemporary’ active technological civilization, on average they must last much longer than our present lifetime.”
The current senior astronomer of the SETI institute, Seth Shostak, weighed in on Frank and Sullivan’s new equation and their search for advanced alien civilizations.
“With so many stars and planets filling the cosmos, it boggles the mind to think that we’re the only clever life to have made an appearance Frank and Sullivan use new research indicating that roughly one in five stars is orbited by a planet that could nurture biology. After that, it’s just a matter of counting up the tally of stars in the visible universe, and saying that — with all the suitable real estate that’s out there, if we’re the only place with intelligent life, then we’ve really won the mother of all lotteries.”
Shostak further added that he believes that the odds that there is no alien life in the universe are “very, very small.” He also warned against being too optimistic or pessimistic about the new equation and what it could mean for the search for and potential discovery of advanced alien civilizations in the universe or even our own galaxy.
According to Shostak, when it comes to the search for alien civilizations, humanity could ultimately end up being the aliens if we discover what we are looking for.
Oddly enough, while humanity has been searching for alien civilizations seemingly forever and has long speculated about the existence of life on other planets, it was only very recently that science confirmed that other stars are orbited by planets in the same manner as Earth orbits around its sun. The first extrasolar world wasn’t confirmed until the early 1990’s, which means an ancient question pertaining to the possibility of alien civilizations was answered in just the last couple of decades.
What do you think? Do you think the new equation will help with the search for advanced alien civilizations? Do you think that the universe is teeming with life as the study suggests, or are alien civilizations the stuff of science fiction?
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