They call it the $100 million question: are we alone in the universe?
The question so captured the imagination of billionaire Yuri Milner that he invested $100 million into the search for alien signals. Milner joined eminent scientists like Professor Stephen Hawking, Lord Martin Rees and Frank Drake in one of the most thrilling searches of our time.
“Are humans alone in the universe, or is there intelligent life out there somewhere?”
New research published in Astrobiology takes us one step closer to an answer. Scientists now claim that it is possible to assign a probability to the question of whether any other advanced technological civilizations have ever existed, according to Science Daily.
The researchers have revised the famous Drake equation, which provides a way to make estimates about the likelihood of alien civilizations developing.
The Drake equation was developed by astrophysicist Frank Drake in 1961. Drake wished to use the equation to estimate the number of advanced civilizations likely to exist in the Milky Way galaxy. Variables in Drake’s 8-variable equation included the rate of formation of stars in the galaxy, and the number of planets, per solar system, with an environment suitable for life.
Scientists had always been able to make confident predictions about some of the variables in the Drake equation. However, when it came to variables such as L — the probably longevity of other advanced civilizations — scientists could only really guess.
Now, in 2016, researchers have managed to collapse the 8 variable Drake equation into a much more manageable 3 variable equation, according to Eureka Report. Importantly, Adam Frank and Woodruff Sullivan, who offer their revised equation is a new paper, have eliminated the troublesome L variable.
Frank and Sullivan’s formulation encourages the positing of a slightly different question: What is the number of advanced civilizations likely to have developed over the history of the observable universe?
Physics professor Adam Frank, one of the co-authors of the paper, put it this way: “The question of whether advanced civilizations exist elsewhere in the universe has always been vexed with three large uncertainties in the Drake equation.”
Frank said that only some critical information was known. “We’ve known for a long time approximately how many stars exist. We didn’t know how many of those stars had planets that could potentially harbor life, how often life might evolve and lead to intelligent beings, and how long any civilizations might last before becoming extinct.”
A report by Inverse claims that the Drake equation simply got “older and wrong” and had to be revised.
“But equations get older and equations get wrong. The Drake Equation, which takes into account various factors like the rate of star formation, the fraction of stars that could form planetary systems, the number habitable planets in those systems, and so on, is now 55 years old. It doesn’t reflect the new information SETI researchers have collected since the 1960s.”
Planetary searches by satellites like NASA’s Kepler have shown that roughly one-fifth of stars have planets that are in the “habitable” zone. That is, roughly one-fifth of stars could potentially support life as we know it.
The new Sullivan and Frank paper calculates that the odds of advanced life evolving on a habitable planet would have to be “astonishingly low” in order for human kind to be the universe’s first advanced civilization.
Frank and Sullivan provided an exact figure: humans are likely to be alone in the universe only if the odds of a civilization developing on a habitable planet are less than about one in 10 billion trillion.
This has been dubbed a huge blow in favor of alien life “optimists” — those who believe aliens have existed, do exist and/or will exist.
“[O]ther intelligent, technology producing species very likely have evolved before us.”
[Image via Ksanawo/Shutterstock]