Astronomer calculates the odds of intelligent alien life emerging

A new study discovers the likelihood of extraterrestrial life in the universe.

Astronomer calculates the odds of intelligent alien life emerging
Image by IgorZh
  • A Columbia University astronomer calculates the odds of extraterrestrial life emerging.
  • The probability comes out in favor of aliens existing.
  • The search for life in space should be encouraged, concludes the scientist.

    • The sheer amount of space boggles the mind and makes one wonder, where are all the aliens? Surely, we aren't the only ones who made it out onto a cosmic rock alive. Of course, there might be numerous reasons we have not encountered aliens yet, from having poor technology to the aliens not desiring to be seen. A new study tries to take a statistical approach to the question, finding out the likelihood of complex extraterrestrial life emerging on other planets.

      For his new paper, David Kipping of Columbia University's Department of Astronomy, used the statistical technique called Bayesian inference to arrive at the conclusion that there's a greater chance than not that aliens should exist. The odds he calculated come out 3 to 2 for the aliens.

      Kipping based his analysis on the chronology of life's development within 300 million years of the Earth's oceans forming and the human evolution on the planet. He wondered how often life would emerge if we were to repeat Earth's history over and over.

      To figure this out, he used the method of Bayesian statistical inference, which works by updating the probability of a hypothesis when new evidence or information appears.

      "The technique is akin to betting odds," Kipping explained. "It encourages the repeated testing of new evidence against your position, in essence a positive feedback loop of refining your estimates of likelihood of an event."

      He came up with four possible answers, as reported in the press release:

      • life is common and often develops intelligence
      • life is rare but often develops intelligence
      • life is common and rarely develops intelligence
      • life is rare and rarely develops intelligence

      Do aliens exist? If they did, would we know?

      Using Bayesian math, Kipping pitted the models against each other. According to him, the "key result here is that when one compares the rare-life versus common-life scenarios, the common-life scenario is always at least nine times more likely than the rare one."

      This means that life is 9 times more likely to emerge than not. But would this life be intelligent? The answer here is more muddled and less optimistic. Still, Kipling concluded that under similar circumstances and conditions to Earth, the odds are 3:2 that some planet out there would sport complex, intelligent life like ours.

      Why are these odds lower? Kipping thinks that as humans appeared rather late in Earth's habitable history, it's clear their existence was not a foregone conclusion. "If we played Earth's history again, the emergence of intelligence is actually somewhat unlikely," he pointed out.

      He also maintains that while the likelihood of alien life may not be overwhelming, it's still quite strong, and "the case for a universe teeming with life emerges as the favored bet."

      Check out his paper published in PNAS, Proceeding of the National Academy of Sciences.

      This is what aliens would 'hear' if they flew by Earth

      A Mercury-bound spacecraft's noisy flyby of our home planet.

      Image source: sdecoret on Shutterstock/ESA/Big Think
      Surprising Science
      • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
      • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
      • Yes, in space no one can hear you scream, but this is still some chill stuff.

      First off, let's be clear what we mean by "hear" here. (Here, here!)

      Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

      All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.

      BepiColombo

      Image source: European Space Agency

      The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

      Into and out of Earth's shadow

      In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

      The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

      In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

      When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

      Magentosphere melody

      The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

      BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

      MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

      Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

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