Astronomer calculates the odds of intelligent alien life emerging

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

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.

      Yug, age 7, and Alia, age 10, both entered Let Grow's "Independence Challenge" essay contest.

      Photos: Courtesy of Let Grow
      Sponsored by Charles Koch Foundation
      • The coronavirus pandemic may have a silver lining: It shows how insanely resourceful kids really are.
      • Let Grow, a non-profit promoting independence as a critical part of childhood, ran an "Independence Challenge" essay contest for kids. Here are a few of the amazing essays that came in.
      • Download Let Grow's free Independence Kit with ideas for kids.
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      The surprise reason sleep-deprivation kills lies in the gut

      New research establishes an unexpected connection.

      Reactive oxygen species (ROS) accumulate in the gut of sleep-deprived fruit flies, one (left), seven (center) and ten (right) days without sleep.

      Image source: Vaccaro et al, 2020/Harvard Medical School
      Surprising Science
      • A study provides further confirmation that a prolonged lack of sleep can result in early mortality.
      • Surprisingly, the direct cause seems to be a buildup of Reactive Oxygen Species in the gut produced by sleeplessness.
      • When the buildup is neutralized, a normal lifespan is restored.

      We don't have to tell you what it feels like when you don't get enough sleep. A night or two of that can be miserable; long-term sleeplessness is out-and-out debilitating. Though we know from personal experience that we need sleep — our cognitive, metabolic, cardiovascular, and immune functioning depend on it — a lack of it does more than just make you feel like you want to die. It can actually kill you, according to study of rats published in 1989. But why?

      A new study answers that question, and in an unexpected way. It appears that the sleeplessness/death connection has nothing to do with the brain or nervous system as many have assumed — it happens in your gut. Equally amazing, the study's authors were able to reverse the ill effects with antioxidants.

      The study, from researchers at Harvard Medical School (HMS), is published in the journal Cell.

      An unexpected culprit

      The new research examines the mechanisms at play in sleep-deprived fruit flies and in mice — long-term sleep-deprivation experiments with humans are considered ethically iffy.

      What the scientists found is that death from sleep deprivation is always preceded by a buildup of Reactive Oxygen Species (ROS) in the gut. These are not, as their name implies, living organisms. ROS are reactive molecules that are part of the immune system's response to invading microbes, and recent research suggests they're paradoxically key players in normal cell signal transduction and cell cycling as well. However, having an excess of ROS leads to oxidative stress, which is linked to "macromolecular damage and is implicated in various disease states such as atherosclerosis, diabetes, cancer, neurodegeneration, and aging." To prevent this, cellular defenses typically maintain a balance between ROS production and removal.

      "We took an unbiased approach and searched throughout the body for indicators of damage from sleep deprivation," says senior study author Dragana Rogulja, admitting, "We were surprised to find it was the gut that plays a key role in causing death." The accumulation occurred in both sleep-deprived fruit flies and mice.

      "Even more surprising," Rogulja recalls, "we found that premature death could be prevented. Each morning, we would all gather around to look at the flies, with disbelief to be honest. What we saw is that every time we could neutralize ROS in the gut, we could rescue the flies." Fruit flies given any of 11 antioxidant compounds — including melatonin, lipoic acid and NAD — that neutralize ROS buildups remained active and lived a normal length of time in spite of sleep deprivation. (The researchers note that these antioxidants did not extend the lifespans of non-sleep deprived control subjects.)

      fly with thought bubble that says "What? I'm awake!"

      Image source: Tomasz Klejdysz/Shutterstock/Big Think

      The experiments

      The study's tests were managed by co-first authors Alexandra Vaccaro and Yosef Kaplan Dor, both research fellows at HMS.

      You may wonder how you compel a fruit fly to sleep, or for that matter, how you keep one awake. The researchers ascertained that fruit flies doze off in response to being shaken, and thus were the control subjects induced to snooze in their individual, warmed tubes. Each subject occupied its own 29 °C (84F) tube.

      For their sleepless cohort, fruit flies were genetically manipulated to express a heat-sensitive protein in specific neurons. These neurons are known to suppress sleep, and did so — the fruit flies' activity levels, or lack thereof, were tracked using infrared beams.

      Starting at Day 10 of sleep deprivation, fruit flies began dying, with all of them dead by Day 20. Control flies lived up to 40 days.

      The scientists sought out markers that would indicate cell damage in their sleepless subjects. They saw no difference in brain tissue and elsewhere between the well-rested and sleep-deprived fruit flies, with the exception of one fruit fly.

      However, in the guts of sleep-deprived fruit flies was a massive accumulation of ROS, which peaked around Day 10. Says Vaccaro, "We found that sleep-deprived flies were dying at the same pace, every time, and when we looked at markers of cell damage and death, the one tissue that really stood out was the gut." She adds, "I remember when we did the first experiment, you could immediately tell under the microscope that there was a striking difference. That almost never happens in lab research."

      The experiments were repeated with mice who were gently kept awake for five days. Again, ROS built up over time in their small and large intestines but nowhere else.

      As noted above, the administering of antioxidants alleviated the effect of the ROS buildup. In addition, flies that were modified to overproduce gut antioxidant enzymes were found to be immune to the damaging effects of sleep deprivation.

      The research leaves some important questions unanswered. Says Kaplan Dor, "We still don't know why sleep loss causes ROS accumulation in the gut, and why this is lethal." He hypothesizes, "Sleep deprivation could directly affect the gut, but the trigger may also originate in the brain. Similarly, death could be due to damage in the gut or because high levels of ROS have systemic effects, or some combination of these."

      The HMS researchers are now investigating the chemical pathways by which sleep-deprivation triggers the ROS buildup, and the means by which the ROS wreak cell havoc.

      "We need to understand the biology of how sleep deprivation damages the body so that we can find ways to prevent this harm," says Rogulja.

      Referring to the value of this study to humans, she notes,"So many of us are chronically sleep deprived. Even if we know staying up late every night is bad, we still do it. We believe we've identified a central issue that, when eliminated, allows for survival without sleep, at least in fruit flies."

      Withdrawal symptoms from antidepressants can last over a year, new study finds

      We must rethink the "chemical imbalance" theory of mental health.

      Bottles of antidepressant pills named (L-R) Wellbutrin, Paxil, Fluoxetine and Lexapro are shown March 23, 2004 photographed in Miami, Florida.

      Photo Illustration by Joe Raedle/Getty Images
      Surprising Science
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