And now for some news from the world of science. Calculating the odds of intelligent life in the universe outside the sphere of our own Earth will be of most interest to SFR authors perhaps, but there are plot bunnies to be found in an item on growing tiny livers in the lab, too. And we may all benefit from a technology that promises the manufacture of a new type of transparent face mask. Read on for more details.
Odds of Sentient Life Better Than 3:2: Scientists have long known that primitive life arose on Earth almost as soon as conditions were stable enough for it some four billion years ago. But the time required for those simple lifeforms to evolve into sentient humans capable of our complex technological civilization required a very long period of time. Given all the factors that affected that journey from no life to sentient life to “advanced civilization,” what are the odds that other such life exists in the universe?
In a paper published this month in the Proceeding of the National Academy of Sciences, David Kipping, an assistant professor in Columbia's Department of Astronomy, uses a statistical technique called Bayesian inference to calculate those odds. Initially, the probabilities fall into four main categories: Life is common and often develops intelligence; life is rare but often develops intelligence; life is common but rarely develops intelligence; and, finally, life is rare and rarely develops intelligence.
Kipping then ran the scenarios against each other using data from the geological and biological record of Earth over and over again. This is the essence of the Bayesian inference method, “to weigh the models against each other,” according to Kipping. In the professor’s analysis, based on carbon-13-depleted zircon deposits, life emerged some 300 million years after formation of the Earth’s oceans, a blink of an eye in geologic time. Given similar conditions, the odds are very good that life would emerge in the same way on other planets.
Whether that life evolves into complex, differentiated and intelligent forms is more difficult to determine, however, given humanity’s late appearance on Earth’s stage. Kipping puts them at somewhere between 3:2 and 50:50. He remains optimistic, however. "The analysis can't provide certainties or guarantees, only statistical probabilities based on what happened here on Earth," Kipping said. "Yet encouragingly, the case for a universe teeming with life emerges as the favored bet. The search for intelligent life in worlds beyond Earth should be by no means discouraged."
Tiny Human Livers Transplanted into Rats: Okay, this one sounds like some kind of horror movie plot, but the experiment, performed successfully by scientists at the University of Pittsburgh, may have real benefits for the 40,000 Americans with liver disease, especially the 14,000 waiting for a liver transplant. The scientists converted skin cells donated by human volunteers to stem cells, which can be directed (through the use of hormones and other chemicals) to grow into any type of organ cell in the human body. In this case they were directed to grow into liver cells placed in a “scaffold” of rat tissue stripped of any rat cells, producing livers of a size that could be transplanted into five lab rats specially prepared to receive the tiny, fully functional human livers.
The livers did their jobs as human organs would for four days, using a functioning vascular and bile duct network. At the end of that time, the rats were euthanized and analyzed to determine the results. The organs had secreted urea and bile acids as they should have, though there were problems with blood flow and clotting at the graft sites.
Information for today’s post provided by:
“New study estimates the odds of life and intelligence emerging beyond our planet,” Science Daily, May 18, 2020 https://www.sciencedaily.com/releases/2020/05/200518162639.htm
“Tiny Human Livers Grown in The Lab Have Been Successfully Transplanted Into Rats,” by Peter Dockrill, Science Alert, msn.com https://www.msn.com/en-us/news/technology/tiny-human-livers-grown-in-the-lab-have-been-successfully-transplanted-into-rats/ar-BB14Xy00
“These Transparent Face Masks Might Make You Feel Normal Again,” by Courtney Linder, Popular Mechanics, June 10, 2020 https://www.popularmechanics.com/technology/design/a32823925/transparent-surgical-face-mask/