August 30, 2023: The fate of our universe, a new technique for keeping organs on ice for months and Idalia makes landfall. —Andrea Gawrylewski, Chief Newsletter Editor | | | The universe is constantly expanding—at an ever faster rate. Physicists are investigating three possible outcomes to this expansion: the big freeze (the universe will continue to calmly enlarge and cool off); the big rip (the universe will expand so rapidly that it will tear itself apart); or the big crunch (eventually the universe's expansion will reverse and contract in on itself). Whatever happens will be determined by the balance of dark matter, dark energy, and regular matter and energy in space.
How it works: What's causing the expansion in the first place? "Dark energy" (so-named because scientists still don't know what it is) permeates the empty part of the universe—the vacuum. Whatever "it" is, it exerts a repulsive force that pushes everything apart and tugs against gravity.
How fast is it happening? Multiple techniques measure the speed of expansion. One involves observing the early cosmos and extrapolating to present times, and the other makes direct observations of the nearby universe. But the two methods consistently yield different answers. This is called the Hubble Tension and suggests that there may be some kind of phenomenon in physics going on that we haven't quite figured out yet. | | | Researchers have successfully preserved rat kidneys for 100 days before thawing and transplanting them into other rats. Before rapidly cooling the organs, scientists flooded them with iron oxide nanoparticles and a cryoprotective solution. After 100 days (pretty remarkable), they thawed the organs with an alternating magnetic field which caused the nanoparticles to oscillate and warm the tissue.
Why this matters: Transplant times are measured in hours, and thousands of donated organs are discarded every year. Freezing organs is possible, but until now, thawing them damages the tissues and makes them unusable. The research team hopes to start testing their freeze/thaw technique on human organs within the next six months.
What the experts say: Ideally, for each organ recipient who does not know when the transplant might come, says Erik Finger, a transplant surgeon at the University of Minnesota, "you can say, 'What's in the freezer?' and pick out what's best for this particular patient today." | | | • The passage of more time between when a crime is committed and when it is punished leads judges to levy more severe penalties. | 4 min read | | | • Male rhesus macaques living on an island off Puerto Rico have more sex with males than females. The monkeys tend to form more well-developed social ties with other males with whom they have sex and also experience greater reproductive success. | 7 min read | | | • A group of 19 neuroscientists, philosophers and computer scientists have come up with a checklist of criteria that, if met, would indicate that an AI system has become conscious. | 5 min read | | | • Many of you sent me encouraging and insightful advice for how to cover bad news (especially about climate change) in this newsletter. Reporting on solutions was one suggestion. It reminded me that earlier this year one of the lead authors of the latest report from the International Panel on Climate Change, climate scientist Stephanie Roe, wrote for us, outlining the things we can do to cut greenhouse gas emissions right now. | 7 min read | | | • Thousands of scientists told Nature that they're leaving X (formerly known as Twitter). | Nature | | | • A profile of Avi Loeb, the controversial theoretical physicist and alien hunter (written by Scientific American editor Seth Fletcher). | The New York Times | | | • Naomi Klein follows her "doppelganger" (Naomi Wolf) down the conspiracy theory rabbit hole--and examines why millions of people have entered an alternative political reality. | The Guardian | | | Credit: NOAA/NESDIS/STAR GOES-East - Geocolor Composite | | | At 7:45 A.M. EDT on Wednesday, Hurricane Idalia made landfall near Keaton Beach in Florida's Big Bend as a strong Category 3 storm. It had previously reached Category 4 strength. Just look at that eye! | | | Expanding universes, mysterious dark energy, quantum entanglement. You can dive into these brain twisters and more in our latest collector's edition, called "Mind-Bending Physics." Find a hard copy on newsstands and some bookstores. | Thanks for reading Today in Science and for all the great suggestions and feedback. Keep it coming. And see you tomorrow! | —Andrea Gawrylewski, Chief Newsletter Editor | Correction: In last Friday's Today in Science, I incorrectly wrote that a star's color is determined by the thermonuclear fusion in its core. A few sharp-eyed readers alerted me of this error and they're right: a star's color is determined by the star's surface temperature. The figures that were cited for the coolest and hottest stars represent surface temperatures. | | | | Subscribe to this and all of our newsletters . | | | | Scientific American
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