Over the past 7,000 years, as mighty civilizations rose and crumbled, another saga was playing out in the southern reaches of the world.
Just off the tip of the Antarctic Peninsula, a colony of gentoo penguins have long made tiny Ardley Island their home. At times, the colony rose to a mighty power, holding absolute dominion over the mile-long strip of land their forefathers swam, waddled and slid their way to some time around 5,700 B.C. But, nature deals harshly with hubris, and the penguins were laid low by not one, but three volcanic eruptions. Despite this, they return. Read More
Hey, your shoe is untied, and now scientists know why: the combination of foot stomping and leg swinging cause the laces to slip apart.
Yes, a child could have told you this, but there’s a reason scientists gave knots a closer look. Knots are everywhere, from stitches used in surgery to steel cables used in construction. Sailors are familiar with the clove hitch, bowline and cleat hitch. Even DNA is a snarled knot. With knots holding so much together, scientists thought it couldn’t hurt to clearly explain how they come undone. Read More
Going to the dentist may not be any fun today, but 13,000 years ago it would have been outright traumatic.
Before the age of painkillers, specialized tools and antibiotics, dentists used a variety of crude implements to ply their trade. A pair of incisors unearthed in Tuscany and recently analyzed by Italian researchers were hollowed out with sharpened rocks and stuffed with traces of bitumen and organic matter in what appears to be an early attempt at dental fillings. Read More
New research into the cephalopod genome is undermining our assumptions about evolution, and the role that DNA mutations play in updating a species’ physiology.
Researchers from the Marine Biological Laboratory in Woods Hole and Tel Aviv University have been studying how cephalopods — squids, octopuses, cuttlefish and nautiluses — edit their genome, and found that instead of relying on DNA mutations to adapt, they have the ability to make changes to their RNA, the genetic “messengers” that carry out the instructions written by DNA. This means that their fundamental genetic code remains largely the same from generation to generation, while changes occur at the level of the individual and don’t carry over to their offspring. Read More
On the list of exoplanets that could hold life, GJ 1132b wouldn’t come near making the cut. It’s a super-Earth whose upper atmosphere reaches 500 degrees Fahrenheit (260 degrees Celsius), meaning it only gets hotter as you move down. It’s barely a hair away from its star, completing a year in 1.6 Earth days.
Life is incredibly unlikely to survive there. Yet it may be one of the most important planets to come along in the search for life. So why’s that?
Well, it’s because it has an atmosphere.
GJ 1132b orbits an M-dwarf star. M-dwarfs are the most numerous stars known in the universe, but also some of the most turbulent. While they can last trillions of years, the first few billion years of their lives are spent expelling violent flare events.
Most of these M-dwarfs likely have planets, and a handful of known planets around these stars are in the habitable zone. These early flare events may sweep away those atmospheres, leaving what could have held liquid pools of water and an Earth-like atmosphere instead barren rocks.
And yet GJ 1132b has an atmosphere, according to research from the European Southern Observatory and the Max Planck Institute. The atmosphere appears to have abundant water vapor and methane with a similar thickness to that of Venus.
The research, published in The Astronomical Journal, suggests that planets around M-dwarf stars can retain atmospheres even after their turbulent early years. GJ 1132b, which is about 39 light years away, is considered an older planet. Thus, other M-dwarf planets might be able to retain their atmospheres, and planets in the habitable zone could have a way to actually host life rather than showing false promise.
Instruments like the James Webb Space Telescope may be able to glance at other M-dwarf planets to see if atmospheric retention is common or if 1132b is an outlier.
This article originally appeared in Astronomy.com.
TRAPPIST-1 opens up an exciting field for astronomers: a small, nearby, compact planetary system with seven Mars- to Earth-size worlds orbiting in days or weeks instead of months and years. What’s more, because their star is small and cool, all the planets may be habitable.
Maybe. Two new papers are out on TRAPPIST-1. One makes the chances for life even more ripe, while the other virtually strips away all chances of habitability. Read More
Researchers keep moving the goal posts on exercise. For a while, the trend was to show benefits of minimal exercise, perhaps as an olive branch to people too busy for a full workout. Lately, the trend is essentially to say effort matters; more exercise means better health. So which is right? Both are. But one overrides standard health guidelines.
Health institutions say people need about 150 minutes of moderate or 75 minutes of intense aerobic exercise each week. Moderate exercise might be brisk walking or active gardening, while intense exercise would include uphill cycling, sprints, tennis or squash. Read More
Ancient cannibalism may not have been as nutritious as previously thought, a new calorie-counting study finds, which means ancient cannibalism may have been more complex than often thought.
Nowadays cannibalism is associated with fictional serial killer Hannibal Lecter or by desperate souls as a last resort, such as the Donner Party or the survivors of the Andes flight disaster. But studies suggest cannibalism was practiced since prehistory, and even performed by extinct human lineages. For instance, at Neanderthal sites, researchers discovered unmistakable signs of butchery on human bones and found scraps of human remains in fossilized excrement. Read More
Millions of years ago, two primates engaged contentedly in a grooming ritual that is still commonplace today. Searching diligently for pesky ticks and other insects, they cast them to the ground without so much as an afterthought. But one of those ticks would endure after landing in a patch of sticky sap, becoming entombed in amber with blood still flowing from a wound on its back.
That’s the story that one researcher has pieced together from the body of a tick, gorged with blood, found trapped in amber in the Dominican Republic. The specimen is estimated to be anywhere from 15 to 45 million years old, which would make it the oldest preserved mammalian blood cell specimen. The discovery is all the more exciting given it contains a blood-cell-eating parasite commonly carried by ticks.
Earth’s been around for 4.5 billion years. And during that time, our star has gotten stronger with age. Yet the planet’s climate has stayed relatively stable.
That apparent contradiction recently prompted an investigation by Gavin Foster of the University of Southampton and his colleagues. The scientists suspected that as the sun’s power increased throughout Earth’s history, greenhouse gases must have declined.
To find out, they combed through more than 100 papers in search of an answer, compiling 1,500 estimates of carbon dioxide levels covering the last 420 million years. Their hunch about Earth’s history was right — greenhouse gases were much higher in the distant geological past — but it’s actually the future that’s most shocking.
Once the team had charted past CO2 levels, they plotted them alongside future predictions from the United Nations’ Intergovernmental Panel on Climate Change.
Their research, published Tuesday in Nature Communications, found that future carbon dioxide levels could eventually surpass anything in the geological record.
CO2 levels could hit a record 410 parts per million (ppm) by next month. That’s already the highest since humans existed. And atmospheric scientist Ralph Keeling, who’s in charge of tracking global CO2 levels at Scripps, recently told me he thinks we can count on hitting at least 450 ppm based on current activity.
But Foster’s study shows that if humanity sticks to business as usual, by next century, Earth will have more carbon dioxide than at any time in the last 50 million years. That’s roughly 700 to 900 ppm. If you visited the planet back then, a time period called the Eocene, you’d find a world with Arctic crocodiles and Alaskan palm trees.
Burn fossil fuels for another couple centuries and we’ll have atmospheric greenhouse gas levels not seen since 420 million years ago. Alarmingly, that’s taking Earth back to conditions that existed before land plants expanded enough to help create a nice, habitable planet for complex life to take hold.
It’s clear that life will have a hard time holding on at all if humanity pushes toward 5,000 ppm — a number that doesn’t factor in the sun’s increased power. Some scientists think we’d hit that level by burning all of the planet’s fossil fuels.
Of course, it’s unlikely that would happen. But this study does show the awesome power humanity now wields over its environment.
“There’s enough (fossil fuels) in the ground to take you to 1,000 ppm or more, but I don’t think that’s going to happen,” former NASA scientist James Hansen told me earlier this year. But even much lower CO2 levels aren’t considered safe.
“[A level of] 450 ppm would guarantee disaster,” Hansen said. “If you leave it in place long enough, it would guarantee that you do lose the coastal cities.”
Eric Betz is an associate editor of Discover. He’s on Twitter: @ericbetz.