It may sound like something out of “Chicken Little,” but at some point in the history of Saturn’s moon Iapetus, the sky was actually falling: Scientists reported this week that an entire 800-mile-long mountain range along the moon’s equator formed after it fell from space.
Iapetus doesn’t feature the telltale signs of volcanism and geologic activity that typically build mountains, which had made the existence of the bulging equatorial ridge a bit of a mystery. In a new study, researchers constructed 3-D maps of the mountain range using images captured by the Cassini spacecraft. By analyzing the shape of the triangular peaks, some up to 12 miles high, researchers concluded that the mountains were created from material that crashed onto the surface of Iapetus at some point in its history. Read More
Every day, thousands of cars and trucks rumble across bridges all over the U.S. Their drivers probably don’t give much thought to the fish swimming in the rivers, lakes or bays below. But the fish notice them: They can hear those noisy engines passing overhead, and according to a new study, they are having to shout to communicate over the din.
The effects of sonar and other human-made sounds on the communication of marine mammals such as whales and dolphins is well documented. But fish “talk” too – so far, researchers have identified about 800 different species of fish that use vocal signals. One of them is the blacktail shiner, which lives in parts of the Southeast, Midwest and in Texas. Dan Holt, a fisheries biologist at Auburn University in Alabama, wondered how the shiner responds to the loud traffic on bridges in the area.
“You don’t hear much about freshwater systems,” he says. “But I drive over three or four bridges just coming to work, and a lot of times, we’re out collecting data by bridges, and we hear that noise. This fish is exposed to a lot of different types of sounds — boat traffic, 18-wheelers, lots of bridge noise,” he says.
Scientists have increasingly realized that DNA is only part of what makes us us — perhaps equally important is how our genes’ activity is modified by a process called epigenetics. Recently this cutting-edge field has turned its attention to some very old DNA: Researchers today announced they have reconstructed methylation maps for our extinct relatives. The findings might explain certain differences in appearances between Neanderthals, Denisovans, and us, as well as the prevalence of disease.
Epigenetics is a branch of science that explores how the expression of our DNA can be influenced by external factors without the DNA itself changing. Research in the field has focused on DNA methylation. This is when a chemical compound called a methyl group attaches to DNA. This can regulate an individual’s genetic expression and even be passed down through generations. DNA methylation has been linked to disease and also to an individual’s appearance and behavior. This is the first time, however, that an archaic pattern of methylation has been reconstructed for early humans.
Exoplanets are fun and all, but those hot Jupiters and super Neptunes and such are kind of beside the point. Everyone knows the real search is for a planet like ours: rocky, smallish, and capable of hosting liquid water. And now scientists have found one, named Kepler-186f — an Earth-sized planet in its star’s habitable zone, the area where conditions aren’t too hot or too cold, but just right, for liquid water to be possible.
In the dark caves of Brazil, certain insects take sexual role-play to a whole new level. Female insects of the newly discovered genus Neotrogla have highly elaborate, spiky penises, which they insert into males’ vagina-like organ to reproduce.
Reversed sex roles have been identified in several other species, including male seahorses that undergo pregnancy. However, after studying the mating habits of Neotrogla, which represents four distinct species, researchers have determined that this is the first example of an animal with sex-reversed genitalia. Read More
It’s the stuff of 3rd-grade sex ed: sperm meets egg to make baby. But, surprisingly, scientists have actually been in the dark about one crucial step: how the two sex cells recognize each other amidst the fluid frenzy in the Fallopian tubes. Now researchers have announced that they’ve found the missing piece of this fertilization puzzle, and that the discovery could lead to individualized fertility treatments and hormone-free birth control.
Back in 2005, researchers found the first half of the the puzzle: a binding protein on the surface of sperm they called Izumol (after a Japanese marriage shrine). In the decade since then, scientists have been searching for Izumol’s counterpart on egg cells. Essentially, they’d found the plug but couldn’t locate the outlet.
Today researchers at Cambridge announced they’ve found that outlet: a receptor protein on the surface of the egg cell. They’ve found it on the eggs of pigs, opossums, mice and even humans.
It’s not just Williamsburg anymore — young people across the U.S. revere the beard. The facial hair craze is so popular that some men are paying as much as $7,000 for a beard transplant. However, if the trend continues, new research indicates why it will eventually reverse course: We find beards attractive only when they’re rare.
Those grim “over the hill” party favors are often deployed ironically by those who want to razz their friends or partners when they turn 30 or 40. But it may be more honest than we care to admit: A new study suggests humans’ cognitive speed peaks at age 24, and that it’s a steady downhill descent from there.
The study is limited by the fact that it only focused on video game players. But in analyzing a dataset of over 3,000 StarCraft 2 players between the ages of 16 and 44, researchers determined that in-game response times, or cognitive speed, peaked in players at 24 years of age. Read More
If you ask for directions in the small city of Oss in the Netherlands, a local may tell you to merge onto Highway N329 and take the first exit after the highway ceases glowing in the dark. No, you haven’t mistranslated the conversation. Dutch engineers are testing glow-in-the-dark road markings along a 500-meter stretch of N329 to see if glowing roads could someday replace streetlights.
The road markings are painted with a photo-luminescent powder that charges during the day and releases a greenish glow at night. Once the paint absorbs sunlight, it can glow for up to eight hours in the dark. The N329 now features a triple-striped pattern of glowing lines on each side of the highway. Read More
The bottom of the ocean is a largely unknown habitat — but now you can explore it from the comfort of your desk chair. The National Oceanic and Atmospheric Administration is live-streaming its three-week investigation of the Gulf of Mexico basin.
The ship Okeanos Explorer set out last Thursday to examine the location and contents of deep-sea habitats in the gulf. The team of scientists will conduct multiple dives using sea rovers, each capable of diving up to 6,000 meters, between now and the end of the month. This is the third leg of a three-part mission that started in February, and the data collected will provide a deeper level of knowledge about deep-ocean habitats than ever before. Read More