68900761
submission
sciencehabit writes:
Only a small number of worlds look anything like Earth: roughly the same size and at the right distance from their star for liquid water to be present. But are these Earth-like exoplanets really made from the same sort of stuff—a rocky surface, an iron core, and just a dash of water? A new study suggests that exoplanets, at least up to 1.6 times the mass of Earth, follow pretty much the same recipe as our home. Indeed, scientists have come up with the core ingredients to make such a world. So if we’re looking for life out there, we can probably ignore anything bigger than that.
68894009
submission
sciencehabit writes:
First there was the Sawzall, a reciprocating saw that is the go-to tool for tearing down walls and cutting up unwanted material. Now there’s the “Jawzall,” a tool invented by a Cornell University undergraduate and her colleagues to assess just how deadly different shark bites can be. Researchers have long known the puncture power of various shark teeth, but many sharks also shake their heads as they chow down on their prey, ripping its flesh. To learn more about such gnashing, the student mounted four to 10 teeth from a variety of sharks onto separate sawing blades. Then she and her colleagues videotaped how well the teeth sliced through a dead salmon after six back-and-forth cuts. After 12 back-and-forth cuts, teeth got through just 7% of the tissue cut on the first six cuts. Even though sharks grow new teeth every month, such rapid wear may limit how often they can eat.
68839013
submission
sciencehabit writes:
When predators get close, the bright, orange-lipped “disco clam” flashes them to scare them off. But it's not just the light that's important. Researchers have found that the clam has sulfur in its fleshy lips and tentacles and suspect that, like another clam species that drop tentacles laden with sulfuric acid to deter predators, the disco clam's sulfur also gets converted into a distasteful substance. The flashing may warn predators away, similar to the bright orange of a monarch butterfly warning birds of its toxic taste.
68410875
submission
sciencehabit writes:
Scientists have taken a closer look at a rare half-female, half-male northern cardinal spotted a few years ago in Rock Island, Illinois. It turns out being a split-sex “gynandromorph” isn't all fun and games. The cardinal didn’t appear to have a mate, and observers never heard it sing. On the other hand, it wasn’t “subjected to any unusual agonistic behaviors from other cardinals,” according to the paper.
68372273
submission
sciencehabit writes:
To win a mate, Lyssomanes viridis males must often do battle with one another, extending their colorful fangs, waving their forelegs in combative displays, and head-butting each other until one of them gives way. But males who fight every battle to the fullest end up exhausted or dead. So how do jumping spiders decide which other males they’re willing to fight? To find out, researchers designed their own computer-animated jumping spiders and had them confront live specimens in a lab. The animated spiders varied in body size as well as in fang and leg length; in each case, the scientists observed whether the live spiders would escalate a battle. Surprisingly, the spiders were just as willing to fight animations with long legs and fangs than those with less imposing weapons. But they consistently retreated from challenges made by animations that had significantly bigger bodies than their own. That suggests that the size difference between spiders—rather than body size alone—may be the best predictor of whether two males end up in combat.
68366753
submission
sciencehabit writes:
Researchers have unearthed a fossil fish so well preserved, it still has traces of eye tissues. What’s more, these fossil tissues reveal that the 300-million-year-old fish called Acanthodes bridgei, like its living relatives, possessed two types of photoreceptors called rods and cones—cells that make vision possible. This is the first time that mineralized rods and cones have been found conserved in a vertebrate fossil. The discovery of cones, which help the eye see colors, is suggestive of the presence of color vision in fish for at least 300 million years.
68334351
submission
sciencehabit writes:
Climate change will cost U.S. coastal areas twice what analysts had predicted, according to a new study. Researchers had estimated that preparing coastal cities, repairing property damages, and relocating inhabitants for future sea level rise could have a roughly $500 billion price tag by 2100. But storm surge from tropical cyclones can cause additional local rises in sea level rise; that figure hits about $1 trillion.
68334335
submission
sciencehabit writes:
A study published today indicates that the scientific peer review system does a reasonable job of predicting the eventual interest in most papers, but it may shoot an air ball when it comes to identifying really game-changing research. Papers that were accepted outright by one of the three elite journals tended to garner more citations than papers that were rejected and then published elsewhere. And papers that were rejected went on to receive fewer citations than papers that were approved by an editor. But there is a serious chink in the armor: All 14 of the most highly cited papers in the study were rejected by the three elite journals, and 12 of those were bounced before they could reach peer review. The finding suggests that unconventional research that falls outside the established lines of thought may be more prone to rejection from top journals.
68330579
submission
sciencehabit writes:
Compared to those of other primate, human bones are weak, with a relative lack of spongy bone that makes our skeletons lighter and increases our risk of fractures and osteoporosis. The the driving force behind the change might be modern human’s sedentary lifestyle, free of the bone-strengthening exercise of chasing down prey and spending hours foraging for food. A second study further supports that hypothesis by comparing the density of spongy bone in the hip joints of nonhuman primates, ancient hunter-gatherers, and ancient farmers. The hunter-gatherers’ hip joints were about as strong as those of the apes, whereas the ancient farmers’ hips showed a significant loss of spongy bone. The researchers conclude that a lack of rigorous exercise, rather than any evolutionary pressure toward lighter skeletons, is the reason for modern human’s weak bones.
68160443
submission
sciencehabit writes:
About 1% of the light that strikes plants is re-emitted as a faint, fluorescent glow—a measure of photosynthetic activity. Today, scientists released a map of this glow as measured by the Orbiting Carbon Observatory-2, a NASA satellite launched in July with the goal of mapping the net amount of carbon in the atmosphere. The map reveals that tropical rainforests near the equator are actively sucking up carbon, while the Corn Belt in the eastern United States, near the end of its growing season, is also a sink. Higher resolution fluorescence mapping could one day be used to help assess crop yields and how they respond to drought and heat in a changing climate.
68160349
submission
sciencehabit writes:
Each year, Science’s editors choose a singular scientific achievement as Breakthrough of the Year. Past winners have included the discovery of the Higgs boson, cancer immunotherapy, and the first quantum machine. This year’s winner captured the world’s attention and reminded us of the immense scope of human scientific accomplishment—as well as how far we have yet to go. Meet this year’s Breakthrough and check out our nine amazing runners-up!
68156945
submission
sciencehabit writes:
In the United States, almost no one can trace their ancestry back to just one place. And for many, the past may hold some surprises, according to a new study. Researchers have found that a significant percentage of African-Americans, European Americans, and Latinos carry ancestry from outside their self-identified ethnicity. The average African-American genome, for example, is nearly a quarter European, and almost 4% of European Americans carry African ancestry.
68156027
submission
sciencehabit writes:
Have you ever stared at a map on your phone, utterly confused, as your GPS cryptically directed you to “head east”? It turns out that the entorhinal region of the brain—an area best known for its role in memory formation—may be at least partly to blame for your poor sense of direction. According to a study published online today in Current Biology, this brain region may help humans decide which direction to go to reach a destination. In the study, participants explored a virtual, square room with four unique objects in each corner and different landscapes on each of the four walls. Once they were familiar with the environment, the volunteers had to navigate a series of paths from one corner to another while the researchers monitored their brain activity with functional magnetic resonance imaging. The entorhinal region has long been known to help people identify which direction they’re facing already, but to plan a route, navigators must also imagine the direction of their destination. The study showed that this brain region likely also has a role in decisions about which directions to face next to get where we want to go. And as the participants imagined their way through the virtual room, the researchers found that the strength of the signal from this region was directly related to navigational performance.
68152535
submission
sciencehabit writes:
There are places on comet 67P/Churyumov-Gerasimenko where cauliflowerlike textures appear in the dusty crust, like goose bumps under the skin. Scientists using the Rosetta spacecraft—which arrived at 67P in August and became the first mission to orbit and land on a comet—now think they may have discovered the source of these patterns on cliff faces and in deep pits: layer upon layer of rounded nodules, 1 to 3 meters across. These spherules, dubbed dinosaur eggs, could be the fundamental building blocks that clumped together to form the comet 4.5 billion years ago.
68078697
submission
sciencehabit writes:
It’s springtime on Titan, Saturn’s giant and frigid moon, and the action on its hydrocarbon seas seems to be heating up. Near the moon’s north pole, there is growing evidence for waves on three different seas, scientists reported here today at a meeting of the American Geophysical Union. Researchers are also coming up with the first estimates for the volume and composition of the seas. The bodies of water appear to be made mostly of methane, and not mostly ethane as previously thought. And they are deep: Ligeia Mare, the second biggest sea with an area larger than Lake Superior, could contain 55 times Earth’s oil reserves.
