Glowing Blue Waves Explained
Sea of Stars
Photograph by Doug Perrine, Alamy
Pinpricks of light on the shore seem to mirror stars above in an undated picture taken on Vaadhoo Island in the Maldives.
The biological light, or bioluminescence, in the waves is the product of tiny marine life-forms called phytoplankton—and now scientists think they know how some of these sea beasts create their brilliant blue glow.
Various species of phytoplankton are known to bioluminesce, and their lights can be seen in oceans all around the world, said marine biologist and bioluminescence expert Woodland Hastings of Harvard University. (Also see “Glowing Sea Beasts: Photos Shed Light on Bioluminescence.”)
“I’ve been across the Atlantic and Pacific, and I’ve never seen a spot that wasn’t bioluminescent or a night that [bioluminescence] couldn’t be seen,” Hastings said.
The most common type of marine bioluminescence is generated by phytoplankton known as dinoflagellates. A recent study co-authored by Hastings has for the first time identified a special channel in the dinoflagellate cell membrane that responds to electrical signals—offering a potential mechanism for how the animals create their unique illumination.
—Ker Than
Could Space Travel Make Astronauts Go Blind?
Sad news for our space adventurers: A new study indicates that time spent in zero gravity may be bad for their vision.
When they orbit the Earth or travel far beyond it, astronauts have the privilege of seeing our whole planet in one glance, or the close-up face of the moon. But new evidence points to a worrisome downside to that opportunity: their time spent in zero-gravity may be permanently damaging their eyes. New Scientist reports that in a study MRI scans from 27 astronauts who had spent a total of 108 days in space, “four had bulging of the optic nerve, three had kinks in the nerve sheath, and six had flattening of the eyeball.” The findings affirm those of an earlier study of 300 astronauts that found vision damage reported by 29 percent of those who had completed short-term missions and 60 percent for those who had spent longer.
The researchers suspect that the changes in gravity are the culprit. “One potential mechanism is that blood which normally pools in the legs is shifted toward the skull, raising pressure,” Larry Kramer, the study’s lead author told New Scientist.
The problem could present a significant challenge for more-distant space travel in the future, such as manned missions to Mars. Unless techniques can be found to counter the damage, impaired vision may make it difficult for astronauts to navigate unknown terrain and monitor their spacecraft’s displays.
Image: NASA.
A Sliver of Saturn’s Moon Enceladus
NASA’s Cassini spacecraft snapped this picture of a dark Enceladus, the sixth-largest of Saturn’s moons and one of the most interesting to scientists because of the presence of water ice on its surface and geological activity. In the image, some of this icy geological action is visible at the moon’s southern end where plumes of water-ice spray up from the terrain. Cassini took the picture at a distance of 83,000 miles on February 20, 2012.
Strong Solar Flares Still Shooting Out from Active Sun
The sun is continuing its active streak this week, firing off another solar flare late Thursday (March 8) from the same region that produced this week’s strong solar storm. More
Iridescent Dinosaurs
Photo illustration courtesy Jason Brougham, University of Texas
According to a new study, Microraptors—four-winged, feathered dinosaurs that lived 125 million years ago—sported Earth’s earliest known iridescence, as pictured in this illustration.
Recent research suggests the pigeon-size Microraptor’s feathers glimmered black and blue in sunlight, like feathers of modern crows or grackles.
The findings are the earliest evidence of iridescence in any creature-bird or dinosaur, said study leader Julia Clarke, a paleontologist at the University of Texas at Austin.
Clarke and colleagues also suggest this iridescent coloring may have helped make Microraptor’s tail feathers even more eye-catching to mates.
Using an electron microscope, the researchers compared tiny, pigment-containing structures called melanosomes in a Microraptor fossil to melanosomes of living birds.
The team found that Microraptor’s melanosomes were narrow, elongated, and organized in a sheetlike orientation—features that produce an iridescent sheen on modern feathers.
“This study gives us an unprecedented glimpse at what this animal looked like when it was alive,” study team member Mark Norell, chair of the American Museum of Natural History’s Division of Paleontology, said in a statement.
(See “True-Color Dinosaur Revealed: First Full-Body Rendering.”)
The new findings are detailed in this week’s issue of the journalScience.
—Ker Than
How Do You Tell Time On Mars?
Synchronizing rovers on Mars with their drivers on Earth is a bit of a challenge
On the Image: Sunrise At Gale Crater The sun rises over Gale Crater on Mars, the future home of the newest Mars rover, Curiosity. Rover scientists will upload commands overnight — Mars time — so the rover can start its day bright and early. NASA/JPL
When NASA’s new Mars rover lands on the Red Planet this summer, it’s safe to assume it’ll be sometime in the morning or early afternoon at the Jet Propulsion Laboratory in California, home of the rover science and engineering teams. So that means it’ll be mid-afternoon on the East Coast, evening in Europe, and so on — pretty easy to figure out the time zones. But what time will it be on Mars? What time zone will Curiosity live in — and how can you even tell?
Timekeeping on Mars is a bit like telling time on Earth, because the planets are similar in lots of ways. But there are just enough differences to drive a person slightly crazy. To start with, the Martian day, or sol, is 39 minutes and 35 seconds longer than a day on Earth. This isn’t a lot, but it adds up quickly when you’re living on Mars time—as the Curiosity team will. And a Martian year lasts 668.59 sols, about 1.88 times an Earth year. Seasons last much longer and are much more extreme, thanks in part to Mars’ deeply eccentric orbit.
Saturn’s Icy Moon Dione Has Oxygen Atmosphere
Credit: NASA/JPL/Space Science Institute
A NASA spacecraft circling Saturn has discovered a wispy oxygen atmosphere on the ringed planet’s icy moon Dione, but you wouldn’t want to live there. For one thing, you wouldn’t be able to breathe — Dione’s atmosphere is 5 trillion times less dense than the air at Earth’s surface, scientists say. [Full Story]
NASA scientist may have to turn down free space trip
The NASA employee won a trip on XCOR’s two-person Lynx space plane.
In the Image: PRIVATE LAUNCH: XCOR Aerospace’s Lynx spacecraft is shown launching into space with a science payload on its dorsal side in this artist’s illustration. (Image: XCOR)
There Are Way More Blood Types Than You Think
In the image: Bryan Ballif, University of Vermont Bryan Ballif, a University of Vermont biologist, in front of his mass spectrometer. Joshua Brown, University of Vermont, 2012
Researchers at the University of Vermont have discovered two new proteins on red blood cells that confirm the testable existence of two new blood types. It’s an important discovery, one that’ll greatly reduce the risk of incompatible blood transfusions among tens of thousands of people. But what we were more struck by in this press release was the fact that these two new blood types—named Junior and Langereis—bring the total number of recognized blood types up to 32. 32!
Turns out there’s much more than just A, B, AB, and O: there are now 28 other, rarer types, often named after the person in whom they were discovered. These rarer types are identified by the presence of a particular group of antigens (substances that tell your immune system to send out antibodies), and many, like the Kell and MNS blood types, can actually be concurrent with more common blood types like A or O.
But the discovery of new blood types is pretty rare; the last new one was discovered more than a decade ago. So it’s big news that two were discovered at the same time. The Junior and Langereis groups are particularly prevalent in East Asia, especially Japan. Says University of Vermont biologist Bryan Ballif: “More than 50,000 Japanese are thought to be Junior negative and may encounter blood transfusion problems or mother-fetus incompatibility.”
The study appears in the February issue of Nature Genetics.
In a New Vein
New Amphibians Without Arms or Legs Discovered
Photograph courtesy S.D. Biju
The embryo of a newly discovered caecilian species, Chikila fulleri, is revealed in microscopic detail inside its translucent egg.
Also visible is the embryo’s white yolk supply, which provides the legless amphibian enough nourishment to emerge from its egg as a miniature adult (most amphibians go through a tadpole-like, swimming stage in their early development).
Some young caecilians are known to feast on their mother’s skin after hatching. Such behavior has yet to be observed in the newfound Indian species, however.
ScienceShot: A Brain Wave Worth a Thousand Words
If it wasn’t enough that scientists could read your memories, they can now listen in on them, too. In a new study, neuroscientists connected a network of electrodes to the hearing centers of 15 patients’ brains (image above) and recorded the brain activity while they listened to words like “jazz” or “Waldo.” They saw that each word generated its own unique pattern in the brain. So they developed two different computer programs that could reconstruct the words a patient heard just by analyzing his or her brain activity. Reconstructions from the better of the two programs (the third sound in the audio; the first sound is the word the subjects heard, and the second is the other computer program’s reconstruction) were good enough that the researchers could accurately decipher the mystery word 80% to 90% percent of the time. Because there’s evidence that the words we hear and the words we recall or imagine trigger similar brain processes, the study, published online today in PLoS Biology, suggests scientists may one day be able to tune in to the words you’re thinking—a potential boon for patients who are unable to speak due to Lou Gehrig’s disease or other conditions.
See more ScienceShots.
It’s Official: Physics Is Hard
Students and researchers alike have long understood that physics is challenging. But only now have scientists managed to prove it. It turns out that one of the most common goals in physics—finding an equation that describes how a system changes over time—is defined as “hard” by computer theory.
That’s bad news for physics students who hope that a machine can solve all their homework problems, but at least their future jobs in the field are safe from automation. Physicists are often interested in mathematically describing how a system behaves: for instance, a formula tracks the motions of the planets and their moons in their complicated dance around the sun. Researchers work out these equations by measuring the objects at various points in time and then developing a formula that links all of those points together, such as filling in a video from a set of snapshots. With each new variable, however, it becomes tougher to find the right equation.
Computers can speed things up by sifting through potential solutions at breakneck speed, but even the world’s top supercomputers meet their match with a certain class of problems, known as “hard” problems. These problems take exponentially more time to solve with every additional variable that is thrown into the mix—an extra planet’s motion, for instance. Sometimes, hard problems can be made easier through clever mathematical maneuvering, but quantum physicist Toby Cubitt of the Complutense University of Madrid and colleagues have stamped out that hope for physics equations that describe a system through time.
Mathematicians recognize a set of truly hard problems that can’t be simplified, Cubitt explains. They also know that these problems are all variations of one another. By showing that the challenge of turning physics data into equations is actually one of those problems in disguise, the team showed this task is also truly hard. As a result, any general algorithm that turns a data set into a formula that describes the system over time can’t be simplified so that it can run on a computer, the team reports in an upcoming issue of Physical Review Letters.
The physics equations are in good company, according to computer scientist Stephen Cook of the University of Toronto in Canada, who was not involved in the work. “Literally thousands of problems” fall into this category of truly hard problems, he says. There’s still a shred of hope that physicists will find a way to turn these supposedly unsimplifiable problems into computer-solvable forms. If such an easier route were to turn up, profound knock-on effects would ripple through mathematics because it would mean all the other hard problems could be simplified as well.
The Clay Mathematics Institute in Cambridge, Massachusetts, offers a $1 million prize to anyone who discovers such a universal problem-tenderizer. Mathematicians, however, strongly suspect that it can’t be done (although the Clay Institute will also pay you $1 million for proving that suspicion true). In that case, “there is no smarter way” for computers to work out these physics equations “than brute-force checking” of each possible equation, Cubitt says. Still, he muses, if computers find these equations so difficult to figure out, why have physicists been able to calculate so many of them?
Physicist Heinz-Peter Breuer of the University of Freiburg in Germany suggests it’s because physicists give their brains—and their computers—a head start. They set the stage with the laws of physics that have already been developed by the likes of Newton, Maxwell, and Einstein, and this gives the outline of the equation, he says. The experimental data only have to fill in the details. Physics may be tough for computers, but real scientists get around it by standing on the shoulders of giants.
There really could be a giant planet hidden far beyond Pluto
Pluto is about forty times the distance from the Sun as Earth. But the Solar System is over 50000 times that length across, meaning it could be hiding some huge secrets. That’s now looking like a small but real possibility. More »
Advertisments for scanning electron microscopes take you into the world of nano-monsters
Biological flying machine? Terrifying monster of the deep? Nope - this is just a scanning electron microscopy image of a Lamnacarus ornatus, or common mite.
Industrial microscopy company FEI sells a variety of imaging rigs, including the one that produced this image. To show what their SEM machines can do, FEI created an incredible image gallery of shots taken with their equipment. Here is just a tiny subset of what you can see if you visit their site.
Click to embiggen! See more at the FEI image site, which is organized both by subject matter and by type of imaging device.
In the image:
1. A worm found in hydrothermal vents - its mouth can turn inside-out.
2. Here is the same worm with its mouth tucked back inside. Very Alien-esque.
3. Gah! What is that? Oh, only hibiscus pollen
4. Here are the mouthparts of a caterpillar, showing the sensory organs.
5. FEI says this is an “image of sperm tails tangled up in a seminiferous tubule.” The sperm mature inside this tubule before thrusting into the world.
6. This is a coccolithophorid, or tiny marine organism. Yes, it looks completely amazing.
