SAN DIEGO — On some planets that orbit whirling stars, spring and autumn might be the best time to hit the beach, whereas summer offers a midyear respite from sweltering heat. These worlds’ orbits can take them over regions of their sun that radiate wildly different amounts of heat.
“Seasons on a planet like this must be really strange,” says Jonathon Ahlers, a graduate student at the University of Idaho in Moscow, who presented his findings June 15 at a meeting of the American Astronomical Society. Some stars spin so fast that they bulge in the middle. That bulge pushes the equator away from the blazing core, making it much cooler than the poles. A fraction of these stars also host planets that travel on cockeyed orbits, which take these worlds alternately over the poles and equator of their sun.
Ahlers developed computer simulations to see how the differences in solar energy combined with the tilted orbits might affect a planet’s seasons. The outcome depends on how the planet’s axis is tipped relative to its orbit. For a world whose north and south poles periodically face the star’s equator, “you get a cooler summer than normal and an extremely cold winter, but spring and autumn can be hotter than summer,” says Ahlers. “You get two distinct hottest times of the year.”
How that plays out depends on how the planet is built: an atmosphere or oceans could mitigate climate extremes. Ahlers has yet to work out those details. “It’s doing a lot,” he says, “but what, I don’t really know yet.”
No, that’s not the sun. It’s Jupiter, ablaze with infrared light in new images taken in preparation for the Juno spacecraft’s July 4 arrival at the king of the planets. This image shows how heat welling up from deep within the planet gets absorbed by gas in the atmosphere, which can tell researchers how stuff moves around beneath Jupiter’s thick blanket of clouds. Juno won’t look for infrared light, but it will (among other things) measure how much microwave radiation is being blocked by water lurking within Jupiter’s atmosphere.
The map is pieced together from multiple images obtained at the Very Large Telescope in Chile over the past several months. Ground-based images such as these will help researchers understand what Juno is peering at each time it swoops in close to Jupiter’s clouds over the next 20 months.
Normally harmless mouth bacteria can be a bad influence. When they pal around with tooth- and gum-attacking microbes, they can help those pathogens kick into high gear. This teamwork lets infections spread more easily — but also could offer a target for new treatments, scientists report online June 28 in mBio.
The way that bacteria interact with each other to cause disease is still poorly understood, says study coauthor Apollo Stacy, of the University of Texas at Austin. Lab work often focuses on individual bacteria species, but managing the communities of microbes found in living organisms is a more complex task. The new finding suggests that bacteria can change their metabolism in response to the presence or absence of other bacteria. A benign species of bacteria excretes oxygen, allowing the second species to switch to a more efficient aerobic means of energy production and helping it become a more robust pathogen. This is the first time a normally harmless mouth bacterium has been shown to change a pathogen’s metabolism to make the microbe more dangerous, says Vanessa Sperandio, a microbiologist at University of Texas Southwestern Medical Center in Dallas who wasn’t part of the study. Similar interactions have been shown between gut bacteria, she says, but “it’s a very new field of research and there are very few examples.”
Stacy and his collaborators examined the relationship between two species of bacteria that tend to grow in the same place in the mouth. One, Streptococcus gordonii, is found in healthy mouths and only occasionally causes disease. The other, Aggregatibacter actinomycetemcomitans, frequently causes aggressive tooth and gum infections.
The researchers knew from previous work that the pathogenic bacteria grew better with a coconspirator. To figure out why, Stacy says, “we asked, ‘What genes do they need to live when they’re by themselves?’” The team compared the solo-living genes to those active in the pathogen while growing alongside S. gordonii. The analysis revealed that the pathogenic bacteria switched their metabolism when S. gordonii was around.
When A. actinomycetemcomitans grew alone, they produced energy without using oxygen — a slow way to grow. But with S. gordonii nearby, the pathogenic bacteria took advantage of the oxygen released by their neighbors and increased their energy production. When tested in mice, that increased energy let the pathogen grow faster and survive better in a wound.
The findings are part of a growing body of research showing that bacteria can sense the presence of other bacteria and adjust their behavior accordingly. “This system has allowed us to begin to understand that microbes are really astute at evaluating this biochemistry, and in response, they have very specific behaviors,” says Marvin Whiteley, a microbiologist at the University of Texas at Austin who worked with Stacy.
Stacy plans to test the phenomenon in other bacteria pairs to see whether it holds up beyond these two species. Understanding the way bacteria interact with each other could let doctors target infections more efficiently, he says. For instance, if a bacterial infection isn’t responding to antibiotic treatment, targeting the sidekick bacteria might help take the primary pathogen down.
For women thinking about fertility treatments, there may be one less thing to worry about.
A long-term study shows that women who underwent in vitro fertilization are not significantly more likely to develop breast cancer than women in the general public or women who opted for other fertility treatments. The results are reported July 19 in JAMA.
The fertility treatment alters progesterone and estradiol levels in women trying to get pregnant. Yo-yoing hormones have been linked to an increase in a woman’s odds of developing breast cancer, but studies are divided on whether IVF itself actually ups cancer risk.
Alexandra van den Belt-Dusebout of the Netherlands Cancer Institute in Amsterdam and her colleagues tracked 19,158 women who underwent in vitro fertilization treatment between 1983 and 1995 and 5,950 women who underwent other fertility treatments between 1980 and 1995.
Following up two decades later, the team found that 948 of the women had developed breast cancer. But breast cancer rates didn’t differ much between groups: 163.5 per 100,000 women for those who had IVF compared to 167.2 women on other fertility treatments and 163.3 women in the general public.
It’s time for a final farewell to the comet lander Philae.
The European Space Agency announced that on July 27 it would shut off the equipment that the Rosetta spacecraft uses to listen in on communications from Philae. The lander, which touched down on comet 67P/Churyumov-Gerasimenko in November 2014, briefly transmitted data before entering a deep slumber.
Except for a brief awakening in June and July 2015, Philae has been silent ever since. Now, as the solar-powered Rosetta gets farther from the sun, scientists need to conserve power by shutting off nonessential equipment. So Rosetta will listen no more.
Rosetta will continue scientific operations around comet 67P for another two months before completing its mission, when it will join Philae, descending down onto the comet.
You’ve got to see it to be it. A heightened sense of red color vision arose in ancient reptiles before bright red skin, scales and feathers, a new study suggests. The finding bolsters evidence that dinosaurs probably saw red and perhaps displayed red color.
The new finding, published in the Aug. 17 Proceedings of the Royal Society B, rests on the discovery that birds and turtles share a gene used both for red vision and red coloration. More bird and turtle species use the gene, called CYP2J19, for vision than for coloration, however, suggesting that its first job was in sight. “We have this single gene that has two very different functions,” says evolutionary biologist Nicholas Mundy of the University of Cambridge. Mundy’s team wondered which function came first: the red vision or the ornamentation.
In evolution, what an animal can see is often linked with what others can display, says paleontologist Martin Sander of the University of Bonn in Germany, who did not work on the new study. “We’re always getting at color from these two sides,” he says, because the point of seeing a strong color is often reading visual signals.
Scientists already knew that birds use CYP2J19 for vision and color. In bird eyes, the gene contains instructions for making bright red oil droplets that filter red light. Other forms of red color vision evolved earlier in other animals, but this form allows birds to see more shades of red than humans can. Elsewhere in the body, the same gene can code for pigments that stain feathers red. Turtles are the only other land vertebrates with bright red oil droplets in their eyes. But scientists weren’t sure if the same gene was responsible, Mundy says.
His team searched for CYP2J19 in the DNA of three turtle species: the western painted turtle, Chinese soft-shell turtle and green sea turtle. All three have the gene. Both birds and turtles, the researchers conclude, inherited the gene from a shared ancestor that lived at least 250 million years ago. (Crocodiles and alligators, close relatives of birds and turtles, probably lost the gene sometime after splitting from this common ancestor, Mundy says.)
Next, the scientists turned their attention to the gene’s function. Mundy’s team studied western painted turtles, which have a striking red shell. As in red birds, CYP2J19 is active in the eyes and bodies of these turtles, the scientists found, suggesting that the gene is involved in both vision and coloration. Because most birds and turtles can see red, but only some have red feathers or scales, the researchers think the great-granddaddy of modern turtles and birds probably used the gene for vision, too. Whether that common ancestor was colored red is unclear.
That very old reptile would have passed CYP2J19 down to its descendants, including dinosaurs. Mounting evidence has pointed to dinosaurs as colorful, with good color vision. But the specifics of their coloration have been elusive. This study points to red as one color they could probably see, and perhaps display.
“If you would have asked me 10 years ago, ‘Will we ever know the color of dinosaurs?’” Sander says, “I would have said, ‘No way!’” But studies like this one are a new lens into dinosaur color. Seeing can mean displaying, and this study is solid evidence that dinosaurs saw red, Sander says. In the past, “we couldn’t really say that.”
These orderly patterns of dark blue dots indicate where individual chlorine atoms are missing from an otherwise regular grid of atoms. Scientists manipulated these vacancies to create a supersmall data storage device.
The locations of vacancies encode bits of information in the device, which Sander Otte of Delft University of Technology in the Netherlands and colleagues describe July 18 in Nature Nanotechnology. The team arranged and imaged the vacancies using a scanning tunneling microscope. The storage system, which can hold a kilobyte of data, must be cooled to a chilly −196° Celsius to work. To demonstrate the technique, the researchers transcribed an excerpt from a famous 1959 lecture by physicist Richard Feynman, “There’s Plenty of Room at the Bottom,” which predicted the importance of nanotechnology. In each block, paired rows represent letters. Blocks marked with an “X” were unusable. The encoded 159 words of text fill a region a ten-thousandth of a millimeter wide.
If scaled up, the researchers say, the technology could store the full contents of the U.S. Library of Congress in a cube a tenth of a millimeter on each side.
Activity of a gene that lowers levels of caffeine-degrading enzymes in the liver is associated with how much coffee people drink, researchers say August 25 in Scientific Reports. The more active the gene, called PDSS2, the less coffee people drank.
Researchers tracked the coffee-drinking habits of 1,207 people in remote Italian villages and 1,731 people from the Netherlands. The researchers looked for an association between sipping java and people’s genetic makeup. The Dutch quaffed, on average, more than five cups of filtered coffee per day; the Italians sipped about two cups of espresso. In the Italians, 21 genetic variants in DNA surrounding the PDSS2 gene were linked to coffee consumption, Nicola Pirastu, of the University of Edinburgh, and colleagues found. The strongest-acting variant changed espresso consumption by 1.09 cups per day. Only five of the variants found in the Italians seemed to alter coffee-drinking in Dutch people, and did so to a lesser extent.
Given the larger size of the cups, Dutch people consume about three times as much caffeine per cup as the Italians do. Other caffeine-processing genes, such as CYP1A2 (SN Online: 4/8/11), may control coffee consumption habits at higher caffeine doses, while PDSS2 limits low-level caffeine intake, the researchers speculate.
Plastic cling wrap with nano-sized pores could give “cool clothes” a new meaning.
The material lets heat escape, instead of trapping it like traditional fabrics, Stanford University materials scientist Yi Cui and colleagues report in the Sept. 2 Science. It could help people keep cool in hot weather, Cui says, and even save energy by reducing the use of air conditioning.
“It’s a very bold new idea,” says MIT physicist Svetlana Boriskina, who wrote an accompanying commentary. Demand for the new material could be far-reaching, she says. “Every person who wears clothes could be a potential user of this product.” Current cooling devices include wearable fans and wicking fabrics; both rely on evaporation to cool human skin. But skin also sheds heat in another way — as infrared radiation. Clothing holds this heat close to the body, Cui says. If infrared radiation could instead pass through fabric, he reasoned, people would feel a lot cooler.
But the fabric would have to be transparent only to infrared wavelengths. To visible light, it would need to be opaque. Otherwise, the clothing would be see-through.
Cui found just one material that satisfied both requirements: a commercially available plastic used in lithium-ion batteries. The material, called nanoporous polyethylene, or nanoPE, is a cling wrap‒like plastic that lets infrared radiation through. But unlike cling wrap, the material isn’t clear: It blocks visible light.
Tiny pores speckled throughout the fabric act as obstacles to visible light, Boriskina says. When blue light, for example, hits the pores, it scatters. So do other colors. The light “bounces around in different directions and scrambles together,” she says. To human eyes, the resulting color is white.
The pores scatter visible light because they’re both in the same size range: The diameters of the pores span 50 to 1,000 nanometers, and the wavelengths of visible light range from 400 to 700 nanometers. Infrared light emitted by the body has a much larger wavelength, 7,000 to 14,000 nanometers, so the plastic’s tiny pores can’t block it. To infrared light, the pores are barely bumps in the road, not barriers. The pores are kind of like small rocks at a beach, Boriskina says. They’ll interfere with the motion of small waves, but big waves will wash right over.
Cui and colleagues tested nanoPE by laying it on a hot plate warmed up to human skin temperature — 33.5° Celsius. NanoPE raised the “skin” temperature by just 0.8 degrees(to 34.3° C). “But when you put on cotton, my God, it rose to 37,” Cui says. “It’s hot!”
The researchers also tried to make nanoPE more wearable than plastic wrap. They coated it with a water-wicking chemical, punched holes in it to make it breathable, and layered it with cotton mesh. Now, the team is working on weaving the fabric to make it feel more like traditional textiles.
“Within five years, I hope someone will start wearing it,” Cui says. “And within 10 years, I hope most people will be wearing it.”
A new map of the galaxy, the most precise to date, reveals positions on the sky for over 1 billion stars both within and beyond the Milky Way.
This new galactic atlas, courtesy of the European Space Agency’s Gaia spacecraft, also provides distances to roughly 2 million of those stars, laying the groundwork for astronomers who want to piece together the formation, evolution and structure of the Milky Way.
“This is a major advance in mapping the heavens,” Anthony Brown, an astrophysicist at Leiden University in the Netherlands, said September 14 at a news briefing. “Out of the 1 billion stars, we estimate that over 400 million are new discoveries.” There are no major cosmic revelations yet; those will develop in the months and years to come as astronomers pore over the data. This catalog of stars is just a first peek at what’s to come from Gaia, which is spending five years gathering intel on a wide variety of celestial objects.
The final survey will eventually provide a 3-D map of over 1 billion stars. It will also chart positions of roughly 250,000 asteroids and comets within the solar system, 1 million galaxies, and 500,000 quasars — the blazing cores of galaxies lit up by gas swirling around supermassive black holes. Mission scientists also expect they will turn up over 10,000 undiscovered planets orbiting other stars.
“It’s a very democratic mission,” said project scientist Timo Prusti. “Anything that looks like a [point of light] gets caught up and observed.”
Gaia launched on December 19, 2013, and eventually settled into its home about 1.5 million kilometers from Earth on an orbit that follows our planet around the sun (SN Online: 12/19/13). Regular science observations started in July 2014. This first data release, described in a series of papers being published online starting September 14 in Astronomy & Astrophysics, contains data obtained through September 2015.
The spacecraft repeatedly scans the sky with two telescopes pointed in different directions. To make the 3-D map, Gaia measures each star’s parallax, a subtle apparent shift in the position of the star caused by the changing viewing angle as the spacecraft loops around the sun. By measuring the amount of parallax, and knowing the size of Gaia’s orbit, astronomers can triangulate precise distances to those stars. With distances in hand, astronomers can figure out how intrinsically bright those stars are, which in turn will help researchers understand how stars evolve. A detailed stellar map could also help chart the Milky Way’s distribution of dark matter, the elusive substance that is thought to make up the bulk of the mass in all galaxies and reveals itself only through gravitational interactions with stars and gas.
One controversy that astronomers are eager to resolve with Gaia is the distance to the Pleiades star cluster, one of the closest repositories of youthful stars. A previous Gaia-like mission, the Hipparcos satellite, came up with a distance of about 392 light-years. Estimates based on simulations of how stars evolve as well as observations from the Hubble Space Telescope and ground-based radio observatories pin the Pleiades at about 443 light-years away (SN Online: 4/28/14).
“Clusters give you a sense of the evolution of stars at different ages,” says Jo Bovy, an astrophysicist at the University of Toronto who is not involved with the Gaia mission. “The Pleiades is a nearby cluster that we can study well — it’s one of the cornerstones.” All of the stars in the Pleiades are roughly 100 million years old, and so provide a snapshot of a relatively young stellar age. Nailing down the distance reveals the intrinsic brightness of the stars, which is crucial to understanding how stars develop in their early years.
Gaia appears to be leaning toward the larger distance, Brown said, but there’s still too much uncertainty in the data to say anything definitive. “It’s too early to say how the controversy will be resolved. But Gaia will pin it down.”
The Pleiades distance debate, as well as a clearer picture of how the Milky Way is put together, will have to wait for future data releases from Gaia. The next release is planned for late 2017; the final catalog won’t be available until 2022.
“Those will be much more interesting,” Bovy says. “Then we can actually start using our modeling machinery and see how stars are distributed throughout the galaxy. We can test our understanding of dark matter and our understanding of how the Milky Way formed.”
