“Junk DNA” may be an essential part of a worm’s inheritance.
Parts of this not-so-disposable DNA serves as a “watermark” to authenticate a Caenorhabditis elegans roundworm’s own genes and distinguish them from foreign genes that need to be shut down, researchers report in the July 14 Cell.
Genes bearing the watermarks — called PATCs — are protected against being shut down. These genes also tend to be active in the germ line (eggs and sperm and the cells that give rise to them). Genes without authentication codes get turned off, especially in the germ line, the researchers discovered. That raises the possibility that other species, perhaps even humans, issue their own germline gene work permits. Researchers have known that C. elegans’ set of genetic instructions, its genome, is littered with PATCs (short for periodic An/Tn clusters), but didn’t know why. PATCs are short stretches of the DNA building blocks adenine or thymine separated by other building blocks, or bases; each run goes about 10 bases on average until the start of the next A or T cluster (for instance, TTTTTaatggAAAA etc.). About 10 percent of the worm’s genome is marked with the A or T clusters, says study coauthor Christian Frøkjær-Jensen, a geneticist at Stanford University.
While other animals don’t seem to have the regular patterns of A’s and T’s exactly like C. elegans does, “the general idea that species can mark segments of their genomes and protect them from silencing … could apply to other organisms,” says Andrew Spence, a geneticist at the University of Toronto who was not involved in the study.
In 2006, Stanford University geneticist Andrew Fire and colleagues pointed out that the A-T tattoos were often associated with genes that are active in the germ line. Those watermarks were found in filler DNA, called introns, sandwiched between the parts of a gene containing the information used to make protein. Introns are snipped out and thrown away before an RNA copy of a gene is read by protein-building machinery. Introns sometimes contain information about how to regulate genes. That seems to be what the PATCs are doing.
Fire and colleagues postulated that the PATCs helped C. elegans protect its own genes from being disabled by molecular defense mechanisms that halt the incursion of foreign DNA. (Fire won the 2006 Nobel Prize in physiology or medicine (SN: 10/7/06, p. 229) for the discovery of one such mechanism, a gene-silencing system called RNA interference or RNAi.) Alien DNA from viruses or selfish bits of genetic material known as transposons, or jumping genes, can wreak havoc on a genome, damaging genes that they hop into. It is important to stop the jumping genes in the germ line because DNA in those cells will be passed on to future generations.
To combat the jumpers, C. elegans and other organisms deploy an army of small interfering RNAs that shred RNA copies of foreign genes. Other small RNAs, known as piRNAs, direct cell machinery that stretches molecular hazard tape across DNA where transposons and other aliens settle. Such off-limits territory is called heterochromatin, and genes there are turned off. Sometimes, though, some important native genes that need to stay on get trapped behind the lines. PATCs may be the operating permits that let native genes in heterochromatin remain active. In 2006, Fire and colleagues had no data to back up their idea. The new study puts Fire’s hypothesis to the test. “Oh my gosh, did they test it. It is really a thorough and complete analysis,” says geneticist Susan Strome of the University of California, Santa Cruz.
In the new study, Fire, Frøkjær-Jensen and colleagues engineered a gene for a fluorescent jellyfish protein with an intron containing PATC watermarks. When the researchers inserted the PATC-containing gene in a heterochromatin region of the genome, the gene turned on and made the worm’s germline cells glow. But the same jellyfish gene without PATCs was turned off. Those results are evidence that PATCs protect genes against getting turned off. Exactly how that happens isn’t yet known.
Strome isn’t sure that other organisms need DNA certificates to allow their genes to turn on in rough neighborhoods. C. elegans worms have unusual chromosomes. Nearly two-thirds of each chromosome is heterochromatin wasteland. The PATC permits may be necessary only in such extreme cases, she says.
Fire says he’s not yet ready to declare that all junk DNA may be useful. “Certainly there is gold in what we see here,” he says, “but the question is whether it is all gold.”
Before the demise of Japan’s latest X-ray satellite, Hitomi, the probe might have put to rest speculation about radiation from dark matter in a cache of galaxies.
In 2014 astronomers reported that several galaxy clusters appeared to inexplicably produce X-ray photons with energies of about 3.5 kiloelectron volts. The researchers suggested that the radiation could be coming from the decay of sterile neutrinos — hypothetical particles that are one candidate for the elusive dark matter that is thought to bind galaxies and clusters together.
Before the Hitomi X-ray satellite (aka ASTRO-H) failed on March 26, it got a look at the Perseus galaxy cluster, a horde of galaxies about 232 million light-years away. The telescope saw no sign of the previously reported X-ray photons, scientists report in a paper online July 25 at arXiv.org. A similar search of the dwarf galaxy Draco last year with the XMM-Newton satellite also failed to turn up the mystery X-rays. The no-show photons make it less likely that sterile neutrinos are the dark matter particles that scientists have been looking for.
Hitomi spun itself to death less than six weeks after it launched, when a problem with its control system caused the spacecraft to rotate out of control. The Japanese space agency is considering building Hitomi 2.0 for a possible launch in 2020.
The moon is one tough satellite. With no atmosphere, it endures a barrage of incoming asteroids and comets that pit its surface with a constellation of craters. A new map (above) reveals 222 recent impact craters (in yellow), 33 percent more than simulations predicted. Scientists spotted the features by analyzing about 14,000 pairs of before-and-after images captured by the Lunar Reconnaissance Orbiter from 2009 to 2015. (Red dots note new craters whose impacts were observed from Earth.)
The craters — up to 43 meters in diameter — were probably formed by small meteoroids crashing into the crust. Using the image pairs, the researchers created ratio images, which highlight how the impacts alter the reflectance of the moon’s surface. That perspective illuminated the starburst debris patterns around the craters (below, left). The scientists also found about 47,000 “splotches,” faint marks several to tens of meters across (below right, before and after shown). Most result from secondary debris being jettisoned by impacts and spattering the surface, the researchers propose in the Oct. 13 Nature. Those splotches would “churn” the upper two centimeters of lunar soil in about 81,000 years, more than 100 times faster than previous predictions that didn’t include the smudges, researchers say. That revelation could improve interpretations of remote-sensing data and help engineers design equipment to better withstand the occasional speckling of soil, says study coauthor Mark Robinson, a planetary geologist at Arizona State University in Tempe. “All of the images we’re taking … and the discoveries we’re making are feeding forward into future human exploration of the moon,” he says.
Microcins MĪ-kro-sins n. Bacterial proteins that kill rival bacteria
Competition is cutthroat in the crowded world of the intestines, so bacteria have evolved ways to kill rivals for a survival advantage. One strain of bacteria, called Escherichia coli Nissle 1917, has tiny proteins called microcins that may help E. coli’s host fight pathogens that cause gut inflammation, researchers at the University of California, Irvine report online October 31 in Nature.
Microcins take action only when bacteria are starved for iron, which happens in an inflamed gut. The proteins go after bacteria, many of them pathogens, that make iron-scavenging proteins, the researchers found. E. coli Nissle’s microcins killed diarrhea-inducing bacteria called Salmonella enterica in the guts of infected mice. Microcins also helped Nissle outcompete a different, nasty strain of E. coli.
As science journalists look back on the top stories of the year, scientists push on, asking the next questions and chasing fresh data. What big discoveries might they deliver in 2017? Science News writers reveal what they are watching for — and hoping for — in the year ahead. Bruce Bower Behavioral Sciences “I look forward to seeing where the reproducibility debate goes,” says Bruce Bower, referring to recent reports that many findings in psychology (and other sciences) don’t hold up in repeat experiments (SN: 4/2/16, p. 8). Some psychology journals now publish multilab replication efforts that often challenge influential findings, such as the claim that willpower decreases the more you use it. Bower wonders whether the current hubbub over failed replications will prompt psychologists, as well as researchers in other disciplines, to experiment with new ways of doing science. “I would be lying if I said I was optimistic, but I’m ready to be proven wrong,” says Bower. He believes social and cognitive psychology rely far too heavily on significance testing and too many researchers don’t generate and test alternative explanations for statistically significant results. “It’s a general problem of not developing and integrating theories.” As for the types of stories he looks for, Bower says he chases anything that sheds light on what makes us human — what distinguishes us from other species and what unites us, both biologically and culturally.
Emily Conover Physics Emily Conover isn’t yet over the discovery of gravitational waves, which is “still the darling of the physics world,” she says. But in 2017 she’ll be focused on experiments seeking “weird stuff in physics.” Neutrino experiments will be searching for differences between matter and antimatter — “a big deal for how everything in the universe came to be,” she says. Researchers with the dark matter experiment ADMX plan to unveil results in their latest search for the light, electrically neutral and still hypothetical axions. “People are focusing on axions because WIMPs aren’t showing up.” And Fermilab’s Muon g-2 experiment will measure the magnetic properties of the muon, a particle like an electron but much more massive. “We could get something new anytime,” Conover says. While particle physicists wait for a big find to shake up the field, researchers studying quantum materials are making steady progress. In 2017, scientists will take that quantum prowess to space. When it arrives at the International Space Station, the Cold Atom Laboratory will offer a stable and isolated environment to study quantum systems known as Bose-Einstein condensates at temperatures as low as a tenth of a billionth of a degree above absolute zero.
Christopher Crockett Astronomy Space missions across our solar system will fill the news in 2017, says Christopher Crockett, with NASA’s Juno probe building a 3-D picture of the inside of Jupiter (SN: 6/26/16, p. 16) and the European Space Agency’s ExoMars orbiter looking for trace gases in the Red Planet’s atmosphere. Cassini’s mission at Saturn will be “the most fun,” says Crockett. “It is the end of the mission, so the engineers are getting braver with the spacecraft.” Planetary scientist Glen Stewart of the University of Colorado Boulder calls it “kamikaze” stuff. “They are taking the spacecraft to places it was never designed to go,” Crockett says. “They are going to start flying close to the rings. And early in 2017, they are going to use the gravity of Titan to slip between the rings and Saturn, and will eventually dive toward the planet.” The findings could fill in details of how the solar system formed and evolved.
August’s solar eclipse (SN: 8/20/16, p. 14) will be big news, Crockett says, and the Event Horizon Telescope (SN: 5/31/14, p. 16) could make headlines, too. The project has linked together telescopes around the world to build a virtual radio dish as wide as Earth that could take a picture of the supermassive black hole at the center of the galaxy. “What they are trying to do is phenomenally difficult,” Crockett says. “We’ll see if that actually works.”
Tina Hesman Saey Molecular Biology “Everybody is CRISPRing everything,” says Tina Hesman Saey, referring to the breakout gene editor that made headlines in 2015. There are efforts to modify chickens to produce hypoallergenic eggs and to create mushrooms that don’t brown. Pigs are being developed to grow organs for transplant into people. Researchers are using CRISPR/Cas9 (SN: 9/3/16, p. 22) as a tool to investigate which genetic variants may cause heart disease and cancer and to learn more about how genes turn on and off.
Still more exciting developments are on the way. Clinical trials in people using CRISPR have begun and more will start in 2017 (SN Online: 11/16/16). “If researchers can actually make headway on curing sickle cell disease or muscular dystrophy, which has shown promise in animals, that would be amazing,” Saey says. She is also anxious to see progress in making functioning gene drives, engineered DNA designed to propel itself through generations of organisms (SN: 12/12/15, p. 16). “What form will it take and would we dare use it? So much of my beat seems to be, ‘We can do these things, but should we do them?’ ”
Saey also believes that there will continue to be more avian flu outbreaks and other emerging diseases. “Bats will get blamed for a lot, even though it is probably not their fault,” she says.
Susan Milius Life Sciences After an exciting year in mosquito science, Susan Milius says she is “suffering through the reruns until we get to Season 2 of great mosquito research.” The basic biology of these diverse insects received quite a bit of attention in 2016 because it mattered for predicting how Zika virus would spread. In particular, Milius wonders how the conflicting results will sort out between U.S. labs that report that a common Culex mosquito can’t transmit Zika and labs in China, Brazil and Canada (work still ongoing) that suggest the species can (SN: 10/29/16, p. 13). “Is it differences in the mosquitoes? In the viruses? What’s going on?” In 2017, a long-debated pest-control test in Florida could release the first genetically modified mosquitoes to fly free-range in the United States. “We are at an interesting time in the application of biology,” Milius says.
But the best stories in organismal biology are the ones you don’t predict: “Given several billion years, all that mindless happenstance evolution has veered way into the improbable.” She points to 2016’s finding that melatonin makes midshipman fish sing (SN: 10/29/16, p. 4). And what’s been supposedly known for years — that spiders can’t hear airborne sounds from across the room (SN: 11/12/16, p. 9) — “can turn out to be just wonderfully wrong.”
Meghan Rosen General Assignment “The world will be keeping a close eye on Puerto Rico,” says Meghan Rosen, where some 2,700 pregnant women have been infected with Zika. As those women give birth, researchers will learn even more about the virus and related birth defects. In the meantime, “there are a handful of vaccines beginning to be tested in humans,” Rosen says (SN: 9/3/16, p. 17). Results of safety testing on a DNA vaccine developed by the National Institutes of Health are expected in 2017. If those data are encouraging, the vaccine could move to Phase II clinical testing. A different vaccine, which uses a purified inactivated form of Zika, also began testing late in 2016. Even with success, Rosen notes, it’s unlikely a vaccine will be widely available before 2018 or 2019. “It sounds like forever,” she says, “but researchers are really hustling along.”
Zika is a topic “I’ll want to follow for years to come,” Rosen says. But she also expects to cover lighter material in 2017 — her typical territory includes dinosaurs and robots. The new journal Science Robotics has launched, and Rosen looks forward to developments in one area in particular: soft robots. “These squishy machines eschew the clunky mechanical bits of old-school robots, instead relying on soft materials such as silicone rubber,” she says. Such robots could offer one way to safely integrate machines into people’s live.
Laura Sanders Neuroscience “Our ability to figure out what the brain is doing, and to really influence it, is going to be a promising area in the coming year,” says Laura Sanders. The Brain Initiative, which launched to both skepticism and excitement in 2013 (SN: 2/22/14, p. 16), “is rolling on and picking up steam.”
Sanders will be tracking developments in new technologies, including neural dust, those miniature ultrasonic devices that recently demonstrated their ability to detect nerve activity in rats (SN: 9/3/16, p. 10). She’s also interested in ultrasound’s potential to influence neural activity, along with other approaches that work from outside the skull and so don’t require brain surgery. In a dramatic example, researchers reported in 2016 that they had helped a patient recover from a minimally conscious state through low-intensity ultrasound stimulation of the thalamus. “It’ll be interesting to see where that goes,” Sanders says. Still, there’s a long way to go between basic brain science and treatments.
Sanders — who was born in the analog age but has children who will be digital natives — is curious to find out how iPads and other digital devices are affecting kids’ brains. “Deep down I’m worried about it because I think there are so many valuable aspects of face-to-face communication,” she says. “The art of conversation is so different from texting.”
Thomas Sumner Earth Sciences “In climate news,” says Thomas Sumner, “2017 is almost certainly going to be cooler than 2016.” El Niño boosted global temperatures, but it has now ended — making it unlikely that 2017 will be another record breaker (SN Online: 6/9/16). “The last time we had a big dropdown, people started saying ‘Global warming doesn’t exist anymore.’ ” Sumner wants to be clear about the science up front: “There is natural variability. We will continue seeing temperature increases in the long run.”
In a special issue in Science News planned for early 2017, Sumner will take readers on a geologic journey back to the dinosaurs’ last days. A recent drilling expedition into the Chicxulub crater (SN Online: 11/17/16) is taking a shot at the long-standing, sometimes heated debate over what killed the vast majority of plant and animal species on the planet 66 million years ago. Did massive volcanic eruptions bring down the dinosaurs? Or did their end come from the fallout of an asteroid that struck Earth’s surface near the Yucatán Peninsula, leaving a crater as wide as New Jersey is long. “It’s a dino mass-murder whodunit,” Sumner says. The drilling team will probably pin down the energy released by the collision and will study the resulting environmental consequences. New clues may offer an answer or spark a whole new round of questions.
It’s kind of daring to write a science book about something that — you must remind your readers — doesn’t exist. That’s James Gleick’s task in Time Travel, an engaging and entertaining look at science that will always remain fiction.
It’s lucidly written, a breeze to read and erudite in assessing a vast range of literary and popular media treatments of time travel as dream and desire. Gleick starts with, and often returns to, H.G. Wells’ The Time Machine, the book (and later films) that introduced the concept of time travel in its modern science fiction sense. Much of Gleick’s account focuses more on time than travel, though — examining the mystery of time’s direction (SN: 7/10/15, p. 15) and the philosophy of time (as in, what is it?). One whole chapter discusses time capsules, which are not exactly as exciting as a TARDIS. But Gleick always turns back to time travel, if only to remind that it is fiction, not physics: “Time travel is a fantasy of the modern era.”
Before the 19th century, “time travel” rarely occurred to anybody, because time didn’t change things much. Activities in ancient and medieval times differed little from life in the 1700s. But then new technologies — steam engines, electricity, telephones among them — infused 19th century thinkers with visions of even more technological progress, and a future worth traveling to. Mark Twain’s A Connecticut Yankee in King Arthur’s Court was all about “the contrast of modern technology with the agrarian life that came before,” Gleick writes.
His tour of the time travel fictional corpus includes mentions of Looney Tunes and Elmer Fudd, Mr. Peabody’s WABAC machine and Arnold Schwarzenegger’s Terminator. In addition to thorough analysis of Wells’ Time Traveller, there are extended discussions of Robert Heinlein’s “By His Bootstraps,” Isaac Asimov’s The End of Eternity, and “Blink,” one of the most famous 21st century episodes of Doctor Who. At times, tidbits injected from films, novels and poetry seem too much, almost like a dictionary of famous time travel quotations, many quite lengthy. Sometimes you’d like to hear more from Gleick and less from everyone else.
It’s also a bit disappointing that Gleick only briefly discusses actual science. There is a vast scientific literature on time travel, including many proposals for how to do it, that Gleick mostly ignores. He does cite a well-known paper by physicist Kip Thorne and colleagues and offers a brief account of logician Kurt Gödel’s earlier work on time loops (possibly permitted by Einstein’s general relativity). And Gleick discusses Stephen Hawking’s “chronology protection conjecture” to emphasize once again that time travel really can’t happen.
Those who remember the rich depth of Gleick’s groundbreaking book Chaos and his insightful biography of Richard Feynman will find much less science here. But there is plenty of science fiction. And as Gleick points out, “the rules of time travel have been written not by scientists but by storytellers.”
A puzzling neutrino shortfall seems to be due to faulty predictions, not a new particle.
In experiments at nuclear reactors, scientists have consistently found about 6 percent fewer antineutrinos, the antimatter form of neutrinos, than expected. That deficit could hint that the lightweight particles are morphing into undetectable new particles called sterile neutrinos (SN: 3/19/16, p. 14). But in a paper published online April 4 at arXiv.org, scientists with the Daya Bay experiment, located near a nuclear power plant in China, point to the calculations that underlie scientists’ predictions to explain the missing antineutrinos.
Inside nuclear reactors, multitudes of antineutrinos are born in radioactive decays of isotopes such as uranium-235 and plutonium-239. Scientists can predict how many antineutrinos each isotope should produce. If sterile neutrinos are the source of the disagreement, detectors should observe an antineutrino deficit from both isotopes. Instead, the researchers found that plutonium-239 agreed with predictions, but researchers detected fewer neutrinos than expected from uranium-235. That means there’s probably something funny with the uranium-235 calculations.
This isn’t the end for sterile neutrinos — there are other hints that they exist. If so, sterile neutrinos could constitute dark matter, an unknown invisible substance that pervades the universe.
Bacteria in the vagina affect whether a drug stops an HIV infection or is itself stopped cold.
A vaginal gel containing tenofovir, an antiretroviral drug used to treat HIV infection, was three times as effective at preventing HIV in women who had healthy vaginal bacterial communities as it was in women with a less beneficial mix. The finding may help explain why the effectiveness of these gels has varied in trials, researchers report in the June 2 Science. “The vaginal microbiota is yet another variable that we have to take into account when we are thinking about why one intervention does or doesn’t work,” says clinical scientist Khalil Ghanem of Johns Hopkins University School of Medicine, who coauthored a commentary accompanying the study.
For women, one strategy to prevent HIV infection is to apply medicated vaginal gels before and after sex. But results have been mixed regarding how well the gels work. The hit-or-miss effectiveness can partly be explained by some patients not taking the medication as prescribed. But study coauthor Adam Burgener, a microbiologist at the Public Health Agency of Canada in Winnipeg, wondered if there might also be a biological explanation.
The main residents of a healthy vaginal microbial community, or microbiota, are Lactobacillus species. The bacteria produce lactic acid, making the vaginal tract more acidic and possibly “less hospitable for potential pathogenic organisms,” Ghanem says.
To examine the effect of the vaginal microbiota on tenofovir, Burgener and colleagues turned to a previous trial of South African women, which showed that the drug reduced HIV infections by 39 percent. During that trial, samples of vaginal mucus were taken. In the new study, the researchers measured bacterial proteins in 688 of those samples to determine the bacteria in the women’s vaginas when the samples were collected.
Just over 400 women’s vaginal microbiota mainly had Lactobacillus species; the microbiota of the other 281 women were dominated by non-Lactobacillus species, such as Gardnerella vaginalis. Within those two groups were women who had used tenofovir vaginal gel and those who had used a non-medicated gel as a placebo. In the Lactobacillus-dominant group, the incidence of HIV was 61 percent lower in women using the medicated gel compared with those using the placebo gel. But in the non-Lactobacillus dominant group, it was only 18 percent lower. There was no appreciable difference in the consistency of the gel’s reported use between the two groups, the researchers note.
“Women with Lactobacillus had three times more protection offered by the gel,” Burgener says. “That’s a pretty remarkable difference in the efficacy of a drug.”
Looking at a random subset of 270 of the samples, the researchers found that the vaginal gel drug levels were lower in the mucus from the non-Lactobacillus group. So, in a test tube, they mixed a laboratory strain of G. vaginalis with tenofovir. After four hours, the amount of tenofovir in the tube had decreased by 50 percent. In a similar experiment with two Lactobacillus species, the amount of the drug remained about the same. It appears that the G. vaginalis bacteria “gobbled up the drug and depleted it,” Burgener says.
It’s known that microbes in the gut can impact the metabolism of medications, says clinical scientist and commentary coauthor Susan Tuddenham of the Johns Hopkins University School of Medicine. “This study tells us that when we are thinking about vaginally delivered medications, we may need to think about the vaginal microbiome as well.”
The work also shows that women closely following directions for vaginal medications “could be doing everything right and still not getting the full benefit of that medication,” Ghanem says.
Particles of light born in space have connected two cities via a quantum link about 10 times longer than any created before.
A quantum-communications satellite beamed photons to Earth, separating them by more than 1,200 kilometers. The feat showed that the particles of light can retain a strange type of interconnectedness, known as quantum entanglement, even when flung to opposite ends of a country, researchers from China report in the June 16 Science. The previous distance record was about 100 kilometers (SN: 6/30/12, p. 10). Launched in 2016, the one-of-a-kind satellite is laying the groundwork for a space-based network of quantum communication. “It’s a huge achievement for quantum entanglement and quantum science,” says physicist Thomas Jennewein of the University of Waterloo in Canada.
Scientists have previously beamed photons up to a satellite and back again (SN Online: 6/5/16), but those particles were not entangled. Until now, no one had distributed entangled particles from space. “China is now clearly taking the world leadership in this area of quantum communication,” Jennewein says.
The technique is expected to have major technological applications. “This experiment is really important for the development of a future quantum internet,” says Anton Zeilinger, a physicist at the University of Vienna. Such a network would allow for ultrasecure communications and could connect quantum computers across the globe (SN: 10/15/16, p. 13).
An ethereal bond between two particles, entanglement is the most essential ingredient of a quantum network. Entangled particles can’t be described independently; instead, they form one unit, even when separated by large distances. Measuring one entangled particle immediately reveals the state of the other. To perform quantum communication, scientists send entangled photons from place to place. But photons can only travel so far through air or optical fibers before the material absorbs the particles, limiting the distance over which communication is possible. In the emptiness of space, however, photons can travel much farther.
Using the satellite, named Micius after an ancient Chinese philosopher, the researchers beamed intertwined photon pairs down to the cities of Delingha in northern China and Lijiang in southern China. There, telescopes aimed at the satellite detected the particles. To confirm that the particles were entangled, and that the weird qualities of quantum mechanics held, the researchers used the photon pairs to perform a Bell test (SN: 9/19/15, p. 12), which analyzes correlations between the two particles. The test reconfirmed the odd physics of the supersmall, at a larger distance than ever before. To perform the experiment, the researchers had to update their quantum equipment to make it work in space. That technological achievement is amazing, says physicist Harald Weinfurter of Ludwig-Maximilians-Universität in Munich. “It’s a huge step from the laboratory experiments to equipment which really works on a satellite,” he says. In space, sensitive components must deal with inhospitable conditions such as fluctuating temperatures and vibrations. Plus, to fit on the satellite, the whole package must be small and lightweight.
Detecting the photons is likewise daunting. Beacon lasers helped researchers point the ground-based telescopes in the right direction to catch the photons, as the satellite zipped past, 500 kilometers above Earth’s surface. The accuracy the researchers achieved is like pinpointing a human hair on the ground from the top of the Eiffel Tower.
In the future, researchers suggest, quantum entanglement will be an important resource for communicating across the globe. “Today we pay bills: electrical bills, water bills,” says coauthor Chao-Yang Lu, a physicist at the University of Science and Technology of China in Hefei. With quantum entanglement such a basic requirement of quantum communication, “maybe someday we will need to pay some entanglement bills.”
Some deep-sea tube worms get long in the tooth … er, tube. Living several decades longer than its shallow-water relatives, Escarpia laminata has the longest known life span for a tube worm, aging beyond 300 years, researchers report in the August Science of Nature.
E. laminata lives 1,000 to 3,300 meters deep in the Gulf of Mexico, near seafloor vents that seep energy-rich compounds that feed bacteria that feed the tube worms. In 2006, biologists marked 356 E. laminata in their natural habitat and measured how much the creatures had grown a year later. To estimate the ages of tube worms of different sizes, the researchers plugged E. laminata’s average yearly growth rate — along with estimates of birthrates and death rates, based on observations of another 1,046 tube worms — into a simulation. The species’s typical life span is 100 to 200 years, the researchers calculate, but some larger tube worms may be more than 300 years old.
With few large predators, deep-sea tube worms have got it good, says study coauthor Alanna Durkin, a biologist at Temple University in Philadelphia. “Once they find a seat at the buffet, they’re pretty set for hundreds of years.” The researchers’ methodology appears robust, says ocean scientist David Reynolds of Cardiff University in Wales, who was not involved in the work. Although variable environmental conditions could affect growth rate over time, he says.
