BALTIMORE — For centuries, clashes between science and religion have made waves within society at large and in the academic world. You probably haven’t heard very much, though, about similar clashes between science and history.

Yet scientists and historians have fundamentally different perspectives on history, especially when it’s the history of science. Scientists tend to celebrate the discoveries of the past that built the knowledge of the present. Historians argue that the scientists of the past should be viewed through the lens of their own time, not evaluated on the relevance of their work to today’s textbooks.

One prominent physicist who objects to the historians’ modus operandi is Nobel laureate Steven Weinberg of the University of Texas at Austin. His 2015 book To Understand the World unabashedly analyzes the scientific past in the light of the present. “I knew from the beginning that I was being naughty,” Weinberg said March 14 at a meeting in Baltimore of the American Physical Society.

In technical terms, Weinberg was engaging in “Whig” history (an allusion to criticisms of British historical accounts involving a prominent political party). Whig historians write (or rewrite) history as a story validating the chain of events that created present-day circumstances. Most historians argue that such an approach distorts the record of the past. Much of what happened in the past had little to do with how things are now, and historical actors certainly had motives other than creating a future they couldn’t even have imagined. “We don’t want to read history only from the winners’ point of view,” commented historian David Wootton, also speaking at the physical society meeting.

But limiting historical accounts to evaluating the past “on its own terms,” without admitting current knowledge into evidence, misses much of the story, Weinberg asserts.

And as Weinberg points out, it’s often hard to understand the past on its own terms anyway. Especially when studying early Greek philosophers, it’s impossible to know very much about the conditions under which they worked and the influences that shaped their thought. Even many of their own writings are missing or fragmentary.

“Our knowledge of present science provides a contrast to the attitudes and methods of the past, attitudes and methods that often obstructed progress,” Weinberg said.
Of course, the notion of progress itself is one of those concepts that some historians deny; it implies a value judgment that things now are somehow better than they used to be. But in science, progress of some sort is very hard to deny. Wootton, the historian, agrees with Weinberg on that point. Wootton believes many historians go too far in denying the notion of progress in many fields, with science being the most prominent example.

“The progress has been real and needs to be studied and explained,” Wootton said. “Understanding the past in its own terms is not enough” — a point he also makes in his recent book The Invention of Science.

Other historians view their task more narrowly, insisting that scientists of the past should be studied in light of their efforts to solve the problems posed in their own day within their own worldview. But that is not the story of science’s past that interests Weinberg.

He agrees that early scientists dealt with different problems. “Scientists of the past were not just like scientists of today who didn’t know as much we know. They had completely different ideas of what there was to know, or how you go about learning it,” he said. “But the point of scientific work is not to solve the problems that happen to be fashionable in your own day — it is to learn about the world.”

So that makes the stories that historians like to tell irrelevant (to him).

“It is the history of the change in the attitudes of what was there to know, and how do you find it out, that seems to me the most interesting … story.” That’s the story, Weinberg believes, that helps in understanding how science has succeeded and perhaps even helps identify present-day mistakes.

“The real story is the progress of science from an earlier day when the most intelligent and well-informed people in the world did not know how to address the mysteries of nature,” he said. “We’re certainly not finished, and we’re undoubtedly still making mistakes. But we have amassed a large amount of reliable knowledge, and more important we have developed techniques for deciding when knowledge really is knowledge or just a mistake. It is a great story. It’s not at an end. But we have learned some things, and if we don’t use the things that we have learned, then the story we tell has no point.”

Scientists have discovered how one microbe plays it cool.

Until now, it was a mystery how Pseudomonas syringae bacteria turn water into ice at temperatures above a normal freezing point. P. syringae pulls off its cool trick by rearranging nearby water molecules, researchers in the United States and Germany report online April 22 in Science Advances. This chill ability makes the microbes useful in making artificial snow at ski resorts.

Researchers knew that a particular protein on the microbes’ membranes was somehow responsible for making ice form. The team found that this ice nucleation protein, inaZ, acts as a mold for ice crystals. Alternating water-repelling and water-attracting parts of the protein tug nearby water molecules into an orderly, icelike arrangement. Once arranged into an ice-promoting formation, water molecules can quickly disperse heat energy.
This alignment process becomes more prominent as water temperatures drops toward 5˚ Celsius, a degree above the freezing point of the water the team used in their experiment (which contained a heavy form of hydrogen). Outside the lab, P. syringae can crystallize water at around –2˚ C, several degrees above the temperature at which ice crystals commonly form.

Understanding how P. syringae freezes water could inform science beyond the slopes. In gardens, the bacteria can wreak havoc on frost-sensitive plants. And ice-forming bacteria play an important role in climate by affecting patterns of cloud formation and precipitation, the researchers say.

The galaxy is starting to feel a little crowded. Over 1,000 planets have just been added to the roster of worlds known to orbit other stars in the Milky Way, researchers announced May 10 at a news briefing. This is the largest number of exoplanets announced at once.

Most of the 1,284 worlds are larger than Earth but smaller than Neptune. Many of those are probably big balls of gas. But over 100 of the new discoveries are smaller than 1.2 times the diameter of Earth. “Those are almost certainly rocky in nature,” said Timothy Morton, an astrophysicist at Princeton University. Nine planets also lie within the habitable zone, the distance from the star where liquid water could conceivably collect on the surface of the planet. Morton and colleagues detail their findings in the May 10 Astrophysical Journal.
This announcement roughly doubles the number of planets discovered by NASA’s planet-hunting workhorse, the Kepler space telescope, which has now found 2,325 exoplanets. Kepler spent nearly four years staring at about 150,000 stars in the constellations Cygnus and Lyra, watching for subtle dips in starlight as planets crossed in front of their suns. While Kepler has since moved on to other investigations (SN: 6/28/14, p. 7), this latest haul comes from those first four years of observing.

The planet bonanza comes courtesy of a new statistical calculation that allows researchers to feel confident that a detection is a real world. Impostors such as companion stars can mimic the signal from a planet. Traditionally, each planet candidate must be followed up with intensive observations from ground-based telescopes. But with over 4,000 candidates in the queue, confirming each one would take a long time. The calculation takes into account the details of how a passing planet should dim and brighten the starlight along with how common impostors should be and provides a reliability score for each candidate. Planets in this study are those whose score is greater than 99 percent.

Techniques such as these should help confirm planets detected by upcoming missions such as the Transiting Exoplanet Survey Satellite, scheduled to launch in late 2017. Some of those planets found by TESS will in turn come under the gaze of the James Webb Space Telescope, which will launch in 2018 and investigate their atmospheres (SN: 4/30/16, p. 32).

Editor’s Note: This story was updated May 17, 2016, to correct the key in the graphic to indicate that previously detected planets include all transiting planets discovered, not just the ones found by Kepler.

A form of multicellular life visible to the naked eye may have emerged nearly a billion years earlier than scientists once thought.

At 1.56 billion years old, fossils discovered in north China represent the best evidence yet for the early existence of large eukaryotes, paleobiologist Maoyan Zhu of the Chinese Academy of Sciences in Nanjing and colleagues report May 17 in Nature Communications.

Eukaryotes, which have cells containing nuclei and other membrane-wrapped machinery, include everything from plants to people. The new find could mark when single-celled eukaryotes became multicellular organisms capable of drawing energy from the sun, says geobiologist Shuhai Xiao of Virginia Tech in Blacksburg, who was not involved in the research. “That’s why it’s important,” he says. “The fossils represent one of the major transitions in evolution.”
Remains of early life on Earth are scarce and sometimes hard to interpret (SN: 2/8/14, p. 16). Some scientists point to evidence of life from as early as 3.8 billion years ago; rocks in Greenland, for example, contain traces of carbon that could be cellular remnants. Harder evidence for microbes comes from what appear to be fossils of actual cells speckling 3.4-billion-year-old sandstone in Australia.

Signs of multicellular life crop up later in the fossil record, roughly 1.2 billion years ago, Zhu says. But until now, clear evidence for large-scale multicellular organisms, like the ones Zhu’s team reports, date back just 635 million years. The team’s new find — consisting of 167 fossils, some up to 30 centimeters long and 8 centimeters wide (roughly the size of a man’s footprint) — places these life-forms much further back in time, when Earth was hot and oxygen was scarce.

The fossils are compressions: cells squashed flat into ribbons — like a garden hose crushed beneath a car’s tire, or like kelp. In fact, the organisms may have looked “very similar to some algae living in the shallow sea today,” Zhu says.

After stretching ropy bodies along the shore, the ancient sea life was preserved in layers of mudstone. Inside the stone, the researchers found closely packed cells and organic carbon, evidence of cellular remains. Zhu can’t explain why such a large time gap exists between his find and similar large-scale fossils, but he suspects the problem may be with preservation of such old material.

Scientists once considered the time period when these organisms lived to be the “boring billion,” though that view seems to be shifting (SN: 11/14/15, p. 18). People thought that “there was very little evolutionary change, and not much going on geochemically,” Xiao says. The new work “tells us a different story.”

Two more of the ingredients for life as we know it have turned up in space, this time from a comet orbiting the sun. While hints of both have been seen in comets before, this is the clearest evidence to date.

Glycine, the smallest of the 20 amino acids that build proteins, is floating in the tenuous atmosphere of comet 67P/Churyumov-Gerasimenko, researchers report online May 27 in Science Advances. Comet 67P’s atmosphere also holds phosphorus, which is essential to DNA and RNA. Both detections support the idea that comets are at least partly responsible for seeding early Earth with material needed for life.
The phosphorus, glycine and a handful of other organic molecules were detected by the European Space Agency’s Rosetta spacecraft, which has been in orbit around 67P since August 2014 (SN: 9/6/14, p. 8). Kathrin Altwegg, a planetary scientist at the University of Bern in Switzerland, led the study.

Previous searches for glycine in comets Hale-Bopp and C/1996 B2 (Hyakutake) turned up nothing. Glycine was seen in samples from the Stardust mission, which flew through the tail of comet Wild 2 in 2004 and brought comet dust back to Earth, but those measurements were complicated by lab contamination. Scientists have detected hints of phosphorus in comet Halley.

Life’s ingredients keep turning up in cosmic environments. Meteorites carry amino acids and simple sugars have been seen in interstellar clouds(SN: 10/9/04, p. 237). And several of the essential molecules for DNA and RNA, such as ribose, have been created in laboratory experiments that simulate ice grains exposed to ultraviolet radiation from young stars (SN: 4/30/16, p. 18).

From California to China, desert moss (Syntrichia caninervis) braves life in hot deserts and still stays hydrated. What’s its secret? The moss gathers water via a topsy-turvy collection system in its leaves.

Moss leaves have tiny hairlike points at their ends called awns. Previous evidence pointed to a potential role for the awns in water collection and prompted Tadd Truscott of Utah State University and his colleagues to zero in on the structures.

Imaging exposed a system of barbs that line the awns and catch tiny airborne water droplets, the team reports June 6 in Nature Plants. When the air is misty, foggy or the least bit humid, trapped dewdrops move up grooves in the moss leaves by capillary action. The tiny drops form a bigger drop to be absorbed and stored by the plant. When it rains, moss awns reduce splash and capture raindrops by the same mechanism.

Most desert plants, especially cacti, get their water from roots, but moss may not be the only plant that uses unique leaf structures to stock up on water, the team argues.

For the second time, scientists have glimpsed elusive ripples that vibrate the fabric of space. A new observation of gravitational waves, announced by scientists with the Advanced Laser Interferometer Gravitational-Wave Observatory, LIGO, follows their first detection, reported earlier this year (SN: 3/5/16, p. 6). The second detection further opens a new window through which to observe the universe.

“The era of gravitational wave astronomy is upon us,” says astronomer Scott Ransom of the National Radio Astronomy Observatory in Charlottesville, Va., who is not involved with LIGO. “Now that there’s two, you can’t get around that anymore.”

Both sets of cosmic quivers were wrought in cataclysmic collisions of black holes. But the latest observation indicates that such merging pairs of black holes are a varied bunch — the newly detected black holes were much smaller than the first pair. And this time, scientists concluded that one in the pair was spinning like a top.
“The most important thing is that it’s a second one,” says LIGO spokesperson Gabriela González of Louisiana State University in Baton Rouge. “But it’s important that it’s different, because it shows that there’s a spectrum of black hole systems out there.”

The two black holes in the most recent detection were about eight and 14 times the mass of the sun and were located roughly 1.4 billion light-years from Earth, the scientists estimate. When the pair fused, they formed one bloated black hole with a mass 21 times that of the sun. One sun’s worth of mass was converted into energy and carried away by the gravitational waves, LIGO scientists announced June 15 in San Diego during a meeting of the American Astronomical Society.
“Gravitational astronomy is real,” LIGO laboratory executive director David Reitze said in a news conference. “The future is going to be full of binary black hole mergers for LIGO.”

A paper describing the finding was published online June 15 in Physical Review Letters.

As the two black holes spiraled around each other and slammed together, they churned up cosmic undulations that stretched and squeezed space — as predicted by Einstein’s general theory of relativity. These waves careened across the universe, reaching LIGO’s twin detectors in Hanford, Wash., and Livingston, La., on December 26, 2015.

Each L-shaped LIGO detector senses the minuscule stretching and squeezing of space across its two 4-kilometer arms. As a gravitational wave passes through, one arm lengthens while the other shortens. Laser light bouncing back and forth in the arms serves as an ultrasensitive measuring stick that can pick up those subtle length changes (SN: 3/5/16, p. 22). As the gravitational waves rumbled past Earth in December, they stretched and squeezed the arms by less than a thousandth the width of a proton. “That’s very, very small,” González said. “That’s like changing the distance between Earth and the sun by a fraction of an atomic diameter.” This tiny deviation, appearing in both detectors nearly simultaneously, was enough to pick out the telltale ripples.

Compared with LIGO’s previously detected black hole merger, this one was a more minor dustup. These black holes were less than half the size of those in the first merger (30 and 35 solar masses according to a recently revised estimate). And the signal of their coalescence was more subtle, hiding under the messy wiggles in the data that result from random fluctuations or unwanted signals from the environment.
The first detection stunned scientists, due to the surprisingly large masses of the black holes and the whopping signals their gravitational waves left in the data. But the new black hole merger is more in line with expectations.
“This is comfort food,” says physicist Emanuele Berti of the University of Mississippi in Oxford, who is not involved with LIGO. “If you had asked me before the first detection, I would have bet that this would have been the first kind of binary black hole to be observed, not the monster we saw.”

There’s little question about whether the signal is real — a false alarm of this magnitude should occur only once in 200,000 years. “It’s very, very exciting,” says physicist Clifford Will of the University of Florida in Gainesville. It “looks like a very solid discovery.”

In a new twist, the scientists found that one of the two merging black holes was spinning. It was rotating at a speed at least 20 percent of its maximum possible speed. Using gravitational waves to study how pairs of black holes twirl could help scientists understand how they form.

The scientists used their data to put general relativity through its paces, looking for deviations from the theory’s predictions. But the black holes’ behavior was as expected.

LIGO also saw hints of a third black hole collision on October 12. The evidence was not strong enough to claim a definitive detection, though.

LIGO is currently offline, undergoing improvements that will allow the detectors to peer even further out into space. Scientists expect it to be back up and running this fall, churning out new detections of gravitational waves. “Now we know for sure that we’ll see more in the future,” González says.

AUSTIN, TEXAS — Success of an indoor spraying campaign to combat malaria on an African island may have started a worrisome trend in local mosquito evolution.

Since 2004, using pesticides inside homes has eradicated two of four malaria-spreading Anopheles mosquitoes on Bioko Island in Equatorial Guinea, vector biologist Jacob I. Meyers of Texas A&M University in College Station reported June 19 at the Evolution 2016 meeting. Numbers of the remaining two species have dropped. Yet the dregs of these supposedly homebody species are showing a rising tendency to fly outdoors looking for a blood meal, Meyers and colleagues cautioned. The results were also reported April 26 in Malaria Journal.

If the mosquitoes continue to shift toward outside bloodsucking, the campaign could lose some of its bite. Repeated treatments of indoor walls with pesticides that kill mosquitoes clinging to them may not be so effective if the pests venture from home.

What’s changing about these mosquitoes remains to be seen, but this looks like more than simple opportunism, Meyers said. Bed nets are not common, so Meyers doubts that the mosquitoes fly outdoors because no one is available to bite indoors. Nor does their reaction look like escape from repellent pesticides: Outdoor biting didn’t consistently rise after a spraying. The next step is to check for a genetic basis for the shift. Lots of research has explored physiology that lets insects resist pesticides, Meyers said, but the onset of possible resistant behavior has barely been explored.

Bottoms up, from the distant past. Thanks to a new method of analyzing the chemicals in liquids absorbed by clay containers, researchers have uncorked the oldest solid evidence of grape-based wine making in Europe, and possibly the world, at a site in northern Greece.

Chemical markers of red wine were embedded in two pieces of a smashed jar and in an intact jug discovered in 2010 in the ruins of a house destroyed by fire around 6,300 years ago at the ancient farming village of Dikili Tash.
After successfully testing the new technique on replicas of clay vessels filled with wine, then emptied, the scientists identified chemical markers of grape juice and fermentation in clay powder scraped off the inner surfaces of the Dikili Tash finds. None of the vessels contained visible stains or residue, researchers report online May 24 in the Journal of Archaeological Science.

Remains of crushed grapes found near the ancient jar shards and jug had already indicated that Dikili Tash farmers made wine or grape juice, say chemist Nicolas Garnier of École Normale Supérieure in Paris and archaeobotanist Soultana Maria Valamoti of Aristotle University of Thessaloniki in Greece.

Previous reports of ancient wine have largely relied on chemical markers of grapes but not the fermentation necessary to turn them into wine, leaving open the possibility that containers held grape juice. The “juice versus wine” conundrum applies to roughly 7,400-year-old jars from Iran (SN: 12/11/04, p. 371), Garnier says.