AUSTIN, Texas — If alien microbes crash-land on Earth, they may get a warm welcome.

When people were asked how they would react to the discovery of extraterrestrial microbial life, they give generally positive responses, researchers reported at a news conference February 16 at the annual meeting of the American Association for the Advancement of Science.

This suggests that if microbial life is found on Mars, Saturn’s icy moon Enceladus (SN: 5/13/17, p. 6) or elsewhere in the solar system, “we’ll take the news rather well,” said Michael Varnum, a social psychologist at Arizona State University in Tempe. What’s more, the tone of news reports announcing potential evidence for intelligent aliens suggests people would welcome that news, too.
Varnum and colleagues asked about 500 online volunteers — all in the United States — to describe how they would react if they learned scientists had discovered alien microbes. Varnum’s team analyzed each response using software that determined the fraction of words indicating positive emotion, such as “nice,” and negative emotion, like “worried.” The program also scanned for reward- and risk-focused words, such as “benefit” and “danger.”
People generally used more positive and reward-oriented words than negative and risk-oriented ones to describe their anticipated reactions. The same held true when participants were asked how they expected everyone else to take the news.
In another study, Varnum’s team asked about 500 U.S.-based volunteers to read one of two newspaper articles. One from 1996 reported the discovery of evidence for fossilized Martian microbes in a meteorite (SN: 8/10/96, p. 84). In the second, researchers announced in 2010 that they had created a synthetic bacterial cell in the lab (SN: 6/19/10, p. 5).
Both groups responded favorably to the articles, but the people who read about Martian microbes had a more positive reaction. This suggests that while people feel good about discoveries of any previously unknown life-forms, they are particularly keen on finding aliens, Varnum says.

But “any finding that comes from one population — like Americans — you have to take with a grain of salt,” Varnum says. He and his colleagues now hope to gather responses from participants of different cultures, to compare how people across the globe would take the news of alien microbes.

Psychologist and SETI researcher Douglas Vakoch, who heads the nonprofit organization Messaging Extraterrestrial Intelligence in San Francisco, suggests researchers also gauge reactions to different scenarios of alien microbial discovery. The Martian meteorite described in the 1996 article “has been on Earth for a long time and nothing bad has happened,” says Vakoch, who wasn’t involved in the work. “That’s a really safe scenario.” But, he wonders, are people as gung-ho about the prospect of finding live microbes on other planets or aboard meteorites?

And what if the aliens were intelligent? “If you find intelligent life elsewhere, [you] know that you’re not the only kid on the block,” says Seth Shostak, an astronomer at the SETI Institute in Mountain View, Calif. Knowing that human intelligence isn’t so special after all could provoke a much different emotional response than finding mere microbes “like pond scum in space,” Shostak says.

To get a sense of how people would feel about finding intelligent aliens, Varnum analyzed reports that the interstellar asteroid ‘Oumuamua could be an alien spaceship (SN Online: 12/18/17). The news articles took a largely positive angle. So the broader public might also take kindly to the discovery of little green men, Varnum says.

Tap — gently — the plump rear of a young Nessus sphinx hawk moth, and you may hear the closest sound yet discovered to a caterpillar voice.

Caterpillars don’t breathe through their mouths. Yet a Nessus sphinx hawk moth, if disturbed, will emit from its open mouth a sustained hiss followed by a string of scratchy burplike sounds. “Hard to describe,” says animal behaviorist Jayne Yack of Carleton University in Ottawa, who urges people just to listen to it for themselves.
This newfound noise from young Amphion floridensis may startle birds or other would-be predators not expecting something as generally quiet as most caterpillars to erupt in sound.

The discovery marks the fourth sound-producing mechanism in caterpillars that Yack and colleagues have found. Some caterpillars use their spiracles, respiratory pores along the flanks, to toot sounds. Caterpillars take in oxygen and release waste carbon dioxide through these pores. These gases, which don’t depend on the caterpillar version of blood to travel throughout the body, move through a branching air duct system of increasingly tiny pipes. Two other kinds of caterpillar noises involve mouthparts rubbing against each other. But none of those noisemakers are involved here, researchers report online February 26 in Journal of Experimental Biology.

Instead, the new anatomical studies and computer modeling suggest that these caterpillars speak by pulling air in through their mouths and into their guts and then releasing it. The rush of air inward could create the first hissing part, and outrushes could make the string of scratchy burps. There’s no sign of a special sound-making flap in the gut, but air whooshing through a constriction could make noisy turbulence. That could give a caterpillar voice its own version of teakettle squeals. In miniature, of course.

BOSTON — The bond between parent and child is powerful enough to override fear. New research shows that if a parent sits with a young child during a potentially scary situation, the child isn’t as afraid of it later.

The study is in line with research suggesting that during particular stages of development, a strong connection with a caregiver tamps down activity in the amygdala, the brain structure that helps process fear and spurs the fight-or-flight response.
“Fight or flight is pointless if you are tiny,” said developmental neuroscientist Nim Tottenham of Columbia University, who presented the work March 26 at a Cognitive Neuroscience Society meeting. For young kids, the bond with a caregiver not only helps ensure survival but also makes kids feel safe, enabling them to approach the world with confidence, Tottenham said. “Attachment is a strategy that has worked very well; it trumps everything.”

Kids from ages 3 to 5 were shown two shapes — a green triangle and a blue square. Just the square was accompanied by a loud, fingers-on-the-chalkboard kind of noise. Some kids had a parent sitting next to them while they saw the shapes; others sat with a researcher. After the parents left, kids chose which door to go through to get a present: one with the scary blue square on it, the other with the innocuous green triangle.

Kids paired with the experimenter avoided the door with the blue square. But kids who had sat next to a parent showed a slight preference for that door, even though they knew they would collect the same present from behind either door.

Stephen Hawking, a black hole whisperer who divined the secrets of the universe’s most inscrutable objects, left a legacy of cosmological puzzles sparked by his work, and inspired a generation of scientists who grew up reading his books.

Upon Hawking’s death on March 14 at age 76, his most famous discovery — that black holes aren’t entirely black, but emit faint radiation — was still fueling debate.

Hawking “really, really cared about the truth, and trying to find it,” says physicist Andrew Strominger of Harvard University, who collaborated with the famed scientist. Hawking “was deeply committed, his whole life, to this quest of understanding more about the physical universe around us.”

After earning his Ph.D. in 1965 at the University of Cambridge, Hawking continued studying cosmology there for the rest of his life. Due to a degenerative illness, amyotrophic lateral sclerosis, or ALS, Hawking gradually lost control of his body, requiring a wheelchair and eventually a voice synthesizer to speak. Yet his desire to uncover nature’s secrets remained boundless.
In one of the most significant realizations of his career, Hawking reported in 1974 that black holes emit a faint glow of particles. This effect arises from quantum mechanics, which states that a sea of transient particles and antiparticles pervades all of space. These “virtual” particles usually annihilate in an instant, but if one of those particles is lost inside a black hole’s boundary, or event horizon, its partner can escape, producing what’s now known as Hawking radiation (SN: 5/31/14, p. 16).

As a result, black holes can gradually evaporate and disappear. This led to a still unresolved paradox: Throw an encyclopedia into a black hole and the information will eventually be lost. But according to quantum mechanics, information can never be destroyed.

Many solutions have been proposed for this problem, but none has stuck. In 2016, Hawking and colleagues proposed a path toward a solution: Black holes might have “soft hair,” low-energy particles that would retain information about what fell inside (SN: 2/06/16, p. 16). Hawking’s collaborators, including Strominger, are still working on the research. Standing at the interface between two seemingly incompatible theories — quantum mechanics, which describes the very small, and the general theory of relativity, which describes gravity — the quandary and its resolution may eventually help reveal a unified theory of quantum gravity.

Hawking made many other contributions, including studies of spacetime curvature during the Big Bang and the possibility that mini black holes might have formed in the universe’s infancy. Despite their groundbreaking nature, Hawking’s ideas remained largely theoretical, says Harvard theoretical astrophysicist Avi Loeb. Hawking radiation, for example, has never been directly detected. “That’s, unfortunately, why he didn’t get the Nobel Prize,” Loeb says.
Yet Hawking achieved a level of fame uncommon among scientists. He excelled at making abstruse science digestible to the public. With his books, most notably the best-selling A Brief History of Time, first published in 1988, Hawking inspired countless future scientists and science lovers (including the author of this article). Theoretical cosmologist Katie Mack of North Carolina State University in Raleigh first opened the book when she was about 10 years old. “I found it so fascinating at the time,” she says. “I found out that Stephen Hawking was called a cosmologist and so I said I wanted to be a cosmologist.” Hawking similarly motivated dozens of her colleagues, Mack says.

Hawking remained active in research even in the last months of his life. A paper on which he is a coauthor, which was updated in the weeks before his death, considered the physics of multiverses, the possibility that a slew of other universes exist in addition to our own.

A funeral was held for Hawking on March 31. Later this year, his ashes will be interred in Westminster Abbey in London, where they will rest alongside the remains of other famous British scientists, including Isaac Newton and Charles Darwin.

While the data was amassing, suddenly there came a tapping,
As of something gently rapping, rapping at LIGO’s door.

The source of a mysterious glitch in data from a gravitational wave detector has been unmasked: rap-tap-tapping ravens with a thirst for shaved ice. At the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, in the desert of Hanford, Wash., scientists noticed a signal that didn’t look like gravitational waves, physicist Beverly Berger said on April 16 at a meeting of the American Physical Society.

A microphone sensor that monitors LIGO’s surroundings caught the sounds of pecking birds on tape in July 2017, Berger, of the LIGO Laboratory at Caltech, said. So the crew went out to the end of one of the detector’s 4-kilometer-long arms to check for evidence of the ebony birds at the scene.

Sure enough, frost covering a pipe connected to the cooling system was covered in telltale peck marks from the thirsty birds. One raven, presumably seeking relief from the desert heat, was caught in the act. Altering the setup to prevent ice buildup now keeps the ravens from tapping, evermore.

After a two-day delay, the planet-hunting TESS telescope successfully launched into a clear blue sky at Cape Canaveral, Fla., at 6:51 p.m. EDT on April 18.

TESS, the Transiting Exoplanet Survey Satellite, is headed to an orbit between the Earth and the moon, a journey that will take about two months. In its first two years, the telescope will seek planets orbiting 200,000 nearby, bright stars, and identify the best planets for further study. TESS’ cameras will survey 85 percent of the sky by splitting it up into 26 zones and focusing on each zone for 27 days apiece.

TESS launched on a SpaceX Falcon 9 rocket. A previous launch attempt on April 16 was scrubbed so that SpaceX could run more tests on the rocket’s guidance, navigation and control system. SpaceX recovered the rocket’s first stage booster on an autonomous drone ship and hopes to reuse the rocket on a future launch.

Quantum entanglement has left the realm of the utterly minuscule, and crossed over to the just plain small. Two teams of researchers report that they have generated ethereal quantum linkages, or entanglement, between pairs of jiggling objects visible with a magnifying glass or even the naked eye — if you have keen vision.

Physicist Mika Sillanpää and colleagues entangled the motion of two vibrating aluminum sheets, each 15 micrometers in diameter — a few times the thickness of spider silk. And physicist Sungkun Hong and colleagues performed a similar feat with 15-micrometer-long beams made of silicon, which expand and contract in width in a section of the beam. Both teams report their results in the April 26 Nature.
“It’s a first demonstration of entanglement over these artificial mechanical systems,” says Hong, of the University of Vienna. Previously, scientists had entangled vibrations in two diamonds that were macroscopic, meaning they were visible (or nearly visible) to the naked eye. But this is the first time entanglement has been seen in macroscopic structures constructed by humans, which can be designed to meet particular technological requirements.

Entanglement is a strange feature of quantum mechanics, through which two objects’ properties become intertwined. Measuring the properties of one object immediately reveals the state of the other, even though the duo may be separated by a large distance (SN: 8/5/17, p. 14).

Quantum mechanics’ weird rules typically apply to small fry — atoms, electrons and other tiny particles — and not to larger things such as cats, chairs or buildings. But that division leads to a confounding puzzle. “Atoms behave like atoms, and cats behave like cats, and so where is that transition in between?” says physicist Ben Sussman of the National Research Council of Canada in Ottawa, who was not involved in the research.

Now, scientists are extending the dividing line to larger and larger objects. “One of our motivations is to keep on testing how far we can push quantum mechanics,” says Sillanpää, of Aalto University in Finland. “There might be some fundamental limit for how big objects can be” and still be quantum.
In Sillanpää’s experiment, two tiny aluminum sheets — consisting of about a trillion atoms and just barely visible with the naked eye — vibrate like drumheads and interact with microwaves bouncing back and forth in a cavity. Those microwaves play the role of drum major, causing the two drumheads to sync up their motions. In many previous demonstrations of entanglement, the delicate quantum link is transient. But this one was long-lived, persisting as long as half an hour in experiments, Sillanpää says, and, in theory, even longer. “Our entanglement lasts forever, basically.”
Taking a different tactic, Hong and colleagues demonstrated entanglement with two silicon beams, big enough to be seen with a magnifying glass. Within a region of each beam, in a 1-micrometer-long section composed of about 10 billion atoms, the structure expanded and contracted — as if taking deep breaths in and out — in response to being hit with light. Instead of microwaves, Hong and colleagues’ work used infrared light of the wavelength typically transmitted in telecommunications networks made of optical fibers, which means it could be incorporated into a future quantum internet. “From a technology standpoint, that really is crucial,” says physicist John Teufel of the National Institute of Standards and Technology in Boulder, Colo., who was not involved with the work.

Scientists could use such vibrating structures within a quantum network to convert quantum information from one type to another, transitioning from particles of light to vibrations, for example. Once constructed, a quantum internet could allow quantum computers to communicate and provide unhackable communication across the globe (SN: 10/15/16, p. 13).

The ability to entangle these specially designed structures moves scientists a step closer to that vision. “You can really start to think about building real devices with these things,” Sussman says.

New insights into how stars like the sun die might help explain why astronomers find bright planetary nebulae where they’re least expected. Simulations of how these stellar remnants form suggest that smaller stars have cores that heat up fast enough to produce bright nebulae upon their demise, researchers report online May 7 in Nature Astronomy.

A planetary nebula is what’s left over when a sunlike star sheds its outer envelope of gas. Radiation from the stellar core, now exposed, sets the expanding shell of gas aglow, creating the kind of candy-colored clouds seen in spectacular Hubble Space Telescope images, like that of the Cat’s Eye Nebula and the butterfly-shaped NGC 6302 (SN Online: 9/5/13).
Astronomers had thought a star’s mass dictated what sort of nebula it produced, with more massive stars creating the brightest nebulae and stars with lower masses, like the sun, making nebulae too faint to see from another galaxy.

But that idea didn’t match observations: The brightest planetary nebulae in older elliptical galaxies — thought to be home to only low-mass stars — are just as luminous as those in younger, spiral galaxies, where massive stars abound. The puzzle vexed astronomers for decades.

Now, astrophysicist Albert Zijlstra at the University of Manchester in England, and colleagues have simulated planetary nebulae formation based on a new theory of stellar evolution. This theory says that after smaller stars shed their outer envelopes, their bare cores heat up more quickly than previously thought. That allows the cinderlike stellar core to pump more energetic radiation into the surrounding nebula before the gas expands too far out into space, ultimately making for a brighter nebula, explains Christophe Morisset, an astronomer at the National Autonomous University of Mexico in Mexico City not involved in the work.

Simulations showed that stars ranging from 1.1 to three times the mass of the sun produce nebulae with similar brightness. That result could explain why nebulae found in galaxies with stars that are 7 billion years old can be just as bright as those found in galaxies chock-full of 1-billion-year-old stars.
This finding marks “an important step forward” in understanding the universe’s population of planetary nebulae, says Penn State astronomer Robin Ciardullo, who was not involved in the work.

But some mystery still remains: For the most ancient elliptical galaxies with very small stars over 7 billion years old, the simulations didn’t produce planetary nebulae bright enough to match what astronomers see in the sky. So there’s still “a little ways to go” before astronomers can explain why bright nebulae are so ubiquitous, he says.

Going green may mean staying at home.

Global tourism contributes about 8 percent of total greenhouse gas emissions to the atmosphere, researchers report May 7 in Nature Climate Change. That carbon footprint is about three times as large as tourism-related emissions estimated by previous studies.

The jump is largely because the new study doesn’t just tally up emissions from the traveling itself, like hopping a flight, going on a road trip or taking a cruise. It also looks at the impact of the goods and services that tourists enjoy, from food to shopping to hotel stays.
Who has the biggest carbon footprint? The United States topped the list, as both a top destination for tourists and a source of tourists. Other prosperous nations, such as Canada and Germany, also have a big footprint, and increasingly wealthy nations, such as China and Mexico, are catching up in this amazing race.

Take a look at global tourism by the numbers:

4.5 gigatons
The amount of carbon dioxide and other greenhouse gases that came from tourism in 2013.

2.7 percent
The share of the global total of emissions that comes just from Canadians and Mexicans traveling to the United States for tourism.

300 kilograms
Increase, from 2009 to 2013, in the yearly carbon footprint for each inhabitant of the tiny island nation of the Maldives as a result of international tourism.

$4.7 trillion
The amount of money, in U.S. dollars, spent on global tourism in 2013. That’s up from $2.5 trillion in 2009.

3 percent
Current annual growth in money spent on global tourism, which translates to tourism-related emissions of 6.5 gigatons of carbon dioxide and other greenhouse gases by 2025.

It’s vacation season — time for swimming pools, hot tubs and water parks. But you might want to think twice before getting wet, says a new report from the U.S. Centers for Disease Control and Prevention.

From 2000 to 2014, public health officials from 46 states and Puerto Rico reported 493 outbreaks associated with treated recreational water, resulting in more than 27,000 illnesses and eight deaths, according to a report in the May 18 Morbidity and Mortality Weekly Report. Hotel pools and hot tubs were the setting for about a third (32 percent) of the outbreaks, followed by public parks (23 percent), club/recreational facilities (14 percent) and water parks (11 percent).

Most of the infections were from three organisms that can survive chlorine and other commonly used disinfectants: Cryptosporidium, a parasite that can cause gastrointestinal problems; Pseudomonas, a bacteria that causes swimmer’s ear; and Legionella, a bacteria that causes a pneumonia-like illness.

So, what to do? The CDC recommends a few steps before diving in: Don’t swallow pool water. Don’t let children with diarrhea in the water. And use test strips to measure levels of pH, bromine and chlorine in the water. The cleaner the water, the safer to swim.