TIME space

Alien Star Had a Close Call With Our Solar System

About 70,000 years ago

A red dwarf known as Scholz’s star passed through the edge of our solar system less than a lightyear away from the sun about 70,000 years ago, according to a new paper.

In the paper, published in the journal The Astrophysical Journal Letters, scientists write that they believe the Scholz’s star and its brown dwarf companion passed through the far part of our solar system called the outer Oort Cloud. There is no other known star that has come so close.

The scientists who spotted it needed to determine whether it was coming toward the solar system or flying away from it. Through their calculations, they were able to determine that the star is 20 light years away, BBC reports, and that it passed the solar system and is heading away. They estimated the flyby likely happened around 70,000 years ago.

There were concerns that the star could have affected with the gravitational orbits of the comets that reside in the Oort Cloud, but researchers concluded that its impact was “negligible.”

TIME space

Why Pluto Matters: A Short History of a Small (Non-)Planet

Pluto No Longer Classified As A Planet
NASA / Getty Images This undated image taken by the Hubble telescope shows Pluto and its moons: Charon, Nix, and Hydra.

Feb. 18, 1930: Pluto is first identified in photographs of the night sky

When it was first discovered, Pluto was the coolest planet in the solar system. Before it was even named, TIME surmised that “the New Planet,” 50 times farther from the sun than Earth, “gets so little heat from the sun that most substances of Earth would be frozen solid or into thick jellies.”

The astronomer Clyde W. Tombaugh, then a 24-year-old research assistant at the Lowell Observatory in Flagstaff, Ariz., was the first to find photographic evidence of a ninth planet on this day, Feb. 18, 85 years ago.

His discovery launched a worldwide scramble to name the frozen, farthest-away planet. Since the astronomer Percival Lowell had predicted its presence 15 years earlier, per TIME, and even calculated its approximate position based on the irregularity of Neptune’s orbit, the team at Lowell Observatory considered his widow’s suggestion of “Percival,” but found it not quite planetary enough. The director of the Harvard Observatory suggested “Cronos,” the sickle-wielding son of Uranus in Greek myth.

But the team opted instead for “Pluto,” the Roman god of the Underworld — the suggestion of an 11-year-old British schoolgirl who told the BBC she was enthralled with Greek and Roman mythology. Her grandfather had read to her from the newspaper about the planet’s discovery, and when she proposed the name, he was so taken with it that he brought it to the attention of a friend who happened to be an astronomy professor at Oxford University. The Lowell team went for Pluto partly because it began with Percival Lowell’s initials.

Pluto the Disney dog, it should be noted, had nothing to do with the girl’s choice. Although the cartoon character also made its first appearance in 1930, it did so shortly after the planet was named, as the BBC noted.

And while Pluto was downgraded to “dwarf planet” status in 2006, it remains a popular subject for astronomers. They began discovering similar small, icy bodies during the 1990s in the same region of the solar system, which has become known as the Kuiper Belt. Just because Pluto’s not alone doesn’t make it any less fascinating, according to Alan Stern, director of a NASA mission, New Horizons, that will explore and photograph Pluto in an unprecedented spacecraft flyby on July 14 of this year.

“This epic journey is very much the Everest of planetary exploration,” Stern wrote in TIME last month. “Pluto was the first of many small planets discovered out there, and it is still both the brightest and the largest one known.”

NASA released its first images of Pluto from the New Horizons mission earlier this month, although the probe was still 126 million miles away from its subject; the release was timed to coincide with Tombaugh’s birthday. Stern wrote, when the pictures were released, “These images of Pluto, clearly brighter and closer than those New Horizons took last July from twice as far away, represent our first steps at turning the pinpoint of light Clyde saw in the telescopes at Lowell Observatory 85 years ago, into a planet before the eyes of the world this summer.”

Read TIME’s original coverage of how Pluto got its name, here in the archives: Percival? Cronos?

TIME space

Watch a Meteor Burn Up in a Fiery Ball Over Pennsylvania

The fiery meteor likely left pieces of space rock scattered around western Pennsylvania, scientists say

A meteor burned up in the atmosphere over the skies of Ohio, Pennsylvania and New York Tuesday morning, lighting up in a flare that was reportedly brighter than the full moon.

Dr. William Cooke of the Meteoroid Environments Office at NASA confirmed that a meteor entered the Earth’s atmosphere over western Pennsylvania around 4:50am, the local NBC affiliate reports. It originated from an asteroid belt between Mars and Jupiter.

The 500-pound meteor moved east at a speed of 45,000 miles per hour, but cameras lost track of it 13 miles above the town of Kittanning, Pa., east of Pittsburgh. “There is a good chance of small fragments lying on the ground just to the east of Kittanning,” Cooke said.

[WFMJ]

Read next: Towering Plume Spotted on Mars Remains a Mystery

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TIME Internet

New Google Doodle Honors Alessandro Volta, Forefather of the Modern Battery

Undated picture of Italian physicist and inventor Alexander Volta (1745 - 1827)
AP Photo—AP Undated picture of Italian physicist and inventor Alexander Volta (1745 - 1827)

*Throws metal strips in saltwater, changes world forever*

A new Google Doodle is celebrating what would have been the 270th birthday of the Italian physicist Alessandro Volta, who in the year 1800 published a theory that led to the modern battery.

As TIME wrote back in 2007, Volta “realized metals could produce a current and developed the first battery, or ‘voltaic pile,’ a series of copper and zinc strips in salt water that gave off an electric current instead of static electricity.”

Born Feb. 18, 1745, in Como, Italy, Volta’s invention was the result of a professional competition with Luigi Galvani, who discovered that dissected frogs’ legs would twitch when probed with a wire.

Galvani believed the frogs’ muscles generated the electricity, while Volta thought the animal tissue was only a conductor.

The debate galvanized Volta to experiment with conductivity (often on his own tongue). Eventually, Volta put together a stack of metal disks, and when metal wires were connected to both ends of the stack, an electric current flowed through the pile, proving that animal tissue was not necessary to generate an electric current.

The Google Doodle honors Volta’s discovery with an animated battery that is reminiscent of both a voltaic pile and a battery-life reminder on a modern-day smartphone.

TIME space

Towering Plume Spotted on Mars Remains a Mystery

A formation first spotted by amateur astronomers baffles the pros

It’s not often astronomers are completely stumped—especially when it comes to Mars. The planet that once held nothing but mysteries has been yielding up more and more of its secrets, thanks to the storm of probes we’ve sent its way over the decades, including the seven that are now orbiting it or trundling about on its surface.

But something’s up with Mars at the moment—or at least something was up not long ago—and nobody seems able to explain it. That’s the beats-me conclusion a team of investigators reached in a new paper in Nature, when they attempted to explain a freakish plume that appeared in the Martian atmosphere in March and April of 2012, and might have occurred in 1997 as well.

The newest plume, which rose an unprecedented 155 miles (250 km) high in the Martian sky, was first observed by Wayne Jaeschke, an amateur astronomer in West Chester, Pa. on March 12, 2012. He sent the word out across the amateur astronomer community and soon reports were coming back that yes, other backyard sky-watchers were seeing the same thing. The plume lasted for 11 days and then recurred on April 6, this time hanging around for 10 days. Both phenomena appeared in the same spot in Mars’s southern hemisphere.

Plumes aren’t unheard of on Mars. The planet does have an atmosphere, after all—albeit one only 1% the thickness of Earth’s—and both dust and ice crystals can swirl up into the sky. Aurorae may also appear when charged particles streaming in from the sun interact with the planet’s magnetic field, which can create a plume-like effect.

But ice crystals have never been observed to climb above an altitude of 62 miles (100 km). Aurorae occur higher in the Martian sky, but at a maximum of 80 miles (130 km), they fall short too. And dust storms don’t even come close.

But those three are the only known explanations for what Jaeschke and the others saw—or at least the only known ones—and the mere fact that dust or ice or aurorae have never behaved this way before does not mean that they can’t. So a team of researchers led by Agustín Sánchez-Lavega of the University of the Basque Country in Bilbao, Spain, decided to put all three theories to the test.

The investigators began their work by studying not just the images of the plumes but also roughly 3,500 pictures of Mars captured by amateur astronomers around the world from 2001 to 2014, as well as a series of shots taken by the Hubble space telescope from 1995 to 1999, when it was giving the Red Planet a good going-over. None of these pictures showed anything similar to the 2012 phenomena except for a single shot taken by Hubble on May 17, 1997, which did show a similar plume in a similar spot.

Ice crystals—whether made of water or carbon dioxide—were easy for the researchers to rule out. In addition to the altitude problem, the atmosphere would have to be significantly colder than it typically is at the height at which the plume was observed, and if the crystals were water ice, conditions would also have to be far wetter than they ever get so far above ground. The reflectivity of the plume was similar to what would be expected if light were bouncing off of ice crystals, but that doesn’t fix the other problems.

Dust was even less plausible. In this case, the reflectivity was all wrong and while so called “rocket dust storms” could, in theory blow dust to unprecedented altitudes, no such gales were observed on Mars at the time of the plume in 2012. All this was true of the 1997 plume as well.

And as for aurorae? They struck out too. Incoming solar energy was too weak at the time to put on such a sky show, and even if it had been, the plumes were too dim in the ultraviolet frequencies to be aurora-related.

The astronomy community as a whole seems untroubled that the study concluded with what amounts to a peer-reviewed who knows? “The observation is a big surprise,” said French astronomer Aymeic Spiga, in a statement put out by Nature. “Another puzzle on Mars!” And happily, the conspiracy community has not yet been heard from—whispering on as they did about the mysterious face on Mars photographed by the Viking 1 spacecraft in 1976, which turned out to be nothing more than a mound in the planet’s Cydonia region cast in evocative shadows on the day it was photographed. By 1998, the Mars Global Surveyor revealed that the formation had largely eroded away.

The plumes, if they prove anything, are merely one more sign that we have a great deal to learn about our close planetary neighbor. Life may or may not exist on Mars, but cosmic puzzles surely do.

Read next: Astronauts Vying for One-Way Ticket to Mars May Be on Reality TV

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TIME animals

Penguins No Longer Have a Strong Ability to Taste

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Getty Images

Sweet, bitter and umami flavors can no longer be detected by penguins

Penguins no longer taste their food the way most of the animal kingdom does, according to a new study.

According to the researchers, vertebrates usually have five tastes: sweet, sour, salty, bitter and umami. But after studying the genetic sequencing of Adelie and emperor penguins, analyzing penguin tissue, and comparing the birds genomes to 14 other non-penguin bird species, the researchers discovered that penguins have lost all but the salty and sour tastes.

“Penguins eat fish, so you would guess that they need the umami receptor genes, but for some reason they don’t have them,” said study author Jianzhi Zhang, a professor at the University of Michigan Department of Ecology and Evolutionary Biology in a statement. “These findings are surprising and puzzling, and we do not have a good explanation for them. But we have a few ideas.”

The researchers believe that perhaps over 20 million years ago, the freezing climates of the arctic somehow interfered with the penguins’ ability to taste.

The researchers of the new study, published in the journal Current Biology, were tipped off to the lack of taste among penguins when they were contacted by a genomics institute in China called BGI which had originally sequenced the genomes of the Adelie and emperor penguins and couldn’t find their taste genes.

The researchers there asked the University of Michigan researchers to take a second look to see if what they found was true. Unfortunately for the penguins, they may be missing out on the variety of flavors found in their favorite fish.

TIME space

Surprising Discovery From Really Old Moon Rocks

Where boots have tread: The Apollo 17 landing site, photographed by the Lunar Reconnaissance Orbiter, which revisited the moon in 2009. The lunar module descent stage, the lunar rover, scientific equipment and both footprints and tire tracks are visible.
NASA Where boots have tread: The Apollo 17 landing site, photographed by the Lunar Reconnaissance Orbiter, which revisited the moon in 2009. The lunar module descent stage, the lunar rover, scientific equipment and both footprints and tire tracks are visible.

Samples from Apollo 17, the final lunar landing, tell a violent tale of the early solar system

One of the biggest scientific surprises that came out of the rocks hauled back to Earth by the Apollo astronauts of 60’s and 70’s was the discovery that much of the Moon’s trademark cratering came during a single, catastrophic event. Known as the Late Heavy Bombardment, it was an unimaginably violent fusillade of asteroids or comets (or both) that tore through the inner Solar System about 3.8 billion years ago. The cause is still unknown, although theorists think it might have happened when Jupiter and Saturn readjusted their orbits and another giant planet was ejected from the Solar System entirely.

If the bombardment occurred at all, that is. But a paper in the new journal Science Advances suggests that maybe it didn’t—or at least, not all at once. “It’s not a bad theory,” says lead author Cameron Mercer, of Arizona State University, “and in some parts of the planetary science community, it’s accepted as gospel.”

Until now, the only direct evidence challenging the prevailing, single-bombardment theory had been pockets of impact-related melting in lunar rocks that appear to have been formed at different times. The measurements used as evidence, however, are somewhat crude and far from conclusive.

Now, however, Mercer and his co-authors have used ultraviolet lasers to study lunar samples brought back back by the final Apollo landing mission, Apollo 17, more than 42 years ago, and have found evidence of at least three major melting events, presumably caused by powerful impacts, at 3.8, 3.7 and 3.3 billion years ago. All of that evidence was found in just one rock, but another sample, collected a few hundred feet away, showed evidence of yet another bombardment, this one occurring 3.83 billion years ago. “This calls into question just how well we know the chronology of lunar impacts,” Mercer says.

The problem with the earlier estimates, says co-author Kip Hodges, also at Arizona State, is that they were based on samples weighing tens of milligrams—which is actually large when you’re looking for evidence than can be microscopic. Scientists would heat up the bits of rock, then measure the relative amounts of radioactive potassium-40 to argon that emerged. Since potassium decays into argon at a known rate, they could calculate how long it’s been since the rocks last melted.

But if there are pockets within the samples containing ancient, melted rock of different ages, you’d only get their average ages—and that’s what evidently happened, at least in some cases. The new analysis is a lot more precise: it looks at rock fragments a thousand times smaller. “Thirty-five years ago,” says Hodges, “all we could really say ‘there’s been melting,’ but now we can look with much finer resolution.”

The new analysis is based only on rocks from the Taurus-Littrow valley, where Apollo 17 touched down. Now, says Hodges, “we’ve begun work on rocks from Apollo 16, and we’ve got some coming from Apollo 15 as well.” If Taurus-Littrow alone experienced at least four impact events, there’s no telling how many more might be inferred from samples at the other sites.

Still, even if rocks from all six lunar landings are studied, they represent only a tiny fraction of the entire lunar surface. Extrapolating too much from them would be a little like collecting scoops of rock at half a dozen spots in North America and pretending you understand all of Earth’s geology. The lunar sample set remains narrow even if you add material returned by the Soviet Union’s robotic Luna probes and Moon rocks that have fallen to Earth as meteorites.

“If we want to know the real history,” says Hodges, “we need more samples. It’s really time,” he says, “to start thinking about going back.”

TIME Environment

Life May Have Thrived on Earth 3.2 Billion Years Ago, Study Says

Scientists had previously thought the earliest ecosystems were clinging on to an essentially uninhabitable planet

Scientists have found evidence that life on earth may have blossomed 3.2 billion years ago, a challenge to the previous theory that the planet was a hostile climate until 2 billion years ago.

Researchers from the University of Washington studied ancient rocks and found indications that 3.2 billion years ago life was sucking an essential nutrient, nitrogen, out of the air and converting it into larger structures, according to a report published in the weekly journal Nature.

“Imagining that this really complicated process is so old, and has operated in the same way for 3.2 billion years, I think is fascinating,” lead author Eva Stüeken told UW Today.

Nitrogen is an essential ingredient for life, as everything from viruses and bacteria to complex organisms use the nutrient to build genes.

The process that makes nitrogen easier for organisms to use, called nitrogen fixation, did not emerge until 2 billion years ago. This led scientists to theorize that the earliest ecosystems were clinging on to an essentially uninhabitable planet, but the new study shows that may not be accurate.

“Our work shows that there was no nitrogen crisis on the early earth, and therefore it could have supported a fairly large and diverse biosphere,” said study co-author Roger Buick.

TIME Research

A Quarter of New Psychotic Disorders Linked to ‘Skunk’ Cannabis, Study Says

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Nicholas Belton—Getty Images

Daily users of high-potency marijuana are five times more likely to suffer psychosis than those who never touch it

One in four new cases of psychotic disorders could be directly linked to the use of high-potency “skunk-like” cannabis, a new study has found.

Researchers from King’s College London found smokers of super-strength cannabis, colloquially known as skunk, were three times as likely to develop symptoms of a psychosis than those who don’t use the drug, the BBC reports.

That risk increases to five times as high if the user smokes skunk on a daily basis.

“The results show that psychosis risk in cannabis users depends on both the frequency of use and cannabis potency,” said Dr. Marta Di Forti, lead author of the study.

However, the team found that milder varieties of cannabis such as hashish did not increase the risk of psychotic illness.

Psychosis refers to hallucinations or delusions that can be found in certain psychiatric conditions such as schizophrenia or bipolar disorder.

Read next: Driving While Stoned Is Much Safer Than Driving Drunk, Says a New Study

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TIME space

NASA Wants to Send a Space Submarine to One of Saturn’s Moons

The submarine would explore Kraken Mare, a sea made of liquified natural gas

NASA has already sent rovers to Mars. Now it wants to send a space submarine to Saturn’s largest moon.

The federal space agency hopes to land a submarine to explore Kraken Mare, a methane sea on Saturn’s moon Titan, by 2040, according to a conference presentation. Titan is one of the only bodies in our solar system besides Earth with seas on its surface, though the Kraken Mare is freezing and made of liquified hydrocarbons.

Scientists plan to fly the Titan submarine in a space plane similar to the Boeing X-37. The plane will then drop the submarine into Kraken Mare where it can explore the sea floor’s composition, the tides, the weather and any life forms that may exist there.

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