TIME space

You Can Quit Thanking Comets for Your Water

Comet 67P: Does this thing look like it could quench your thirst?
Comet 67P: Does this thing look like it could quench your thirst? ESA

A new finding from the Rosetta spacecraft upsets a longstanding theory

There was no shortage of drama when the European Space Agency’s probe Philae set down on a comet last month—the first such landing in history. First Philae bounced, then it bounced again, ending up with one of its three legs sticking up in the air, and in the shadow of a cliff that prevented its solar panels from recharging its batteries. For two days, the probe hurried to complete whatever science it could….and then everything went black.

But that hardly spelled the end of the mission. Philae’s mother ship, Rosetta, has continued to orbit comet 67P/Churyumov–Gerasimenko, as it’s been doing since August, taking measurements and images of unprecedented quality. And with nearly a year of close-up observations to go, Rosetta has already come up with one result, described in a new paper in Science, that chief scientist Matt Taylor, of the European Space Agency, labeled “fantastic”: Earth’s oceans, the scientists have concluded, were evidently not created by impacts from comets rich with water ice, despite earlier evidence to the contrary. “We have to conclude instead,” said lead author Kathrin Altwegg, a planetary scientist at the University of Bern, at a press conference, “that the water came from asteroids.”

That’s a big reversal from what scientists were thinking just a few years ago. Back in 2011, the European Herschel space telescope took a hard look at Comet Hartley 2 and determined that its own cache of water, detected as vapor boiling away as Hartley approached the Sun, had a chemical composition very similar to what we see on Earth. It’s all H2O, but some of the H is a rare form of hydrogen known as deuterium, whose atoms carry not just a proton like the ordinary stuff, but a neutron as well. Water molecules made with deuterium are known as “heavy water,” and about three in a thousand water molecules on Earth’s surface are the heavy kind.

Measurements of Halley’s Comet back in the mid-80’s showed a deuterium-to-hydrogen ratio about twice that high, which argued against the idea that comets delivered water to a bone-dry Earth early in the Solar System’s history. But Halley’s came from the Oort Cloud, a spherical swarm of proto-comets orbiting at the far edges of the Solar System. Hartley 2 came from the Kuiper Belt of comets, which lies just beyond Neptune–not exactly nearby, but a whole lot closer. Given what Herschel found at Hartley 2, it appeared that Kuiper belt comets are chemically different from those that hail from the Oort cloud. If so, our water could have cometary origins after all.

The new results from Rosetta say no: Comet 67P, which also comes from the Kuiper belt, has an even greater proportion of heavy water than Halley’s and other Oort cloud objects. Even if significant numbers of comets do have Earthlike water, some clearly don’t—and even a relative few would have made Earth’s proportion of heavy water higher than it is. It’s arguable that 67P is pretty much unique among its Kuiper Belt brethren in having so much deuterium. “That’s not impossible,” said Altwegg dubiously “but….”

If comets didn’t bring us water, and if the Earth was too hot in its youth to hold on to what surface water it might have started out with, there’s still one plausible water carrier. “Today, said Taylor at the press conference, “we know asteroids have very little water, but that was probably not always the case.” The solar system was bombarded by asteroids early in its history, and if they were indeed wetter than they are now, that explains where the water in our oceans, in our seltzer bottles, in our bodies and everywhere else comes from.

Important as this new finding is, it’s likely to be only the first of many Rosetta will make as it rides along with 67P for the next year or so, watching carefully as the warming rays of the Sun bring the comet to life. “It’s a nice start to the science phase of the mission,” Taylor said.

And if you think you’ve heard the last of the Philae lander, think again. Mission controllers are still trying to pinpoint Philae’s precise location on 67P’s surface. That will allow scientists to do at least one more experiment: they’ll send radio pings from Rosetta through body of the comet to bounce off Philae and back to Rosetta. By examining how the radio beams are altered en route, they will be able to figure out whether 67P’s insides are rock-solid or held together relatively loosely.

Locating Philae would also allow scientists to calculate whether the lander might be brought back from the dead six months from now. It’s just possible, said Taylor, that a change in 67P’s orientation could bring Philae back into the sunlight, allowing its solar panels to recharge its batteries. If that happens, the prospects for extraordinary science from this already wildly successful mission will be even greater.

TIME space

Strange Visitors From the Edge of the Solar System

Sometimes a comet isn't a comet
Sometimes a comet isn't a comet Art Montes De Oca; Getty Images

A pair of sort-of comets pose a puzzle for astronomers

The term “Oort Cloud” may be obscure for many people, but it’s familiar terrain for astronomy buffs. It’s a giant spherical swarm of trillions of proto-comets, lurking at the outer fringes of the Solar System, so far away that it may stretch a quarter of the way to the nearest star. They’re proto because they’re not technically comets unless they get knocked out of orbit and fall toward the heat of the Sun, whose warmth turns their long-frozen ices into a halo of dusty gas and, sometimes, a tail as well.

A pair of very unusual objects announced at last week’s Planetary Science Meeting in Tucson, however, have complicated this seemingly straightforward story. The first, found in 2013, has an orbit that clearly shows it came from the Oort Cloud—but while it resembles a comet in some ways, it didn’t light up like one even after it warmed. The second, found just this past September, also came from the fringes of the Solar System. This one doesn’t even resemble a comet, let alone act like one: it looks more like a rocky asteroid.

Except asteroids aren’t supposed to live in the Oort Cloud—and that creates just the sort of mystery scientists love. “We’re all very excited,” admits Karen Meech, of the University of Hawaii, who led the discovery team. But while both objects surprised researchers, both turn out to confirm two pieces of cosmic wisdom, one from a half-century ago and the other much more recent.

The old wisdom comes from Jan Oort himself, the mid-20th-century Dutch astronomer the Oort cloud is named for. He theorized that long-period comets, with highly elongated orbits lasting more than 200 years, came from a distant, spherical cloud that surrounds the Solar System. “He figured this out based on just 13 comets,” says Meech. “It’s really amazing.”

The idea is that the comets formed closer in, along with the rest of the Solar System, but that many were flung outward in gravitational interactions with Neptune and other giant planets. That notion was reinforced long after Oort’s time, when planetary scientists realized that the giant planets might have changed their orbits significantly soon after they were born; that motion would have ejected icy bodies in vast numbers.

Oort also suggested that the objects that eventually fell in again would be especially bright the first time around, since they’d have lots of ice on their surfaces—precisely what happened when Comet Hale-Bopp showed up in 1997. “On their very first passage through the inner Solar System,” says Meech, “all of that sublimates away, so after that you just don’t see them.”

The object discovered in 2013, she says, which is known as (deep breath) C/2013 P2 Pan-STARRS, fits the profile of what an Oort cloud comet should look like on a second or later return to the inner Solar System, and, says Meech “it may be proof at last that Oort was correct.”

Even as the astronomers were trying to figure out what they were seeing, though, the second object, C/2014 S3 Pan-STARRS, showed up (in both cases, the objects were found by the Pan-STARRS1 telescope, atop Mauna Kea, in Hawaii). It didn’t act like a comet either, but unlike the first object, it also didn’t much resemble one, as a close look at its composition revealed.

And that seems to support an idea advanced back in 2011 by Kevin Walsh, of the Southwest Research Institute, along with several colleagues. Their computer models of the newborn Solar System found that the giant planets should indeed have migrated from their original positions, moving first in toward the Sun, then out to where they are today. As they moved out, says Meech, “they would have dragged about fourteen Earth masses worth of material with them and thrown it outward.”

That material, in the form of asteroids, could have ended up in the Oort Cloud along with the proto-comets. Even as recently as a decade ago, this theory would have seemed crazy. Now—as so often happens—the very old solar system is teaching us something very new.

TIME space

Asteroid in a Bag? Bag it, Says MIT Space Scientist

Bad trip? Solar electric propulsion would help redirect an asteroid to lunar orbit
Bad trip? Solar electric propulsion would help redirect an asteroid to lunar orbit NASA

NASA's next great manned mission has always sounded like something of a fever dream. There may be a better way to do the same work.

MIT planetary scientist Richard Binzel calls himself an “asteroid guy.” He’s been studying the rocky planetoids for decades now, so you might think he’d be thrilled with NASA’s plan to snag a very small asteroid in a very large bag and tow it into lunar orbit for astronauts to visit.

In fact, he’s anything but. At a talk last summer, Binzel called the Asteroid Return Mission (or ARM) “the emperor with no clothes, or at best with very thin cloth.” And now he’s written a commentary in the latest issue of Nature laying out his objections in greater detail, but also proposing an alternative. Instead of bringing one of the solar system’s uncounted asteroids to us, he says, we should send astronauts to visit them in a program that could ultimately lead to the goal people have been looking toward since the Space Age began: sending astronauts to Mars.

“In fairness,” Binzel says, “NASA doesn’t really know what to do with its hardware.” That’s never a good thing. Back in 2010, President Obama officially killed the plan to send astronauts back to the Moon and began pushing instead for a visit to an asteroid by 2025. “NASA took that as a mandate,” says Binzel. When they realized they couldn’t pull it off by then with the available budget, he says, they came up with ARM, which quickly became known as “Asteroid in a Bag”—a term that suggests the space community didn’t exactly take it seriously.

But asteroids are whizzing by Earth all the time, and we don’t know about most of them. “The ones we’ve detected so far,” says Binzel, “aren’t the tip of the iceberg. They’re the snowflake on the tip of iceberg.” An asteroid a few miles across can cause the sort of planetwide catastrophe that played a big part in ending the dinosaurs’ dominance of the Earth. And even a smallish one, like the 60-foot rock that fell near Chelyabinsk, Russia last year (and which Binzel helped investigate) can do plenty of damage.

The first part of Binzel’s proposed three-part program, therefore, is to mount an exhaustive telescopic search for Near-Earth Asteroids, or NEO’s, ten meters (33 ft.) across or bigger. He estimates there are about ten million of them—so many, he says, that “at least one passes by as close as the Moon every week (NASA is searching for them already, but there are still plenty of rocks going undetected).

ID’ing the NEO’s that pose a threat is a good thing on its own merits, but these are also the ones that would be easiest for astronauts to visit. The idea, says Binzel: spot a likely candidate as it approaches the Earth and send astronauts out to match its orbit—something like the way relay runners start sprinting before their partner arrives so they’re going at the same speed at the point of baton handoff. “They’d go out and greet it,” he says, “and follow alongside for a few days.” Then the astronauts would peel off and circle back to Earth.

While hanging out with the asteroid, astronauts could do all sorts of exploration. They couldn’t land themselves, because a small asteroid has too little gravity to keep a human from floating off, but they could use robotic landers to beam back all sorts of information, bring samples back for study in Earthly labs, and even prospect for minerals. Astronauts could also test deflection technologies that could someday be used to push a killer asteroid off course to keep Earth safe.

Best of all, says Binzel, a series of asteroid missions of longer and longer durations means you don’t have to jump to Mars all at once without practicing long-distance and long-duration spaceflight first. NASA can flex its exploratory muscles bit by bit, preparing for that ultimate leap. The image he keeps returning to is that of the Gateway Arch, in St. Louis—the great portal to America’s West. When Lewis and Clark returned with their maps of the vast spaces of still untouched mountains and prairies, says Binzel, who has a painting of the adventurers in his MIT office, “it triggered an enormous wave of exploration. Imagine,” he says, “that we knew of a thousand or even thousands of objects that were readily accessible to human spaceflight.” Retrieval gets you one object; a survey will find thousands at a fraction of the cost. What’s not to like?

Read next: Watch This Pilot’s Dramatic Midair Video of the Antares Rocket Explosion


Dead Space Telescope Lives Again!

Kepler, in an artist's rendering: orbiting close to home, but looking far, far away
Kepler, in an artist's rendering: orbiting close to home, but looking far, far away Detlev van Ravenswaay; Getty Images/Picture Press RM

Broken machines don't always get a second act, but thanks to NASA scientists, the Kepler probe—one of the most successful spacecraft ever built—can continue its search for distant planets.

The Kepler telescope has just been resurrected by NASA, nearly a year after it was declared effectively dead, having lost its ability to orient itself with sufficient precision to do it’s job. That’s very big news if you’re interested in, well, the entire galaxy—and here’s why.

The mission of the Kepler probe, which was launched in 2009, was to hunt for planets circling distant stars, a job it does by looking for tiny dips in the stars’ light, which would suggest that something was briefly getting between the telescope and the star. That something—depending on how regular and cyclical the dip in light was—could turn out to be an orbiting planet. Kepler has been wildly successful at its work: in February, it added 715 new planets to its list, bringing its grand total to 962 (the new ones came from data that hadn’t yet been analyzed when Kepler went dark). But with only two working reaction wheels—the devices that make super-accurate pointing possible—the probe just wasn’t steady enough to do the job.

As happens more often than people appreciate, however, NASA scientists came up with an ingenious workaround, so the agency is ponying up two more years’ worth of funding to put the spacecraft back to work. In Kepler’s second life (or its re-animation as a zombie, if you like that idea better), the satellite will use radiation pressure from the Sun to keep it from wobbling. Here’s what we said when the idea was proposed to NASA earlier this year:

What the engineers realized was that they could improve Kepler’s stability by aligning it with the particles of solar wind that stream constantly from the Sun. “It’s like a rowboat pointing upstream,” says [Kepler Deputy Project Manager Charlie] Sobeck. It’s not perfectly stable—the boat, or the spacecraft, will eventually swing around. But it takes only gentle adjustments to correct that drift, and the two remaining reaction wheels are powerful enough to make those tweaks.

Pointing upwind means Kepler can look only out in the direction of the ecliptic—the apparent path of the Sun through the sky during the year (it’s where the constellations of the Zodiac sit), though of course the telescope will always point directly away from the Sun. While the original Kepler field of view lies outside the ecliptic, there are plenty of stars, with plenty of planets to discover, in Kepler’s new, ever-changing field.

Kepler will also be able to pick up exploding stars in distant galaxies, which could help solve the mystery of dark energy, and search for potential killer asteroids as well. And it will keep searching for planets, although it’s now limited to the brightest and closest stars.

Part of the Kepler story has always been the long, arduous road NASA scientists William Borucki trod to get the spaceship off the ground: he came up with the idea in the mid-1980s, and his proposed mission was rejected either four or five times by NASA, depending on how you count, before it was finally approved. Even if the spacecraft fell out of the sky tomorrow, it would be still considered an unalloyed triumph. Now that it’s back in action, expect plenty more discoveries from the telescope that came back from the dead.

TIME asteroids

No, We’re Not All Gonna Die From An Asteroid

Bullseye: A hole left in a frozen lake in Chelyabinsk, thought to have been punched out by a fragment of the meteor that struck in 2013.
Bullseye: A hole left in a frozen lake in Chelyabinsk, thought to have been punched out by a fragment of the meteor that struck in 2013. The Asahi Shimbun

A new report spreads fear about the Earth getting clobbered by a killer rock. But the fact is we get hit all the time and we just don't know it. Move on, nothing to see here (at least for now)

Tell the truth: Did you stay inside today? If you did, was any of it due to the sky-is-falling (literally), Earth-shaking (again, literally) reports that at any moment we could be hit by a city-killing meteor? According to research by Peter Brown of the Meteor Physics Group at the University of Western Ontario, since 2000, there have been 26 meteors that exploded in the Earth’s atmosphere and released the equivalent of at least 1,000 tons of TNT (1 kiloton); four of those packed a bigger punch than the 16-kiloton bomb that leveled Hiroshima.

So scary news, right? Well, not necessarily.

First of all, remember that “exploded in the Earth’s atmosphere” part? That’s no small thing. The atmosphere has been pretty effectively protecting us from harm for a long, long time. Picture the surface of the moon; now picture the surface of the Earth. That’s the difference between a world that stands exposed to the shooting gallery of space and a world that, in effect, wears a bullet-proof vest (OK, plate tectonics and volcanoes resurface the Earth and cover up craters, but not nearly enough to fix the kind of damage that’s been done on the moon).

What’s more, those 26 space rocks over the past 14 years are just the tiniest fraction of the amount of space rubble that rains down on us harmlessly all the time. According to Don Yeomans of the Jet Propulsion Laboratory’s Near Earth Object Program Office—the NASA outfit that tracks the sky for dangerous space ordnance—about 100 tons of rocks and dust enter the atmosphere every day. Most of it is the size of a pea or even a sand grain, he says. But there’s at least one basketball-sized object each day and one as big as a Volkswagen each month—and none of them hurt us.

If the only damage a bigger space rock could do was drill a hole in the ground no larger than itself, there wouldn’t be much to worry about. But the faster an asteroid moves the more energy it’s carrying, and when that energy is released—either in the atmosphere or on the ground—it is indeed like a bomb going off. The asteroid that exploded over the Tunguska region in Russia in 1908 measured only about as far across as a football field and yet unleashed a 40-megaton (or 40 million tons of TNT) blast, wiping out trees across an 825 sq. mi. (2,136 sq. km) footprint of forest. The 2013 Chelyabinsk asteroid that also exploded over Russia, injuring 1,000 people, measured just 66 ft. (20 m) across

Yeomans calculates that his office has now has now found 95% of the asteroids 1 kilometer (.6 mi.) or larger that could do damage on a global scale—say, causing the kind of climate disruption that wiped out the dinosaurs—and 30% of the ones 140 meters (460 ft.) across that could do local or regional damage. Knowing the rocks’ trajectory gives us a chance either to deflect them or at least evacuate the area they’d hit in the unlikely event they were on a collision course with Earth. So is he worried about what Brown and his colleagues in Canada have discovered?

“They’ve taken their data and plotted it up and made it look interesting,” he says. “But there’s only one meteor [Chelyabinsk] that could have done—and did do—any damage.”

The rest? Well, we kind of knew they were there all along. It’s a little like knowing there’s only one burglary in your neighborhood every 10 years, and then learning that three would-be burglars in the vicinity are arrested every week. That’s scary, but all it means is that the police are doing their job—just like the atmosphere is doing its. What’s more, the Canadian findings were publicized in part by an independent group called the B612 Foundation that is trying to raise money for an infrared space telescope that would also hunt for dangerous objects. The people behind B612 are legitimate scientists and include two former astronauts, and NASA plans to use their data if they ever get their instrument launched, but the fact remains that they’re currently seeking backers and it never hurts to play up the stakes.

“They’re in a sales mode,” Yeomans says bluntly.

Even if the B612 group has something important to sell, that doesn’t mean the end is imminent. The Earth has been around for 4.5 billion years; we’ve probably got a pretty good run left.

TIME astronomy

The Next ‘City-Killer’ Asteroid Could Be Closer Than We Think

Asteroid Hit
A February 15, 2013 photo shows a meteorite contrail over the Ural Mountains' city of Chelyabinsk in Russia. Yekaterina Pustynnikova—Associated Press

Asteroid impacts on Earth are three to ten times more common than we imagined, new data shows, with researchers saying that only “blind luck” is preventing a disastrous strike from a "city killer" asteroid

Asteroids as powerful as atomic bombs may hit the Earth more often than we previously thought.

New data shows how and where 26 asteroids collided with our planet from 2000 to 2013, according to research released in a video by the B612 Foundation.

“It shows that asteroid impacts are not rare, but actually three to ten times more common than we previously thought,” said Edward Lu, a member of the B612 Foundation, which was founded by two former astronauts to raise money for a space telescope to spot asteroids heading toward Earth.

“The fact that none of these asteroid impacts shown in the video was detected in advance, is proof that the only thing preventing a catastrophe from a ‘city-killer’ sized asteroid is blind luck,” he added.

B612 Impact Video 4-20-14 H264 from D Josh Rosen on Vimeo.


WANTED: Asteroid Hunters


NASA is enlisting lay people to help locate asteroids as part of its new Grand Challenge

NASA is offering $35,000 in awards to citizen scientists who can help locate asteroids that pose a threat to earth. The “Asteroid Data Hunter” contest is the first in NASA’s “Grand Challenge” series announced in June that is centered on locating asteroid threats to human populations.

Entrants will compete to create algorithms that can improve the images ground-based telescopes capture of asteroids. The winning algorithim must, “increase the detection sensitivity, minimize the number of false positives, ignore imperfections in the data, and run effectively on all computer systems.” Details of the contest, which will take place over the next six months, were revealed at the South by Southwest conference in Austin on Monday as well as online. Registration starts March 17.

“Current asteroid detection initiatives are only tracking one percent of the estimated objects that orbit the Sun,” said Chris Lewicki, President and Chief Engineer of the asteroid mining company Planetary Resources, Inc., which is partnering with NASA on the contest. “Applying distributed algorithm and coding skills to the extensive NASA-funded Catalina Sky Survey data set will yield important insights into the state of the art in detecting asteroids.”


10 Science Myths That Won’t Go Away

These are cannoli, they are not astronauts
These are cannoli, they are not astronauts Getty Images

They're everywhere, they're maddening—and they just ain't so. Here, in no particular order, is the incomplete, and by no means definitive, often painful list of the most common scientific misconceptions out there

I was walking around midtown Manhattan this week when I noticed a news organization with its zipper open. The zipper in question was the headline ticker around a media building on Sixth Avenue, and the news it was announcing was that a group of amateur astronomers in Sicily had just launched a cannoli into space, sending it into the stratosphere attached to a balloon. According to the zipper, the cannoli achieved “low orbit.”

OK, leave aside for the moment that the Sicilian Major Tom made it no higher than 18 miles (30 km), which looks a little like space, but isn’t. Going into orbit, even a “low” one, requires not only much more altitude—on the order of 100 miles (160 km)—but much more speed, at least 17,500 miles per hour in the flat (28,100 km/h). The balloon, you might expect, didn’t quite achieve that.

In fairness, science errors are everywhere and if-it’s-high-up-it-must-be-in-orbit is a comparatively mild one. In no particular order, here is the incomplete, by no means definitive, often painful list of the ten most common scientific misconceptions.

You can kill a virus: No you can’t. You can deactivate it, destroy it, but you can’t kill it. The reason: it wasn’t alive to begin with. One of the requirements for life is the ability to reproduce and the virus is out of luck on that score. It survives only by carjacking a cell first.

Jonas Salk discovered the cure for polio: Discovered? You mean like the last guy who used his desk left the recipe in a drawer? It took eight years of work in a basement lab at the University of Pittsburgh to do what he did. And it wasn’t a cure—there’s never been a cure. Salk created a vaccine, which means, even now, that if you don’t get it and you contract the disease, there’s no help for you. Listen up, anti-vaxxers.

The dark side of the moon: Pink Floyd, I blame you. For the last time: the moon has no dark side. It does have a far side—which has just the same waxing and waning light the near side does. Album titles ain’t science.

Asteroid, meteor, meteorite, what’s the diff? Location, location, location. An asteroid is a big rock that’s out there. A meteor is a big rock that hits our atmosphere. A meteorite is any chunk that hits the ground—or your house or your head.

It’s hot outside: Depends. The temperature at the center of the sun is 27 million °F (15 million °C). The hottest temperature ever achieved in a particle accelerator was 7.2 trillion °F (4 trillion °C). By contrast, the coldest temperature possible, known as absolute zero, is -460 °F (270 °C). In other words, we live only about 500 degrees from the rock bottom of the temperature scale and trillions of degrees from the top. Bundle up.

If it’s called a theory, it’s the same as a hunch: That’s true sometimes, when you’re just beginning to look into a phenomenon. But after a while, the word merely means that you didn’t actually see the event play out—even if all the evidence tells you what happened. The theory of evolution? A fact. The Big Bang theory? A fact. But unless you’re 13.8 billion years old, you weren’t here to witness it all.

Lightning doesn’t strike twice in the same place: Lightning actually doesn’t care. Tall buildings get zapped a lot. Park ranger Roy Sullivan was lit up seven times in his career—before committing suicide in 1983. Can you blame him?

The seasons are caused by distance from the sun: Seems to make sense. When the northern hemisphere leans toward the sun it’s closer and so it’s warmer; when it leans away, its further so it’s colder. But that’s not it. The Earth is 93 million miles away from the solar fires, so a little tilt this way or that doesn’t really matter. It’s the angle at which the sunlight hits—low and oblique versus straight on and hot—that makes the difference.

Primitive humans and dinosaurs crossed paths: Yes, there are people who continue to believe that. No, it’s not true. We were separated by a good 65 million years. Indeed, it’s the extinction of the dinosaurs that made room for little rodent-like mammals (read: your ancestors) to venture out of the shadows and take over the world in the first place. Wilma, we’re home!

One false move and a particle accelerator will kill us all: There was a lot of hand-wringing about this back in 2008 when the Large Hadron Collider was about to be switched on and doomsayers predicted it would create an artificial black hole that would eat Europe. It’s true that some of the most powerful and violent events in the universe are recreated in colliders, but in miniature—a few harmless particles at a time. Relax and enjoy the bosons.

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