TIME space

The Search for Extraterrestrial Air Pollution

A burned-out star, called a white dwarf.
A burned-out star, called a white dwarf. Universal History Archive/UIG/Getty Images

Alien factories could be a sign of life outside our solar system

Astrobiologists have come up with two basic ideas for how to find life on planets outside the solar system. The first is to look for telltale gases in exoplanets’ atmospheres, such as oxygen and methane, that would suggest the presence of some rudimentary life form, like bacteria. The second involves searching for radio or laser signals from some advanced alien civilizations—a longer shot, since the signals would have to be beamed in our direction — and who knows if aliens use lasers or radio?

But now a team of Harvard astronomers has come up with a third way: look for atmospheric gases generated not by biological processes, but by alien factories.

“I was very surprised,” says Avi Loeb, chair of Harvard’s astrophysics department and a co-author of a paper describing the technique, “that nobody has thought before about searching for industrial air pollution.”

It’s probably less surprising to others: Loeb is something of a master at asking nutty-sounding questions, then demonstrating that they’re not nearly as nutty as you might think. He co-authored one paper, for example, on how to look for cities on Pluto, and another on why it makes sense to look for habitable planets orbiting dead stars.

This latest effort is no exception. “It’s not crazy, at least as far as I can tell,” says Heather Knutson, a Caltech astronomer who specializes in looking at exoplanetary atmospheres, and who wasn’t involved in this research. “Avi in particular is willing to speculate on some pretty far-out topics, but no one doubts his ability to calculate the relevant physical models correctly.”

In this case, the relevant models involve chlorofluorocarbons, or CFC’s, the chemicals used in refrigerators and air conditioners. Unlike oxygen and methane, which occur naturally, CFC’s are almost entirely artificial. If an Earth-size planet had just ten times the atmospheric concentration of CFC’s that Earth does, Loeb and his co-authors, Harvard freshman Henry Lin and Smithsonian Observatory scientist Gonzalo Gonzalez Abad found, the gases could be detected with the powerful James Webb Space Telescope, slated for launch in 2018.

There are, Loeb admits, a couple of catches. First, the Webb can only pull this off if a planet in question orbits a white dwarf star—the tiny, white-hot ember left behind when a star like the Sun dies. That’s because the CFCs’ signature would appear as a distortion of starlight passing through the planet’s atmosphere. If the star is much bigger than the planet, most of the light hitting the telescope would bypass the planet entirely, and the distortion would be lost in the glare.

Another issue is that high concentrations of CFC’s might signal a civilization that has already managed to destroy itself. Some of these gases attack and destroy a planet’s protective ozone layer, which is why, here on Earth, the worst offenders were banned in 1987.

But it’s also possible that an alien civilization would have pumped its atmosphere full of CFC’s on purpose, says Loeb. “They act as greenhouse gases,” he says, “so if a planet were at the colder edge of its habitable zone, you could imagine using CFC’s to warm things up.” As for the ozone problem, he says, “they could in principle produce extra ozone as well, or design CFC’s that were less harmful.”

As with many of Loeb’s more speculative ideas, he’s not predicting that we’ll actually find CFC-laced exoplanets—just that we could if they happen to exist, and happen to orbit white-dwarf stars.

The odds of discovery via this method are probably very long. But as physicists Philip Morrison and Giuseppe Cocconi once said of the search for alien radio signals, “The probability of success is difficult to estimate, but if we never search, the chance of success is zero.”



TIME space

Here’s the Solar System’s Weirdest-Looking Comet

The OSIRIS instrument on the European Space Agency's Rosetta spacecraft photographed the mission's destination comet on July 14, 2014, from about 7,500 miles away.
The OSIRIS instrument on the European Space Agency's Rosetta spacecraft photographed the mission's destination comet on July 14, 2014, from about 7,500 miles away. ESA/Rosetta/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Comets are like movie stars—always more glamorous with their makeup on. A new spacecraft is about orbit and land on what might be the homeliest one ever

A comet has a lot to hide. To most people, it’s among the most glamorous objects in the solar system—brilliantly illuminated, racing through space with its glowing tail streaming far behind it. That, at least, is how comets look from great distances, and only when they’re close enough to the sun for the outward-flowing solar wind to light them up and produce those signature tails.

But deeper in space, without the solar floodlights? Not so much. There the comet reveals itself for what it is: a dirty snowball of ice and rock and not a whole lot more. There may be no comet for which that’s truer than the one known unlyrically as 67P/Churyumov-Gerasimenko, as this GIF made up of images taken by the fast-approaching Rosetta spacecraft reveals. The comet is a lumpy, two-lobed body, measuring about 1.8 mi by 3 mi. (3×5 km), which one astronomer compares to a rubber ducky, and most other folks would describe as just plain ugly.

But Rosetta is an anxious suitor all the same. The spacecraft, built by the European Space Agency, has been en route since its launch in 2004. Rosetta will rendezvous with the comet on August 6 and enter orbit around it shortly there after. In November, it will dispatch a small lander down to its surface—becoming the first spacecraft to master either of those maneuvers, never mind both.

The comet may never be much to look at up close, but the science it could yield—offering astronomers their closest ever look at one of the oldest artifacts of the ancient solar system—could more than make up for that. Appearance has never been everything—and in the case of a historic mission like this one, that’s truer than ever.

TIME space

So Where the Heck IS Voyager 1, Anyway?

Adios? Not so fast
Adios? Not so fast NASA/JPL

The first human built object to exit the solar system may not be gone after all

For a space probe that’s at least two decades beyond its sell-by date, Voyager 1 has a pretty impressive record of keeping itself in the news. Even more impressive is the fact that the topic is always the same. Either the aging craft, launched in 1977 to explore first Jupiter, then Saturn, has left the Solar System, en route to an eternal journey into deep space, or it hasn’t.

In 2003, for example, the reports were that Voyager had indeed left. But in 2010, it was merely getting ready to leave. Same thing in 2012. Then, last year, it definitely departed—but it didn’t leave the Solar System exactly. What it did do was depart the heliosphere, the region where the charged particles of the solar wind stream freely outward from the Sun before slamming into the particle clouds of interstellar space to form a shock wave known as the heliopause.

If you’re not confused enough already, you will be. It turns out that nobody actually knows whether Voyager really is outside the heliosphere at all, since all of the tests to date have been indirect, looking for charged particles and other clues that suggest but don’t prove anything. So now a pair of Voyager team scientists have proposed what they insist is a definitive test, in a paper accepted for publication in the journal Geophysical Research Letters.

If the spacecraft is still inside the heliosphere, they say, it should encounter something called the “current sheet,” a place where the Sun’s magnetic field flips from north to south. Even Voyager’s aging instruments could detect that event directly. “If that happens, I think if anyone still believes Voyager 1 is in the interstellar medium, they will really have something to explain,” said co-author George Gloeckler, a space scientist at the University of Michigan, in a press release.The moment of truth, Gloeckler believes, should come sometime in 2016.

Unless it doesn’t, of course. That will mean Voyager left last year after all. But even if the field reversal does happen, it could mean that the heliosphere itself is temporarily expanding, and has briefly caught up with Voyager. So Voyager left, but that, as Michael Corleone famously said in The Godfather, Part III, “Just when I thought I was out…they pull me back in.”

Whether Voyager is inside or outside the heliosphere, there’s no dispute about one thing: it has not left the Solar System, which is the collection of objects that orbit the Sun. The probe is currently about three times as distant as Pluto—but the orbiting Oort Cloud of proto-comets is far more distant than that. Voyager won’t cross that line for many thousands of years.

And at that point, if anyone’s still interested, you can expect a brand new flurry of “is it or isn’t it” stories.


TIME Outer Space

What’s Next For NASA? Asteroids!

NASA aims to continue their space exploration with their Asteroid Redirect Mission.


NASA has not sent astronauts to the moon since 1972. While that remains a historic event, President Barack Obama’s cancellation of the Constellation Program back in 2010 ended hopes indefinitely of the United States returning to the moon any time soon.

Still, that program’s death did not mark the end of NASA’s work and planetary exploration overall. The agency is currently working on its next target: catching an asteroid, pulling it into the moon’s orbit and sending astronauts to its location in order to study it.

The purpose of the mission, according to NASA, is for planetary defense, as the Earth has had instances of asteroid interference in very recent history. Scientists claim that in changing the orbit of an asteroid and studying its composition, Earth could protect itself from another asteroid crashing into its atmosphere.

The Asteroid Redirect Mission, should it be successful, could also be used as a testing ground for a possible mission to Mars in the near future.

TIME space

Chandra Observatory: 15 Years of Glorious Pictures

Human eyes don't know half of what they're missing. But the Chandra Observatory, with its x-ray vision, gives us a stunning peek.

You’ll never see the universe as beautifully as the Chandra Observatory can see it. That’s because Chandra—which is celebrating its 15th anniversary in high-Earth orbit—sees in x-ray frequencies and you don’t. It’s a pity, actually that we’re blind in that bandwidth, because so much of the cosmos makes itself known there. Signals coming from planets, comets, supernovas, from the dark matter in the vast spaces between galaxies, all emit x-ray energy. The portraits they paint, with false color added to make them visible to our eyes, are more than static snapshots. They are, instead, pictures of processes: of matter spinning down the eternal drain of the black hole at the center of our galaxy; of galaxies colliding and merging; of the cool gas swirling at the center of the Andromeda galaxy.

Chandra records all of these cosmic processes—bits of history really, since at their great distances many of them played out in the remote past. In its own short life, it has crossed many boundaries in terrestrial history too. The satellite was lofted by the shuttle Columbia in 1999—a ship that was destined for catastrophe just four years later. It left Earth at a time when the World Trade Towers stood; when Barack Obama was an Illinois State Senator, one year away from losing his bid for a seat in the U.S. House of Representatives; when no one had ever heard of an iPhone. That doesn’t seem like much in a universe whose chapters play out in epochs, not mere years. But for a fragile machine from a fragile planet, 15 long years of exploratory work aren’t bad—especially when the post cards it sends home are so improbably dazzling. —Jeffrey Kluger

TIME Science

45 Years Later: Remembering the First Moon Landing

The mission that made space history


Correction: The original version of this article incorrectly described which Apollo 11 crew members walked on the moon.

On July 16, 1969, a small group of astronauts took one small step for man, and one giant leap for mankind.

It’s been 45 years since Buzz Aldrin and Neil Armstrong became the first people to walk on the moon, leaving those back on Earth to stare at their television screens in awe. The men spent two hours collecting lunar rocks to bring back home to Earth to study.

To commemorate the milestone, the Slooh Space Camera will broadcast live footage from the moon on Sunday, July 20, at 8:30 E.T.

TIME space

See What the Raging Pacific Northwest Fires Look Like From Space


In a photo taken from the International Space Station, smoke blankets a large swath of the western United States

Wildfires across the Pacific Northwest have been blazing since Monday and have scorched large areas of forest as a result of hot, dry weather in Oregon and Washington. A total of 25 large, uncontained wildfires have burned hundreds of thousands of acres, with the single largest affected region in eastern Oregon’s Malheur County where about 369,000 acres of land has been burned. Incredibly, you can see smoke rising above the region from outer space. Reid Wiseman, an astronaut on the International Space Station, posted this photo on his Twitter feed.

TIME space

Apollo 11’s Rarely-Seen Outtakes

For the 45th Anniversary of the moon landing, TIME searched through NASA's archives for these rarely seen images

After 45 years, you’d think there is no picture of the historic Apollo 11 moon landing that hasn’t been seen a thousand times—but you’d be wrong. Like all travelers, Neil Armstrong, Buzz Aldrin and Michael Collins shot a whole lot of frames, and not all of them were keepers. NASA did keep every one of them, of course. Here a few of that are rarely published—mixed with some of the iconic ones that capture best just how extraordinary that long-ago mission was.

TIME space

45 Years Later: 5 GIFs of NASA’s First Moon Landing

On July 20, 1969, Neil Armstrong and Buzz Aldrin became the first two people to land on the lunar surface, while their third crew member, Michael Collins, continued to orbit around the moon. Armstrong and Aldrin arrived in the Lunar Module (LM) Eagle, one of three parts of the Apollo 11 spacecraft which also included a Command Module (CM) Columbia and a Command Service Module (CSM) to support Columbia. Approximately six and half hours after a rocky landing, Armstrong and Aldrin exited the LM and set foot on the moon to begin their Extra Vehicular Activities (EVA), with Armstrong uttering his now famous words, “That’s one small step for man, one giant leap for mankind.”

In addition to performing several experiments and collecting samples from the lunar surface, the two meticulously photographed every stage of the EVA with specially designed Hasselblad cameras (one of which was actually left on the moon to help lighten the load on the LM as they returned to Columbia).

All of the images taken by Aldrin and Armstrong were scanned and archived, and are available to the public through NASA’s Apollo Lunar Surface Journal. Below, in honor of the 45th anniversary of the moon landing, TIME has assembled 5 GIFs from Aldrin, Armstrong, and Collins’ images showing in detail some of the historic moments captured by the Apollo 11 crew.

  • Buzz Aldrin Descends The Lunar Module Ladder

    Buzz Aldrin descends the Lunar Module ladder
    Neil Armstrong—NASA (5); Gif by Mia Tramz for TIME

    Neil Armstrong took two photos of Buzz Aldrin coming out of the hatch of the Lunar Module, and the four more photos as he climbed down the LM’s ladder and hit the foot pad. Aldrin’s ops antenna is visible in the last frame.

  • Buzz Aldrin Makes a Lunar Foot Print

    Buzz Aldrin's foot print on the moon
    Buzz Aldrin—NASA (3); Gif by Mia Tramz for TIME

    In this series of three images, Buzz Aldrin photographs the lunar surface before and after making a foot print on it. He had taken his camera off it its RCU bracket and shot these pictures holding the camera in his gloved hands. This 16mm movie camera mounted in his LM window captured Aldrin on film taking these pictures.

  • Buzz Aldrin Sets Up the EASEP

    Buzz Aldrin sets up the EASEP
    Neil Armstrong—NASA (7); Gif by Mia Tramz for TIME

    In this series of images, Armstrong captures Aldrin setting up the EASEP (Early Apollo Surface Experiments Package). Aldrin has the LRRR (Laser Ranging Retro Reflector) in his right hand, and the seismometer package in his left hand. As of December 2010, the retroreflectors were still being used in conjunction with a dedicated facility at the MacDondald Observatory in Texas.

  • Earthrise Captured from the Command Module

    Earthrise captured from the Command Module
    NASA (8); Gif by Mia Tramz for TIME

    A view of the Earthrise taken from the Command Module Columbia as it was passing over Mare Smythii. Australia is visible at the left on Earth’s surface, just above the lunar horizon.

  • Apollo 11 Lunar Module Rendevous with Command Module

    Apollo 11 Lunar Module Rendevous with Command Module
    Michael Collins—NASA (13); Gif by Mia Tramz for TIME

    This series of images captures the Lunar Module approaching the Command Service Module at rendezvous and was shot handheld by astronaut Michael Collins. Earthrise is visible in the last four frames.

TIME space

United Arab Emirates Says It Will Go To Mars By 2021

Mars Digital Vision/Getty Images

A bold announcement by the United Arab Emirates is more than just an idle boast

The big news out of the Middle East this week is mostly about war and other kinds of tribulation, as it was last week and probably will for weeks to come. War and tribulation, that is, plus a mission to Mars.

According to a report by Reuters, the United Arab Emirates announced it would be creating a space agency by 2021 and sending an umanned probe to the Red Planet—something only the U.S., the USSR/Russian Federation and the European Space Agency have done with any success, while the British, Japanese and Chinese have tried and failed. The jury is still out on an Indian probe, which is currently en route.

So can they do it, or is this just some crazy stunt the UAE hopes nobody will remember when the time comes? The answer: it’s not necessarily crazy. True, the country has no aerospace industry, but a government-backed group based in the Persian Gulf country bought nearly a third of Richard Branson’s Virgin Galactic, a private space tourism company. Moreover, says John Logsdon, a space policy expert and professor emeritus at George Washington University, “The UAE has already been active in space with communications satellites and Earth observation satellites.”

They’ve done this, he says, by purchasing both satellites and launch services from other countries, and they’d almost certainly put together a Mars probe the same way. “Most of the technical work and the launch would be contracted out,” he speculates, “but some of the components could be developed internally.” If that happened, and if UAE space agency engineers were in charge of mission control, he says, “they could appropriately claim that this mission was their own.”

Given the UAE’s deep pockets, it’s certainly possible that the country could pull off such a project, which would bring a new kind of prestige to the region. The Arab world did invent algebra and enjoyed a golden age of science for centuries leading up to the Medieval period and many Arabs dream of the return to that kind of scientific ascendancy. Recent, eye-catching projects—including the successful construction of the world’s tallest building and the world’s largest indoor ski resort—hint at inventive potential.

A Mars mission would obviously be a bit more ambitious, but in the end, it’s really just rocket science, which isn’t as complicated as we sometimes tend to think. Still, it’s one thing to say you’re going to do something like this and quite another to do it. After all, in 1969, NASA was similarly talking about our own manned mission to Mars—with astronauts aboard—in what was then the near future. It could be done, said Wernher von Braun, the rocket engineer behind that year’s successful Moon landing, by 1982.

But it never happened, and who knows if it ever will? The UAE, aided by expertise from other countries, can certainly get a probe to Mars by 2021, in theory.

Whether they’ll actually do it is whole different story.

Your browser, Internet Explorer 8 or below, is out of date. It has known security flaws and may not display all features of this and other websites.

Learn how to update your browser