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Scientists Seek Your Help to Photograph Another Sun's "Pale Blue Dot"

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A simulation of the “pale blue dot”—an Earth-like planet—Project Blue hopes to capture orbiting a star in Alpha Centauri. The color could be attributed to the presence of a substantial atmosphere that allows liquid water to exist on the planet’s surface. Image credit: Jared Males.

 
In 1990, the Voyager I spacecraft took a mosaic of images known as the “family portrait”―a view of the solar system from a distance of 6 billion kilometers. In the image, Earth is captured as a single pixel later immortalized by Carl Sagan, who put the affairs of our “pale blue dot,” as he called it, into perspective:

On it, everyone you ever heard of, every human being who ever lived, lived out their lives. The aggregate of all our joys and sufferings, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilizations, every king and peasant, every young couple in love, every hopeful child, every mother and father, every inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species, lived there—on a mote of dust, suspended in a sunbeam.

The past 26 years have yielded astonishing and wonderful revelations about the cosmos, including proof of the existence of exoplanets―worlds orbiting other stars―with many of them in “habitable zones” around their suns, areas where it’s not too hot and not too cold. These are planets, in other words, that might support life.

For all the artistic renditions, however, and the hypotheses of what such worlds might be like, the totality of our images of those planets exist mostly as waveform graphs, with a scattering of thermal images of gas giants analogous to Jupiter. No rocky world in a habitable zone has ever been imaged directly. Their stars are billions of times brighter than they are, and there is no hardware in space able to “turn off” the light of the star without turning off the habitable-zone planet.

Project Blue intends to change that. It is an effort by a group of scientists, engineers, and space organizations to launch a small telescope into space with the singular goal of directly imaging in visible light (i.e. the light we see with our own eyes) an Earth-like planet around one or more of the stars of Alpha Centauri, and to do so using private funds. Not only might the mission redefine humanity’s place in the universe, but it might also redefine how planetary science missions are funded, launched, and operated.

THE NULL RESULT

Since the 1990s, astronomers have been rigorously engaged in the study of Alpha Centauri, the closest star system to our own, and people have been talking about imaging planets around nearby stars for nearly as long. The Project Blue team, comprised of some of the best minds in the field, came together this summer to work through and settle on the different technical concepts that have long been considered necessary for this sort of mission. A perennial roadblock has been funding—it's simply been too expensive to mount this sort of mission. That roadblock has finally given way.

Even when it was too expensive to attempt the imaging of a habitable exoplanet in Alpha Centauri, however, it was still a good bet. The Project Blue team has chosen to focus on the binary stars Alpha Centauri A and B. The stars are close to our solar system, relatively speaking, which means a space telescope needs only a half-meter mirror. Because the system contains two stars, there is promising potential for discovery. In fact, the Kepler space observatory already discovered a planet around Alpha Centauri B in 2012, though it could not be described as habitable: Its orbit is just 6 million kilometers from its star. (Just this summer, Kepler spotted a planet orbiting Proxima Centauri, a smaller, dimmer star that is closest to our Sun. It, too, has a tight orbit.) 

As for finding a habitable world, imagine you flip two coins. The possible results are: both coins turning up heads; one turning up heads, the other turning up tails; or both turning up tails. If you’re betting on heads, those are great odds. Consider further that in our own solar system, there are three planets in the habitable zone: Venus, Earth, and Mars. (Obviously, only one of the trio is a habitable blue dot.) Suddenly the likelihood of Project Blue successfully photographing something seems a lot higher.

To capture the image, Project Blue will launch a space telescope the size of a small washing machine, equipped with a coronagraph and deformable mirror. A coronagraph can "turn off" the light of the alien suns. That light is focused by the mirror. Because the twin stars in Alpha Centauri are so much like our own Sun, astronomers know where to look to find their habitable zones, and where planets have to be in those zones to host liquid water. Therein lies the key difference between NASA space telescopes and the one to be launched by Project Blue: NASA has to design its telescopes to service hundreds of targets. Project Blue has only one, and a precise target area within the system. If a NASA telescope fails to find something, it moves on to the next thing. If Project Blue fails to find its target, the mission is over.

NASA has passed over this sort of mission in the past because of this "null result"―the possibility of two tails turning up from our coin toss. Peer review panels normally look for a larger context for scientific impact, and however likely it is that habitable planets orbit one of these stars, what would it mean for exoplanets in general if no such planets exist? Very little. It wouldn't tell us anything at all about how common or rare Earth-like planets are around other stars in the galaxy.

This isn't to say there hasn't been excitement for a mission like this. "Excitement" is an understatement. Directly imaging an Earth-like world is a holy grail of exoplanet study.

KICKSTARTING THEIR WAY TO SPACE (AT FIRST) 

The era of commercial space has arrived, and the logical next step is to bring space science into the fold. Such barriers as spacecraft control and access to space are now surmountable thanks to companies like SpaceX, the private company helmed by Elon Musk that is pioneering reusable rockets, and that presently launches orbital payloads and resupplies the International Space Station (with designs to launch astronauts in 2019 and put humans on Mars in the next decade).

“It's a great time to be moving on a project like this using private funding,” Jon Morse, the CEO of BoldlyGo and one of the leaders of Project Blue, tells mental_floss. “It leverages what NASA has been investing in exoplanet research, along with pulling together the technologies and capabilities that commercial space has been developing, which has really brought a lot of the cost down.”

Project Blue is taking a three-pronged approach to raising funds for the mission. The first $1 million will be raised on Kickstarter, in a campaign that begins today. This is analogous to the way NASA funds “Phase A” studies, in which a small percentage of a mission’s cost is provided for scientists to develop a preliminary design. A methodical NASA-like approach to mission development is no accident. Before Jon Morse ran BoldlyGo, he was the director of the Astrophysics division of NASA’s Science Mission Directorate.

Crowdfunding this phase of Project Blue has the added benefit of raising the mission's profile. If nothing else, the public can be invested, literally, in the mission’s success. Afterward, the mission leadership will engage private investors directly to raise another $24 million. Since its announcement last month, the project has been inundated with requests from companies to help provide such things as onboard computing and spacecraft control. “We could not conceive of doing this even a few years ago,” says Morse.

And NASA, while not strictly necessary for mission success, will not be excluded from this endeavor. Project Blue has also approached the agency to establish a Space Act Agreement, in which it will provide modest resources in exchange for a minority role in the mission. NASA has such an agreement with SpaceX. No money is exchanged, but NASA field centers—its facilities around the country—partner with SpaceX to provide expertise and institutional knowledge. For Project Blue, this might mean the use of test facilities, and NASA personnel assigned to the project. This is also analogous to NASA’s participation in certain international missions, where there is no exchange of funds, but in exchange for a small role, NASA provides certain technologies or technical support.

TARGET 2020

The Project Blue team believes it can get the science payload built and integrated into a spacecraft in roughly three years—four on the outside. “We have a pretty good idea of what to do to get the spacecraft built,” says Morse. “Look for it by the end of the decade. It won’t be earlier than late 2019―maybe 2020―to launch. This is a lean-and-mean assessment that’s based on our experience with other payloads that have been developed."

And its effects on commercial and public-private partnerships for science missions would be tectonic. Capturing an image of a "pale blue dot" around one of the Alpha Centauri stars “would be a really compelling scientific result that we think would rival some of the most momentous discoveries in science and space exploration,” says Morse. It would also enable study beyond an imaged habitable world. Scientists could extract from the light wavelengths evidence of things like elements in the atmosphere, water, and perhaps extrapolate signs of life by way of such processes as photosynthesis on the planet's surface.

That our own pale blue dot exists is something of a miracle. So much could have gone wrong, and might yet still. So little keeps the light of civilization flickering. We dream of other blue dots, and write stories, poems, and scholarly research to that effect, but to see it? To know with certainty that it’s there, and that it might too hold the dreams of a species? This recasts the question, “Why are we here?” as something parochial—albeit globally so. Suddenly, “we” encompasses so much more, and “here” so much less. And though Carl Sagan said this about our own dot, he might as well have been saying this about another: “The Earth is a very small stage in a vast cosmic arena ... Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light.”

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Space
Look Up! The Orionid Meteor Shower Peaks This Weekend
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Ethan Miller/Getty Images

October is always a great month for skywatching. If you missed the Draconids, the first meteor shower of the month, don't despair: the Orionids peak this weekend. It should be an especially stunning show this year, as the Moon will offer virtually no interference. If you've ever wanted to get into skywatching, this is your chance.

The Orionids is the second of two meteor showers caused by the debris field left by the comet Halley. (The other is the Eta Aquarids, which appear in May.) The showers are named for the constellation Orion, from which they seem to originate.

All the stars are lining up (so to speak) for this show. First, it's on the weekend, which means you can stay up late without feeling the burn at work the next day. Tonight, October 20, you'll be able to spot many meteors, and the shower peaks just after midnight tomorrow, October 21, leading into Sunday morning. Make a late-night picnic of the occasion, because it takes about an hour for your eyes to adjust to the darkness. Bring a blanket and a bottle of wine, lay out and take in the open skies, and let nature do the rest.

Second, the Moon, which was new only yesterday, is but a sliver in the evening sky, lacking the wattage to wash out the sky or conceal the faintest of meteors. If your skies are clear and light pollution low, this year you should be able to catch about 20 meteors an hour, which isn't a bad way to spend a date night.

If clouds interfere with your Orionids experience, don't fret. There will be two more meteor showers in November and the greatest of them all in December: the Geminids.

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NSF/LIGO/Sonoma State University/A. Simonnet
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Space
Astronomers Observe a New Kind of Massive Cosmic Collision for the First Time
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NSF/LIGO/Sonoma State University/A. Simonnet

For the first time, astronomers have detected the colossal blast produced by the merger of two neutron stars—and they've recorded it both via the gravitational waves the event produced, as well as the flash of light it emitted.

Physicists believe that the pair of neutron stars—ultra-dense stars formed when a massive star collapses, following a supernova explosion—had been locked in a death spiral just before their final collision and merger. As they spiraled inward, a burst of gravitational waves was released; when they finally smashed together, high-energy electromagnetic radiation known as gamma rays were emitted. In the days that followed, electromagnetic radiation at many other wavelengths—X-rays, ultraviolet, optical, infrared, and radio waves—were released. (Imagine all the instruments in an orchestra, from the lowest bassoons to the highest piccolos, playing a short, loud note all at once.)

This is the first time such a collision has been observed, as well as the first time that both kinds of observations—gravitational waves and electromagnetic radiation—have been recorded from the same event, a feat that required co-operation among some 70 different observatories around the world, including ground-based observatories, orbiting telescopes, the U.S. LIGO (Laser Interferometer Gravitational-Wave Observatory), and European Virgo gravitational wave detectors.

"For me, it feels like the dawning of a next era in astrophysics," Julie McEnery, project scientist for NASA's Fermi Gamma-ray Space Telescope, one of the first instruments to record the burst of energy from the cosmic collision, tells Mental Floss. "With this observation, we've connected these new gravitational wave observations to the rest of the observations that we've been doing in astrophysics for a very long time."

A BREAKTHROUGH ON SEVERAL FRONTS

The observations represent a breakthrough on several fronts. Until now, the only events detected via gravitational waves have been mergers of black holes; with these new results, it seems likely that gravitational wave technology—which is still in its infancy—will open many new phenomena to scientific scrutiny. At the same time, very little was known about the physics of neutron stars—especially their violent, final moments—until now. The observations are also shedding new light on the origin of gamma-ray bursts (GRBs)—extremely energetic explosions seen in distant galaxies. As well, the research may offer clues as to how the heavier elements, such as gold, platinum, and uranium, formed.

Astronomers around the world are thrilled by the latest findings, as today's flurry of excitement attests. The LIGO-Virgo results are being published today in the journal Physical Review Letters; further articles are due to be published in other journals, including Nature and Science, in the weeks ahead. Scientists also described the findings today at press briefings hosted by the National Science Foundation (the agency that funds LIGO) in Washington, and at the headquarters of the European Southern Observatory in Garching, Germany.

(Rumors of the breakthrough had been swirling for weeks; in August, astronomer J. Craig Wheeler of the University of Texas at Austin tweeted, "New LIGO. Source with optical counterpart. Blow your sox off!" He and another scientist who tweeted have since apologized for doing so prematurely, but this morning, minutes after the news officially broke, Wheeler tweeted, "Socks off!") 

The neutron star merger happened in a galaxy known as NGC 4993, located some 130 million light years from our own Milky Way, in the direction of the southern constellation Hydra.

Gravitational wave astronomy is barely a year and a half old. The first detection of gravitational waves—physicists describe them as ripples in space-time—came in fall 2015, when the signal from a pair of merging black holes was recorded by the LIGO detectors. The discovery was announced in February 2016 to great fanfare, and was honored with this year's Nobel Prize in Physics. Virgo, a European gravitational wave detector, went online in 2007 and was upgraded last year; together, they allow astronomers to accurately pin down the location of gravitational wave sources for the first time. The addition of Virgo also allows for a greater sensitivity than LIGO could achieve on its own.

LIGO previously recorded four different instances of colliding black holes—objects with masses between seven times the mass of the Sun and a bit less than 40 times the mass of the Sun. This new signal was weaker than that produced by the black holes, but also lasted longer, persisting for about 100 seconds; the data suggested the objects were too small to be black holes, but instead were neutron stars, with masses of about 1.1 and 1.6 times the Sun's mass. (In spite of their heft, neutron stars are tiny, with diameters of only a dozen or so miles.) Another key difference is that while black hole collisions can be detected only via gravitational waves—black holes are black, after all—neutron star collisions can actually be seen.

"EXACTLY WHAT WE'D HOPE TO SEE"

When the gravitational wave signal was recorded, on the morning of August 17, observatories around the world were notified and began scanning the sky in search of an optical counterpart. Even before the LIGO bulletin went out, however, the orbiting Fermi telescope, which can receive high-energy gamma rays from all directions in the sky at once, had caught something, receiving a signal less than two seconds after the gravitational wave signal tripped the LIGO detectors. This was presumed to be a gamma-ray burst, an explosion of gamma rays seen in deep space. Astronomers had recorded such bursts sporadically since the 1960s; however, their physical cause was never certain. Merging neutron stars had been a suggested culprit for at least some of these explosions.

"This is exactly what we'd hoped to see," says McEnery. "A gamma ray burst requires a colossal release of energy, and one of the hypotheses for what powers at least some of them—the ones that have durations of less than two seconds—was the merger of two neutron stars … We had hoped that we would see a gamma ray burst and a gravitational wave signal together, so it's fantastic to finally actually do this."

With preliminary data from LIGO and Virgo, combined with the Fermi data, scientists could tell with reasonable precision what direction in the sky the signal had come from—and dozens of telescopes at observatories around the world, including the U.S. Gemini telescopes, the European Very Large Telescope, and the Hubble Space Telescope, were quickly re-aimed toward Hydra, in the direction of reported signal.

The telescopes at the Las Campanas Observatory in Chile were well-placed for getting a first look—because the bulletin arrived in the morning, however, they had to wait until the sun dropped below the horizon.

"We had about eight to 10 hours, until sunset in Chile, to prepare for this," Maria Drout, an astronomer at the Carnegie Observatories in in Pasadena, California, which runs the Las Campanas telescopes, tells Mental Floss. She was connected by Skype to the astronomers in the control rooms of three different telescopes at Las Campanas, as they prepared to train their telescopes at the target region. "Usually you prepare a month in advance for an observing run on these telescopes, but this was all happening in a few hours," Drout says. She and her colleagues prepared a target list of about 100 galaxies, but less than one-tenth of the way through the list, by luck, they found it: a tiny blip of light in NGC 4993 that wasn't visible on archival images of the same galaxy. (It was the 1-meter Swope telescope that snagged the first images.)

A NEW ERA OF ASTROPHYSICS

When a new star-like object in a distant galaxy is spotted, a typical first guess is that it's a supernova (an exploding star). But this new object was changing very rapidly, growing 100 times dimmer over just a few days while also quickly becoming redder—which supernovae don't do, explains Drout, who is cross-appointed at the Dunlap Institute for Astronomy and Astrophysics at the University of Toronto. "We ended up following it for three weeks or so, and by the end, it was very clear that this [neutron star merger] was what we were looking at," she says.

The researchers say they can't be sure if the resulting object was another, larger neutron star, or whether it would have been so massive that it would have collapsed into a black hole.

As exciting as the original detection of gravitational waves last year was, Drout is looking forward to a new era in which both gravitational waves and traditional telescopes can be used to study the same objects. "We can learn a lot more about these types of extreme systems that exist in the universe, by coupling the two together," she says.

The detection shows that "gravitational wave science is moving from being a physics experiment to being a tool for astronomers," Marcia Rieke, an astronomer at the University of Arizona who is not involved in the current research, tells Mental Floss. "So I think it's a pretty big deal."

Physicists are also learning something new about the origin of the heaviest elements in the periodic table. For many years, these were thought to arise from supernova explosions, but spectroscopic data from the newly observed neutron star merger (in which light is broken up into its component colors) suggests that such explosion produce enormous quantities of heavy elements—including enough gold to put Fort Knox to shame. (The blast is believed to have created some 200 Earth-masses of gold, the scientists say.) "It's telling us that most of the gold that we know about is produced in these mergers, and not in supernovae," McEnery says.

Editor's note: This post has been updated.

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