Archive for the ‘solar system’ Category

A large cluster of objects in space look like something you would “expect an alien civilization to build”, astronomers have said.

Jason Wright, an astronomer from Penn State University, is set to publish a report on the “bizarre” star system – suggesting the objects could be a “swarm of megastructures”.

He told The Independent: “I can’t figure this thing out and that’s why it’s so interesting, so cool – it just doesn’t seem to make sense.”

Speaking to The Atlantic, Mr Wright said: “Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilisation to build. I was fascinated by how crazy it looked.”

The snappily named KIC 8462852 star lies just above the Milky Way, between the constellations Cygnus and Lyra. It first attracted the attention of astronomers in 2009, when the Kepler Space Telescope identified it as a candidate for having orbiting Earth-like planets.

But KIC 8462852 was emitting a stranger light pattern than any of the other stars in Kepler’s search for habitable planets.

Kepler works by analysing light from distant places in the universe — looking for changes that take place when planets move in front of their stars. But the dip in starlight from KIC 8462852 does not seem to be the normal pattern for a planet.

Tabetha Boyajian, a postdoc at Yale, told The Atlantic: “We’d never seen anything like this star. It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out.”

In 2011 the star was flagged up again by several members of Kepler’s “Planet Hunters” team – a group of ‘citizen scientists’ tasked with analysing the data from the 150,000 stars Kepler was watching.

The analysts tagged the star as “interesting “ and “bizarre” because it was surrounded by a mass of matter in tight formation.

This was consistent with the mass of debris that surrounds a young star just as it did with our sun before the planets formed. However this star was not young and the debris must have been deposited around it fairly recently or it would have been clumped together by gravity – or swallowed by the star itself.

Boyajian, who oversees the Planet Hunters project, recently published a paper looking at all the possible natural explanations for the objects and found all of them wanting except one – that another star had pulled a string of comets close to KIC 8462852. But he said even this would involve an incredibly improbable coincidence.

A this stage Mr Wright, the astronomer from Penn State University, and his colleague Andrew Siemion, the Director of SETI (Search for Extra-Terrestrial Intelligence), got involved. Now the possibility the objects were created by intelligent creatures is being taken very seriously by the team.

As civilisations become more technologically advanced, they create new and better ways of collecting energy — with the end result being the harnessing of energy directly from their star. If the speculation about a megastructure being placed around the star system is correct, scientists say it could be a huge set of solar panels placed around the star.

The three astronomers want to point a radio dish at the star to look for wavelengths associated with technological civilisations. And the first observations could be ready to take place as early as January, with follow-up observations potentially coming even quicker.

“If things go really well, the follow-up could happen sooner,” Wright told The Atlantic. “If we saw something exciting… we’d be asking to go on right away.”

http://www.independent.co.uk/news/world/forget-water-on-mars-astronomers-may-have-just-found-giant-alien-megastructures-orbiting-a-star-near-a6693886.html

Thanks to Kebmodee and David Frey for bringing this to the It’s Interesting community.

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Artist's impression of planets discovered by Kepler spacecraft

Our galaxy probably contains at least two billion planets that, like Earth, have liquid water on their surfaces and orbit around their parent stars in the “habitable zone” for life. The nearest, according to astronomers, could be a mere 12 light years away.

A new study, published on Monday in the Proceedings of the National Academy of Sciences, suggests that Earth-like planets capable of supporting life are far more common than previously thought. Using measurements from Nasa’s Kepler space observatory, scientists led by Erik Petigura at the University of California, Berkeley, estimated that 22% of our galaxy’s sun-like stars have rocky planets circling them in the zone where they get roughly the same amount of light energy as Earth receives from the sun. There are around 100bn stars in our galaxy, of which 10% are like the sun.

So far Kepler has studied more than 150,000 stars and identified more than 3,000 candidate planets, but many of these are “gas giants”, similar to Jupiter, that orbit close to their parent stars. If there is life out there, it is far more likely to have evolved on rocky planets with liquid water on their surfaces, similar to Earth.

To get their results, Petigura’s team looked for planets in Kepler data that had a radius up to double that of Earth. They searched for planets that orbited far enough from their star that liquid water would not evaporate, but not so far that the water would all freeze.

Subhanjoy Mohanty, an astrophysicist at Imperial College London who was not involved with the study, said: “This is the first estimate of the frequency of Earth-like planets around sun-like stars, in orbits large enough to lie in the habitable zone of their stars. The finding that roughly one in five sun-like stars may host such planets is an incredibly important one, probably exceeding the expectations of most cautious astronomers.”

He added that the latest analysis increased the chances that there might be life somewhere among the stars. “Previous analyses of Kepler data had shown that red dwarfs – the most common type of star in the galaxy, making up about 80% of the stellar population – very frequently harbour Earth-size planets, including in their habitable zones. This new study shows that the same is true around stars more like our own sun. This is certainly an added impetus for planned future missions which will study the atmospheres of these potentially habitable planets, enabling us to investigate whether they are in fact habitable or not, and also whether their atmospheres show actual biosignatures of existing life.”

Nasa also announced on Monday that the Kepler probe would be given a new lease of life, following fears that it would have to end its mission after only four years in space. In May 2013, scientists discovered that one of the gyroscopic wheels – known as “reaction wheels” – that kept the probe pointing in the right direction had stopped working and, try as they might, Nasa engineers could not restart it. Unable to point itself at the stars with any accuracy, the probe could no longer be used to collect data about the position of new exoplanets.

But it looks as though there could be a solution that involves reorienting the probe to look along the plane of the galaxy, which will allow it to remain stable with only two of its reaction wheels working. “The old saying ‘necessity is the mother of invention’ has rung true here, with engineers and scientists from Nasa and the spacecraft manufacturers having figured out this way to – we hope – recover much of the performance we thought we had lost. We are very excited,” said Bill Chaplin, an astrophysicist at the University of Birmingham in the UK.

If all goes well, the new Kepler mission – dubbed “K2” – will look for planets around smaller stars than the sun, and will also study the stars themselves. “There are a wealth of fantastically interesting targets for astrophysics that can be observed in the ecliptic plane, which were not accessible in the original Kepler field, notably brighter clusters of stars – where the common origins and distances to these stars make the clusters excellent laboratories for testing our understanding of stars – and young, star-forming regions,” said Chaplin.

http://www.theguardian.com/science/2013/nov/04/planets-galaxy-life-kepler

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.

pluto

Pluto’s orbit may host a formation of 10 or more tiny undiscovered moons, which would each measure just 1 to 3 kilometres across, astronomers say.

This preliminary finding could make life even more difficult for the team planning NASA’s New Horizons mission, which is slated to take the first-ever up-close look at the Pluto system in July 2015.

After Pluto’s fifth known moon, a small satellite known as P5, was discovered last year, officials said they may need to redraw the spacecraft’s path to avoid such obstacles.

In the new study, astronomers led by Scott Kenyon of the Harvard-Smithsonian Center for Astrophysics used computer simulations that treat smaller particles statistically.

Once objects get above a certain size, roughly 1 km across, then the programme renders them individually – and this is when the satellites pop up.

It’s hard to say how many there are, the researchers said, as it’s difficult to simulate collisions among these tiny satellites. There could be anywhere from one to more than 10 objects lurking beyond Hydra’s orbit.

While the team can simulate these satellites, they said it’s unlikely they could be spotted, if they exist, from Earth.

The brightness of the potential objects dance with the edge of the Hubble Space Telescope’s capabilities, Kenyon said, and they are likely beyond the reach of even the most sensitive ground-based telescopes, such as the Keck Observatory in Hawaii.

New Horizons might be able to spot smaller satellites before it gets there, but Kenyon said he wasn’t sure when the objects would appear big enough for the spacecraft to detect.

The satellites would be “easily visible” during the spacecraft’s closest approach to Pluto in 2015, researchers said.

The study was submitted for publication in The Astronomical Journal.

http://www.phenomenica.com/2013/03/pluto-may-have-10-more-undiscovered-moons.html

Astronomers have discovered a potential “rogue” alien planet wandering alone just 100 light-years from Earth, suggesting that such starless worlds may be extremely common across the galaxy.

The free-floating object, called CFBDSIR2149, is likely a gas giant planet four to seven times more massive than Jupiter, scientists say in a new study unveiled today (Nov. 14). The planet cruises unbound through space relatively close to Earth (in astronomical terms; the Milky Way galaxy is 100,000 light-years wide), perhaps after being booted from its own solar system.

“If this little object is a planet that has been ejected from its native system, it conjures up the striking image of orphaned worlds, drifting in the emptiness of space,” study leader Philippe Delorme, of the Institute of Planetology and Astrophysics of Grenoble in France, said in a statement.

Delorme and his team detected CFBDSIR2149’s infrared signature using the Canada-France-Hawaii Telescope, then examined the body’s properties with the European Southern Observatory’s Very Large Telescope in Chile. [Video: Rogue Planet Has No Parent Star]

The newfound object appears to be among a stream of young stars called the AB Doradus moving group, the closest such stream to our own solar system.

Scientists think the AB Doradus stars all formed together between 50 million and 120 million years ago. If CFBDSIR2149 is indeed associated with the group — and researchers cite a nearly 90 percent probability — then the object is similarly young.

And if the discovery team is right about CFBDSIR2149’s age, the body is likely a planet, with an average temperature of 806 degrees Fahrenheit (430 degrees Celsius), researchers said.

There’s still a slight chance that CFBDSIR2149 is a brown dwarf — a strange object that’s larger than a planet but too small to trigger the internal nuclear fusion reactions required to become a full-fledged star. Additional observations should help decide the matter.

“We need new observations to confirm that this object belongs to the AB Doradus moving group,” Delorme told SPACE.com via email. “With a good distance measurement and a more accurate proper motion, we will be able to increase (or decrease) the probability that it is indeed a planet.”

The new study was published today in the journal Astronomy & Astrophysics.

The discovery of a starless alien planet would not be shocking, at least not anymore. In the last year or so, astronomers have spotted a number of such orphan worlds — so many, in fact, that some scientists think parentless planets are the rule rather than the exception.

One 2011 study, for example, estimated that rogue worlds outnumber “normal” planets with obvious host stars by at least 50 percent throughout the Milky Way. If that’s the case, the galaxy that includes Earth probably also hosts billions of orphan planets.

And gas giants may be in the minority among these solitary wanderers, researchers say.

“We now know that such massive planets are rare and that Neptunes or Earth-mass planets are much more common,” Delorme said. “We also know that massive objects are more difficult to eject [from solar systems] than light ones. If you follow the rationale, you deduce that ejected exo-Neptunes and ejected exo-Earths should be much more common than objects like CFBDSIR2149.”

It’s exciting to have a starless planet so close to Earth, researchers say. Future telescopes should be able to learn a great deal about CFBDSIR2149, since they won’t have to contend with the overwhelming glare of a nearby host star.

“This object is a really easy-to-study prototype of the ‘normal’ giant planets we hope to discover and study with the upcoming generation of direct-imaging instruments,” Delorme said. “It will help to improve our forecast of these objects’ luminosity and hence help us discover them ―and, once discovered, it will help us understand the physics of their atmospheres.”

http://www.livescience.com/24772-rogue-alien-planet-discovery.html

 

Enceladus is little bigger than a lump of rock and has appeared, until recently, as a mere pinprick of light in astronomers’ telescopes. Yet Saturn‘s tiny moon has suddenly become a major attraction for scientists. Many now believe it offers the best hope we have of discovering life on another world inside our solar system.

The idea that a moon a mere 310 miles in diameter, orbiting in deep, cold space,   1bn miles from the sun, could provide a home for alien lifeforms may seem extraordinary. Nevertheless, a growing number of researchers consider this is a real prospect and argue that Enceladus should be rated a top priority for future space missions.

This point is endorsed by astrobiologist Professor Charles Cockell of Edinburgh University. “If someone gave me several billion dollars to build whatever space probe I wanted, I would have no hesitation,” he says. “I would construct one that could fly to Saturn and collect samples from Enceladus. I would go there rather than Mars or the icy moons of Jupiter, such as Europa, despite encouraging signs that they could support life. Primitive, bacteria-like lifeforms may indeed exist on these worlds but they are probably buried deep below their surfaces and will be difficult to access. On Enceladus, if there are lifeforms, they will be easy to pick up. They will be pouring into space.”

The cause of this unexpected interest in Enceladus – first observed by William Herschel in 1789 and named after one of the children of the Earth goddess Gaia – stems from a discovery made by the robot spacecraft Cassini, which has been in orbit of Saturn for the past eight years. The $3bn probe has shown that the little moon not only has an atmosphere, but that geysers of water are erupting from its surface into space. Even more astonishing has been its most recent discovery, which has shown that these geysers contain complex organic compounds, including propane, ethane, and acetylene.

“It just about ticks every box you have when it comes to looking for life on another world,” says Nasa astrobiologist Chris McKay. “It has got liquid water, organic material and a source of heat. It is hard to think of anything more enticing short of receiving a radio signal from aliens on Enceladus telling us to come and get them.”

Cassini’s observations suggest Enceladus possesses a subterranean ocean that is kept liquid by the moon’s internal heat. “We are not sure where that energy is coming from,” McKay admits. “The source is producing around 16 gigawatts of power and looks very like the geothermal energy sources we have on Earth – like the deep vents we  see in our ocean beds and which bubble up hot gases.”

At the moon’s south pole, Enceladus’s underground ocean appears to rise close to the surface. At a few sites, cracks have developed and water is bubbling to the surface before being vented into space, along with complex organic chemicals that also appear to have built up in its sea.

Equally remarkable is the impact of this water on Saturn. The planet is famed for its complex system of rings, made of bands of small particles in orbit round the planet. There are seven main rings: A, B, C, D, E, F and G, and the giant E-ring is linked directly with Enceladus. The water the moon vents into space turns into ice crystals and these feed the planet’s E-ring. “If you turned off the geysers of Enceladus, the great E-ring of Saturn would disappear within a few years,” says McKay. “For a little moon, Enceladus has quite an impact.”

Yet the discovery of Enceladus’s strange geology was a fairly tentative affair, says Professor Michele Dougherty of Imperial College London. She was the principal investigator for Cassini’s magnetometer instrument. “Cassini had been in orbit round Saturn for more than six months when it passed relatively close to Enceladus. Our results indicated that Saturn’s magnetic field was being dragged round Enceladus in a way that suggested it had an atmosphere.”

So Dougherty and her colleagues asked the Cassini management to direct the probe to take a much closer look. This was agreed and in July 2005 Cassini moved in for a close-up study. “I didn’t sleep for two nights before that,” says Dougherty. “If Cassini found nothing we would have looked stupid and the management team might not have listened to us again.”

Her fears were groundless. Cassini swept over Enceladus at a height of 173km and showed that it did indeed possess an atmosphere, albeit a thin one consisting of water vapour, carbon dioxide, methane and nitrogen. “It was wonderful,” says Dougherty. “I just thought: wow!”

Subsequent sweeps over the moon then revealed those plumes of water. The only other body in the solar system, apart from Earth, possessing liquid water on its surface had  been revealed. Finally came the discovery of organics, and the little moon went from being merely an interesting world to one that was utterly fascinating.

“Those plumes do not represent a torrent,” cautions McKay. “This is not the Mississippi pouring into space. The output is roughly equivalent to that of the Old Faithful geyser in Yellowstone national park. On the other hand, it would be enough to create a river that you could kayak down.

“The fact that this water is being vented into space and is mixed with organic material is truly remarkable, however. It is an open invitation to go there. The place may as well have a big sign hanging over it saying: ‘Free sample: take one now’.”

Collecting that sample will not be easy, however. At a distance of 1bn miles, Saturn and its moons are a difficult target. Cassini took almost seven years to get there after its launch from Cape Canaveral in  1997.

“A mission to Enceladus would take a similar time,” says McKay. Once there, several years would be needed to make several sweeps over Enceladus to collect samples of water and organics. “Then we would need a further seven years to get those samples back to Earth.”

Such a mission would therefore involve almost 20 years of space flight – on top of the decade needed to plan it and to construct and launch the probe. “That’s 30 years in all, a large chunk of any scientist’s professional life,” says McKay.

McKay and a group of other Nasa scientists based at the Jet Propulsion Laboratory in Pasadena are undaunted, however. They are now finalising plans for an Enceladus Sample Return mission, which would involve putting a probe in orbit round Saturn. It would then use the gravity of the planet’s biggest moon, Titan, to make sweeps over Enceladus. Plume samples would then be stored in a canister that would eventually be fired back to Earth on a seven-year return journey.

Crucially, McKay and his colleagues believe such a mission could be carried out at a relatively modest cost – as part of Nasa’s Discovery programme, which funds low-budget missions to explore the solar system. Previous probes have included Lunar Prospector, which studied the moon’s geology; Stardust, which returned a sample of material scooped from a comet’s tail; and Mars Pathfinder, which deployed a tiny motorised robot vehicle on the Red Planet in 1997.

“The criteria for inclusion in the Discovery programme demand that any mission must cost less than $500m, though that does not include the price of launch,” says McKay. “We think we can adapt the technology that was developed on the Stardust mission to build an Enceladus Sample Return. If so, we can keep the cost below $500m. We are finalising plans and will announce our proposals in autumn.”

Such a mission is backed by Dougherty. “I think Enceladus is one of the best bets we now have for finding life on another world in our solar system. It is certainly worth visiting but it is not the only hope we have. The icy moons of Jupiter – such as Ganymede, Callisto and Europa – still look a very good prospect as well.”

And there is one problematic issue concerning Enceladus: time. “Conditions for life there are good at present but we do not know how long they have been in existence,” says McKay. “They might be recent or ancient. For life to have evolved, we need the latter to have been the case. At present, we have no idea about their duration, though geologists I have spoken to suggest that water and organics may have been there for a good while. The only way we will find out is to go there.”

The late entry of Enceladus in the race to find extraterrestrial life adds an intriguing new destination for astrobiologists in their hunt for aliens. Before its geysers were discovered, two main targets dominated their research: Mars and the icy moons of Jupiter. The former is the easiest to get to and has already received visits from dozens of probes. On 6 August, the $2.5bn robot rover Curiosity is set to land there and continue the hunt for life on the Red Planet. “For life to evolve you need liquid water, and although it is clear it once flowed on Mars, its continued existence there is debatable,” says Cockell. “By contrast, you can see water pouring off Enceladus along with those organics.”

Many scientists argue that water could exist deep below the Martian surface, supporting bacteria-like lifeforms. However, these reservoirs could be many metres, if not kilometres, below Mars’s surface and it could take decades to find them. Similarly, the oceans under the thick ice that covers Europa – and two other moons of Jupiter, Ganymede and Callisto – could also support life. But again, it will be extremely difficult for a robot probe to drill through the kilometres of ice that cover the oceans of these worlds.

Enceladus, by these standards, is an easy destination – but a distant one that will take a long time to reach. “No matter where we look, it appears it will take two or three decades to get answers to our questions about the existence of life on other worlds in the solar system,” says Cockell. “By that time, telescopes may have spotted signs of life on planets elsewhere in the galaxy. Our studies of extra-solar planets are getting more sophisticated, after all, and one day we may spot the presence of oxygen and water in our spectrographic studies of these distant worlds – an unambiguous indication that living entities exist there.

However, telescopic studies of extra-solar planets won’t reveal the nature of those lifeforms. Only by taking samples from planets in our solar system and returning them to laboratories on Earth, where we can study them, will we be able to reveal their exact nature and mode of replication – if they exist, of course. The little world of Enceladus could then have a lot to teach us.

http://www.guardian.co.uk/science/2012/jul/29/alien-life-enceladus-saturn-moon

 

An as yet undiscovered planet might be orbiting at the dark fringes of the solar system, according to new research.

Too far out to be easily spotted by telescopes, the potential unseen planet appears to be making its presence felt by disturbing the orbits of so-called Kuiper belt objects, said Rodney Gomes, an astronomer at the National Observatory of Brazil in Rio de Janeiro.

Kuiper belt objects are small icy bodies—including some dwarf planets—that lie beyond the orbit of Neptune.

Once considered the ninth planet in our system, the dwarf planet Pluto, for example, is one of the largest Kuiper belt objects, at about 1,400 miles (2,300 kilometers) wide. Dozens of the other objects are hundreds of miles across, and more are being discovered every year.

(See “Three New ‘Plutos’? Possible Dwarf Planets Found.”)

What’s intriguing, Gomes said, is that, according to his new calculations, about a half dozen Kuiper belt objects—including the remote body known as Sedna—are in strange orbits compared to where they should be, based on existing solar system models. (Related: “Pluto Neighbor Gets Downsized.”)

The objects’ unexpected orbits have a few possible explanations, said Gomes, who presented his findings Tuesday at a meeting of the American Astronomical Society in Timberline Lodge, Oregon.

“But I think the easiest one is a planetary-mass solar companion”—a planet that orbits very far out from the sun but that’s massive enough to be having gravitational effects on Kuiper belt objects.

Mystery Planet a Captured Rogue?

For the new work, Gomes analyzed the orbits of 92 Kuiper belt objects, then compared his results to computer models of how the bodies should be distributed, with and without an additional planet.

If there’s no distant world, Gomes concludes, the models don’t produce the highly elongated orbits we see for six of the objects.

How big exactly the planetary body might be isn’t clear, but there are a lot of possibilities, Gomes added.

Based on his calculations, Gomes thinks a Neptune-size world, about four times bigger than Earth, orbiting 140 billion miles (225 billion kilometers) away from the sun—about 1,500 times farther than Earth—would do the trick.

But so would a Mars-size object—roughly half Earth’s size—in a highly elongated orbit that would occasionally bring the body sweeping to within 5 billion miles (8 billion kilometers) of the sun.

Gomes speculates that the mystery object could be a rogue planet that was kicked out of its own star system and later captured by the sun’s gravity. (See “‘Nomad’ Planets More Common Than Thought, May Orbit Black Holes.”)

Or the putative planet could have formed closer to our sun, only to be cast outward by gravitational encounters with other planets.

However, actually finding such a world would be a challenge.

To begin with, the planet might be pretty dim. Also, Gomes’s simulations don’t give astronomers any clue as to where to point their telescopes—”it can be anywhere,” he said.

Other astronomers are intrigued but say they’ll want a lot more proof before they’re willing to agree that the solar system—again—has nine planets. (Also see “Record Nine-Planet Star System Discovered?”)

“Obviously, finding another planet in the solar system is a big deal,” said Rory Barnes, an astronomer at the University of Washington. But, he added, “I don’t think he really has any evidence that suggests it is out there.”

Instead, he added, Gomes “has laid out a way to determine how such a planet could sculpt parts of our solar system. So while, yes, the evidence doesn’t exist yet, I thought the bigger point was that he showed us that there are ways to find that evidence.”

Douglas Hamilton, an astronomer from the University of Maryland, agrees that the new findings are far from definitive.

“What he showed in his probability arguments is that it’s slightly more likely. He doesn’t have a smoking gun yet.”

And Hal Levison, an astronomer at the Southwest Research Institute in Boulder, Colorado, says he isn’t sure what to make of Gomes’s finding.

“It seems surprising to me that a [solar] companion as small as Neptune could have the effect he sees,” Levison said.

But “I know Rodney, and I’m sure he did the calculations right.”

http://news.nationalgeographic.com/news/2012/05/120511-new-planet-solar-system-kuiper-belt-space-science