This illustration shows how the newly discovered planet may look orbiting its nearby star, which is smaller than Earth's sun

While the planet probably has too thick of an atmosphere and is too hot to support life similar to that found on Earth, the discovery is being heralded as a major breakthrough in humanity’s search for life on other planets.

“The big excitement is that we have found a watery world orbiting a very nearby and very small star,” said David Charbonneau, a Harvard professor of astronomy and lead author of an article on the discovery, which appeared this week in the journal Nature.

The planet, named GJ 1214b, is 2.7 times as large as Earth and orbits a star much smaller and less luminous than our sun. That’s significant, Charbonneau said, because for many years, astronomers assumed that planets only would be found orbiting stars that are similar in size to the sun.

Because of that assumption, researchers didn’t spend much time looking for planets circling small stars, he said. The discovery of this “watery world” helps debunk the notion that Earth-like planets could form only in conditions similar to those in our solar system.

“Nature is just far more inventive in making planets than we were imagining,” he said.

In a way, the newly discovered planet was sitting right in front of astronomers’ faces, just waiting for them to look. Instead of using high-powered telescopes attached to satellites, they spotted the planet using an amateur-sized, 16-inch telescope on the ground.

There were no technological reasons the discovery couldn’t have happened long ago, Charbonneau said.

The planet is also rather near to our solar system — only about 40 light-years away.

Planet GJ 1214b is classified as a “super-Earth” because it is between one and 10 times as large as Earth. Scientists have known about the existence of super-Earths for only a couple of years. Most planets discovered by astronomers have been gassy giants that are much more similar to Jupiter than to Earth.

Charbonneau said it’s unlikely that any life on the newly discovered planet would be similar to life on Earth, but he didn’t discount the idea entirely.

“This planet probably does have liquid water,” he said.

The unusual blast, dubbed SN 2007bi, appears to be a textbook example of a pair-instability supernova, a theoretical type of explosion proposed for very massive stars—those more than 140 times the mass of the sun.

Although most supernovae leave behind black holes or dense stellar corpses called neutron stars, pair-instability explosions would be so intense that the whole star would be obliterated.

Pair-instability supernovae have been hard to spot, however, because stars more than a hundred times the sun’s mass are extremely rare.

Spied in images of a distant dwarf galaxy taken by an automated telescope, SN 2007bi was about 40 times brighter than a typical supernova, and it took about three times longer to reach its maximum brightness.

“Anything that takes that long to rise and is that bright has to have a lot of mass,” said study co-author Peter Nugent, an astrophysicist at the Lawrence Berkley National Laboratory in California.

Hot Core, Unstable Star

Massive stars normally die when they run out of material to sustain nuclear fusion, and all that’s left in their cores is inert iron.

This means the core is no longer producing a steady stream of photons, which in a living star creates outward pressure, keeping the star from being crushed by its own gravity.

Without this stable outward pressure, the star collapses, generating a supernova in which the core gets crunched down to form a black hole or a neutron star.

But for even more massive stellar titans, astronomers think the cores quickly get so hot that their photons start to split apart into pairs of electrons and positrons.

This leads to an instability between the star’s temperature and pressure, sparking a devastating explosion that flings the star’s remains into space.

The star effectively vanishes, although a lingering cloud of expanding gas can remain visible for a while.

Star Explosion

Pair-instability supernovae were first predicted more than 30 years ago. But evidence from previous candidates—including a bright explosion seen in 1999 and another in 2006—were inconclusive, Nugent said.

By contrast, SN 2007bi seems to fit the bill almost perfectly. If confirmed, studies of the newfound supernova could have major implications for computer models of star formation in the early universe, Nugent said.

That’s because pair-instability supernovae were likely much more frequent in the early universe, when stars with masses several hundred times that of our sun are thought to have existed.

When these megastars exploded, the ancient, powerful outbursts scattered debris that might have sown the seeds for future stars.

A pair-instability supernova “may be a one-in-a-trillion type of event,” Nugent said, “but they may actually be very important” in understanding the evolution of the universe.

NASA's Spitzer Space Telescope has spotted a massive, nearly invisible ring around Saturn.

Its diameter is equivalent to 300 Saturns lined up side to side. And its entire volume can hold one billion Earths, NASA Jet Propulsion Laboratory said late Tuesday.

“This is one supersized ring,” said Anne Verbiscer, an astronomer at the University of Virginia in Charlottesville.

Verbiscer and two others are authors of a paper about the discovery published Wednesday in the journal Nature.

The obvious question: Why did it take scientists so long to discover something so massive?

The ring is made up of ice and dust particles that are so far apart that “if you were to stand in the ring, you wouldn’t even know it,” Verbiscer said in a statement.

Also, Saturn doesn’t receive a lot of sunlight, and the rings don’t reflect much visible light.

But the cool dust — about 80 Kelvin (minus 316 degrees Fahrenheit) — glows with thermal radiation. NASA’s Spitzer Space Telescope, used to spot the ring, picked up on the heat.
One of Saturn’s moons, Phoebe, orbits within the ring. As Phoebe collides with comets, it kicks up planetary dust. Scientists believe the ice and dust particles that make up the ring stems from those collisions.

The ring may also help explain an age-old mystery surrounding another of Saturn’s moons: Iapetus.

Astronomer Giovanni Cassini, who first spotted Iapetus in 1671, deduced the moon has a white and dark side — akin to a yin-yang symbol. But scientists did not know why.

The new ring orbits in the opposite direction to Iapetus. And, say researchers, it’s possible that the moon’s dark coloring is a result of the ring’s dust particles splattering against Iapetus like bugs on a windshield.

“Astronomers have long suspected that there is a connection between Saturn’s outer moon Phoebe and the dark material on Iapetus,” said Douglas Hamilton of the University of Maryland in College Park — one of the three authors reporting on the findings in the journal Nature.

This artist's rendering shows one of the so-called exoplanets, or planets outside our solar system.

The existence of the so-called exoplanets — planets outside our solar system — was announced at the European Southern Observatory/Center for Astrophysics, University of Porto conference in Porto, Portugal, according to a statement issued by the observatory.

The announcement was made by a consortium of international researchers, headed by the Geneva Observatory, who built the High Accuracy Radial Velocity Planet Searcher, or HARPS. The device can detect slight wobbles of stars as they respond to tugs from exoplanets’ gravity. That tactic, known as the radial velocity method, “has been the most prolific method in the search for exoplanets,” according to the European Southern Observatory statement.

The instrument detects movements as small as 3.5 km/hr (2.1 mph), a slow walking pace, the observatory said.

With the discovery, the tally of new exoplanets found by HARPS is now at 75, out of about 400 known exoplanets, the organization said, “cementing HARPS’s position as the world’s foremost exoplanet hunter.” The 75 planets are in 30 planetary systems, the European Southern Observatory said.

“HARPS is a unique, extremely high precision instrument that [is] ideal for discovering alien worlds,” Stephane Udry of Geneva University, who made the announcement on behalf of the international consortium that built the instrument, said in the observatory statement. “We have now completed our initial five-year program, which has succeeded well beyond our expectations.”
HARPS has also boosted the discovery of so-called super-Earths — planets with a mass a few times that of Earth. Of the 28 super-Earths known, HARPS facilitated the discovery of 24, the European Southern Observatory statement said. Most reside in multiplanet systems, with up to five planets per system.

Although only 32 were announced Monday, the team knows of many more exoplanets, although more observation is needed before they are formally announced and papers are written about them. “We have tons of them,” Udry said.

In return for building HARPS, the consortium was provided 100 observing nights per year over five years to search for exoplanets, one of the most ambitious searches ever implemented on a global basis, the European Southern Observatory said.

“These observations have given astronomers a great insight into the diversity of planetary system and help us understand how they can form,” team member Nuno Santos said in the statement.

The HARPS findings confirm the predictions of those who study planetary formation, Udry said. “Moreover, those models are also predicting even more … Earth-type planets.”

An important find for the study of planet formation was that three exoplanets were around stars that are metal-deficient, Udry said. Metal-deficient stars are thought to be less favorable for planet formation; however, planets the size of several Jupiters were found orbiting such deficient stars, the European Southern Observatory said.

In addition, the discovery gives “a very strong push” to projects attempting to find and study such exoplanets, Udry said.

According to its Web site, the European Southern Observatory is the foremost intergovernmental astronomy organization in Europe and describes itself as the “world’s most productive astronomical observatory. ” It is supported by 14 European countries

A jet of radiation and energy strikes the edge of another galaxy.

A fleet of space and ground telescopes have captured images of this cosmic violence, which people have never witnessed before, according to a new study released Monday by NASA.

“It’s like a bully, a black-hole bully punching the nose of a passing galaxy,” said astrophysicist Neil deGrasse Tyson, director of the Hayden Planetarium in New York, who wasn’t involved in the research.

But ultimately, this could be a deadly punch.

The telescope images show the bully galaxy shooting a stream of deadly radiation particles into the lower section of the other galaxy, which is about one-tenth its size. Both are about 8.2 billion trillion miles from here, orbiting around each other.

The larger galaxy has a multi-digit name but is called the “death star galaxy” by one of the researchers who discovered the galactic bullying, Daniel Evans of the Harvard-Smithsonian Center for Astrophysics.

Tens of millions of stars, including those with orbiting planets, are likely in the path of the deadly jet, said study co-author Martin Hardcastle of the University of Hertfordshire in the United Kingdom.

If Earth were in the way — and it’s not — the high-energy particles and radiation of the jet would in a matter of months strip away the planet’s protective ozone layer and compress the protective magnetosphere, said Evans. That would then allow the sun and the jet itself to bombard the planet with high-energy particles.

And what would that do life on the planet?

“Decompose it,” Tyson said.

“Sterilize it,” Evans piped in.

The jet attack is relatively new, in deep space time. Hardcastle estimates it’s no more than 1 million years old and can stretch on for another 10 to 100 million years.

“A truly extraordinary act of violence,” Evans said. “The jet violently slams into that lower half of the neighboring galaxy after which the jet dramatically twists and bends.”

The good news is that eventually an area of hot gas that gets hit and compressed by this mysterious jet — astronomers are still baffled by what’s in it and how it works — over millions and billions of years can form stars, Tyson said.

NASA, the National Radio Astronomy Observatory in United States and the University of Manchester in the United Kingdom used ground optical and radio telescopes, the Hubble Space Telescope, the Chandra X-ray Observatory, and the infrared Spitzer Space Telescope to get an image of the violence on various wavelengths, including invisible ones. The results will be published in The Astrophysical Journal next year.

The two galaxies are only 24,000 light-years apart and are in a slow merging process. The jet has already traveled 1 million light-years. A light-year is about 5.88 trillion miles.

Tyson said there are two main lessons to be learned from what the telescopes have found:

“This is a reminder that you are not alone in the universe. You are not isolated. You are not an island.”

And “avoid black holes when you can.”

The supernova, known as SN 2006gy, was believed to be about 150 times as massive as the sun.

The explosion could help astronomers better understand how the first generation of stars in the universe died.

“This supernova stands out as the brightest supernova that’s ever been observed,” said Nathan Smith, astrophysicist at the University of California at Berkeley.

“The reason we’re so excited is because it was so powerful we think it may require a new type of explosion mechanism that we’ve never observed before,” said Smith at a news conference from NASA headquarters in Washington.

A supernova is a rare and often dramatic phenomenon that involves the explosion of most of the material within a star. Supernovas can be very bright for a short time and usually release huge amounts of energy.

A graduate student using a robotic telescope that was part of the Texas Supernova Search project first detected SN 2006gy on September 18, 2006.

For about 70 days it got brighter, peaking with a brightness comparable to 50 billion suns, much brighter than most other supernovas. Supernovas are usually bright for a couple of weeks at most.

Astronomers captured the star’s demise using NASA’s Chandra X-Ray Observatory, and ground- based telescopes at the Lick Observatory in California and the Keck Observatory in Hawaii. The explosion was estimated about 238 million light years away from Earth.

Scientists believe supernova SN 2006gy expelled many of its outer layers in an eruption before its violent collapse.

When it exploded, it plowed into the cooler gases that had already been expelled, creating the brightest light show ever from a supernova.

Mario Livio, astrophysicist from the Space Telescope Science Institute in Baltimore, Maryland, calls the discovery “extraordinarily intriguing” for a theorist such as himself.

“We may be learning something entirely new about how massive stars explode,” said Livio.

“We are seeing a new type of explosion that has so far only existed in theory, and we believe the first stars in the universe exploded by this mechanism. It may provide a new lesson in the evolution of stars, and a star in our own galaxy may do the same thing tomorrow,” he said.

Astronomers say the star that became SN 2006gy expelled a large amount of its mass before it exploded. A huge star in the Milky Way, Eta Carinae, has already erupted in a similar fashion. So if it explodes as a supernova, it could present the best light show seen, because it is a mere 7,500 light years away from our planet.

The orbiting Chandra X-ray Observatory, which began its mission July 23, 1999, can detect and capture images of X-ray sources that are billions of light years away. Scientists all over the world use it to get insight about high temperature events, such as black holes and collapsed stars that are millions of degrees Celsius.

Chandra is the largest satellite deployed from the space shuttle. The observatory was named after Subrahmanyan Chandrasekhar, the Indian-American astrophysicist who worked at the University of Chicago and won the 1983 Nobel prize in physics. “Chandra” means “moon” or “luminous” in the Sanskrit language.

Scientists believe supernova SN 2006gy expelled many of its outer layers in an eruption before its violent collapse.

The most recent planet discoveries bring the number of known exoplanets — planets outside our solar system — to 236, the researchers told a meeting of the American Astronomical Society in Honolulu Monday.

“We are beginning to see that our home is not a rarity in the universe,” said Geoffrey Marcy, a professor of astronomy at the University of California Berkeley, who led the team.

“We are easily able to detect giant planets like Jupiter and Saturn around other stars. Most orbit far from the star like our own Jupiter and Saturn orbit from the sun,” Marcy said in a telephone interview.

“It’s a common structure among planetary systems.”

New techniques allow astronomers to detect planets that are not enormous although Earth-sized objects cannot yet be seen, said the researchers.

Four of the systems also have multiple planets, like Earth’s own with its sun, eight planets (Pluto was demoted from planet status) and smaller orbiting objects.

“We are finding that most stars have not just one planet but when we find one there is a second or a third or a fourth,” Marcy said.

“The … attribute which really has us the most excited is this new planet which we found three years ago,” Marcy said. The Neptune-like planet orbiting the star Gliese 436 has intrigued scientists because it appears to be covered with water — albeit rock-hard, hot water in a most un-Earthlike chemical state because of the intense pressures on the planet.

Earlier this month, Swiss and Belgian researchers imaged the star as this planet crossed between it and the Earth. The tiny change in the star’s light gave them the planet’s diameter and density.

“From the density of two grams per cubic centimeter — twice that of water — it must be 50 percent rock and about 50 percent water, with perhaps small amounts of hydrogen and helium,” Marcy said.

“Now we are very sure it has a rocky core and this giant thick envelope of water,” he added.

“This is why we are jumping out of our clothes. It is the first time we have determined the structure of one of these extrasolar planets. It is rocky like Earth but it has a lot of water which is the essential ingredient for life.”

This is almost certainly happening over and over again, Marcy said. Scientists had theorized this for decades but now the hard evidence is starting to pour in.

“Our Milky Way galaxy has 200 billion stars. I would estimate that 10 percent of them, perhaps, have planets that are habitable,” Marcy said.

“There are hundreds of billions of galaxies, all of which are more or less like our Milky Way Galaxy, which is tens of billions of planets like our own.”

There is one unusual property to our solar system: the nearly circular orbits of the planets, which gives a consistent dose of radiation from the Sun.

Other solar systems seen so far are not usually like this. “Most of the planets are not in circular orbits around the host star but in elongated ones called elliptical orbits,” Marcy said.

“We enjoy nearly constant temperatures throughout the year,” he added. “If the Earth got too close to the sun, the Earth would heat up, the water would boil off and that would be bad.” Too far, and it would freeze.

“An elongated orbit could not sustain life,” Marcy said.

A drawing of the Neptune-like planet orbiting star Gliese 436.

The robot analyzed a patch of soil in Gusev Crater and found it unusually rich in silica. The presence of water would have been necessary to produce such a large silica deposit, scientists said.

“This is a remarkable discovery,” principal investigator Steve Squyres of Cornell University said in a statement. “It makes you wonder what else is still out there.”

Spirit previously found clues of ancient water in the crater through the presence of sulfur-rich soil, water-altered minerals and explosive volcanism. But the latest find is compelling because of the high silica content, researchers said, raising the possibility that conditions may have been favorable for the emergence of primitive life.

It’s unclear how the silica deposit formed. One possibility is that the soil mixed with acid vapors in the presence of water. Others believe the deposit was created from water in a hot spring surrounding.

The durable Spirit and its twin, Opportunity, have been working on overtime since completing their primary, three-month mission in 2004.

For eight months, Opportunity has explored the rim of Victoria Crater on the opposite side of the planet. Scientists are looking for a safe opening to send the rover in.

The mission is managed at NASA’s Jet Propulsion Laboratory in Pasadena.

A patch of Martian soil analyzed by Spirit is rich in silica — strong evidence the red planet was much wetter than it is now.

A black hole is an object with such a powerful gravitational field that nothing, not even light, can escape it if it strays within a boundary known as the event horizon. Einstein’s theory of general relativity says black holes should form whenever matter is squeezed into a small enough space.

Though black holes are not seen directly, astronomers have identified many objects that appear to be black holes based on observations of how matter swirls around them.

But physicists Thibault Damour of the Institut des Hautes Etudes Scientifiques in Bures-sur-Yvette, France, and Sergey Solodukhin of International University Bremen in Germany now say that these objects could be structures called wormholes instead.

Wormholes are warps in the fabric of space-time that connect one place to another. If you imagine the universe as a two-dimensional sheet, you can picture a wormhole as a “throat” connecting our sheet to another one. In this scenario, the other sheet could be a universe of its own, with its own stars, galaxies and planets.

Damour and Solodukhin studied what such a wormhole might look like, and were surprised to discover that it would mimic a black hole so well that it would be virtually impossible to tell the difference.

Hawking radiation

Matter would swirl around a wormhole in the same way as for a black hole, since both objects distort the space around them in the same way.

One might hope to distinguish the two by something called Hawking radiation, an emission of particles and light which should only come from black holes and would have a characteristic energy spectrum. But this radiation is so weak that it would be completely swamped by other sources, such as the background glow of microwaves left over from the big bang, making it unobservable in practice.

Another difference one might hope to exploit is that unlike black holes, wormholes have no event horizon. This means that things could go in a wormhole and come back out again. In fact, theorists say one variety of wormhole wraps back onto itself, so that it leads not to another universe, but back to its own entrance.

Daring plunge

But this does not provide a foolproof test either. Depending on the detailed shape of the wormhole, it could take billions of years or more for things to pop back out after falling in. With the right shape, even the oldest wormholes in our universe would not have had time to spit anything back out yet.

It seems the only way to decide the issue for sure with astronomical black holes is to make a daring plunge inside. That would be a dangerous gamble, because if it is a black hole, the incredibly strong gravitational field inside would tear apart every atom in your body. Even if it turns out to be a wormhole, the forces inside could still be deadly.

Assuming you could survive, and the wormhole was not symmetric, you might find yourself in another universe on the other side. Without further intervention, the wormhole would tend to suck you back in and carry you back to the opening in your universe.

Yo-yo motion

“The spaceship would do this yo-yo motion,” Damour told New Scientist. “[But] if you use your fuel, then you can escape from the attracting power of the wormhole and explore” the space on the other side, he says.

But a friend in either universe might have to wait billions of years to hear back from you, since the transit time could be excruciatingly long.

Such a delay would make meaningful communication with anyone on the other side impossible. But the delay gets smaller with smaller wormholes. If a microscopic wormhole could be found or constructed, the delay across it could be as short as a few seconds, Solodukhin says, potentially making two-way communication possible.

Stephen Hsu of the University of Oregon in Eugene, US, who has studied the formation of black holes and the properties of wormholes, says he agrees that distinguishing between the two types of object with observations is practically impossible, at least with current technology.

Exotic matter

“The most important property of a black hole – that there is a ‘point of no return’ for an object falling in – is not something we can test at the moment,” he told New Scientist.

Still, he says the objects out there suspected to be black holes probably really are black holes rather than wormholes. There are plausible scenarios for forming black holes, he says, such as the collapse of a massive star, but it is not clear how you would form a wormhole.

“Wormholes that might be confused with a macroscopic black hole require some kind of exotic matter to stabilise them, and it is not known whether such exotic matter exists,” he says.

Solodukhin says that a wormhole might form in much the same way that black holes form, such as from a collapsing star. Physicists normally expect in these situations that a black hole would be produced, but Solodukhin says that quantum effects may stop the collapse just short of producing a black hole, leading to a wormhole instead.

Microscopic black holes

He says this mechanism might be inevitable in a more complete picture of physics that unites gravity and quantum mechanics – a longstanding goal of physics. If he is right, then wherever we used to expect black holes to form, wormholes would form instead.

And there might be a way to test the conjecture. Some physicists say that future particle accelerator experiments could produce microscopic black Such tiny black holes would emit measurable amounts of Hawking radiation, proving that they are black holes rather than wormholes. But if Solodukhin is right, and microscopic wormholes are formed instead, no such radiation would be expected. “In that case, you would actually see if it is a black hole or a wormhole,” he says.

An added benefit of wormholes is that they could resolve the so-called black hole information paradox. The only way anything can exit a black hole is in the form of Hawking radiation, but it is not clear how the radiation carries information about the original object that was swallowed. This scrambling effect conflicts with quantum mechanics, which forbids such erasing of information “Theoretically, wormholes are much better than black holes because all these problems with information loss don’t exist in this case,” Solodukhin says. Since wormholes have no event horizons, things are free to leave without first being converted into Hawking radiation, so there is no problem with lost information.