Worlds collide in the Seven Sisters

New-born rocky planets have been detected in the Seven Sisters, the most famous star cluster in the sky. Astronomers have even recorded what look like collisions between the young worlds, similar to that which produced the Earth and the Moon. Evidence for the latest batch of new planets comes from study of a star called HD 23514 in the cluster, which is also known as the Pleiades. The star is a stellar teenager with an untidy room compared to our own Sun - it is 45 times younger and surrounded by dust. Joseph Rhee, of the University of California, Los Angeles, used a heat-seeking camera called MICHELLE on the Gemini North Telescope on Hawaii to look at the warm dust. He believes it was pulverized by catastrophic collisions in a young, evolving planetary system around the young star. They appear to be happening in a zone comparable to that between Mercury and Mars in our own solar system. The new observations, by Dr Rhee and colleagues Inseok Song and Benjamin Zuckerman, indicate that rocky terrestrial planets, perhaps like the Earth, Mars or Venus, are forming or have recently formed. Their discovery will be announced in the Astrophysical Journal. Dr Rhee said: "This is the first clear evidence for planet formation in the Pleiades, and the results we are presenting strongly suggest that terrestrial planets like those in our solar system are quite common." Despite their rocky nature, no one imagines that there could be any life on the planets of HD 23514 as the newly formed planets are still so young. Alien-hunters are looking instead at more mature solar systems such as 55 Cancri and Gliese 581. The Pleiades can be seen with the naked eye during the evening at this time of the year, and were likened to "a swarm of fire-flies" by the poet Tennyson. Although six or seven can easily be spotted, the cluster actually contains around 1,400 stars. • Talking of Gemini, the Royal Astronomical Society has expressed shock at a sudden decision by the Science and Technology Facilities Council to withdraw the UK from the Gemini Observatory. The decision came despite the UK having been a key partner since the start of the project to install twin 8-metre telescopes in Hawaii and Chile to cover the entire sky. In a statement, the RAS Council said the decision to withdraw "appears to have been made without any consultation with the astronomical community." Our picture is an artist's impression of a planetary collision around HD 23514 by Lynette Cook for Gemini Observatory. ©PAUL SUTHERLAND, Skymania.com • What do you think? Skymania welcomes your comments and views. Check out our new guide to Mars too. Please support this site by shopping at Skymania's stores in the USA, the UK, Canada and France. They are powered by Amazon so you can buy with confidence.

Snaps of home from Rosetta probe

The Earth looks beautiful but fragile in a spectacular travel snap from the spaceprobe mistaken for an asteroid. Our home planet appeared as a fine crescent as Europe's Rosetta closed in for a gravity boost that would send it flying back out into the depths of the solar system. The robot craft swooped in at 28,000mph, just 3,290 miles above the sea south-west of Chile at 22.57 UT on Tuesday. As it approached, much of Earth was in shadow except for an illuminated strip around Antarctica. The Wide Angle Camera - part of the craft's Optical Spectroscopic and Infrared Remote Imaging System - produced this wonderful picture by combining images taken at different wavelengths from a distance of less than 50,000 miles. Another image released by the European Space Agency showed the dark side of the Earth, with cities and countries revealed by their artificial lighting. The effect resembled a scattering of jewels but, of course, produces the light pollution that is a curse for astronomers. Click on the image to view an annotated version identifying the different locations. Another light show visible near the top of the Earth's globe is the aurora borealis, or northern lights, dancing around the North Pole. No sonner had Rosetta arrived home than it was off again on its ten-year mission to plant a lander on Comet Churyumov-Gerasimenko. The probe, launched in March 2004, made a similar close pass of Mars in February this year and will pass the Earth again in November, 2009. On its way to the comet, Rosetta will fly close to and study two minor planets, Steins and Lutetia, during two journeys through the asteroid belt in 2008 and 2010. ©PAUL SUTHERLAND, Skymania.com • What do you think? Skymania welcomes your comments and views. Check out our new guide to Mars too. And support this site by visiting Skymania's stores in the USA, the UK, Canada and France. They are powered by Amazon so you can buy with confidence.

'Deadly asteroid' is a spaceprobe

An alert over a close shave by a threatening asteroid has been called off after it was found to be a passing spaceprobe called Rosetta. The alarm was raised by the Minor Planet Center, the world's official HQ for logging newly discovered space rocks and checking for any "Near Earth Objects" that threaten a devastating impact. They issued an email circular to professional observatories last week announcing that an asteroid had been detected that would miss the Earth by a whisker on Tuesday, November 13. The near miss, by 5,600 km - less than half the diameter of the Earth - looked set to be one of the closest on record. The MPC, which is run by the Smithsonian Astrophysical Observatory, Massachusetts, for the International Astronomical Union, even gave the body an official label, 2007 VN84. Detailed observations by astronomers worldwide who discover and monitor potentially deadly asteroids were used to calculate an accurate track for the incoming "missile". Britain's Royal Astronomical Society was preparing a special announcement to the media on Monday to reveal one of the closest cosmic shaves with disaster ever recorded. Then one sharp-eyed scientist, Denis Denisenko, 36, of Moscow, spotted that the asteroid's track matched that of a European comet-chasing spaceprobe called Rosetta. The craft, which is the size of a box van, is scheduled to make a swing past Earth on Tuesday for a gravity boost to speed it like a slingshot on its ten-year journey to Comet Churyumov-Gerasimenko. Rosetta, launched in March, 2004, by the European Space Agency (ESA) has already made one swing-by of Earth in March 2005, another past Mars in February this year, and it will pass us again in November 2009. Ironically, the unmanned probe will also fly close to and study two minor planets, Steins and Lutetia, during two journeys through the asteroid belt in 2008 and 2010. Denisenko emailed an online discussion group for asteroid observers revealing his discovery. Embarrassed officials at the Minor Planet Center were forced to email a fresh circular announcing: "The minor planet 2007 VN84 does not exist and the designation is to be retired." But they added: "This incident highlights the deplorable state of availability of positional information on distant artificial objects (whether in earth orbit or in solar orbit). A single source for information on all distant artificial objects would be very desirable." Despite the red faces, the MPC perform vital work and there have been very real near misses by genuinely threatening asteroids that demand monitoring. The world's biggest digital camera recently joined the search for them. The Rosetta probe, which is due to plant a lander on its target comet in 2014, measures 2.8 x 2.1 x 2.0 metres. Its enormous solar panel "wings" stretch 32 metres from tip to tip and each is 32 sq metres in area. Update: Rosetta's flyby was a complete success with the probe right on course and producing some spectacular photos of the Earth as it approached. Our picture is an ESA artist's impression of Tuesday's flyby by Rosetta. ©PAUL SUTHERLAND, Skymania.com • What do you think? Skymania welcomes your comments and views. Check out our new guide to Mars too. And support this site by visiting Skymania's stores in the USA, the UK, Canada and France. They are powered by Amazon so you can buy with confidence.

New planet 'may be home to aliens'

Excited astronomers have discovered a new planet that could be home to alien life, they revealed tonight. The world is orbiting a nearby star like the Sun in its so-called "habitable zone" - just the right distance for liquid water to exist. It is the fifth planet to be identified in orbit around the star 55 Cancri, a star very similar in type and age to our own Sun, making it a virtual twin of our own solar system. The star, which is dimly visible to the naked eye in the constellation of Cancer, now holds the record for the number of worlds in orbit, after our own Sun. It lies just 41 light-years away - right on our cosmic doorstep. Scientists said the new planet is 45 times the mass, or size of the Earth, and has a year 260 days long - the time it takes to orbit 55 Cancri. It was found by measuring the tiny wobble it causes to the star as it orbits. Detecting this was a triumph for the astronomers and took them 18 years of study from Lick Observatory, California, because it had to be separated from the effects of the other planets. The planet is 72.5 million miles from 55 Cancri, a little less than the distance of the Earth from the Sun, but at an ideal distance for the warmth that life as we know it would need to exist. Computers had previously identified the star as an ideal candidate to house Earth's twin. Geoff Marcy, of the University of California, said last night: "The discovery has me jumping out of my socks. We now know that our own Sun and its family of planets is not unusual." He said that if there is a moon going around this new planet, it would have a rocky surface. Water could form lakes or seas and produce the conditions for life to begin. But he added: "Then all bets are off as to how life could evolve on that moon." Fellow discoverer Debra Fischer, of San Francisco State University, said she expected that other Earth-like planets could exist in the star's habitable zone. She said: "I bet that gap is not empty." She added: "55 Cancri is very much like our own sun. It is about the same size and the same age. It is a solar system that is packed with planets. It has profound implications for how we search for Earth-like planets." She went on: "The gas-giant planets in our solar system all have large moons. If there is a moon orbiting this new, massive planet, it might have pools of liquid water on a rocky surface." In April, astronomers revealed they had discovered a planet resembling Earth in the habitable zone of a dwarf planet called Gliese 581 in the constellation of Libra. And since this report was written, another solar system resembling ours and possibly containing a planet like Earth, has been located by an international team of astronomers. Nasa associate administrator Alan Stern said: "It is amazing to see our ability to detect extrasolar planets growing. We are finding solar systems with a richness of planets and a variety of planetary types comparable to our own." Answering questions, Debra Fischer said the new planet was more massive than Uranus or Neptune but less massive than Saturn, "so we don't know what it will look like." Geoff Marcy said that, although it was speculative to say there were moons in orbit around the new planet, there were moons around ALL the giant planets in our own solar system. He felt that, if the planet was like one of the giant planets in our solar system, then it was unlikely to be home to life itself, but conditions on one of its moons could be suitable. Water has already been discovered a steam in the atmosphere of another giant planet beyond the solar system. And last month, results from the Spitzer space telescope revealed that a planet like Earth could be forming around a further star. Update: February 2008. Nasa have awarded a $1 million grant to fund plans for a new space telescope which will detect new Earths, continents, oceans, clouds - and even aliens! This post has been our most popular ever. If you are interested in reading more about prospects for alien life, here are some titles at our US Amazon store, and also at our UK Amazon shop. ©PAUL SUTHERLAND, Skymania.com • What do you think? Skymania welcomes your comments and views. Check out our new guide to Mars too. And support this site by visiting Skymania's stores in the USA, the UK, Canada and France. They are powered by Amazon so you can buy with confidence.

Three new planets, thanks to eBay

They do say that you can find anything on eBay. Now British planet-hunters have used the auction site to help discover three new worlds outside the solar system. The planets - all giants around the size of Jupiter - were spotted using the team's robotic observatories in the Canary Islands and South Africa. But amazingly, they had to turn to the internet auction site to source vital equipment needed to carry out their cosmic search. Each observatory is fitted with a bank of eight powerful cameras to form a £30,000 instrument called SuperWASP - the Wide Area Search for Planets - which produces high-resolution pictures of the sky. The £2 million project uses computers to watch millions of stars a night for tiny fades in their starlight that reveal any distant planets passing in front of them. The SuperWASP lenses need to be of such high quality that they cost £4,000 each. But to their horror, the team assembling the equipment discovered that they were 13 lenses short and camera giant Canon had stopped making them. Dr Carole Haswell, an astronomer at the Open University in Milton Keynes, hit on the idea of the idea of trying to find them online. She said: "I was a complete novice on eBay whan I first used it to buy the lenses so it was a bit nerve-wracking, especially as our purchasing dept were less than thrilled about the whole idea. "The OU was the only university prepared to even countenance the plan!" The SuperWASP team set up their own account on eBay and, to their great relief, managed to track down the vital telephoto lenses from a dealer in South Korea. One of the new planets, dubbed WASP-3, was found with the team's observatory on La Palma in the Canaries. The others, labelled WASP-4 and WASP-5, were detected from Sutherland in South Africa and are the brightest planets around other stars found in the southern hemisphere. The UK team have previously discovered two other planets outside the solar system. More than 200 of these so-called exoplanets have been spotted by astronomers around the world. SuperWASP scientist Professor Andrew Cameron, of St Andrews University, Scotland, said: "All three planets are similar to Jupiter, but are orbiting their stars so closely that their 'year' lasts less than two days. These are among the shortest orbital periods yet discovered." Virtually all planets so far found have been so-called "hot Jupiters" in rapid orbits around their parent stars, including the hottest planet yet identified last May. The new planets are so close to their stars that temperatures must be too hot for life as we know it to exist. But experts say their discovery boosts the chances that there are also many Earth-sized planets waiting to be discovered as technology improves. Europe's Corot probe, launched last year, has the capability to find smaller worlds like Earth. By monitoring the change in light as a planet passes in front of its parent star, astronomers can tell a lot about it - even what the planet's atmosphere is made of. Dr Coel Hellier, of Keele University, said: "When we see a transit we can deduce the size and mass of the planet and also what it is made of, so we can use these planets to study how solar systems form." The photo shows one of the SuperWasp cameras. Picture: David Anderson ©PAUL SUTHERLAND, Skymania.com • What do you think? Skymania welcomes your comments and views. Check out our new guide to Mars too. And support this site by visiting Skymania's stores in the USA, the UK, Canada and France. They are powered by Amazon so you can buy with confidence.