Posted on by Nancy Atkinson

New Search Technique May Lead to Discovery of Extra-solar Earth-Like Planets

The Holy Grail in the search for extra-solar planets would be to find an Earth-like world orbiting another star. A group of UK astronomers believe they have good chance of being the first to find such a planet with a revolutionary new camera called RISE. With RISE, scientists will search for extra-solar planets using a technique called “transit timing,” which may provide a short-cut to discovering Earth-like planets with existing technology.

The two primary techniques to find extra-solar planets are usually only sensitive to massive, gas giant planets in close orbit around their parent star, so-called “Hot Jupiters.” Firstly, planets can be found through their gravitational pull on the star they orbit – as the extra-solar planet moves the star wobbles back and forth, and by measuring this movement astronomers can deduce the presence of a planet. Secondly, the transit search technique looks for the changes in a star’s brightness as a planet passes in front of it.

But neither of these techniques is currently good enough to find small extra-solar planets similar to the Earth. With the new transit timing technique, the RISE camera will look for Earth-mass planets in orbit around stars already known to host Hot Jupiters.

Transit timing works on the principle that an isolated hot Jupiter planet orbiting its host will have a constant orbital period (i.e. its ‘year’ remains the same) and therefore it will block out the light from its parent star in a regular and predictable way. During the planet’s transit events, RISE can very accurately measure the rise and fall in the amount of light reaching the Earth from the parent star – the camera can be used to pinpoint the time of the centre of the event to within 10 seconds. RISE is a fast-read camera. It has a fixed “V+R” filter and reimaging optics giving a 7 x 7 acrminute field of view to maximize the number of comparison stars available. An e2V frame transfer detector is used to obtain a cycle time of less than 1 second.

Hot Jupiter planet. Image Credit: ESA

By observing and timing their transits, astronomers hope to detect small changes in the orbital periods of known hot Jupiters caused by the gravitational pull of other planets in the same system. In the right circumstances, even planets as small as the Earth could be found in this way.

“The potential of transit timing is the result of some very simple physics, where multi-planet systems will gravitationally kick one another around in their orbits – an effect often witnessed in our own Solar System,” said PhD student Neale Gibson of Queen’s University Belfast. “If Earth-mass planets are present in nearby orbits (which is predicted by current Hot-Jupiter formation theories) we will see their effect on the orbit of the larger transiting planets. RISE will allow us to observe and time the transits of extrasolar planets very accurately, which gives us the sensitivity required to detect the effect of even small Earth-mass planets.”

RISE was designed by astronomers at Queen’s University in collaboration with Liverpool John Moores University and is now installed on the 2 meter Liverpool Telescope on the Canary Island of La Palma. For more information about the RISE Camera, see Neale Gibson’s homepage.

Original News Source: NAM Press Release

Posted on by Nancy Atkinson

STEREO Spacecraft Captures Footage of a Solar Tsunami

A solar tsunami blasted its way through the sun’s lower atmosphere on May, 19 2007, and the action was captured by the twin STEREO spacecraft. Solar tsunamis are launched by huge explosions near the Sun’s atmosphere, called coronal mass ejections (CMEs). Although solar tsunamis share much in common with tsunamis on Earth, the solar version can travel at over a million kilometers per hour. Last year’s tsunami blasted and rolled for about 35 minutes, reaching peak speeds around 20 minutes after the initial flare. The observations were made by a team from Trinity College, Dublin.

“The energy released in these explosions is phenomenal; about two billion times the annual world energy consumption in just a fraction of a second. In half an hour, we saw the tsunami cover almost the full disc of the Sun, nearly a million kilometers away from the epicenter,” said David Long, a member of the team that made the observations.

STEREO’s Extreme Ultraviolet Imager (EUVI) instruments monitor the Sun at four wavelengths which correspond to temperatures ranging between 60,000 and 2 million degrees Celsius. At the lowest of these temperatures, scientists can see structures in the chromosphere, a thin layer of the solar atmosphere that lies just above the Sun’s visible surface. At temperatures between 1 and 2 million degrees Celsius, scientist can monitor features at varying levels in the solar corona.

The SOHO spacecraft, which was launched in 1995, also monitors the Sun at these wavelengths but only took images four times per day, giving scientists rare snapshots of these tsunamis. STEREO’s EUVI instruments take an image every few minutes to create a series, making it possible for scientists to track how the wave spreads over time.

Click here for a Quicktime animation of the event.

This is the first time that a tsunami has been observed at all four wavelengths, which enabled the team to see how the wave moved through the different layers of the solar atmosphere.

“To our surprise, the tsunami seems to move with similar speed and acceleration through all the layers. As the chromosphere is much denser than the corona, we’d expect the pulse there to drag. It’s a real puzzle,” said Dr. Peter Gallagher, another member of the team.

Artist

To complicate matters, the interval between images is not the same for all four cameras. At the time of the tsunami, the cameras monitoring radiation at 1 million degrees Celsius were set to take an image every 2.5 minutes. They recorded much higher speeds and accelerations for the wave than the other cameras, which were on 10 or 20 minute cycles. By taking a sample of one image in four, the data from these cameras matched the lower values observed in the other layers.

“We’ve thought for some time that the tsunamis might be caused by magnetic shockwaves but, in previous snapshots, the waves appeared to be travelling too slowly. However, we’ve seen from this set of observations that if the time interval between images is too long, it’s easy to underestimate the speed that the waves are moving. With a few more rapid-sequence observations of solar tsunamis, we should finally be able to identify the cause of these waves,” said Gallagher.

The discovery will be presented by David Long at the RAS National Astronomy Meeting in Belfast on Wednesday April 2, 2008.

For more information and animations, see Trinity College’s pageabout the solar tsunami.

Original News Source: RAS press release

Posted on by Nancy Atkinson

Early Universe Had Burst of Star Formation

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Just as humans develop and grow the fastest when we are young, it also appears our universe grew and developed stars at an incredibly fast rate when it was young, too. New measurements from some of the most distant galaxies helps support evidence that the strongest burst of star formation in the history of the universe occurred about two billion years after the Big Bang. An international team of astronomers from the UK, France, Germany and the USA have found evidence for a dramatic surge in star birth in a newly discovered population of massive galaxies. The astronomers have been studying five specific galaxies that are forming stars at an incredible rate. The galaxies also have large reservoirs of gas to power star formation for hundreds of millions of years. These galaxies are so distant that the light we detect from them has been travelling for more than 10 billion years, meaning we see them as they were about a three billion years after the Big Bang.

The recent discovery of a new type of extremely luminous galaxy during this early epoch of the universe – one that is very faint in visible light, but much brighter at longer, radio wavelengths – is the key to the new results. Using a new and much more sensitive camera that detects radiation emitted at sub-millimeter wavelengths (longer than the wavelengths of visible light that we see with but somewhat shorter than radio waves), astronomers first found this type of galaxy in 1997. In 2004 a group of astronomers proposed that these distant “submillimetre-galaxies” might only represent half of the picture of rapid star formation in the early Universe. They suggested that a population of similar galaxies with slightly hotter temperatures could exist but have gone largely unnoticed.

The team of scientists searched for the missing galaxies using observatories around the world: the MERLIN array in the UK, the Very Large Array (VLA) in the US (both radio observatories), the Keck optical telescope on Hawaii and the Plateau de Bure submillimetre observatory in France. The instruments found and pinpointed the galaxies, measured their distances and then confirmed their star-forming nature through the detection of the vastly extended gas and dust.

Click here for more images and a movie of the Sub-millimeter Star Forming Galaxies.

The new galaxies have extremely high rates of star formation, far higher than anything seen in the present-day universe. They probably developed after the first stars and galaxies had already formed in what would have been a perfectly smooth Universe. Studying these new objects gives astronomers an insight into the earliest epochs of star formation after the Big Bang.

This information was presented by Dr. Scott Chapman from the Institute of Astronomy in Cambridge at the Royal Astronomy Society’s National Astronomy Meeting on April 1, 2008. Chapman’s work is supported by a parallel study made by PhD student Caitlin Casey.

Original News Source: Royal Astronomy Society Press Release

Posted on by Nancy Atkinson

Supernova Alert: Supernova Factories Discovered

Two “supernova factories,” rare clusters of Red Supergiant (RSG) stars, have recently been discovered. Together they contain 40 RSGs, which is nearly 20% of all the known RSGs in the Milky Way, and all 40 are on the brink of going supernova. “RSGs represent the final brief stage in a massive star’s lifecycle before it goes supernova,” said Dr. Ben Davies of the Rochester (New York) Institute of Technology. “They are very rare objects, so to find this many in the same place is remarkable.”


The two clusters are located next to each other on the edge of the central galactic bar, a long bar of stars within the central bulge of our Milky Way Galaxy. This galactic bar is believed to be made up of about 30 million stars, most of them older, red stars, and stretches 27,000 light-years from end to end. The bar is plowing through the disc of the Milky Way, and astronomers believe the interaction between the bar and the disc triggered the star formation event, creating the uncommon clusters.

The clusters are about 20,000 light years from Earth and about 800 light years from each other. Cluster 1 contains 14 RSGs and is 12 million years old; Cluster 2 contains 26 RSGs and is 17 million years old. Massive stars are rarely observed because they burn their fuel up very quickly. RSGs are doubly rare because they are only a brief period of that short life cycle.

Dr. Davies said, “The next supernova could go off in one of these clusters at any time. We estimate that it’s about 5000 years between explosions for these clusters and we can see the remnants of a supernova that went off around 5000 years ago. That means that the next one could be any time between today and 7008 AD.”

Red Supergiant Stars. Image Credit: Rochester Institute of Technology
The team identified the clusters initially using the mid-infrared Galactic Plane survey (GLIMPSE), a huge database of images taken by the Spitzer Space Telescope. They found two distinct groupings of bright stars very close to one another in the constellation of Scutum. Using the Keck Telescope in Mauna Kea, Hawaii, they were then able to pin-point the exact distance from Earth of each star in each group. These observations showed that, in each group, large numbers of stars were at exactly the same distance from Earth, and therefore were members of the same cluster.

“The discovery of these clusters gives us a great opportunity to answer some long-standing questions in astrophysics,” said Davies, “such as exact mechanisms of how massive stars evolve toward supernovae, and how the Galactic Bar can trigger huge starburst events in the Milky Way.”
Davies presented his findings at the Royal Astronomy Society’s National Astronomy Meeting in Belfast on April 1, 2008.

Original News Source: Royal Astronomy Society Press Release

Posted on by Nancy Atkinson

SuperWASP are Super Planet-Finding Observatories

The United Kingdom’s Wide Area Search for Planets, known as SuperWASP consists of two 8-camera robotic observatories that cover both hemispheres of the sky. In the past 6 months an international team of astronomers have used these unique observatories to discover 10 new extra-solar planets, making SuperWASP the most successful planet-hunting observatory in the world. The discovery of these planets was announced on April 1 by Dr. Don Pollacco of Queen’s University in Belfast at the Royal Astronomy Society’s National Astronomy Meeting in the UK.

All told, scientists have found more than 270 extrasolar planets since the the early 1990s. Most of these are detected through their gravitational influence on the star they orbit. As a planet orbits a star, it tugs the star back and forth. However, making these discoveries depends on looking at each star over a period of weeks or months, making the pace of discovery fairly slow.

But SuperWASP uses a different method. The two sets of cameras watch for events known as transits, where a planet passes directly in front of a star and blocks out some of the star’s light, so from the Earth the star temporarily appears a little fainter. The SuperWASP cameras work as robots, surveying a large area of the sky at once and each night astronomers have data from millions of stars that they can check for transits. The transit method also allows scientists to deduce the size and mass of each planet.

SuperWASP-North is located on the island of La Palma, just off the Northwestern coast of Africa, and SuperWASP-South is at the southern tip of Africa at the South African Astronomical Observatory near Sutherland, South Africa.

SuperWasp Cameras. Image Credit: SuperWASP project & David Anderson

The observatories are quite simple, but effective. They use 8 high quality digital cameras to take pictures of the sky and simply measure any changing brightness of the stars.

Each possible planet found using SuperWASP is then observed by astronomers working at the Nordic Optical Telescope on La Palma, the Swiss Euler Telescope in Chile and the Observatoire de Haute Provence in southern France, who use precision instruments to confirm or reject the discovery.

45 planets have now been discovered using the transit method, and since they started operation in 2004 the SuperWASP cameras have found 15 of them, which makes SuperWASP by far the most successful discovery instruments in the world. The SuperWASP planets have a variety of masses, between a middleweight 0.5 and a huge 8.3 times that of Jupiter. A number of these new worlds are quite exotic. For example, a year on WASP-12B (its orbital period) is just 1.1 days. The planet is so close to its star that its daytime temperature could reach a searing 2300 degrees Celsius.

Dr. Pollacco is delighted with the results. “SuperWASP is now a planet-finding production line and will revolutionize the detection of large planets and our understanding of how they were formed. It’s a great triumph for European astronomers.”

Original News Source: Royal Astronomy Society press release

Posted on by Nancy Atkinson

Explaining Dark Matter and Contradicting the Big Bang

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It’s well-known that “Big Bang” was a derogatory name given to the cosmological theory of the expanding (not exploding) universe in an attempt to discredit the idea. But, the name stuck and with the discovery of the cosmic microwave background (CMB) in 1964, the theory has stuck, too. However, every once in awhile, a new idea comes out which claims to contradict the Big Bang Theory. The latest comes from researchers Robert K. Soberman and Maurice Dubin who say they know what dark matter is comprised of, and their new ideas provide a better explanation for the CMB, as well as the galactic red shift, two observations that currently support the Big Bang Theory.

Soberman and Dubin believe dark matter is actually made of cosmic meteoroids — clumps of hydrogen and helium atoms, which they call “cosmoids.” The two researchers say cosmoids were found in a new evaluation of data detected by Pioneer 10 & 11. This dark and fragile matter exists in the “near absolute zero cold and almost forceless space between galaxies from material expelled in stellar winds. Little, if any radiation is emitted at that temperature, hence its invisibility,” say Soberman and Dubin in a paper they released on March 25, 2008.

While the cosmic microwave background seems to cover the sky smoothly in all directions, this is unlike visible matter which is clumped into galaxies. The two researchers hypothesize that cosmoids were drawn gravitationally into our galaxy, the solar system and the immediate Earth vicinity, and radiate at 2.735 K which is “erroneously interpreted as the big bang cosmic microwave background.””Hence, this locally smooth distribution of cosmoids makes the radiation look the same in all directions to us.

Soberman and Dubin say that even variations discovered by satellites such as COBE and WMAP do not explain the distribution of visible matter, and that cosmoids provide a better alternative explanation.

The cosmoid proposal also explains the galactic redshift, according to Soberman and Dubin. Cosmoids absorb and re-emit light from distant galaxies, and that should redshift the light in a way that is subtly different from a Doppler redshift generated by an expanding universe. They say that the subtle difference should be relatively easy to spot with a few observations.

They will conduct several tests which they expect will contradict Big Bang predictions. The test include mixing hydrogen with a small amount of helium and cooling it to 2.735 K to see if cosmoids form, and measuring the red shift of cosmoids (dark matter) lying within 1 AU of the sun.

“Bereft of the two supporting pieces of evidence, the big bang hypothesis should collapse. Any hypothesis worthy of consideration should offer predictions that allow choice between it and competitor(s). This model concludes with analytical and experimental predictions, the results of which should contradict the big bang hypothesis,” say Soberman and Dubin.

Soberman and Dubin do not mention anything about the third “pillar” of the Big Bang Theory, which is the distribution of hydrogen and helium throughout the cosmos, which closely matches the predictions of the Big Bang Theory.

While this new theory is sure to raise more than just a few eyebrows, it demonstrates what’s great about science. All theories — whether long-standing mainstays of current scientific understanding or new, upstart ideas – will undergo constant scrutiny and testing. It will be interesting to see what Soberman and Dubin’s tests reveal.

Original News Sources: ArXiv Blog, and ArXiv

Posted on by Nancy Atkinson

Want to Find Evidence of Life on Another Planet? Look for Cellulose

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Until recently, the oldest evidence of biological material on Earth came from fragments of ancient protein found in Tyrannosaurus Rex dinosaur fossils, dated at 68 million years old. But scientists from the University of North Carolina have found even more ancient biological material — cellulose microfibers—that date to over 250 million years old. These samples of cellulose were found in pristine ancient salt deposits deep beneath the New Mexico desert. This finding comes on the heels of researchers finding huge salt deposits on Mars with the Odyssey orbiter, as well as the Mars Exploration Rover Spirit finding a patch of bright soil that’s believed to be rich with salt. Combined, these findings may help point out destinations for future Mars missions looking for past life on the Red Planet.

“In looking for evidence of life on Mars, for bacteria or higher plants that existed on Mars or another planet in the solar system, then looking for cellulose in salt deposits is probably a very good way to go,” said Jack D. Griffith, Ph.D., from UNC who found the cellulose microfibers. “Cellulose appears to be highly stable and more resistant to ionizing radiation than DNA. And if it is relatively resistant to harsh conditions such as those found in space, it may provide the ideal ‘paper trail’ in the search for life on other planets.”

Cellulose is the major structural component of plant matter and is very tough and resilient. Cellulose is one of the most abundant biological materials on Earth, with plants, algae and bacteria generating an estimated 100 gigatons each year.

The salt samples retrieved by Griffith are from an underground repository for nuclear waste, about 2,000 feet below the surface. In examining the content of fluid salt and salt crystals with an electron microscope, Griffith and his team found abundant cellulose microfibers that were “remarkably intact.”

The cellulose microfibers were as small as five nanometers in diameter, but also, there were tangles of the fibers, creating ropes and mats . “The cellulose we isolated from the ancient salt deposits is very much like real, modern day cellulose: it looks like cellulose, behaves like cellulose, it’s chopped up by the same enzymes that cut modern day cellulose and it’s very intact,” Griffith said.

Griffith said DNA was also was observed, but in much lesser amounts than cellulose.
Bright Soil on Mars. Credit: NASA/JPL-Caltech/Cornell
Whether life ever existed on Mars is the biggest scientific question driving Mars research. Scientists think the salt deposits formed on Mars approximately 3.5 to 3.9 billion years ago. “By their nature, salt deposits point to a lot of water, which potentially could remain standing in pools as it evaporates,” said Phil Christensen, principal investigator for Mars Odyssey spacecraft’s Thermal Emission Imaging System. “That’s crucial. For life, it’s all about a habitat that endures for some time.”

Whether there was enough time for biological life to develop on Mars is the big question hoped to be answered by the Phoenix mission, which will soon land on Mars’ polar region on May 25, 2008 and the future Mars Science Laboratory mission, tentatively scheduled to launch in 2009.

Original News Source: Physorg.com

Posted on by Nancy Atkinson

Break Up of Antarctic Ice Shelf

If anyone is denial about climate change possibly occuring on Earth, please take a look at this. This animation highlights the rapid loss of ice recently on the Wilkins Ice Shelf in Antarctica. Between February 28 and 29, 2008 an area of about 400 sq km disintegrated into large and small icebergs within 24 hours. As a result of the recent collapse, the remaining shelf, which totals about 14 500 sq km, is now only supported by a 6 km strip of ice. This strip is already rifted, and the remaining strip is in danger of breaking up as well.

The Wilkins Ice Shelf is a broad plate of floating ice south of South America on the Antarctic Peninsula. Since the ice shelf is already floating, this event will not cause a rise in sea level. However, ice shelves on the Antarctic Peninsula are sandwiched by extraordinarily raising surface air temperatures and a warming ocean, making them important indicators for on-going climate change.
Credits: ESA - M. Braun, Bonn University, Center for Remote Sensing of Land Surfaces
Thousands of years of accumulated and compacted snow on the Antarctic central plateau have formed a mighty ice sheet which flows under gravity towards the coastal plane. Along the coast the ice gradually floats on the sea – to form massive ledges known as ice shelves. But as the temperature has increased, several ice shelves have broken up and disintegrated.

The images used for this annimation were taken by the ESA’s Envisat satellite. Within days of its launch, Envisat captured the disintegration of the Larsen-B ice shelf in Antarctica on 18 March 2002. Scientists estimate Larsen-B had been stable since the last ice age 12,000 years ago.

These images were acquired as part of ESA’s support to the International Polar Year (IPY) 2007-2008, a large worldwide science programme focused on the Arctic and Antarctic.

Original News Source: ESA Press Release

Posted on by Nancy Atkinson

Planet Formation Revealed?

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One of the biggest unresolved questions of planet formation is how a thick disc of debris and gas surrounding young stars eventually evolves into a thin, dusty region with planets. This entire process, of course, has never actually been observed. But recently, and for the first time, a group of astrophysicists produced an image of material surrounding a star which seems to be coalescing into a planet.

The image was produced from a coronagraph attached to a telescope in Hawaii. It shows a horseshoe-shaped void in the disc of materials surrounding the star AB Aurigae, with a bright point appearing as a dot in the void.

“The deficit of material could be due to a planet forming and sucking material onto it, coalescing into a small point in the image and clearing material in the immediate surroundings,” said researcher Ben Oppenheimer, an astrophysicist at the American Museum of Natural History in New York. “It seems to be indicative of the formation of a small body, either a planet or a brown dwarf.”

A brown dwarf is considered a star that’s not massive enough to generate the thermonuclear fusion to create an actual star.

From what we know about planet formation, planets seem to be natural by-product of stars. But how does all this happen? Stars form when clouds of gas and dust contract under gravity, and if there’s enough compression and heat, sooner or later a nuclear reaction is triggered, and voilà: a star. If there’s any left-over material surrounding the young star, eventually the disc of dust and/or gas may congeal into planets. But the details of this process are unknown.

AB Aurigae is a well-studied star. It’s young, between one and three million years old, and can provide information on how stars and objects that orbit them form. And scientists hope that by studying this star, we can learn more about how planets form from the initial thick, gas-rich disk of debris that surrounds young stars. The observation of stars slightly older than AB Aurigae shows that at some point the gas is removed, but no one knows how this happens. AB Aurigae could be in an intermediate stage, where the gas is being cleared out from the center, leaving mainly dust behind.

“More detailed observations of this star can help solve questions about how some planets form, and can possibly test competing theories,” says Oppenheimer. And if this object is a brown dwarf, our understanding of them must be revamped as brown dwarfs are not believed to form in circumstellar materials, Oppenheimer said.

Original New Source: National Science Foundation Press Release

Posted on by Nancy Atkinson

Endeavour and Crew Back Home Safely (Video)

After 16 days in space and 250 orbits of the Earth, space shuttle Endeavour touched down at Wednesday evening at NASA’s Kennedy Space Center in Florida, bringing the STS-123 mission to a flawless end. The mission launched in darkness on March 11, and returned home with a rare night landing – and both were spectacular sights. For those of you keeping score at home, Endeavour’s main gear touchdown took place at 8:39:08 p.m. EDT at a mission elapsed time of 15 days, 18 hours, 10 minutes and 55 seconds.

Endeavour lands. Image credit: NASA
Mission managers said the crew was in good health and spirits. “I got to talk to the crew, and the crew was just having a fantastic time reflecting on their mission and looking up at their vehicle that just landed,” said Shuttle Launch Director Mike Leinbach. “They were glad to be home, very proud of the work they did, and we’re very proud of the work they did, too.”

On board Endeavour were Mission Specialists Takao Doi of the Japan Aerospace Exploration Agency, Robert L. Behnken, and Rick Linnehan; Pilot Gregory H. Johnson; Commander Dominic Gorie; and Mission Specialist Mike Foreman, as well as European Space Agency astronaut Léopold Eyharts, who returned to Earth aboard Endeavour after almost 50 days in space on the International Space Station. The 16 day mission was one of the longest space shuttle missions, with 5 spacewalks for station construction that included attaching a Japanese Pressurized Module and putting together Dextre, a robotic handyman that will be available to assist in station construction and maintenence tasks.

If you missed seeing the landing last night, here’s a link to video from NASA