Galaxy merger dilemma solved

April 21, 2010 By Leave a Comment

Washington, April 21 (ANI): A long-standing dilemma about the mass of infrared bright merging galaxies has finally been solved by scientists at the Naval Research Laboratory (NRL).

Dr. Barry Rothberg along with Dr. Jacqueline Fischer used new data from the 8-meter Gemini-South telescope in Chile along with earlier results from the W. M. Keck-2 10-meter and University of Hawaii 2.2-meter telescopes in Hawaii and archival data from the Hubble Space Telescope, to solve the problem.

Galaxies in the Universe generally come in two shapes, spiral, like our own Milky Way, and elliptical, in which the stars move in random orbits.

The largest galaxies in the Universe are elliptical in shape and how they formed is central to our understanding how the Universe has evolved over the last 15 billion years.

The long-standing theory has been that spiral galaxies merge with each other forming most of the elliptical galaxies in the Universe.

Spiral galaxies contain significant amounts of cold hydrogen gas. When they merge, the beautiful spiral patterns are destroyed and the gas is converted into new stars and with it, large amounts of dust. The dust is heated by the young stars and radiates energy at infrared wavelengths.

Until recently scientists thought that these infrared bright merging galaxies were not massive enough to be the precursors of most elliptical galaxies in the Universe.

The conventional method of measuring mass in dusty IR-bright galaxies uses near-infrared light, which can penetrate dust, to measure the random motions of old-stars.

The larger the random motions, the more mass is present. When spirals merge, gas from both galaxies forms a central rotating disk which then forms new stars.

These young stars outshine the old stars at near-infrared wavelengths making it appear as if the old stars have less random motion. Rothberg and Fischer instead observed the random motions of old stars at shorter wavelengths effectively using the dust to block the light from the young stars.

Their new results showed that the old stars in merging galaxies have large random motions, which means they will eventually become very massive elliptical galaxies.

The new research has been published in the Astrophysical Journal. (ANI)

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Newly discovered exoplanet may have water

March 19, 2010 By Leave a Comment

Washington, March 19 (ANI): Scientists have suggested that the newly discovered planet Corot-9b is temperate enough to allow the presence of liquid water.

Corot-9b was found on 16 May 2008 and orbits its star every 95.274 days, a little longer than Mercury takes to go round the Sun.

It is the first transiting planet to have both a longer period and a near-circular orbit.

A transit is a kind of eclipse and occurs when a celestial body passes in front of its host star and blocks some but not all of the star’s light.

Corot-9b’s orbit is slightly elliptical but at closest approach to its parent star it reaches a distance of 54 million kilometers.

Although that is only about the distance of Mercury in our Solar System, it is by far the largest orbit of any transiting planet found so far.

Because it orbits a star cooler than our Sun, calculations estimate that Corot-9b’s temperature could lie somewhere between -23 degrees C and 157 degrees C.

Corot-9b has a radius around 1.05 times that of Jupiter but only 84 percent of the mass. This leads to a density of 0.90 g/cc, or 68 percent that of Jupiter.

“Corot-9b is the first exoplanet that is definitely similar to a planet in our Solar System,” said Hans Deeg, a researcher at the Instituto de Astrofisica de Canarias.

The similarity is caused by the fact that Corot-9b is sufficiently far from its star to prevent tidal forces from heating its interior.

Tidal forces are created by the strength of gravity weakening from the front to back of the celestial body.

When the difference between the near side and the far side is great, the tidal force can prevent the planet from spinning quickly, forcing it to only show one face to the star.

It can also provide heat to the interior of the planet, changing its physical condition.

Based on calculations, neither of these is possible in this case.

“Although we don’t know, because we can’t see the planet directly, there is reason to believe that this planet has a normal day-night cycle,” said Malcolm Fridlund, ESA Project Scientist for Corot.

It means that lacking a tidal heat source, Corot-9b’s interior is likely to have remained similar to the gas giants in our Solar System. (ANI)

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Earth and Venus might be involved in a long-distance relationship

March 17, 2010 By Leave a Comment

Washington, March 17 (ANI): New calculations by scientists have suggested that Venus and Earth might literally be involved in a long-distance relationship, with our planet speculated to be tugging on the core of Venus and exerting control over its spin.

Whenever Venus and Earth arrive at the closest point in their orbits, Venus always presents the same face to us.

This could mean that Earth’s gravity is tugging subtly on Venus, affecting its rotation rate.

That idea, raised decades ago, was disregarded when it turned out that Venus is spinning too fast to be in such a gravitational “resonance”.

But Earth could still be pulling on Venus by controlling its core, according to calculations by Gerard Caudal of the University of Versailles-Saint Quentin, France.

According to a report in New Scientist, Caudal made large assumptions about Venus’s interior, which we know little about.

For his hypothesis to be correct, the planet would, like Earth, need a solid core surrounded by a liquid layer.

This could allow the solid core to rotate slower than the rest of the planet.

The core would also have to be asymmetric or heterogeneous, so that Earth can exert a variable tug as Venus spins.

“For the resonance to be possible, there should be something that the gravity of the Earth could grasp,” Caudal said.

This latter requirement could be problematic for the hypothesis, according to Jean-Luc Margot of the University of California, Los Angeles.

“In order to maintain a resonance, the inner core must be out of round by a significant amount,” he noted.

Yet persistent imperfections in planetary cores tend to smooth out because the core is hot and under great pressure, according to David Stevenson of the California Institute of Technology in Pasadena.

“Still, the resonance theory is worth revisiting,” he said.

“Watching for changes in Venus’s spin over time using radar observations may reveal more about what’s going on inside the planet,” said Margot. (ANI)

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Craters on Vesta and Ceres could pinpoint Jupiter’s age

September 14, 2009 By Leave a Comment

Washington, September 14 (ANI): A new study that models the cratering history of Vesta and Ceres, which are the largest two objects in the asteroid belt, could help pinpoint when Jupiter began to form during the evolution of the early Solar System.

The study, carried out by scientists at the Italian National Institute for Astrophysics in Rome, explored the hypothesis that one or both objects formed during Jupiter’s formation by modeling their cratering histories during the birth of the giant planet.

Their simulation described Jupiter’s formation in three stages: an initial accretion of its core followed by a stage of rapid gas accretion.

This is, in turn, followed by a phase where the gas accretion slows down while the giant planet reaches its final mass.

During the last two phases, Jupiter’s gravitational pull starts to affect more and more distant objects.

For each of these phases, the team simulated how Jupiter affected the orbits of asteroids and comets from the inner and outer Solar System, and the likelihood of them being moved onto a collision path with Vesta or Ceres.

According to Dr. Diego Turrini, who presented the results of the study at the European Planetary Science Congress in Potsdam, Germany, “We found that the stage of Jupiter’s development made a big difference on the speed of impacts and the origin of potential impactors.”

“When Jupiter’s core approaches its critical mass, it causes a sharp increase in low-velocity impacts from small, rocky bodies orbiting nearby to Vesta and Ceres which lead to intense and uniform crater distribution patterns. These low-speed collisions may have helped Vesta and Ceres gather mass,” he said.

“Once Jupiter’s core has formed and the planet starts to rapidly accrete gas, it deflects more distant objects onto a collision course with Ceres and Vesta and the impacts become more energetic,” he added.

The third stage of Jupiter’s formation is complicated by a period known as the Late Heavy Bombardment, which occurred around 3.8 to 4.1 billion years ago.

During this time, a significant number of objects, rich in organic compounds, from the outer Solar System were injected on planet-crossing orbits with the giant planets and may have reached the Asteroid Belt.

In addition, Jupiter is thought to have migrated in its orbit around this time, which would have caused an addition flux of impactors on Vesta and Ceres.

The team will have an opportunity to confirm their results when NASA’s Dawn space mission reaches Vesta in 2011 and then flies on for a further rendezvous with Ceres in 2015. (ANI)

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‘Sailing spacecraft’ may be used to keep watch on Earth’s polar regions

September 12, 2009 By Leave a Comment

London, September 11 (ANI): If engineers have their way, Earth’s polar regions would soon have watchmen, in the form of ‘sailing’ spacecrafts poised above the planet, relaying vital data on polar climate change or solar storms.

“Solar sailing” has long been a dream for space engineers, who have envisaged craft exploring the depths of the solar system, propelled only by light.

Such craft could be lighter to launch and would range farther than craft using conventional fuel.

But, according to a report in The Times, scientists are now also exploring more realistic applications that could be deployed in the short term.

Because they will never run out of fuel, solar sailing craft could be used to stay in orbits that would be impossible for conventional satellites.

Once launched into space, solar sailing craft would unfurl giant sails of thin reflective material. Photons – particles of light – hitting the sails would transfer energy to the craft.

Although this force is tiny, in the weightless and airless conditions of space, the craft could build up great speeds.

The constant force provided by solar sails could also be used to hold craft in position indefinitely by effectively expanding the solar system’s natural balancing points.

These, known as Lagrange points, exist where the gravitational attractions from two celestial bodies are exactly equal.

According to Colin McInnes, a mechanical engineer at the University of Strathclyde, “Even if you’ve got quite a small force from your solar sail you can shift the Lagrange point quite substantial distances. Even quite a modest solar sail can have a big effect.”

“Because you’ve got that small continuous force it gives you vantage points for observation that you can’t get with conventional spacecraft because you would run out of propellent fairly quickly,” he said.

Solar sailing craft would be able to hover above the polar regions, where conventional satellites cannot provide a constant view.

“Given the polar region is of great interest to climate change and environmentally monitoring, having an observation point above the poles is of practical interest,” Professor McInnes said.

If positioned near a Lagrange point closer to the Sun, solar sailing craft could also give early warnings of solar storms that threaten to disrupt the Earth’s telecommunications, he added. (ANI)

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Andromeda galaxy expanded by cannibalizing on stars from other galaxies

September 3, 2009 By Leave a Comment

London, September 3 (ANI): A new research has shown that the vast Andromeda galaxy appears to have expanded by cannibalizing on stars from other galaxies.

According to a report by BBC News, when an international team of scientists mapped Andromeda, they discovered stars that they said were “remnants of dwarf galaxies”.

This consumption of stars has been suggested previously, but the team’s ultra-deep survey has provided detailed images to show that it took place.

This shows the “hierarchical model” of galaxy formation in action.

The model predicts that large galaxies should be surrounded by relics of smaller galaxies they have consumed.

The scientists charted the outskirts of Andromeda in detail for the first time. They discovered stars that could not have formed within the galaxy itself.

Pauline Barmby, an astronomer from the University of Western Ontario told BBC News that the pattern of the stars’ orbits revealed their origin.

“Andromeda is so close that we can map out all the stars,” she said. “And when you see a sort of lump of stars that far out, and with the same orbit, you know they can’t have been there forever,” she added.

Andromeda, which is approximately 2.5 million light years away from Earth is still expanding, say the scientists.

The researchers also saw a “stream of stars” of a nearby galaxy called Triangulum “stretching” towards Andromeda.

According to Dr Scott Chapman, reader in astrophysics at the Institute of Astronomy, University of Cambridge, “Ultimately, these two galaxies may end up merging completely. Ironically, galaxy formation and galaxy destruction seem to go hand in hand.”

Nickolay Gnedin, an astrophysicist from the University of Chicago, described the work as showing “galactic archaeology in action”. (ANI)

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India’s first moon mission Chandrayaan-I “definitely over”, says project director(Lead: Chandrayaan-I)

August 29, 2009 By Leave a Comment

Bangalore, Aug 29(ANI): India’s ambitious moon mission — Chandrayaan-I — came to an abrupt end on Saturday after losing radio with the spacecraft.

“The mission is definitely over. We have lost contact with the spacecraft. It (Chandrayaan-1) has done its job technically…100 per cent. Scientifically also, it has done almost 90-95 percent of its job,” said M Annadurai, Project Director of the Chandrayaan-1 mission.

However, Indian Space Research Organisation (ISRO) chairman G. Madhavan Nair said scientists will evaluate the performance of the mission over the next two days before deciding whether or not to call it off.

Earlier, in the day the flamboyant spacecraft had lost the radio control at around 1.30 a.m. IST, increasing fears of a premature end of the spacecraft.

According to a press release by the ISRO, the deep Space Network at Byalalu near Bangalore has not received any signal form the spacecraft since midnight.

“Radio contact with Chandrayaan-I spacecraft was abruptly lost at 0130 Hrs (IST) on August 29, 2009. Deep Space Network at Byalalu near Bangalore received the data from Chandrayaan-I during the previous orbit upto 0025 Hrs (IST),”the press release states.

The ISRO has ordered for a detailed review of the data received by the spacecraft, “Detailed review of the Telemetry data received from the spacecraft is in progress and health of the spacecraft subsystems is being analysed,” press release states.

Earlier, on July 17, the flamboyant moon mission Chandrayaan-I, had lost a major sensor. The scientific community then feared the premature end of the spacecraft.

The Chandrayaan-I, which was launched from Satish Dhawan Space Centre at Sriharikota in Andhra Pradesh in October 2008, has completed over 350 days in orbit making more than 3400 orbits around the Moon and providing large volume of data from sophisticated sensors.

The spacecraft was equipped with Terrain Mapping Camera, Hyper-spectral Imager, Moon Mineralogy Mapper etc.,

The ISRO scientists expressed confidence of attaining most of the scientific objectives of the mission.

Addressing the Ninth convocation of the International Institute of Information and Technology at Bangalore last month, Nair said the tracking and detection of several factors by Chandrayaan are important steps in mapping the mineralogical composition of moon’s surface, which in turn would enable further study in its origin and evolution.

“I think I am happy to say that Chandrayaan has been completely successful in collecting all the data what we wanted. First was the three dimensional of the lunar surface, also getting the mineral content of the surface and then trying to use the extra instruments,” said Nair.

“All this went on very well and we are more or less very happy that the mission is complete,” he added.

Nair also added that the second moon mission would be launched by 2012. (ANI)

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India’s first moon mission may be over, says project director

August 29, 2009 By Leave a Comment

Bangalore, Aug 29 (ANI):India’s ambitious moon mission — Chandrayaan-I — has probably ended after losing radio contact since Saturday noon, said its project director M. Annadurai, but Indian Space Research Organisation (ISRO) chairman G. Madhavan Nair said scientists will evaluate the performance of the mission over the next two days before deciding whether or not to call it off.

Earlier, in the day the flamboyant spacecraft had lost the radio control at around 1.30 a.m. IST, increasing fears of a premature end of the spacecraft.

According to a press release by the ISRO, the deep Space Network at Byalalu near Bangalore has not received any signal form the spacecraft since midnight.

“Radio contact with Chandrayaan-I spacecraft was abruptly lost at 0130 Hrs (IST) on August 29, 2009. Deep Space Network at Byalalu near Bangalore received the data from Chandrayaan-I during the previous orbit upto 0025 Hrs (IST),”the press release states.he ISRO has ordered for a detailed review of the data received by the spacecraft, “Detailed review of the Telemetry data received from the spacecraft is in progress and health of the spacecraft subsystems is being analysed,” press release states.

Earlier, on July 17, the flamboyant moon mission Chandrayaan-I, had lost a major sensor. The scientific community then feared the premature end of the spacecraft.

The Chandrayaan-I, which was launched from Satish Dhawan Space Centre at Sriharikota in Andhra Pradesh in October 2008, has completed over 350 days in orbit making more than 3400 orbits around the Moon and providing large volume of data from sophisticated sensors.

The spacecraft was equipped with Terrain Mapping Camera, Hyper-spectral Imager, Moon Mineralogy Mapper etc.,

The ISRO scientists expressed confidence of attaining most of the scientific objectives of the mission.

Addressing the Ninth convocation of the International Institute of Information and Technology at Bangalore last month, Nair said the tracking and detection of several factors by Chandrayaan are important steps in mapping the mineralogical composition of moon’s surface, which in turn would enable further study in its origin and evolution.

“I think I am happy to say that Chandrayaan has been completely successful in collecting all the data what we wanted. First was the three dimensional of the lunar surface, also getting the mineral content of the surface and then trying to use the extra instruments,” said Nair.

“All this went on very well and we are more or less very happy that the mission is complete,” he added.

Nair also added that the second moon mission would be launched by 2012. (ANI)

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Comets, not asteroids, scarred Moon’s face about 4 billion years ago

July 29, 2009 By Leave a Comment

London, July 28 (ANI): A new study of ancient rocks in Greenland has suggested that icy comets – not rocky asteroids – launched a dramatic assault on the Earth and moon around 3.85 billion years ago, thus causing the lunar surface to become scarred.

“We can see craters on the moon’s surface with the naked eye, but nobody actually knew what caused them – was it rocks, was it iron, was it ice?” Uffe Grae Jorgensen, an astronomer at the Niels Bohr Institute in Copenhagen, Denmark, told New Scientist.

“It’s exciting to find signs that it was actually ice,” he said.

Evidence suggests that the Earth and moon had both formed around 4.5 billion years ago.

But, almost all the craters on the moon date to a later period, the “Late Heavy Bombardment” 3.8 to 3.9 billion years ago, when around 100 million billion tonnes of rock or ice crashed onto the lunar surface.

To find out whether asteroids or comets were the main culprits for the bombardment, Jorgensen decided to measure levels of the element iridium in ancient terrestrial rocks.

Iridium is rare on the Earth’s surface because almost all of it bound to iron and sank into the Earth’s core soon after the planet had formed. But iridium is relatively common in comets and meteorites.

His team calculated the amount of iridium that asteroids would leave on the Earth and moon compared to comets.

Because comets have more volatile elements and higher impact speeds due to their more elongated orbits around the sun, they would create giant plumes on impact, allowing more iridium to escape into space than during asteroid impacts.

The team predicted that asteroid bombardment would leave iridium levels of 18,000 and 10,000 parts per trillion in rocks on the Earth and moon respectively, while the same figures for comet bombardment would be about 130 and 10.

Ancient moon rocks returned by NASA’s Apollo missions have already confirmed that the lunar iridium levels are 10 parts per trillion or less.

To find out the terrestrial value, Jorgensen’s team sampled some of the world’s oldest rocks from Greenland, aged 3.8 billion years, and asked a Japanese laboratory to assess their iridium levels more accurately than ever before.

They contained iridium levels of 150 parts per trillion, which strongly suggests comets, rather than asteroids, caused the violent bombardment. (ANI)

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Venus may once have been more Earth-like

July 14, 2009 By Leave a Comment

Paris, July 14 (ANI): Venus Express has charted the first map of the planet’s southern hemisphere at infrared wavelengths, which hints that Venus may once have been more Earth-like, with both, a plate tectonics system and an ocean of water.

The map comprises over a thousand individual images, recorded between May 2006 and December 2007.

Because Venus is covered in clouds, normal cameras cannot see the surface, but Venus Express used a particular infrared wavelength that can see through them.

Although radar systems have been used in the past to provide high-resolution maps of Venus’s surface, Venus Express is the first orbiting spacecraft to produce a map that hints at the chemical composition of the rocks.

The new data is consistent with suspicions that the highland plateaus of Venus are ancient continents, once surrounded by ocean and produced by past volcanic activity.

“This is not proof, but it is consistent. All we can really say at the moment is that the plateau rocks look different from elsewhere,” said Nils Muller at the Joint Planetary Interior Physics Research Group of the University Munster and DLR Berlin, who headed the mapping efforts.

The rocks look different because of the amount of infrared light they radiate into space, similar to the way a brick wall heats up during the day and gives off its heat at night.

Besides, different surfaces radiate different amounts of heat at infrared wavelengths due to a material characteristic known as emissivity, which varies in different materials.

The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument captured this infrared radiation during Venus’s night-time orbits around the planet’s southern hemisphere.

The new map shows that the rocks on the Phoebe and Alpha Regio plateaus are lighter in colour and look old compared to the majority of the planet.

On Earth, such light-coloured rocks are usually granite and form continents.

Granite is formed when ancient rocks, made of basalt, are driven down into the planet by shifting continents, a process known as plate tectonics.

The water combines with the basalt to form granite and the mixture is reborn through volcanic eruptions.

“If there is granite on Venus, there must have been an ocean and plate tectonics in the past,” said Muller.

The new map gives astronomers another tool in their quest to understand why Venus is so similar in size to Earth and yet has evolved so differently. (ANI)

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‘Noisy’ stars mask planet’s true size

July 10, 2009 By Leave a Comment

Sydney, July 10 (ANI): A German study has suggested that astronomers observing exoplanets around other stars may be underestimating their size because of active stars that add ‘noise’ to the observation of exoplanets using the transit method.

The transit method detects exoplanets as they pass in front of their parent star, reducing the amount of light reaching telescopes on, and orbiting, Earth.

Although the transit method isn’t the best method for detecting exoplanets, it provides a reliable estimate of its size and mass.

According to a report by ABC News, PhD student Stefan Czesla of the Hamburg Observatory in Germany, and colleagues, examined the giant exoplanet Corot-2b, using data from the French COROT satellite.

Discovered in 2007, Corot-2b is three and a half times the mass of Jupiter and orbits its star in just 1.74 days.

After closely examining the light curves recorded by COROT, which involved splitting them into their red, green and blue components, the researchers determined that the exoplanet is 3 percent bigger than previously thought.

Czelsa and colleagues believe this discrepancy may be true for other exoplanets around active stars.

“For planets found around active stars, the determination of their exact physical parameters is considerably complicated by stellar activity,” said Czesla.

“Bright and dark spots on the star can modify the transit light curves, something that isn’t accounted for in models currently used to calculate an exoplanet’s size,” he explained.

According to Dr John Greenhill of the University of Tasmania, the research also highlights the limitation of the transit method in detecting exoplanets, particularly those smaller than Jupiter.

“The two techniques that have netted the most planets, the radial velocity technique and the transit method, are limited by the noisiness of stars,” he said.

“In principle, it looks like we won’t be able to detect planets the size of Neptune and Uranus, and even Saturn using these methods because of that limit,” he added. (ANI)

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Largest ever survey of very distant galaxy clusters completed

July 1, 2009 By Leave a Comment

Washington, July 1 (ANI): An international team of researchers led by a UC (University of California) Riverside astronomer has completed the largest ever survey designed to find very distant clusters of galaxies.

Named the Spitzer Adaptation of the Red-sequence Cluster Survey, “SpARCS” detects galaxy clusters using deep ground-based optical observations from the CTIO 4m and CFHT 3.6m telescopes, combined with Spitzer Space Telescope infrared observations.

In a universe which astronomers believe to be 13.7 billion years old, SpARCS is designed to find clusters, snapped as they appeared long ago in time, when the universe was 6 billion years old or younger.

Clusters of galaxies are rare regions of the universe consisting of hundreds of galaxies containing trillions of stars, plus hot gas and mysterious dark matter.

Most of the mass in clusters is actually in the form of invisible dark matter which astronomers are convinced exists because of its influence on the orbits of the visible galaxies.

“We are looking at massive structures very early in the universe’s history,” said Gillian Wilson, an associate professor of physics and astronomy who leads the SpARCS project.

The SpARCS survey has discovered about 200 new cluster candidates.

“It is very exciting to have discovered such a large sample of these rare objects,” Wilson said.

“Although we are catching these clusters at early times, we can tell by their red colors that many of the galaxies we are seeing are already quite old. We will be following up this new sample for years to come, to better understand how clusters and their galaxies form and evolve in the early universe,” he added.ANI)

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Americans to see International Space Station on Fourth of July

July 1, 2009 By Leave a Comment

Washington, July 1 (ANI): The skies of the Unites States of America are all set to lit up on the fourth of July with a spectacular view of the International Space Station (ISS) as it orbits 220 miles above Earth.

Many locations will have unusually long sighting opportunities of as much as five minutes, weather permitting, as the station flies almost directly overhead.

The largest spacecraft ever built, the ISS also is the most reflective. It will be brighter than most stars at dawn and dusk, appearing as a solid, glowing light, slowly traversing the predawn or evening sky.

It is visible when lit by the sun while the ground below is not in full daylight. It moves across the sky too fast for conventional telescopes, but a good set of binoculars can enhance the viewing experience, even revealing some detail of the station’s structure.

The station circles Earth every 90 minutes.

It is 357 feet long, about the length of a football field including the end zones, and 45 feet tall. Its reflective solar arrays are 240 feet wide, a wingspan greater than that of a jumbo jet, and have a total surface area of more than 38,000 square feet.

An international crew of six astronauts, including American flight engineer Michael Barratt, is aboard the complex conducting research and continuing its assembly. (ANI)

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Most successful space mission finally ends

July 1, 2009 By Leave a Comment

Paris, July 1 (ANI): Ulysses, the joint ESA/NASA solar orbiter mission, one of the longest and most successful space missions ever conducted, has finally ended, with ground controllers sending commands to shut down the satellite’s communications on June 30.

The mission had been predicted to end in July 2008, when the satellite’s weakened power supply was expected to fall below the minimum required to keep fuel lines from freezing, without which Ulysses would be uncontrollable.

At that time, the ESA/NASA operations team planned to continue operating the spacecraft in a reduced capacity for a few more weeks.

However, through smart engineering and real time innovation, controllers determined they could keep the lines from freezing by briefly firing the thrusters every few hours.

In fact, Ulysses has continued gathering valuable scientific data throughout most of the past year – until June 30, after a decision was taken to end the mission due to continuing weak power and the unavailability of ground station time.

The joint ESA/NASA mission operations team under Nigel Angold, ESA Mission Operations Manager, monitored the final activity from the Ulysses Mission Support Area (MSA) at NASA’s Jet Propulsion Laboratory (JPL), California, USA.

Launched by Space Shuttle Discovery on 6 October 1990, the 18-year, 8-month mission has returned a wealth of scientific data on the space environment above and below the poles of the Sun.

At the time of sending the last commands, Ulysses was located approximately 1.5 astronomical units from Earth and the one-way radio signal time was approximately 45 minutes.

“This has been an amazing adventure. Although we have said a sad farewell, Ulysses will remain a unique landmark in the exploration of space, something we can all be incredibly proud of,” said Richard Marsden, ESA’s Ulysses Project Scientist and Mission Manager.

During its life, Ulysses made nearly three complete orbits of the Sun.

The probe revealed for the first time the three-dimensional character of galactic cosmic radiation, energetic particles produced in solar storms and the solar wind.

Not only has Ulysses allowed scientists to map constituents of the heliosphere in space, its longevity enabled the Sun to be observed over a longer period of time than ever before. (ANI)

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Native seeds may feed future human colonies in space

June 29, 2009 By Leave a Comment

Sydney, June 29 (ANI): An Australian experiment with native plant seeds has raised hopes for self-sustaining human colonies in space, with the seeds, taken into space last year, showing no signs of “fatigue” or damage after surviving more than 28,000 orbits of the earth.

According to a report in The Sydney Morning Herald, the seedlings of the golden wattle, waratah, flannel flower and wollemi pine accompanied NASA astronaut Dr Gregory Chamitoff on his six-month space odyssey.

At the request of NSW’s (New South Wales’) Botanic Gardens Trust, Dr Chamitoff took the seeds on the Space Shuttle Discovery mission to the International Space Station in May 2008.

While tests are still being conducted on the seedlings, which returned to earth in November last year, conservationists are encouraged by preliminary findings.

The seeds are being germinated and “fast-track” aged at the Trust’s NSW Seedbank at Mount Annan Botanic Garden in Sydney’s southwest.

“With habitats under increasing threat, seedbanking on earth, and perhaps in space, will be part of an integrated conservation program for species threatened by extinction due to global warming or other sudden changes to their habitat,” said Trust executive director Dr Tim Entwisle.

“As a species (humans) have an impact upon the other species of the world and we have the possibility of damaging the environment where we lose the biodiversity because of our actions,” said Entwisle.

“We also are a species that understands these things and, therefore, I think we have a moral imperative to do these kinds of things and protect the environment.” he added.

For NASA, the findings also present the opportunity to plan for possible space colonies.

“As soon as we get back to the moon and even before we reach Mars, we’re going to have to figure out how to recycle as much as we can and provide as much food sources as we can in space,” Dr Chamitoff said.

“From NASA’s perspective, we are interested in seeds that might be hardy enough to survive long duration exposure to the space environment and then germinate in greenhouses in Space or on other planets,” he added.

“Ultimately, this will be essential to support self-sustaining outposts or colonies in Space with food and oxygen,” he explained.

The NSW Seedbank tests on the seedlings will monitor their growth, vigour and life span compared to control seeds. (ANI)

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Astronomers probe close to supermassive black hole’s edge

May 28, 2009 By Leave a Comment

Paris, May 28 (ANI): Astronomers have used new data from ESA’s (European Space Agency’s) XMM-Newton spaceborne observatory, to probe closer than ever to a supermassive black hole lying deep at the core of a distant active galaxy.

The galaxy – known as 1H0707-495 – was observed during four 48-hr-long orbits of XMM-Newton around Earth, starting in January 2008.

The black hole at its center was thought to be partially obscured from view by intervening clouds of gas and dust, but these current observations have revealed the innermost depths of the galaxy.

“We can now start to map out the region immediately around the black hole,” said Andrew Fabian, at the University of Cambridge, who headed the observations and analysis.

X-rays are produced as matter swirls into a supermassive black hole.

The X-rays illuminate and are reflected from the matter before its eventual accretion. Iron atoms in the flow imprint characteristic iron lines on the reflected light.

XMM-Newton detected two bright features of iron emission in the reflected X-rays that had never been seen together in an active galaxy.

These bright features are known as the iron L and K lines, and they can be so bright only if there is a high abundance of iron.

Seeing both in this galaxy suggests that the core is much richer in iron than the rest of the galaxy.

The direct X-ray emission varies in brightness with time. During the observation, the iron L line was bright enough for its variations to be followed.

A painstaking statistical analysis of the data revealed a time lag of 30 seconds between changes in the X-ray light observed directly, and those seen in its reflection from the disc.

This delay in the echo enabled the size of the reflecting region to be measured, which leads to an estimate of the mass of the black hole at about 3 to 5 million solar masses.

The observations of the iron lines also reveal that the black hole is spinning very rapidly and eating matter so quickly that it verges on the theoretical limit of its eating ability, swallowing the equivalent of two Earths per hour.

This new technique will enable the astronomers to map out the process in all its glorious complexity, taking them to previously unseen regions at the very edges of this and other supermassive black holes. (ANI)

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Missing planets proof of destructive power of stars’ tides

May 2, 2009 By Leave a Comment

Washington, April 28 (ANI): Astronomers have come across first time evidence of the destructive power of stars’ tides, in the form of missing planets outside our solar system.

According to University of Washington astronomer Rory Barnes, the idea that gravitational forces might pull a planet into its parent star has been predicted by computer models only in the last year or so, and this is the first evidence that such planet destruction has already occurred.

“When we look at the observed properties of extrasolar planets, we can see that this has already happened. Some extrasolar planets have already fallen into their stars,” he said.

Computer models can show where planets should line up in a particular star system, but direct observations show that some systems are missing planets close to the stars where models say they should be.

The research involves planets that are close to their parent stars. Such planets can be detected relatively easily by changes in brightness as their orbits pass in front of the stars.

But, because they are so close to each other, the planet and star begin pulling on each other with increasingly strong gravitational force, misshaping the star’s surface with rising tides from its gaseous surface.

“Tides distort the shape of a star. The bigger the tidal distortion, the more quickly the tide will pull the planet in,” Jackson said.

According to Jackson, the destruction is slow but inevitable.

“The orbits of these tidally evolving planets change very slowly, over timescales of tens of millions of years,” Jackson said.

“Eventually, the planet’s orbit brings it close enough to the star that the star’s gravity begins tearing the planet apart,” he added.

“So, either the planet will be torn apart before it ever reaches the surface of the star, or in the process of being torn apart, its orbit eventually will intersect the star’s atmosphere and the heat from the star will obliterate the planet,” he further added.

Jackson hopes new observations will provide new lines of evidence to investigate how a star’s tides can destroy planets.

“For example, the rotation rates of stars tend to drop, so older stars tend to spin more slowly than younger stars,” he said.

“However, if a star has recently consumed a planet, the addition of the planet’s orbital angular momentum will cause the star to rapidly increase its spin rate. So, we would like to look for stars that are spinning too fast for their age,” he added. (ANI)

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Scientists announce discovery of lightest exoplanet found so far

April 22, 2009 By Leave a Comment

Munich, April 22 (ANI): Scientists have announced the discovery of the lightest exoplanet found so far, which is only about twice the mass of our Earth.

The planet, “e”, lies in the famous star system Gliese 581.

The finding is the outcome of more than four years of observations using the most successful low-mass-exoplanet hunter in the world, the HARPS spectrograph attached to the 3.6-metre ESO telescope at La Silla, Chile.

Planet Gliese 581 e orbits its host star – located only 20.5 light-years away in the constellation Libra (“the Scales”) – in just 3.15 days.

“With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet,” said co-author Xavier Bonfils from Grenoble Observatory.

Being so close to its host star, the planet is not in the habitable zone.

From previous observations, also obtained with the HARPS spectrograph at ESO’s La Silla Observatory and announced two years ago, this star was known to harbour a system with a Neptune-sized planet (ESO 30/05) and two super-Earths (ESO 22/07).

With the discovery of Gliese 581 e, the planetary system now has four known planets, with masses of about 1.9 (planet e), 16 (planet b), 5 (planet c), and 7 Earth-masses (planet d).

“It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 – the one around 51 Pegasi,” said Mayor.

“The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years,” he added. (ANI)

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Scientists announce discovery of lightest exoplanet found so far

April 22, 2009 By Leave a Comment

Munich, April 22 (ANI): Scientists have announced the discovery of the lightest exoplanet found so far, which is only about twice the mass of our Earth.

The planet, “e”, lies in the famous star system Gliese 581.

The finding is the outcome of more than four years of observations using the most successful low-mass-exoplanet hunter in the world, the HARPS spectrograph attached to the 3.6-metre ESO telescope at La Silla, Chile.

Planet Gliese 581 e orbits its host star – located only 20.5 light-years away in the constellation Libra (“the Scales”) – in just 3.15 days.

“With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet,” said co-author Xavier Bonfils from Grenoble Observatory.

Being so close to its host star, the planet is not in the habitable zone.

From previous observations, also obtained with the HARPS spectrograph at ESO’s La Silla Observatory and announced two years ago, this star was known to harbour a system with a Neptune-sized planet (ESO 30/05) and two super-Earths (ESO 22/07).

With the discovery of Gliese 581 e, the planetary system now has four known planets, with masses of about 1.9 (planet e), 16 (planet b), 5 (planet c), and 7 Earth-masses (planet d).

“It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 – the one around 51 Pegasi,” said Mayor.

“The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years,” he added. (ANI)

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An effective way to deflect an Earth-threatening asteroid

April 17, 2009 By Leave a Comment

Washington, April 17 (ANI): A scientist in the US has found an effective way to deflect an Earth-threatening asteroid, by attaching a long tether and ballast to the incoming object.

The theory has been put forward by David French, a doctoral candidate in aerospace engineering at North Carolina (NC) State University, US.

According to French, by attaching the ballast, “you change the object’s center of mass, effectively changing the object’s orbit and allowing it to pass by the Earth, rather than impacting it.”

NASA’s Near Earth Object Program has identified more than 1,000 “potentially hazardous asteroids” and they are finding more all the time.While none of these objects is currently projected to hit Earth in the near future, slight changes in the orbits of these bodies, which could be caused by the gravitational pull of other objects, push from the solar wind, or some other effect could cause an intersection,” French explained.

So French, and NC State Associate Professor of Mechanical and Aerospace Engineering Andre Mazzoleni, studied whether an asteroid-tether-ballast system could effectively alter the motion of an asteroid to ensure it missed hitting Earth.

“The Earth has been hit by objects from space many times before, so we know how bad the effects could be,” said French.

“Using a tether somewhere between 1,000 kilometers to 100,000 kilometers to divert an asteroid sounds extreme,” he said.

But, French said that when you compare this theory to other schemes, it seems a far sensible approach.

That’s because other schemes include: a call for painting the asteroids in order to alter how light may influence their orbit; a plan that would guide a second asteroid into the threatening one; and using nuclear weapons to blow up the asteroid. (ANI)

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