Time to go atomic on space station

THE International Space Station will soon host the most accurate clock ever sent into space. It will allow for better synchronisation of clocks on Earth and also probe exotic physics.

The experiment, called Atomic Clock Ensemble in Space (ACES), will be built by EADS Astrium and is scheduled to fly to the space station in 2014, the European Space Agency announced last week. It will keep track of time by measuring the frequency of microwaves absorbed by cooled caesium atoms.

On Earth, the accuracy of caesium clocks is limited by gravity. The atoms are cooled by using lasers to slow them down, then tossed upwards into a cavity where measurements are made to determine the precise frequency of microwave radiation that they absorb and emit. In microgravity, the atoms linger in the cavity, allowing for longer and more accurate measurements, explains John Prestage of NASA's Jet Propulsion Laboratory in Pasadena, California, who is not involved in the project.

ACES should be at least 100 times as accurate as the clocks on GPS satellites, adds Prestage.

Using the space-station clock as a common point of reference, ground-based atomic clocks could be more accurately compared with one another. What's more, variations between atomic clocks could reveal if a physical constant called alpha – which governs the electromagnetic force – is not constant after all.

Has the question of life beyond earth been answered finally by Gliese 581?

The cosmos never ceases to amaze us with its sheer size and splendor. The star studded sky above us and the vast unexplored eternity that lay beyond us have always captured both human mind and human heart. While the glitz and shine of the stars and the spectacular celestial aura have drawn us towards them, it is impossible to deny that our space programs are barely at a stage of infancy, with 99.9% of the universe still left unexplored. It is this magic of finding something new each day, each moment, each time you point your telescope in to the sky that hold our imagination and ignites our senses. The universe around us is so kind that you can randomly look at any part of it and it still will give you a surprise or two. You can call that either our luck or our sheer ignorance.

But since ages, the question that has intrigued us the most is, ‘Are we alone in the universe?’ This one question has always baffled our thoughts, challenged our imagination and of course made Spielberg in to a movie making icon. But off late scientists are starting to believe more and more that the answer to that question is ‘No’. The discovery of Gliese 581 was one of the most exciting moments in extra-solar planetary researcher. The star is said to be having a planetary system and now researchers claim that they have found two planets that might be conducive to existence of life on them.

Astronomers have found an Earth-massed planet orbiting within the habitable zone of a distant star. This would mean that liquid water could be on its surface - and maybe even life! Any planet needs to be at a right distance from its own sun, so as to be able to maintain conditions that help the sustenance of life on it. If it is too close to the star, it looses the water on its surface due to excessive heat and if it is too far, it might be too cold to harbor life. Two separate teams of astronomers have found out in two different ways that the system of Gliese 581 has planets in the habitable zone. They did this by calculating and comparing the position of Earth and the planet on which they believe life could exist.

The first team lead by Franck Selsis calculated that the inner boundary of this habitable zone around Gliese 581 should be somewhere between 0.7 and 0.9 astronomical units and the outer zone should be between 1.7 and 2.4 AU. At least one planet orbiting Gliese 581 falls within this range. Now that is indeed exciting news. I always thought that we would find life beyond earth first on Titan- Saturn’s largest moon. But I still think the problem is that we look for life that is organic-similar to ourselves in nature. Why can’t life have evolved out of Platinum and gold somewhere else in the cosmos? Now that would be ‘Rich life’, if not intelligent.

Super-Hot Planet With Unique Comet-Like Tail Discovered

"Since 2003 scientists have theorized the lost mass is being pushed back into a tail, and they have even calculated what it looks like," said astronomer Jeffrey Linsky of the University of Colorado in Boulder, leader of the COS study. "We think we have the best observational evidence to support that theory. We have measured gas coming off the planet at specific speeds, some coming toward Earth. The most likely interpretation is that we have measured the velocity of material in a tail."

The planet, located 153 light-years from Earth, weighs slightly less than Jupiter but orbits 100 times closer to its star than the Jovian giant. The roasted planet zips around its star in a short 3.5 days. In contrast, our solar system's fastest planet, Mercury, orbits the Sun in 88 days. The extrasolar planet is one of the most intensely scrutinized, because it is the first of the few known alien worlds that can be seen passing in front of, or transiting, its star. Linsky and his team used COS to analyze the planet's atmosphere during transiting events. During a transit, astronomers study the structure and chemical makeup of a planet's atmosphere by sampling the starlight that passes through it. The dip in starlight because of the planet's passage, excluding the atmosphere, is very small, only about 1.5 percent. When the atmosphere is added, the dip jumps to 8 percent, indicating a bloated atmosphere.

COS detected the heavy elements carbon and silicon in the planet's super-hot, 2,000-degree-Fahrenheit atmosphere. This detection revealed the parent star is heating the entire atmosphere, dredging up the heavier elements and allowing them to escape the planet.

The COS data also showed the material leaving the planet was not all traveling at the same speed. "We found gas escaping at high velocities, with a large amount of this gas flowing toward us at 22,000 miles per hour," Linsky said. "This large gas flow is likely gas swept up by the stellar wind to form the comet-like tail trailing the planet."

Hubble's newest spectrograph has the ability to probe a planet's chemistry at ultraviolet wavelengths not accessible to ground-based telescopes. COS is proving to be an important instrument for probing the atmospheres of "hot Jupiters" like HD 209458b.

Another Hubble instrument, the Space Telescope Imaging Spectrograph (STIS), observed the planet in 2003. The STIS data showed an active, evaporating atmosphere, and a comet-tail-like structure was suggested as a possibility. But STIS wasn't able to obtain the spectroscopic detail necessary to show a tail, or an Earthward-moving component of the gas, during transits. The tail was detected for the first time because of the unique combination of very high ultraviolet sensitivity and good spectral resolution provided by COS.

Although this extreme planet is being roasted by its star, it won't be destroyed anytime soon. "It will take about a trillion years for the planet to evaporate," Linsky said.

The results appeared in the July 10 issue of The Astrophysical Journal.

Men Are From Mars

Neuroscientists Find That Men And Women Respond Differently To Stress

There are many books and movies that highlight the psychological differences between men and women -- Men are From Mars, Women are From Venus, for example; but now, neurologists say they have brain images that prove male and female brains do work differently -- at least under stress.

Same species, different genders … And now, a new high-tech scientific study reveals the differences between men and women may really start at the top. Researchers at the University of Pennsylvania used a high-tech imaging method to scan the brains of 16 men and 16 women. The subjects were placed inside a functional magnetic resonance imaging machine, or fMRI.

"Using this state-of-the art-functional magnetic resonance imaging technique, we try to directly visualize what the human brain does during stress," Jiongjiong Wang, Ph.D., a research assistant professor of radiology and neurology at the University of Pennsylvania in Philadelphia, told Ivanhoe.

Researchers then purposely induced moderate performance stress by asking the men and women to count backward by 13, starting at 1,600. Researchers monitored the subject's heart rate. They also measured the blood flow to the brain and checked for cortisol, a stress hormone.

When the scans were completed, neuroscientists consistently found differences between the men's stressed-out brains and the women's. Men responded with increased blood flow to the right prefrontal cortex, responsible for "fight or flight." Women had increased blood flow to the limbic system, which is also associated with a more nurturing and friendly response.

Doctors say this information may someday lead to a screening process for mood disorders. "In the future, when physicians treat patients -- especially depression, PTSD -- they need to take this into account that really, gender matters," Dr. Wang explains.

Other experts caution that hormones, genetics and environmental factors may influence these results, bringing to light yet another difference between men and women. Neuroscientists say the changes in the brain during stress response also lasted longer in women.

WHAT IS fMRI? Magnetic resonance imaging (MRI) uses radio waves and a strong magnetic field rather than X-rays to take clear and detailed pictures of internal organs and tissues. fMRI uses this technology to identify regions of the brain where blood vessels are expanding, chemical changes are taking place, or extra oxygen is being delivered.

These are indications that a particular part of the brain is processing information and giving commands to the body. As a patient performs a particular task, the metabolism will increase in the brain area responsible for that task, changing the signal in the MRI image. So by performing specific tasks that correspond to different functions, scientists can locate the part of the brain that governs that function.

FIGHT OR FLIGHT: Certain events act as "stressors," triggering the nervous system to produce hormones to respond to the perceived danger. Specifically, the adrenal glands produce more adrenaline and cortisol, releasing them into the bloodstream. This speeds up heart and breathing rates, and increases blood pressure and metabolism. These and other physical changes help us to react quickly and effectively under pressure.

This is known as the "stress response," or more commonly, as the "fight or flight response." But if even low levels of stress go on too long, it can be detrimental to one's health. The nervous system remains slightly activated and continues to pump out extra stress hormones over an extended period, leaving the person feeling depleted or overwhelmed, and weakening the body's immune system.

STRESS-REDUCING TIPS: There are several easy, practical things people can do to reduce the amount of stress in their lives. (1) Be realistic and don't try to be perfect, or expect others to be so. (2) Don't over-schedule; cut out an activity or two when you start to feel overwhelmed. (3) Get a good night's sleep. (4) Get regular exercise to manage stress -- just not excessive or compulsive exercise -- and follow a healthy diet. (5) Learn to relax by building time into your schedule for reading or a nice long bath.

Worldwide Hunt To Solve The Mystery Of Gamma-Ray Bursts

Gamma-ray bursts are short-lived events, lasting between a few milliseconds to a few minutes. The brightest of them emit more energy in a few seconds than our Sun will emit in its whole 10 billion year lifetime. Gamma ray bursts are occurring several times daily somewhere in the universe, fortunately at huge distances from our solar system. These fleeting explosions are precursors to the births of black holes.

The Swift Gamma Ray Burst Explorer satellite is a NASA mission with substantial UK and Italian participation. Swift was designed to solve the mystery of the origin of gamma ray bursts by pinpointing the burst and measuring the emissions from the huge fireball that occurs in the first few seconds of the burst's lifetime.

Scientists at Leicester's Space Research Centre are part of the international team working on the Swift, having had a major role in the development of the X-ray telescope, which has been responsible for many of the discoveries made by Swift.

Since its launch in 2004, Swift has discovered over 292 gamma-ray bursts, and pin-pointed a further 320 bursts detected by other satellites. Swift's rapid response - it was named after the bird, which catches its prey "on the fly" - has been critical to understanding these titanic events.

Record-Breaking X-Ray Blast Briefly Blinds Space Observatory

The blindingly bright blast came from a gamma-ray burst, a violent eruption of energy from the explosion of a massive star morphing into a new black hole. "This gamma-ray burst is by far the brightest light source ever seen in X-ray wavelengths at cosmological distances," said David Burrows, senior scientist and professor of astronomy and astrophysics at Penn State University and the lead scientist for Swift's X-ray Telescope (XRT).

Although the Swift satellite was designed specifically to study gamma-ray bursts, the instrument was not designed to handle an X-ray blast this bright. "The intensity of these X-rays was unexpected and unprecedented" said Neil Gehrels, Swift's principal investigator at NASA's Goddard Space Flight Center. He said the burst, named GRB 100621A, is the brightest X-ray source that Swift has detected since the observatory began X-ray observation in early 2005. "Just when we were beginning to think that we had seen everything that gamma-ray bursts could throw at us, this burst came along to challenge our assumptions about how powerful their X-ray emissions can be," Gehrels said.

"The burst was so bright when it first erupted that our data-analysis software shut down," said Phil Evans, a postdoctoral research assistant at the University of Leicester in the United Kingdom who wrote parts of Swift's X-ray-analysis software. "So many photons were bombarding the detector each second that it just couldn't count them quickly enough. It was like trying to use a rain gauge and a bucket to measure the flow rate of a tsunami."

The software soon resumed capturing the evolution of the burst over time, and Evans recovered the data that Swift had detected during the software's brief shutdown. The scientists then were able to measure the blast's X-ray brightness at 143,000 X-ray photons per second during its fleeting period of greatest brightness, which is more that 140 times brighter than the brightest continuous X-ray source in the sky -- a neutron star that is more than 500,000 times closer to Earth than the gamma-ray burst, and that sends a 'mere' 10,000 photons per second streaming toward Swift's telescopes.

Gamma-ray bursts typically begin with a bright flash of high-energy gamma-rays and X-rays, then fade away like a fireworks display, sometimes leaving behind a disappearing afterglow in less-energetic wavelengths, including optical and ultraviolet. Surprisingly, although the energy from this burst was the brightest ever in X-rays, it was merely ordinary in optical and ultraviolet wavelengths.

The Swift scientists were able to estimate the overall brightness of GRB 100621A by sampling the photons at some distance from its overexposed center -- a standard correction technique. Scientists who study the Sun use a similar approach to observe the Sun's corona by blocking out its much-brighter center. "With this burst, we had to sample the photons twice as far from the center as we ever had to go before," Burrows said. "The correction factor for the X-rays from GRB 100621A was 168 times larger than for a typical gamma-ray burst and 5 times larger than for the brightest burst we previously had seen. We never thought we'd see anything this bright."

Automated analysis of the Swift XRT data is performed at the University of Leicester in the United Kingdom, which has been studying X-rays from outer space for the past half century. Evans was the first to see the processed data from the burst's initial blast. "When I first saw the strange data from this burst, I knew that I had discovered something extraordinary," he said. "It was an indescribable feeling when I realized, at that moment, that I was the only person in the whole universe who knew that this extraordinary event had occurred. Now, after our analysis of the data, we know that this burst is one for the record books."

Other members of the research team include Tilan Ukwatta at NASA Goddard Space Flight Center and Valerio D'Elia and Giulia Stratta at the ASI Science Data Center in Italy.

Early Stages Of Crater Birth

The resulting craters form in 100 milliseconds or less. By using high-speed video cameras that can capture up to 15,000 frames per second, the team could track individual sand particles as they were ejected from the impact.

Most of the material thrown up by the impact took to the air during the impact's "main stage", landing within a few crater radii of where the projectile hit. But the high-speed video also revealed particles kicked up in a relatively unstudied early stage.

During this phase of crater formation material is flung fastest and farthest, for example creating the long rays of the moon's Tycho crater and, potentially, launching a number of meteoroids into space from the surface of the moon and Mars.

The new experiments show the material released during this early stage is ejected faster and at a lower angle than the main stage.

Crater makers

Learning more about how such debris is ejected could help researchers to piece together the trajectory, speed and other properties of the bodies – such as comets, meteoroids and asteroids – that have made craters on the moon and other bodies, Hermalyn says.

This is the first time particle tracking has been used to measure the speeds and angles of particles thrown out in the early stage of impact, says Jay Melosh of Purdue University in West Lafayette, Indiana.

The speeds of impacts in the experiment are much lower than the average for bodies like the moon and so can't reproduce effects such as melting and vaporisation that more energetic impacts cause, says Melosh. But he says the experiment could be an important check for computer models of impacts.

Hubble Telescope Turns 20

The Hubble space Telescope celebrated the 20th anniversary of its launch on April24,2010,with NASA releasing a new photograph from the orbiting observatory of a cosmic pillar of gas & dust in Carina Nebula galaxy.The photograph showed three light-years-tall towers of cool hydrogen laced with dust rising from the walls of the nebula,which where reminiscent of Hubble's classic "Pillars of Creation".

Hubble,named after the astronomer Edwin P.Hubble.

Super-Massive Black Holes Found

The ASTRONOMY & ASTROPHYSICS reported that there are four super-massive black holes.The scientists used the world's two largest optical/infrared telescopes,Keck,on top of Mauna Kea in Hawaii to find these black holes or dying stars that are called active galactic. For the first time, the team observed a quasar with an active galactic nucleus,as part of the group of four black holes.Scientists believe that these active nuclei are powered by accreting super-massive black holes.The accreting gas and dust are especially bright in the optical and infrared regions of electromagnetic spectrum.