Comet-like Tail of Star Mira!!

A glowing, comet-like tail has been discovered trailing behind a double star called Mira, a phenomenon never seen before. It may contain clues about the star's activity over the past 30,000 years.Mira, which means "wonderful" in Latin, is one of the best-studied star systems in the sky and lies 350 light years from Earth. One star in the pair, called Mira A, is a bloated, ageing red giant that sheds large amounts of gas and dust into space, while the other, Mira B, is a dense stellar corpse called a white dwarf.
Previous studies had shown that some of the material from Mira A's wind has collected into a disc – which could potentially form planets – around Mira B (see Dying star's wind creates planetary nursery).
Now astronomers led by Christopher Martin of Caltech in Pasadena, US, have discovered the long tail, which is visible only in far ultraviolet light. They happened upon it using NASA's Galaxy Evolution Explorer (GALEX) satellite, which was surveying the sky at ultraviolet wavelengths.The tail extends 13 light years from Mira – if it were visible in the sky, it would span the width of four full Moons. It appears to trace the path of Mira's motion across the sky over the past 30,000 years, based on its size and Mira's speed, which has been previously measured.
Martin's team believes the tail is created as a result of Mira A's stellar wind – an outflow of gas and dust from the star – hitting ambient gas as it moves through space. Fast-moving electrons generated by the collision then strike hydrogen molecules in surrounding gas, producing ultraviolet light. This creates a glowing trail behind Mira as it travels through the galaxy at 130 kilometres per second. the tail could shed light on why some stars turn into white dwarfs and others explode as supernovae.stars such as Mira A, which start out with a few times the mass of the Sun, avoid this fate by shedding most of their mass in stellar winds to become placid white dwarfs

4 Suns in this SolarSystem!!

Here in our Solar System, we've only got one star: the Sun. That gives us nice predictable daily and annual cycles; night and day, the seasons, that sort of thing. Astronomers have found a newly forming extrasolar planetary system that has 4 stars. The discovery, made using NASA's Spitzer Space Telescope, revealed a dusty disk surround a pair of stars in the quadruple-star system HD 98800.The system itself is pretty complicated, so bear with me as I try to explain it. There are two pairs of binary stars; 2 + 2 = 4 stars in total. These two binary groupings are separated by 50 astronomical units (AU); approximately the distance between the Sun and Pluto. Around one of these binary pairs, astronomers discovered two belts of material.The first belt sits at approximately 1.5 to 2 AU (twice the distance from the Sun to the Earth), and seems to consist of fine grains of dust. The second belts is further out at approximately 5.9 AU and is probably made up of asteroids or comets.
The sunsets would be spectacular.

New Asteroid Group Found!!

A new space rock has been found that devotedly travels around with Mars as it orbits the Sun, bringing the total number of such 'groupies' to four. But astronomers say it was Mars – not its tiny companions – that originally insinuated itself into the rock group billions of years ago.The asteroid, called 2007 NS2, was discovered by astronomers at the La Sagra Observatory in southern Spain on 14 July. Based on its brightness, it is estimated to be about 1 kilometre across.It follows Mars in its orbit, occupying a spot called L5, which lags the Red Planet by 60° as it moves around the Sun. It shares L5 with two other objects, while a fourth object orbits 60° ahead of Mars at a point called L4.Objects that wander into the L4 and L5 points of a planet tend to be confined there by the combined gravity of the planet and the Sun.
How Mars got its Trojans is uncertain, but the Red Planet may have collected them at a much earlier period, just after the dawn of the solar system a little more than 4.5 billion years ago
At that time, an embryonic Mars may have been kicked around the solar system through gravitational interactions with other planetary embryos. Any asteroids that happened to be at the L4 and L5 points of its new orbit would have been trapped there by the Red Planet's gravityEarth has no known Trojans, perhaps because our home planet is too heavy to have been knocked around the same way that Mars was, Morbidelli says. "Mars jumped around because of its small mass, but not the Earth," he says. Mars is just 11% as massive as the Earth.
Although no asteroids are known to occupy Earth's L4 and L5 points, there are a handful of so-called Earth co-orbital asteroids. These objects have corkscrew orbits, slowly looping around Earth, while following its orbital motion around the Sun. This configuration is unstable, so these objects are only temporary companions to Earth.One such object, a 200-metre-wide asteroid called 2004 GU9, has been looping around Earth this way for 500 years, but is expected to eventually drift away.

Jupiter with four Moons!!!

I have taken this photo with my canon 4 megapixel 4x zoom digcam without using any exposure settings! taken from vangani with 8" telescope. I like it coz thefour moons are clearly visible!!

Baby galaxies sighted at dawn of universe

Astronomers have spotted the most distant galaxies known, from an era when the universe was just 4% its present age. Objects like these could be responsible for lifting the veil on the so-called cosmic 'dark ages', by making the universe transparent to light.
Because it takes light from distant galaxies billions of years to reach us, we see them as they were long ago, when the universe was much younger.

Previously, the most distant galaxy known had been found at a redshift of 7 – corresponding to a time when the universe was about 750 million years old (see First generation of galaxies glimpsed forming).
Now, astronomers led by Daniel Stark of Caltech in Pasadena, California, US, have found several galaxies at a redshift of about 9. A redshift of 9 corresponds to an era just 500 million years after the big bang – 4% the universe's present age of 13.7 billion years.

The team used the Keck II Telescope on Mauna Kea, Hawaii, US, to look for distant galaxies. They were able to improve the sensitivity of their search by taking advantage of a phenomenon called gravitational lensing, where the gravity of nearby objects bends and focuses light from more distant objects.
The team searched parts of the sky surrounding nearby galaxy clusters, where this lensing effect is most pronounced. They spotted two objects that appear to be at redshift 9, called Abell 68 c1 and Abell 2219 c1.
Their light appears to be that of excited hydrogen gas, redshifted by the expansion of the universe. But this alone is not enough for a firm identification, because excited oxygen from a closer object would shine at the same wavelength.
The astronomers were able to rule out the nearby object scenario because excited oxygen should also shine at a second wavelength, which these objects do not appear to do.

Since the astronomers only searched a minute fraction of the sky, even if only two of the objects are truly distant galaxies, this would suggest that these tiny galaxies were abundant in the early universe.
Rough calculations suggest that they would be abundant enough to play a significant part in lifting the veil on the cosmic dark ages. For most of the first few hundred million years of the universe's history, the universe was largely opaque to light because hydrogen atoms absorbed it everywhere.
Radiation from unknown sources later ripped electrons from the hydrogen atoms – a process called reionisation – so that it no longer absorbed light, making the universe transparent.

Previously, astronomers suspected that galaxies were rare 500 million years after the big bang, and that reionisation was largely carried out by objects at redshift 6, which corresponds to about 900 million years after the big bang (see Hubble heats debate over ionised universe).
But the detection of these objects suggests that these earlier objects may have a played a bigger role than previously believed

Scientists have reported the first conclusive evidence of water vapour in the atmosphere of an extrasolar planet. Before we load up the spaceships to search for life, however, consider the fact that this planet, HD 189733b, is larger than Jupiter, and orbits its parent star in just 2.2 days. That's hot hot water.
The discovery was made using the mighty Spitzer space telescope. The astronomers pointed Spitzer at the parent star, and measured the chemical consistency of its light as the planet passed in front - aka, transited. As the starlight dimmed - blocked by the planet - the chemical constituents of the star changed to show a distinctive pattern. Astronomers know that only water can absorb these specific wavelengths of infrared radiation.

This planet is certainly a "hot Jupiter". It contains 1.15 the mass of Jupiter (and 1.25 the diameter), but it orbits its parent star at a distance of only 4.5 million km. In comparison, our own Mercury is a distant 70 million km from the Sun.
It's close, so it's hot. Its atmospheric temperature is about 1000 Kelvin (more than 700 C). With this heat, all the water vapour in its atmosphere can't condense, rain or form clouds.
It's also tidally locked to its parent star, only showing one face to the star at all times (like the Moon and the Earth). This constant facing probably generates fierce winds that sweep around the planet from the day side to the night side.
Not the best place to find life, but still, an amazing discovery

No Stars found in this Dark Galaxy!!!??!!

An international team of astronomers have conclusive new evidence that a recently discovered "dark galaxy" is, in fact, an object the size of a galaxy, made entirely of dark matter. Although the object, named VIRGOHI21, has been observed since 2000, astronomers have been slowly ruling out every alternative explanation. In a new research paper, entitled 21-cm synthesis observations of VIRGOHI 21 – a possible dark galaxy in the Virgo Cluster, researchers provide updated evidence about this mysterious galaxy. They have now performed a high resolution observations of VIRGOHI21 using the Westerbork Synthesis Radio Telescope (WSRT), to better pin down the quantities of neutral hydrogen gas. They also did followup observations with the Hubble Space Telescope, looking for any evidence of stars.Astronomers first suspected there was an invisible galaxy out there when they spied galaxy NGC 4254. This unusual-looking galaxy appears to be one partner in a cosmic collision. All the normal evidence is there: gas is being siphoned away into a tenuous stream, and one of its spiral arms is being stretched out. But the other partner in this collision is nowhere to be seen.The researchers' calculated that an object with 100 billion solar masses must have careened past NGC 4254 within the last 100 million years, creating the gas stream, and tearing at one of its arms. This was the clue that an invisible dark matter galaxy might be lurking nearby. A detailed search turned up a mysterious object called VIRGOHI21, located about 50 million light-years from Earth. Were it a normal galaxy, you would be able to see it in a powerful amateur telescope. But there's nothing there. Even in the Hubble Space Telescope, not a single star is shining from this massive region of space.It was only visible in radio telescopes, which could detect the radio emissions from neutral hydrogen gas located in the cloud. When they first published their research a few years ago, the astronomy community was understandably skeptical, and proposed several alternative theories to explain the mysterious object.For example, there could be additional mass associated with VIRGOHI21, and not just dark matter. The discovery of red giant stars in the region would give some indication that this was a more normal interaction. But Hubble turned up nothing.It's possible that VIRGOHI21 has always been this way, formed from primordial dark matter and neutral hydrogen after the Big Bang. It's been cruising the Universe ever since, disrupting galaxies as it goes.However, there do seem to be ways that galaxies and their dark matter can be separated. Only a few months ago, a ring of dark matter was found surrounding a group of colliding galaxy clusters by the Hubble Space Telescope. Perhaps VIRGOHI21 is the wreckage from one of these cluster collisions; a shred of dark matter hurled out into space.It could be that there are many of these dark galaxies out there. A new sky survey, carried out with the 305-metre (1000-foot) Aricebo radio telescope in Puerto Rico should tease out more of these objects in the future. The survey is called the Arecibo Galaxy Environment Survey (AGES).