Burts of Gamma Rays from Blackhole...

A black hole has been spotted belching out a burst of gamma rays after gulping down part of a nearby star, something never seen before. Such violent burps may actually be the most common type of explosive "gamma-ray burst" in the universe.
The event was named GRB 070610 after the date of its discovery by NASA's Swift satellite on 10 June 2007.

At first it looked like another ordinary long gamma-ray burst (GRB) in a distant galaxy. These outbursts are thought to be the death cries of massive stars collapsing to form black holes.

But this GRB seems to have a different provenance altogether. They suspect that the black hole in the system had some kind of a giant hiccup while chowing down on matter stolen from its companion star. This gamma-ray hiccup behaviour has never been seen before and scientists are not sure how to explain it. But though the burst was much less powerful than typical long GRBs, such events are still quite violent. A similar system called V4641 Sgr set the record for spewing matter out at the highest speed ever observed in our galaxy during a similar outburst, observed in X-rays, in 1999.

It's clearly an unusual event. There's yet another way that nature found to make GRBs, which is very interesting. Low energy
"The reason we haven't seen something like this before is not because it's rare but because it's a low-energy event," Kasliwal says, explaining that this burst is intrinsically about 100 trillion times less powerful than previously observed long GRBs. Those more powerful long GRBs have only been observed in other galaxies and are thought to occur in our own galaxy less than once every 100,000 years

Four Massive Galaxies Colliding...

Four massive galaxies are colliding in the largest galactic merger ever seen, new observations reveal. The smash-up is shedding light on how the biggest galaxies in the universe form – and why many of them stopped giving birth to stars billions of years ago.

Astronomers classify mergers according to the relative sizes of the galaxies involved. Now, researchers led by Kenneth Rines of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US, have found the largest major merger ever seen. It involves a quartet of galaxies at the centre of a galactic cluster known as CL0958+4702, which lies about 5 billion light years from Earth.Three of the merging galaxies are the size of the Milky Way, while the other is about three times as massive
Star plume
Using infrared observations by the Spitzer Space Telescope and optical images from the WIYN Observatory in Arizona, US, the team also discovered a colossal, fan-shaped 'plume' of old, red stars trailing about 360,000 light years from the merger, apparently tossed out of the galaxies as they spiralled towards each other. "That's the other fairly amazing thing – the number of stars in the plume is about three Milky Ways' worth. Eventually, about half of those stars will likely fall into the merged galaxies – which are expected to coalesce into a single mammoth galaxy in about 100 million years – while the other half will float freely outside it, he says. That suggests other free-floating stars previously found within galaxy clusters were also ejected from their birth galaxies during major mergers. This answers the question of how you form the most massive galaxies in the universe." That is because the most massive galaxies yet observed – weighing about 10 times the Milky Way – are found at the centres of nearby galaxy clusters, which are seen as they are now, 13.7 billion years after the big bang. Interestingly, the four merging galaxies are made of old, red stars, suggesting each had lost the gas necessary to form new stars long beforehand, within 5 billion years of the big bang. That agrees with other recent observations showing that galaxies within clusters – which typically contain hundreds of galaxies – contain fewer young stars than those lying outside clusters. The four newly discovered merging galaxies lie 5 billion light years away, meaning astronomers see them as they were 5 billion years ago!!!

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