Gamma ray burst from Eta Carina

The US Fermi telescope has detected a massive explosion in space which scientists say is the biggest gamma-ray burst ever detected, a report published on Thursday in Science Express said.The spectacular blast, which occurred in the Carina constellation, produced energy ranging from 3,000 to more than five billion times that of visible light, astrophysicists said."Visible light has an energy range of between two and three electron volts and these were in the millions to billions of electron volts," astrophysicist Frank Reddy of US space agency NASA told AFP."If you think about it in terms of energy, X-rays are more energetic because they penetrate matter. These things don't stop for anything - they just bore through and that's why we can see them from enormous distances," Reddy said.Gamma-ray bursts are the universe's most luminous explosions, which astronomers believe occur when massive stars run out of nuclear fuel.As a star's core collapses into a black hole, jets of material powered by processes not yet fully understood blast outward.The jets bore through the collapsing star and continue into space, where they interact with gas previously shed by the star, generating bright afterglows that fade with time.Using the Gamma-Ray Burst Optical/Near-Infrared Detector (GROND) on a telescope at the European Southern Observatory in Chile, a team led by Jochen Greiner of Germany's Max Planck Institute for Extraterrestrial Physics determined that the huge gamma-ray burst occurred 12.2 billion light years away.The sun, by comparison, is eight light minutes from earth.With the extraordinary distance taken into account, scientists worked out that the blast exceeded the power of nearly 9,000 ordinary supernovae, some of the most energetic explosions known, which occur at the end of a star's life time.The gas jets emitting the initial gamma rays moved at one-ten-thousandth of a percentage point less than the speed of light, the scientists said."This burst's tremendous power and speed make it the most extreme recorded to date," a statement issued by the US Department of Energy said.

Google Earth's find

No, the lost city of Atlantis has not been found.according to Google.Google Earth images showing what appeared to be a grid of streets on the ocean floor off the coast of Africa were actually tracks left by boat sonar.Britain's Daily Telegraph caused the brief flurry of excitement among Atlantis hunters by publishing Google Earth pictures on Friday of an unexplained grid on the seabed 1000km off the northwestern coast of Africa.An Atlantis expert told the paper that the grid was located at one of the possible sites of Atlantis, the legendary city described by Greek philosopher Plato.Google, however, had another explanation."It's true that many amazing discoveries have been made in Google Earth — a pristine forest in Mozambique that is home to previously unknown species, a fringing coral reef off the coast of Australia, and the remains of an Ancient Roman villa, to name just a few," Google said in a statement."In this case, however, what users are seeing is an artifact of the data collection process."Bathymetric (or seafloor terrain) data is often collected from boats using sonar to take measurements of the seafloor. The lines reflect the path of the boat as it gathers the data," Google said. Truth or coverup?

British and French nuclear subs collide oops!

A costly and most embarrassing mistake.

A collision between French and British nuclear submarines was a hugely improbable one-off, but it was no surprise that they did not detect each other, experts said on Monday.For one nuclear-powered, nuclear arms submarine to collide with another one in the middle of an ocean was unprecedented and sheer bad luck, they said.Experts played down the chances of a nuclear disaster, saying the subs were designed to be robust and a collision was unlikely to trigger a nuclear reaction.(lets hope they are correct)Stephen Saunders, the editor of Jane's Fighting Ships and a retired commodore, nonetheless called it a "very serious incident"."As far as I am aware, it is the first time that the submarines of two friendly nations have been involved in such an accident," he said."No doubt there are a number of technical issues to be investigated, but the root of the problem appears to be procedural. These submarines should not have been in the same place at the same time."Even if two submarines do find themselves in the same area, it is still bad luck to have run into each other - ie to be in the same place at the same depth."Lee Willett, head of the maritime studies program at the Royal United Services Institute (RUSI), a defence and security think-tank, said the incident was a complete one-off."These are the strategic crown jewels of a nation. The whole purpose of a sea-based nuclear deterrent is to hide somewhere far out of sight and out of mind," he told AFP."Given that there are a very, very small number of SSBNs (Ship Submersible Ballistic Nuclear) in the world, the chances of two SSBNs being in the same bit of water at the same time is unprecedented."The fact that they couldn't hear each other is actually less surprising."Saunders explained: "The modus operandi of most submarines, particularly ballistic missile submarines, is to operate stealthily and to proceed undetected."This means operating passively (ie not transmitting on sonar) and making as little noise as possible."While in parallel much effort has gone into improving the capability of sonars to detect other submarines, detection was clearly made too late or not at all in this case."Willett added: "Submarines don't go around advertising their position by pinging away with their sonar. It's very hard to hear stuff under water because of all the ambient noise."SSBNs listen passively using their sensing equipment but if you're listening for something that's making no noise, you can't hear it."The RUSI expert said despite the close NATO and European Union ties between Britain and France, the two countries would be very reticent to share information on what their nuclear submarines were up to."Despite how close these relations are, they are the ultimate tools of national survival in the event of war. Therefore it's the very last thing you would share with anybody."However, he added: "This may raise the question of agreeing on water space management issues: you go there, we go there. Those agreements may exist already."Both nations have now lost a big part of their SSBN capability for a period of time."Clearly it's not something they would be keen to repeat."

WEEKEND FIREBALLS

A daylight fireball over Texas on Sunday, Feb. 15th, triggered widespread reports that debris from a recent satellite collision was falling to Earth. Those reports were premature. Researchers have studied video of the event and concluded that the object was more likely a natural meteoroid about one meter wide traveling more than 20 km/s--much faster than orbital debris. Meteoroids hit Earth every day, and the Texas fireball was apparently one of them. There's more: On Friday, Feb. 13th, people in central Kentucky heard loud booms, felt their houses shake, and saw a fireball streaking through the sky. This occurred scant hours after another fireball at least 10 times brighter than a full Moon lit up the sky over Italy. Although it is tempting to attribute these events to debris from the Feb. 10th collision of the Iridium 33 and Kosmos 2251 satellites, the Kentucky and Italy fireballs also seem to be meteoroids, not manmade objects. Italian scientists are studying the ground track of their fireball, which was recorded by multiple cameras, and they will soon begin to hunt for meteorites. (time will tell whether this information or the original "satellite debris" is correct or perhaps a bit of both)

Firestorm

The bushfires that claimed at least 180 lives (currently standing at 189) in Australia were fanned by sudden wind changes, drought-like conditions and native trees which can explode in towering fireballs under extreme heat.Survivors told again and again how they were taken by surprise by the speed of the blaze as it leapt carefully constructed firebreaks and engulfed buildings before people could gather their senses to flee.Many of the victims were found charred in their cars on country roads short distances from their homes, having left their dash too late."I've never seen anything like this. It was like a mushroom cloud, an orange ball of fire above us, and when the southerly winds came up it just took off and roared up the gullies," Rob Langston, a volunteer firefighter for 30 years, told The Australian newspaper Tuesday.The fires affected an area of 3,000 square kilometres (1,200 square miles) -- territory larger than Luxembourg or nearly three times the size of Hong Kong -- and wiped entire towns off the map within about 24 hours on the weekend.They were fanned by a heatwave that sent temperatures soaring to 46 C (115 F) around the southern city of Melbourne, combined with hot northerly winds which switched and changed at critical moments.
Witnesses saw native flora such as eucalypt hardwoods and smaller, fragrant tea-trees explode as the flames ignited their natural oils.Used in everything from shampoos and cold treatments to insect repellents, such oils vaporise in intense heat and hang in the air waiting to ignite when the flames arrive, sending embers flying into the air."In five seconds it went right down the creek and up and over the houses there," 76-year-old Alf Gonnella told The Australian, describing how the clumps of tea-trees "went whoomp" around his property.Victoria's Country Fire Authority warned Tuesday the town of Healesville, about 50 kilometres (31 miles) northeast of Melbourne, was still in danger from "heavy ember attack," a phenomenon survivors describe as a storm of hot coals.Victoria Harvey, a resident of Kinglake which was destroyed on Saturday, told reporters of a businessman who lost two of his children as they waited in the car while he dashed inside to collect something from his house."He apparently went to put his kids in the car, put them in, turned around to go grab something from the house, then his car was on fire with his kids in it and they burnt," she said.
Australia's native forests need fire to regenerate and survive; it is part of a cycle that the indigenous Aborigines encouraged and harnessed but which European settlers have never managed to control.

Comet

COMET TAIL: Comet Lulin (C/2007 N3) is approaching Earth and putting on a good
show for amateur astronomers. On Feb. 4th, observers witnessed a
"disconnection event." A gust of solar wind tore off part of the comet's tail in
plain view of backyard telescopes. Photos of the event are featured on today's
edition of http://spaceweather.com. Activity in the comet's tail and atmosphere
will become even easier to see in the weeks ahead as Lulin nears closest
approach on Feb. 24th. At that time the comet will lie only 38 million miles
from Earth and it should be visible to the naked eye. In the meantime, please
note that Feb. 5th-7th, is an especially good time to find Comet Lulin in the
pre-dawn sky. The comet is gliding beautifully close to the naked-eye double
star Zubenelgenubi. Just point your binoculars at the double star and the comet
will materialize right beside it.