Something wiped out most of the life on Earth 250 million years ago. Evidence has been building that it was an asteroid or comet strike that made Earth unlivable nearly instantly. But other scientists think that it wasn't instantaneous; instead, they found fossil evidence that the extinction occurred over the course of 10 million years. A group of volcanoes in Siberia spewed out gas continuously that set off a runaway greenhouse effect. Lowered oxygen levels in the atmosphere combined with intense heat would have hit life a deadly double blow.

Scientists have known for many years that Regulus spins faster than our own Sun, but astronomers from Georgia State University have observed it more precisely and discovered that it's shaped like an egg. This massive star has 5 times the diameter of our own Sun, and yet it completes a rotation in only 15.9 hours (our own Sun takes a month to rotate once). This extreme speed gives Regulus a bulging waistline; in fact, it's spinning at 86% of its breakup speed. Any faster, and the star would actually tear itself apart.

NASA's Swift space observatory has seen its first Gamma-Ray Burst (GRB), probably the birth of a black hole. Swift detected the explosion on January 17, and turned to face it within 200 seconds - enough time to watch the explosion with its X-Ray telescope. This is the first time an X-Ray observatory has ever watched a GRB while it was bursting, and not just the afterglow. Swift is still in its checkout phase, so its Ultraviolet/Optical telescope wasn't ready to image the GRB yet, but it should be ready by February 1.

When Huygens descended through Titans clouds, snapping hundreds of pictures, it revealed a world with many similar physical features to our own planet: clouds, rivers, lakebeds, islands, rocks and dust. But Titan is cold, plunging below -170?C; a temperature where methane can exist as both a liquid and a gas. Huygens saw a series of drainage channels running from brighter highlands to flatter, darker regions. It landed in a material that has the consistency of loose sand. Instead of rocks, Huygens is surrounded by boulders of water ice, and instead of dirt, the probe found hydrocarbon particles that settled out of the atmosphere.

NASA's Opportunity Rover has discovered a meteorite on the surface of Mars, near the wreckage of its heat shield. The pitted object is about the size of a basketball, and contains mostly iron and nickel. Stoney meteorites are much more common than iron meteorites here on Earth, so it's possible that many of the "rocks" the rovers have seen could actually be meteorites. If it turns out that meteorites are common, it will tell scientists quite a bit about how quickly the region has eroded.

Astronomers have used the European Southern Observatory's Very Large Telescope (VLT) to watch a small, faint companion as it orbits around a larger star. By measuring its orbit, the astronomers have been able to estimate that its mass is 93 times that of Jupiter. This is much less than a normal star, but twice as heavy as predicted by theory. If these brown dwarfs and free floating extrasolar planets are heavier than expected, then astronomers have been overestimating the number of them in the Universe.

The European Space Agency's Mars Express spacecraft took this image of Claritas Fossae, a series of linear fractures located in the Tharsis region of Mars. It's located on the Tharsis rise, which is south of the three large volcanoes known as the Tharsis Montes. It has linear fractures up to 150 km (93 miles) across, which were created when the whole Tharsis region bulged up several kilometres. The smooth surfaces are places where the area was covered by lava flows.

Rockets look pretty impressive. Huge plumes of smoke and flame billow out of their base, while much further up, their tops, so slowly then oh so quickly, ascend into the heavens. Over in a few moments, the awe inspiring launches are the cumulation of years of analysis and design. Alfred J. Zaehringer and Steve Whitfield in their book 'Rocket Science' give an insight into some of the more basic design elements. Their perspective, as it were, is literally 'from the trenches' as Zaehringer defended against the V2 rockets of World War II and then went on to assist with the up-rating of the Saturn C5 and the assessment of solid rocket systems. The result is a concise, yet broad overview of rocketry.

Jean-Jacques Dordain, the Director General of the European Space Agency and Anatoly Perminov, the Head of the Russian Federal Space Agency have signed an agreement that will promote cooperation and partnership in the development of new launch systems. The two agencies are already working together to build and launch Soyuz rockets from the ESA's spaceport in French Guiana. They now plan to begin developing a new launcher with reusable liquid engines and upper stages. They hope to have their new rockets flying by 2020.

B-15A is a giant iceberg off the coast of Antarctica, and it's now on a collision course with a floating pier of ice called the Drygalski ice tongue. Satellite photos showed B-15A rushing towards the tongue, but then it slowed down in the last couple of days. Scientists think that there's a shallow seabed underneath the Drygalski ice tongue that has protected it from these kinds of collisions for so long - it's been there for at least 4000 years. B-15A is 120 km (75 miles) long, and contains about 2000 square km (772 sq miles), so it just have the momentum to do the trick.

Any idea how deep the eye could go if there was no atmosphere to scatter starlight? Ever wonder what optical and physical principles limit the eye's ability to see small, faint things? Have you given thought to how the "why" of astronomy changed before and after the telescope? In this article Jeff Barbour explores the limits of human sight - with and without the telescope. Learn more about the equipment available to contemporary amateurs making backyard astronomy the "extra-terrestrial" hobby of choice.

Red dwarfs are smaller and cooler than our own Sun, but they account for 70% of the stars in our galaxy. Astronomers have wondered why there are so many red dwarfs, but they never seem to have protoplanetary discs of dust surrounding them, indicating the formation of new planets. These stars are too small to remove dust the way larger stars do it, but astronomers from UCLA think they could be using a process called "stellar wind drag". Even though they're smaller, red dwarfs can have very intense magnetic fields, producing a powerful solar wind. It's this solar wind that removes the dust, hiding evidence of planet formation.

Scientists at the European Space Agency now believe that Huygens landed with a splat when it reached the surface of Titan last Friday. They reached this conclusion because the probe's downward-facing High Resolution Thermal Imager camera lens has accumulated material since Huygens landed. This means that the probe has probably been settling down into the muck. Another possiblity, though, is that it steamed hydrocarbons off the surface which are collecting on the lens.

Greetings, fellow SkyWatchers! Is it back? Yes. But this time it's Antares and Mars! The Moon will be out in full force this week - but what a wonderful place to explore. There is no astronomical delight more loaded with detail than our own natural satellite, so join us as we walk in the Alpine Valley, climb Mons Pico, survey the terrain of Clavius and even scale the "Great Wall"! There be a grand lunar occultation this week and the "Magnificent Machholz" will perform a 'fly-by' on Mirfak. Not enough? Then lend me your ears as you'll discover Radio JOVE. We'll color the cloudy skies with atmospheric phenomena and learn which "Twin" has many secrets! So open your eyes to the skies...

Because here's what's up!

Here's a beautiful 1280x1024 desktop wallpaper of barred spiral galaxy NGC 1300 taken by the Hubble Space Telescope. This image was unveiled last week at the annual meeting of the American Astronomical Society. Barred spirals are different from regular spiral galaxies because the arms don't spiral all the way to the centre of the galaxy, but instead are connected to straight bars that contain the nucleus of the galaxy. The galaxy lies 69 million light-years away in the constellation of Eridanus.

Most large galaxies have the familiar spiral shaped disc surrounding a central bulge. But when and how do these galaxies take on their characteristic shape? New observations from the European Space Agency surveying 195 galaxies have given astronomers some clues. They've theorized that large galaxies go through a process called "spiral galaxy rebuilding", where galaxies collide, merge, and then begin a period of furious star formation. Part of the gas that didn't fall in rebuilds a disc around the galactic core creating a new spiral galaxy. This process could be repeated many times, building up the galaxy over billions of years.

After a seven year journey, the European Space Agency's Huygens probe is now on the surface of Titan. The probe entered Titan's smoggy atmosphere right on time, and slowed itself down using a series of parachutes. It then gathered data using its camera and science instruments for just over 2 hours until it landed. The probe then relayed all its data through Cassini back to Earth, where scientists will be poring over it for years. Preliminary data indicate that the probe did land safely on some kind of solid surface, but the controllers aren't sure what it was yet. Photographs and more results will be announced later today. (Make sure you check the forum, where we're posting links to pictures as we get them.)

The powerful W. M. Keck Observatory in Hawaii took this image of a dying star nicknamed the "Water Fountain Nebula". This nebula is 6500 light-years away in the direction of the constellation Scorpius, and was imaged at near-infrared wavelengths. The double corkscrew structure of the nebula indicates that there's probably a rapidly spinning remnant at the centre which is blasting out twin jets of material. By taking photos of the nebula again in a few years, astronomers will be able to understand how nebulas like this evolve over time.

A researcher from Indiana University Bloomington has discovered what could be primordial hydrogen, unchanged since the Big Bang. This hydrogen was found in galaxy UGC 5288, located 16 million light years away from Earth. When studied with the National Science Foundation's Very Large Array radio telescope in New Mexico, the galaxy seems to be surrounded by a huge disk of hydrogen gas. This could be a place to examine pristine hydrogen that hasn't been "polluted" by heavier elements created in stars.