Four and a half billion years ago, a fluffy "snowball" coalesced out of the cloud of ice, dust and debris still surrounding our Sun. Most of the snowballs like it later merged to become the planets we know. This one, however, had a chance flyby with a young planet, probably Jupiter. Jupiter's gravity propelled it out into the far reaches of the Solar System, where it remained in deep freeze, among many others like it, as a member of the so-called Oort cloud.

Eventually, the tug of gravity from a passing star slowed it down ever so slightly, and that was enough to send it plummeting back toward the Sun, into the region where it had formed billions of years earlier. By a great quirk of irony Jupiter was again in its path. This time, the planet's gravity captured it into a long, elliptical orbit. On July 7, 1992, it executed a cosmic hole-in-one, passing through Jupiter's slender ring and breaking apart under the planet's ripping tides.

On the night of March 24, 1993, astronomers Eugene and Carolyn Shoemaker and David Levy were searching the skies when they noted an oddly shaped blotch near Jupiter. It was a comet to be sure, but quite unusual in shape. The next morning it became known as Shoemaker-Levy 9, or SL9 for short. With additional detections, its prior history as a body disrupted by Jupiter became clear. As new data accumulated, however, SL9 became even more remarkable, because astronomers realized that it had evaded Jupiter for the last time. In July 1994, the world watched as the broken fragments of SL9 plunged into Jupiter one by one. Few comets are ever featured on the front page of the New York Times, but the July 19 headline read, "Earth-Sized Storm and Fireballs Shake Jupiter as a Comet Dies." SL9 went out with a bang. The impacts left behind blotches in Jupiter's clouds but, after a few months, they faded away. End of story.

Or so we thought. As we have just published in the journal Science Express, this story has an unexpected epilogue.

First of the parasitic parasites to be discovered in a natural environment points to hidden diversity.

A genomic survey of the microbial life in an Antarctic lake has revealed a new virophage - a virus that attacks viruses. The discovery suggests that these life forms are more common, and have a larger role in the environment, than was once thought.

An Australian research team found the virophage while surveying the extremely salty Organic Lake in eastern Antarctica. While sequencing the collective genome of microbes living in the surface waters, they discovered the virus, which they dubbed the Organic Lake Virophage (OLV).

The OLV genome was identified nestling within the sequences of phycodnaviruses - a group of giant viruses that attack algae. Evidence of gene exchange, and possible co-evolution, between the two suggests that OLV preys on the phycodnavirus. Although OLV is the dominant virophage in the lake, the work suggests others might be present.

By killing phycodnaviruses, the OLV might allow algae to thrive. Ricardo Cavicchioli, a microbiologist at the University of New South Wales in Sydney, Australia, and his colleagues found that mathematical models of the Organic Lake system that took account of the virophage's toll on its host showed lower algal mortality and more blooms during the lake's two ice-free summer months.

"Our work reveals not only an amazing diversity in microbial life in this lake, but also how little we understand about the complexity of the biological functions at work," says Cavicchioli. The findings are published in the Proceedings of the National Academies of Science¹.

The Deepwater Horizon oil spill of 2010 devastated the Gulf of Mexico ecologically and economically. However, a new study published in Conservation Letters reveals that the true impact of the disaster on wildlife may be gravely underestimated. The study argues that fatality figures based on the number of recovered animal carcasses will not give a true death toll, which may be 50 times higher than believed.

"The Deepwater oil spill was the largest in US history, however, the recorded impact on wildlife was relatively low, leading to suggestions that the environmental damage of the disaster was actually modest," said lead author Dr Rob Williams from the University of British Columbia."This is because reports have implied that the number of carcasses recovered, 101, equals the number of animals killed by the spill."

The team focused their research on 14 species of cetacean, an order of mammals including whales and dolphins. While the number of recovered carcasses has been assumed to equal the number of deaths, the team argues that marine conditions and the fact that many deaths will have occurred far from shore mean recovered carcasses will only account for a small proportion of deaths.

To illustrate their point, the team multiplied recent species abundance estimates by the species mortality rate. An annual carcass recovery rate was then estimated by dividing the mean number of observed strandings each year by the estimate of annual mortality.

The team's analysis suggests that only 2% of cetacean carcasses were ever historically recovered after their deaths in this region, meaning that the true death toll from the Deepwater Horizon disaster could be 50 times higher than the number of deaths currently estimated.

"This figure illustrates that carcass counts are hugely mis-leading, if used to measure the disaster's death toll," said co-author Scott Kraus of the New England Aquarium "No study on carcass recovery from strandings has ever recovered anything close to 100% of the deaths occurring in any cetacean population. The highest rate we found was only 6.2%, which implied 16 deaths for every carcass recovered."

Saturn is sending out mixed signals in recent data from NASA's Cassini spacecraft and the NASA/ESA Hubble Space Telescope

Like a petulant adolescent, Saturn is sending out mixed signals.

Recent data from NASA's Cassini spacecraft show that the variation in radio waves controlled by the planet's rotation is different in the northern and southern hemispheres. Moreover, the northern and southern rotational variations also appear to change with the Saturnian seasons, and the hemispheres have actually swapped rates. These two radio waves, converted to the human audio range, can be heard in a new video available online.

Early this morning, at 5:20 am EDT, MESSENGER captured this historic image of Mercury. This image is the first ever obtained from a spacecraft in orbit about the Solar System's innermost planet. Over the subsequent six hours, MESSENGER acquired an additional 363 images before downlinking some of the data to Earth. The MESSENGER team is currently looking over the newly returned data, which are still continuing to come down. Tomorrow, March 30, at 2 pm EDT, attend the NASA media telecon to view more images from MESSENGER's first look at Mercury from orbit.

The dominant rayed crater in the upper portion of the image is Debussy. The smaller crater Matabei with its unusual dark rays is visible to the west of Debussy. The bottom portion of this image is near Mercury's south pole and includes a region of Mercury's surface not previously seen by spacecraft. Compare this image to the planned image footprint to see the region of newly imaged terrain, south of Debussy. Over the next three days, MESSENGER will acquire 1185 additional images in support of MDIS commissioning-phase activities. The year-long primary science phase of the mission will begin on April 4, and the orbital observation plan calls for MDIS to acquire more than 75,000 images in support of MESSENGER's science goals.

A curtain of flame halts firefighters trying to rescue a family inside a burning home. One with a special backpack steps to the front, points a wand at the flame, and shoots a beam of electricity that opens a path through the flame for the others to pass and lead the family to safety.

Scientists today described a discovery that could underpin a new genre of fire-fighting devices, including sprinkler systems that suppress fires not with water, but with zaps of electric current, without soaking and irreparably damaging the contents of a home, business, or other structure. Reporting at the 241st National Meeting & Exposition of the American Chemical Society (ACS), Ludovico Cademartiri, Ph.D., and his colleagues in the group of George M. Whitesides, Ph.D., at Harvard University, picked up on a 200-year-old observation that electricity can affect the shape of flames, making flames bend, twist, turn, flicker, and even snuffing them out. However, precious little research had been done over the years on the phenomenon.

"Controlling fires is an enormously difficult challenge," said Cademartiri, who reported on the research. "Our research has shown that by applying large electric fields we can suppress flames very rapidly. We're very excited about the results of this relatively unexplored area of research."

The first analysis of nuclear fission products in the atmosphere over Seattle provides a unique insight into the nature of the disaster.

When the Fukushima nuclear disaster began to unfold after the 11 March earthquake and tsunami, it quickly became clear that anything downwind was in for a sprinkling of radioactivity. So Jonathan Diaz Leon and pals at the University of Washington in Seattle were ready.

These guys began removing air filters from the intake to the ventilation system of the Physics and Astronomy building at the University of Washington and then measuring the levels of radiation they were emitting. Initially, the filters contained nothing out of the ordinary. Then, sometime between 12pm on 17 March and 2pm on 18 March, the radiation levels began to rise.

A 12-year-old child prodigy has astounded university professors after grappling with some of the most advanced concepts in mathematics.

Jacob Barnett has an IQ of 170 - higher than Albert Einstein - and is now so far advanced in his Indiana university studies that professors are lining him up for a PHD research role.

The boy wonder, who taught himself calculus, algebra, geometry and trigonometry in a week, is now tutoring fellow college classmates after hours.

Between 75 and 80 per cent of all volcanic activity on Earth takes place at deep-sea, mid-ocean ridges. Most of these volcanoes produce effusive lava flows rather than explosive eruptions, both because the levels of magmatic gas (which fuel the explosions and are made up of a variety of components, including, most importantly CO2) tend to be low, and because the volcanoes are under a lot of pressure from the surrounding water.

Over about the last 10 years however, geologists have nevertheless speculated, based on the presence of volcanic ash in certain sites, that explosive eruptions can also occur in deep-sea volcanoes.

But no one has been able to prove it until now.

By using an ion microprobe, Christoph Helo, a PhD student in McGill's Department of Earth and Planetary Sciences, has now discovered very high concentrations of CO2 in droplets of magma trapped within crystals recovered from volcanic ash deposits on Axial Volcano on the Juan de Fuca Ridge, off the coast of Oregon.

Scientists have been arguing for years about microscopic structures in 3.5-billion-year-old rocks: some think they are the earliest fossilized life yet found, while others see just geology. A new study says the structures are not fossils after all, and cautions that how we interpret such structures will affect our search for life beyond Earth.

Structures thought of as the oldest known fossils of microbes might actually be microscopic mineral formations not associated with life, suggesting that astrobiologists have to be careful calling alien objects "life" when scientists have trouble telling what is or was alive on Earth.

More than 20 years ago, microscopic structures uncovered in the roughly 3.5-billion-year-old Apex Chert formation in western Australia were described as the oldest microbial fossils. These structures were interpreted as cyanobacteria, once known as blue-green algae, embedded in a silica-loaded rock formed in a shallow marine setting. These structures were all detected in slices of rock just 300 microns thick, or roughly three times the diameter of a human hair.