Space

For several decades, scientists have thought that the Solar System formed as a result of a shock wave from an exploding star — a supernova — that triggered the collapse of a dense, dusty gas cloud that contracted to form the Sun and the planets.

Models of this formation process have only worked under the simplifying assumption that the temperatures during the violent events remained constant but astrophysicists at the Carnegie Institution’s Department of Terrestrial Magnetism (DTM) say their new model says that a supernova could indeed have triggered the Solar System’s formation under the more likely conditions of rapid heating and cooling.


The “birth rate” for stars is certainly not easy to determine. Distances in the universe are far too great for astronomers to be able to count all the newly formed celestial bodies with the aid of a telescope so it is fortunate that emerging stars give themselves away by a characteristic signal known as “H-alpha” emissions.

The larger the number of stars being formed in a particular region of the firmament, the more H-alpha rays are emitted from that region.

More newborn stars are apparently emerging around the universe than previously assumed, say researchers at Bonn University who published a paper in “Nature” explaining that a systematic error in the method of estimation has resulted in a lower number.

The detailed study, called the ACS Nearby Galaxy Survey Treasury (ANGST) program, explored a region called the Local Volume, where galaxy distances range from 6.5 million light-years to 13 million light-years from Earth.

A typical galaxy contains billions of stars but looks smooth when viewed through a conventional telescope because the stars appear blurred together. In contrast, the galaxies observed in this new survey are close enough to Earth that the sharp view provided by Hubble's Advanced Camera for Surveys and Wide Field Planetary Camera 2 can resolve the brightness and colour of some individual stars. This allows scientists to determine the history of star formation within a galaxy and tease out subtle features in a galaxy's shape.


Plenty of sun and some ice for water sounds like a lovely place for a moon base, doesn't it?

Three-dimensional views of the mountainous terrain surrounding a “peak of eternal light” near the Moon’s south pole have been released by the European Space Agency. Dr Detlef Koschny will present the images at the European Planetary Science Congress in Münster on Friday 26th September. Images taken by the AMIE camera carried by ESA’s SMART-1 mission have been used to create digital elevation model of the peak, which is almost continuously exposed to sunlight.

“AMIE is not a stereo camera, so producing a 3-D model of the surface has been a challenge,” said Dr Koschny. “We’ve used a technique where we use the brightness of reflected light to determine the slope and, by comparing several images, put together a model that produces a shadow pattern that matches those observed by SMART-1.”


I'm obsessed with the apocalypse. No joke.

I always carry a mini-emergency kit stuffed in an Altoids tin, and I know that if the apocalypse comes, my husband and I are supposed to meet at our apartment, grab our pre-packed bags, maybe the cat, and head for the hills. 

We own a Grundig self-powered radio with hand crank and charger for cell phones with various adapters. Survival manuals. Canned food. Bottled water. Check. Check. Check.

Zombies, watch out! We're armed. Nuclear attack? No prob--we've got pills for that.

But what if the apocalypse isn't zombies? What if it's not radiation poisoning we've got to be worried about? What if it's simply some giant celestial object bearing down on us?--I'd need several pills to handle that. 

Sounds improbable? Think again.

Illustration by LYNETTE R COOK

Over a decade after it exploded, one of the nearest supernovae in the last 25 years has been identified. This result was made possible by combining data from the vast online archives from many of the world’s premier telescopes.

The supernova, called SN 1996cr, was first singled out in 2001 by Franz Bauer. Bauer noticed a bright, variable source in the Circinus spiral galaxy, using NASA's Chandra X-ray Observatory. Although the source displayed some exceptional properties Bauer and his Penn State colleagues could not identify its nature confidently at the time.

It was not until years later that Bauer and his team were able to confirm that this object was a supernova. Clues from a spectrum obtained by ESO’s Very Large Telescope led the team to start the real detective work of searching through data from 18 different telescopes, both ground- and space-based, nearly all of which existed. Because this object was found in an interesting nearby galaxy, the public archives of these telescopes contained abundant observations.


Using data from NASA's Wilkinson Microwave Anisotropy Probe (WMAP), scientists have identified an unexpected motion in distant galaxy clusters. The cause, they suggest, is the gravitational attraction of matter that lies beyond the observable universe.

"The clusters show a small but measurable velocity that is independent of the universe's expansion and does not change as distances increase," says lead researcher Alexander Kashlinsky at NASA's Goddard Space Flight Center in Greenbelt, Md. "We never expected to find anything like this."

Kashlinsky calls this collective motion a "dark flow" in the vein of more familiar cosmological mysteries: dark energy and dark matter. "The distribution of matter in the observed universe cannot account for this motion," he says.


Observations from NASA’s Cassini spacecraft have been used to build, for the first time, a 3-D picture of the sources of intense radio emissions in Saturn’s magnetic field, known as the Saturn Kilometric Radiation (SKR).

Saturn Kilometric Radiation is the most intense component of radio emissions from Saturn. It was discovered by NASA’s Voyager spacecraft in 1980. The radio emissions have frequencies between about 10 kilohertz and 1.2 megahertz. This corresponds to the Long Wave and Medium Wave broadcasting bands.

The results were presented by Dr Baptist Cecconi, of LESIA, Observatoire de Paris, at the European Planetary Science Congress on Tuesday 23rd September.

The SKR radio emissions are generated by high-energy electrons spiralling around magnetic field lines threaded through Saturn’s auroras. Previous Cassini observations have shown that the SKR is closely correlated with the intensity of Saturn’s UV aurora and the pressure of the solar wind.


Two terrestrial planets in orbit around a sun-like star, BD +20 307, recently suffered a violent collision, astronomers at University of California Los Angeles, Tennessee State University, and California Institute of Technology will report in a December issue of the Astrophysical Journal, the premier journal of astronomy and astrophysics.

“It’s as if Earth and Venus collided with each other,” said Benjamin Zuckerman, UCLA professor of physics and astronomy and a co-author on the paper. “Astronomers have never seen anything like this before; apparently major, catastrophic, collisions can take place in a fully mature planetary system.”


A gamma-ray burst is, in a sense, a look back in time. Scientists have now seen one that happened farther back in time than any other seen before. Even before the existence of the Milky Way.

Gamma-ray bursts (GRBs) are the most powerful and brightest explosions of energy in our universe. They last only a few milliseconds to several minutes and they outshine all other sources of gamma rays combined. Astronomers now think that most GRBs are associated with the explosive deaths of massive stars. These stars collapse and explode when they run out of nuclear fuel.