Heavens

On 24 February 2009, the NASA/ESA Hubble Space Telescope captured a photo sequence of four moons of Saturn passing in front of their parent planet. The moons, from far left to right, are the white icy moons Enceladus and Dione, the large orange moon Titan, and icy Mimas. Due to the angle of the Sun, they are each preceded by their own shadow.

Peering into the tumultuous heart of the nearby Perseus galaxy cluster, Hubble discovered a large population of small galaxies that have remained intact while larger galaxies around them are being ripped apart by the gravitational tug of other galaxies.

The Hubble images provide further evidence that the undisturbed galaxies are enshrouded by a "cushion" of dark matter that protects them from their rough-and-tumble neighbourhood.

GREENBELT, Md. -- A new map combining nearly three months of data from NASA's Fermi Gamma-ray Space Telescope is giving astronomers an unprecedented look at the high-energy cosmos. To Fermi's eyes, the universe is ablaze with gamma rays from sources ranging from within the solar system to galaxies billions of light-years away.

For decades, distant galaxies that emitted their light six billion years ago were no more than small specks of light on the sky. With the launch of the Hubble Space Telescope in the early 1990s, astronomers were able to scrutinise the structure of distant galaxies in some detail for the first time. Under the superb skies of Paranal, the VLT's FLAMES/GIRAFFE spectrograph (ESO 13/02) — which obtains simultaneous spectra from small areas of extended objects — can now also resolve the motions of the gas in these distant galaxies (ESO 10/06).

About 100 million light-years away, in the constellation of Piscis Austrinus (the Southern Fish), three galaxies are playing a game of gravitational give-and-take that might ultimately lead to their merger into one enormous entity. A new image from the Advanced Camera for Surveys on the NASA/ESA Hubble Space Telescope allows astronomers to view the movement of gases from galaxy to galaxy, revealing the intricate interplay among them.

"With lots of methane in the atmosphere, it becomes clear why Pluto's atmosphere is so warm," says Emmanuel Lellouch, lead author of the paper reporting the results.

Pluto, which is about a fifth the size of Earth, is composed primarily of rock and ice. As it is about 40 times further from the Sun than the Earth on average, it is a very cold world with a surface temperature of about minus 220 degrees Celsius!

CLEMSON — Clemson University space physicists have traveled around the world to launch rockets to test atmospheric conditions.

This shows the fourth launch of a rocket at Poker Flat Research Range. Center: time exposure of first- and second-stage firetrail. Background: auroral arc in the north.Scientists most recently launched a salvo of four rockets over Alaska to study turbulence in the upper atmosphere. The launches took place at Poker Flat Research Range north of Fairbanks as part of a NASA sounding rocket campaign.

The oldest isolated pulsar ever detected in X-rays has been found with NASA's Chandra X-ray Observatory. This very old and exotic object turns out to be surprisingly active.

The pulsar, PSR J0108-1431 (J0108 for short) is about 200 million years old. Among isolated pulsars -- ones that have not been spun-up in a binary system -- it is over 10 times older than the previous record holder with an X-ray detection. At a distance of 770 light years, it is one of the nearest pulsars known.

Interstellar space dust from a dead star identified by a research team led by The University of Nottingham could unlock some of the mysteries of the early universe.

Dr Loretta Dunne and her team have found new evidence of huge dust production in the Cassiopeia A supernova remnant, the remains of a star that exploded about 300 years ago. The paper is set to be published in the Monthly Notices of the Royal Astronomical Society.

The Helix Nebula, NGC 7293, lies about 700 light-years away in the constellation of Aquarius (the Water Bearer). It is one of the closest and most spectacular examples of a planetary nebula. These exotic objects have nothing to do with planets, but are the final blooming of Sun-like stars before their retirement as white dwarfs. Shells of gas are blown off from a star's surface, often in intricate and beautiful patterns, and shine under the harsh ultraviolet radiation from the faint, but very hot, central star.

On long, dark winter nights, the constellation of Orion the Hunter dominates the sky. Within the Hunter's sword, the Orion Nebula swaddles a cluster of newborn stars called the Trapezium. These stars are young but powerful, each one shining with the brilliance of 100,000 Suns. They are also massive, containing 15 to 30 times as much material as the Sun.

Where did the Trapezium stars come from? The question is not as simple as it seems. When it comes to the theory of how massive stars form, the devil is in the details.

CAMBRIDGE, Mass.--Satellites orbiting the Earth must occasionally be nudged to stay on the correct path. MIT scientists are developing a new rocket that could make this and other spacecraft maneuvers much less costly, a consideration of growing importance as more private companies start working in space.

The rotating black hole has been described as one of nature's most perfect objects.

As described by the Kerr solution of Einstein's gravitational field equations, its spacetime geometry is completely characterized by only two numbers — mass and spin — and is sometimes described by the aphorism "black holes have no hair.''

A particle orbiting a rotating black hole always conserves its energy and angular momentum, but otherwise traces a complicated twisting rosette pattern with no discernible regularity.

GREENBELT, Md. - While waiting for high-energy outbursts and cosmic explosions, NASA's Swift Gamma-ray Explorer satellite is monitoring Comet Lulin as it closes on Earth. For the first time, astronomers are seeing simultaneous ultraviolet and X-ray images of a comet.

"We won't be able to send a space probe to Comet Lulin, but Swift is giving us some of the information we would get from just such a mission," said Jenny Carter, at the University of Leicester, U.K., who is leading the study.

The first gamma-ray burst to be seen in high-resolution from NASA's Fermi Gamma-ray Space Telescope is one for the record books. The blast had the greatest total energy, the fastest motions and the highest-energy initial emissions ever seen.

"We were waiting for this one," said Peter Michelson, the principal investigator on Fermi's Large Area Telescope at Stanford University. "Burst emissions at these energies are still poorly understood, and Fermi is giving us the tools to understand them."