Space

GRB 080319B was so intense that, despite happening halfway across the Universe, it could have been seen briefly with the unaided eye. In a Nature paper, Judith Racusin of Penn State University, and a team of 92 co-authors report observations across the electromagnetic spectrum that began 30 minutes before the explosion and followed it for months afterwards.

"We conclude that the burst's extraordinary brightness arose from a jet that shot material almost directly towards Earth at almost the speed of light - the difference is only 1 part in 20 000," says Guido Chincarini, a member of the team.

Gamma-ray bursts are the Universe's most luminous explosions. Most occur when massive stars run out of fuel. As a star collapses, it creates a black hole or neutron star that, through processes not fully understood, drives powerful gas jets outward. As the jets shoot into space, they strike gas previously shed by the star and heat it, thereby generating bright afterglows.


Astronomers have been able to study planet-forming discs around young Sun-like stars in unsurpassed detail, clearly revealing the motion and distribution of the gas in the inner parts of the disc. This result, which possibly implies the presence of giant planets, was made possible by the combination of a very clever method enabled by ESO's Very Large Telescope.

Planets could be home to other forms of life, so the study of exoplanets ranks very high in contemporary astronomy. More than 300 planets are already known to orbit stars other than the Sun, and these new worlds show an amazing diversity in their characteristics. But astronomers don't just look at systems where planets have already formed - they can also get great insights by studying the discs around young stars where planets may currently be forming. "This is like going 4.6 billion years back in time to watch how the planets of our own Solar System formed," says Klaus Pontoppidan from Caltech, who led the research.


When scientific terms become part of the cultural fabric they often lose their meaning. Biology has had its share of modern misunderstandings with 'evolution' becoming colloquial rather than scientific, along with the general term 'theory', which today is used by anyone with a crackpot notion about particle physics, math or the end of the world due to a tunnel in Switzerland.

So it goes. That's why today we have advertising claims like 'the next evolution in cars' and then press releases about the 'missing link' in comets.

Hey, we don't shape the culture, we just try to cut through it. So this time we will talk about the 'missing link' between an Oort cloud and Halley's comet and discuss the 'evolution' of these mysterious space bodies, which will make biologists here irritated. Later on we can use terms like 'genesis' and 'creation' in their place so religious folks can feel slighted also.

Why mention all that? Well, we run out of science terms to use when there is no previous explanation for an object, so we have to fall back on cultural ones in order to convey why something is important. In this instance, a team of scientists has found an unusual object whose backward and tilted orbit around the Sun is just baffling enough that it may tell us about the origins of some comets.

You heard me. Researchers from the Canada-France Ecliptic Plane Survey project have discovered an object that orbits around the Sun -- backwards. And it is tilted at an angle of 104 degrees, almost perpendicular to the orbits of the planets. Take a look:




A strange mix of oxygen found in a stony meteorite that exploded February 8, 1969 over Pueblito de Allende, Mexico has puzzled scientists ever since. Small flecks of minerals lodged in the stone and thought to date from the beginning of the solar system have a pattern of oxygen types, or isotopes, that differs from those found in all known planetary rocks, including those from Earth, its Moon and meteorites from Mars.

Now scientists from UC San Diego and Lawrence Berkeley National Laboratory have eliminated one model proposed to explain the anomaly: the idea that light from the early Sun could have shifted the balance of oxygen isotopes in molecules that formed after it turned on. When they beamed light through carbon monoxide gas to form carbon dioxide, the balance of oxygen isotopes in the new molecules failed to shift in ways predicted by the model they report in the September 5 issue of Science.


Astronomers have taken the closest look ever at the giant black hole in the center of the Milky Way. By combining telescopes in Hawaii, Arizona, and California, they detected structure at a tiny angular scale of 37 micro-arcseconds - the equivalent of a baseball seen on the surface of the moon, 240,000 miles distant. These observations are among the highest resolution ever done in astronomy.

Using a technique called Very Long Baseline Interferometry (VLBI), a team of astronomers led by Doeleman employed an array of telescopes to study radio waves coming from the object known as Sagittarius A* (A-star). In VLBI, signals from multiple telescopes are combined to create the equivalent of a single giant telescope, as large as the separation between the facilities. As a result, VLBI yields exquisitely sharp resolution.

The Sgr A* radio emission, at a wavelength of 1.3 mm, escapes the galactic center more easily than emissions at longer wavelengths, which tend to suffer from interstellar scattering. Such scattering acts like fog around a streetlamp, both dimming the light and blurring details. VLBI is ordinarily limited to wavelengths of 3.5 mm and longer; however, using innovative instrumentation and analysis techniques, the team was able to tease out this remarkable result from 1.3-mm VLBI data.


ESO's Wide Field Imager has captured the intricate swirls of the spiral galaxy Messier 83, a smaller look-alike of our own Milky Way. Shining with the light of billions of stars and the ruby red glow of hydrogen gas, it is a beautiful example of a barred spiral galaxy, whose shape has led to it being nicknamed the Southern Pinwheel.

This dramatic image of the galaxy Messier 83 was captured by the Wide Field Imager at ESO's La Silla Observatory, located high in the dry desert mountains of the Chilean Atacama Desert. Messier 83 lies roughly 15 million light-years away towards the huge southern constellation of Hydra (the sea serpent). It stretches over 40 000 light-years, making it roughly 2.5 times smaller than our own Milky Way. However, in some respects, Messier 83 is quite similar to our own galaxy. Both the Milky Way and Messier 83 possess a bar across their galactic nucleus, the dense spherical conglomeration of stars seen at the centre of the galaxies.


Another piece of the jigsaw in understanding how neutron stars work has been put in place following the discovery by scientists of the origin of the high energy emission from rotation-powered pulsars.

Pulsar systems containing neutron stars accelerate particles to immense energies, typically one hundred times more than the most powerful accelerators on Earth. Scientists are still uncertain exactly how these systems work and where the particles are accelerated.

Now a team of researchers from the UK and Italy, led by Professor Tony Dean of the University of Southampton, has detected polarized gamma-ray emission from the vicinity of the Crab Nebula - one of the most dramatic sights in deep space. By using spectroscopic imaging and measuring the polarization - or the alignment - of the waves of high energy radiation in the gamma-ray band, they have shown that these energetic photons originate close to the pulsar.


A powerful collision of galaxy clusters has been captured with NASA's Chandra X-ray Observatory and Hubble Space Telescope. Like its famous cousin, the so-called Bullet Cluster, this clash of clusters provides striking evidence for dark matter and insight into its properties.

Like the Bullet Cluster, this newly studied cluster, officially known as MACSJ0025.4-1222, shows a clear separation between dark and ordinary matter. This helps answer a crucial question about whether dark matter interacts with itself in ways other than via gravitational forces.


How do galaxies form? The most widely accepted answer to this fundamental question is the model of 'hierarchical formation', a step-wise process in which small galaxies merge to build larger ones. One can think of the galaxies forming in a similar way to how streams merge to form rivers, and how these rivers, in turn, merge to form an even larger river.

This theoretical model predicts that massive galaxies grow through many merging events in their lifetime. But when did their cosmological growth spurts finish? When did the most massive galaxies get most of their mass?


The systematics of celestial bodies needs to be revised, say researchers at the Argelander Institute of Astronomy of the University of Bonn. Brown dwarfs, to-date merely regarded as stars which were below normal size, may well be stellar ‘miscarriages' and need to be treated as a separate class in addition to stars and planets.

Brown dwarfs (or BDs) are what scientists call objects which populate the galaxies apart from the stars. Unlike the latter, they cannot develop high-yield hydrogen fusion as in the interior of our sun due to their low mass (less than about 8% of the sun’s mass). But in addition to this brown dwarfs and stars also seem to be different in their ‘mating behavior’.