Space

A group of scientists from Durham University say they have found the "missing link" between small and super-massive black holes. The researchers have discovered that a strong X-ray pulse is emitting from a giant black hole in a galaxy 500 million light years from Earth.

The pulse has been created by gas being sucked by gravity on to the black hole at the centre of the REJ1034+396 galaxy.

X-ray pulses are common among smaller black holes, but the Durham research is the first to identify this activity in a super-massive black hole. Most galaxies, including the Milky Way, are believed to contain super-massive black holes at their centers.




An international team of scientists predict that our galaxy, the Milky Way, contains a disk of ‘dark matter’, in a paper published in Monthly Notices of the Royal Astronomical Society.

Astronomers Dr. Justin Read, Professor George Lake and Oscar Agertz of the University of Zurich, and Dr. Victor Debattista of the University of Central Lancashire used the results of a supercomputer simulation to deduce the presence of this disk. They explain how it could allow physicists to directly detect and identify the nature of dark matter for the first time.

Unlike the familiar ‘normal’ matter that makes up stars, gas and dust, ‘dark’ matter is invisible but its presence can be inferred through its gravitational influence on its surroundings. Physicists believe that it makes up 22% of the mass of the Universe (compared with the 4% of normal matter and 74% comprising the mysterious ‘dark energy’). But, despite its pervasive influence, no one is sure what dark matter consists of.


A long-standing scientific belief holds that stars tend to hang out in the same general part of a galaxy where they originally formed. Some astrophysicists have recently questioned whether that is true, and now new simulations show that, at least in galaxies similar to our own Milky Way, stars such as the sun can migrate great distances.

What's more, if our sun has moved far from where it was formed more than 4 billion years ago, that could change the entire notion that there are parts of galaxies – so-called habitable zones – that are more conducive to supporting life than other areas are.

"Our view of the extent of the habitable zone is based in part on the idea that certain chemical elements necessary for life are available in some parts of a galaxy's disk but not others," said Rok Roškar, a doctoral student in astronomy at the University of Washington. "If stars migrate, then that zone can't be a stationary place."





Natarajan found that ultra-massive black holes, which lurk in the centers of huge galaxy clusters like the one above, seem to have an upper mass limit of 10 billion times that of the Sun. (Credit: NASA)

There appears to be an upper limit to how big the universe’s most massive black holes can get, according to new research led by Yale University astrophysicist Priyamvada Natarajan and Ezequiel Treister, a postdoctoral fellow at the University of Hawaii.


Burst Alert! March 19th was an exciting day for NASA. We know “why” it was special, but we don’t know “why why” it was special. They finally explain the why why today, and you can read all about it in Nature tomorrow. There was something amazing about GRB 080319B and the other cosmic bursts that NASA’s Swift satellite detected that day. (See NASA's animation of what they think happened). "Even by the standards of gamma-ray bursts, this burst was a whopper," says Swift lead scientist Neil Gehrels of NASA. "It blows away every gamma ray burst we’ve seen so far." Here’s the why (we'll get to the why why in a second):
What do you call a supernova that is not as powerful and doesn't destroy the star?

A babynova? Subnova?

We'll need to think of something, according to Berkeley astronomer Nathan Smith, because that is what happened in 1843 to Eta Carinae, the galaxy's second most studied star.

Eta Carinae (η Car) is a massive, hot, variable star visible only from the Southern Hemisphere, and is located about 7,500 light years from Earth in a young region of star birth called the Carina Nebula. It was observed to brighten immensely in 1843, and astronomers now see the resulting cloud of gas and dust, known as the Homunculus nebula, wafting away from the star. A faint shell of debris from an earlier explosion is also visible, probably dating from around 1,000 years ago.


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.