Sunday, June 11, 2006

Massive-star supernovae found to be major space dust factories

Technorati Tags: or and or and or and or and or and or and or and or

Massive-star supernovae found to be major space dust factories

Supernova Dust Factory in M74, Image Credit: NASA/JPL-Caltech/STScI.
PIA08533: Supernova Dust Factory in M74, Mission: Spitzer Space Telescope (SST), Spacecraft: Spitzer Space Telescope (SST), Instrument: Infrared Array Camera (IRAC), Product Size: 2325 samples x 2329 lines, Produced By: California Institute of Technology.
Full-Res JPEG: PIA08533.jpg (325.5 kB), An unaccounted for source of space dust which spawns life in the universe has been identified by an international team of scientists. They report in Science Express that Type II supernovae – where a massive star comes to the end of its life and releases its cataclysmic energy – are the culprits.

Space dust is composed of small particles, made of elements such as carbon, silicon, magnesium, iron and oxygen, which are the building blocks from which the earth was made. Until recently, it was thought that this dust was mainly formed by old sun-like stars known as red giants. But the amount of dust found in young galaxies in the early universe seems unlikely to be due to old stars.

Supernovae produced by short-lived massive stars have long been suspected as the dust factories but they are fairly rare events that only happen approximately once every hundred years in a galaxy, making it harder for researchers to find and analyse whether dust is formed in their aftermath.

NASA’s Spitzer Space Telescope allowed the researchers to peer further into the universe, allowing them to observe a supernova whose explosion was discovered in 2003 in the spiral galaxy Messier 74, which is approximately 30 million light-years away. Their results suggest for the first time that dust can form efficiently in supernovae, using up about five per cent of the heavy elements available.

Professor Mike Barlow, of the UCL Department of Physics & Astronomy and one of the authors of the study, says: “Dust particles in space are the building blocks of comets, planets and life, yet our knowledge of where this dust was made is still incomplete. These new observations show that supernovae can make a major contribution to enriching the dust content of the universe.”

The researchers used the space-based Spitzer and Hubble telescopes and the ground-based Gemini North Telescope atop Mauna Kea in Hawaii. The study was led by Dr Ben Sugerman of the Space Telescope Science Institute in Baltimore, and members of the Survey for the Evolution of Emission from Dust in Supernovae (SEEDS) collaboration, which is led by Professor Barlow.

Although researchers have detected many supernovae in the past at visible wavelengths, supernova 2003gd is only one of three in the universe that have been seen at infrared wavelengths producing dust. Supernovae dim and expand into space fairly quickly, so scientists require extremely sensitive telescopes to study them even a few months after the initial explosion. While astronomers have suspected that most supernovae do produce dust, their ability to study this dust production in the past has been limited by technology.

As dust condenses in supernova ejections it produces three observable phenomena: (1) emission at infrared wavelengths; (2) an increase in obscuration of the supernova’s light at visible wavelengths; (3) greater obscuration by the newly formed dust of emission from gas that is expanding away from us, on the far side of the supernova, than from gas expanding towards us, at the front of the supernova.

“One of the difficulties in trying to detect infrared emissions from distant galaxies is the extreme sensitivity of the detectors to heat from other sources,” explains Professor Barlow.

“Infrared is primarily heat radiation, so the Spitzer Space Telescope must be cooled to near absolute zero (-273 degrees Celsius) so that it can observe infrared signals from space without interference from the telescope’s own heat.”

Infrared measurements of supernova 2003gd made 500-700 days after the outburst revealed emission consistent with newly formed cooling dust. Sophisticated modelling of the observed infrared emission and of the measured obscuration at visible wavelengths implied that solid dust particles equivalent to up to seven thousand earth masses had formed.

Dr Ben Sugerman, of the Space Telescope Science Institute in Baltimore who led the study, says: “People have suspected for 40 years that supernovae could be producers of dust, but the technology to confirm this has only recently become available. The advantage of using Spitzer is that we can actually see the warm dust as it forms.”

Professor Robert Kennicutt, of the University of Cambridge’s Institute of Astronomy and a co-author of the study, added: “These results provide an impressive demonstration of how Spitzer observations of supernovae can provide unique new insights into the processes that produce dust in the universe.”

Notes to editors

The paper, ‘Massive-Star Supernovae as Major Dust Factories’ was published in the June 8 Science Express edition of the journal Science.

NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology. JPL is a division of Caltech.

For further information, please contact:

Judith H Moore,UCL Media Relations, Tel: +44 (0) 20 7679 7678, Mobile: +44 (0)77333 075 96, Out-of-hours: +44 (0)7917 271 364, Email: judith.moore@ucl.ac.uk

Professor Mike Barlow, UCL Department of Physics & Astronomy, Tel: +44 (0) 20 7679 7160, Email: mjb@star.ucl.ac.uk,

Dr Ben Sugerman, The Space Telescope Science Institute in Baltimore, Email: sugerman@stsci.edu

Related: Keywords Nanotech, science - Sunday, June 04, 2006 New unified force theory predicts measured values of physics, Sunday, Sunday, May 28, 2006 Growing glowing nanowires to light up the nanoworld , Sunday, May 14, 2006 Scientists Create the First Synthetic Nanoscale Fractal Molecule, Sunday, May 14, 2006 World’s tiniest test tubes get teensiest corks, Sunday, May 07, 2006 Blood-Compatible Nanoscale Materials Possible Using Heparin, Sunday, April 30, 2006 Micro-pump is cool idea for future computer chips, Sunday, April 16, 2006 Self-Powered Nanoscale Devices, Sunday, April 09, 2006 Nanopore Method Genome Sequencing, Sunday, April 02, 2006 Quantum dot method rapidly identifies bacteria, March 26, 2006 'Custom' nanoparticles, cancer diagnosis and treatment, Sunday, March 26, 2006, Green nanochemistry, American Chemical Society symposium, Sunday, March 19, 2006 nanotechnologists demonstrate artificial muscles powered by highly energetic fuels, Sunday, Sunday, March 12, 2006 magnetic phenomenon may improve RAM memories, February 26, 2006 Nanoscience study shows that quantum dots 'talk', Sunday, February 26, 2006 Nano-bots to undertake major tasks?, Sunday, February 19, 2006 Nanotech to improve health care delivery, Sunday, February 19, 2006 nano-canary in the nanotoxicology coalmine, Sunday, December 04, 2005 Nano-cages 'fill up' with hydrogen, Sunday, November 13, 2005 Testing toxicity of nanomaterials, Sunday, October 23, 2005 single-molecule car, 'Nanocar', Sunday, August 28, 2005 Writing at the nanoscale, Thursday, May 26, 2005 discontinuous palladium, siloxane self-assembled monolayer, Sunday, May 08, 2005 Center for Nanoscale Materials, Monday, April 25, 2005 Nanomagnets, Nanocomposite, Monday, March 21, 2005 porphyrin tubes may lead to new nanodevices, inexpensive hydrogen fuel.

New World Cup football will unsettle goalkeepers

Technorati Tags: and or and or and or and or

New World Cup football will unsettle goalkeepers, predicts scientist

Courtesy Adidas. For editorial use only! Additional clearance required for commercial, wireless or promotional use. Images may not be altered or modified.The new football that will be used for the first time in the World Cup’s opening game on Friday (9 June 2006) is likely to bamboozle goalkeepers at some stage of the tournament, a leading scientist has warned.
The Adidas ‘Teamgeist’ football has just 14 panels - with fewer seams - making its surface ‘smoother’ than conventional footballs which have a 26 or 32 panel hexagon-based pattern.

This makes it aerodynamically closer to a baseball and, when hit with a slow spin, will make the ball less stable, giving it a more unpredictable trajectory in flight.
“With a very low spin rate, which occasionally happens in football, the panel pattern can have a big influence on the trajectory of the ball and make it more unpredictable for a goalkeeper,” said Dr Ken Bray, a sports scientist at the University of Bath and author of the new popular science book How to score – science and the beautiful game.

“Because the Teamgeist ball has just 14 panels it is aerodynamically more similar to the baseball which only has two panels."
Courtesy Adidas. For editorial use only! Additional clearance required for commercial, wireless or promotional use. Images may not be altered or modified.
“In baseball, pitchers often throw a ’curve ball’ which is similar to a swerving free kick and the rotating seam disrupts the air flow around the ball in much the same way as a football does."

“Occasionally though, pitchers will throw a ’knuckleball’ which bobs about randomly in flight and is very disconcerting for batters."
“It happens because pitchers throw the ball with very little spin and as the ball rotates lazily in the air, the seam disrupts the air flow around the ball at certain points on the surface, causing an unpredictable deflection."

“With the world’s best players in Germany this summer, there are bound to be plenty of spectacular scoring free kicks."

“But watch the slow motion replays to spot the rare occasions where the ball produces little or no rotation and where goalkeepers will frantically attempt to keep up with the ball’s chaotic flight path.”

The ball, which has been used by teams competing in the World Cup in practice sessions, has already been criticised by England goalkeeper Paul Robinson and Germany goalkeeper Jens Lehmann for its light-weight and unpredictable behaviour.

How to score: science and the beautiful game is published by Granta Press and is available at £10.99. (ISBN: 1862078327)

The University of Bath is one of the UK's leading universities, with an international reputation for quality research and teaching. In 16 subject areas the University of Bath is rated in the top ten in the country. View a full list of the University's press releases: bath.ac.uk/news/releases

adidas unveils +Teamgeist™ Match Ball for the 2006 FIFA World Cup

Related: Keywords baseball, Sports, Sunday, May 21, 2006 Bush Welcomes 2006 U.S. Winter Olympic and Paralympic Teams (VIDEO), Friday, April 07, 2006 2005-06 NCAA Sports Champions (VIDEO), Tuesday, April 04, 2006 President Bush, Baseball Opening Day 2006, Wednesday, March 08, 2006 Play Ball! Inaugural World Baseball Classic, Tuesday, November 08, 2005 President Bush delivers a pitch, Monday, August 15, 2005 Little League Regional Championship, Wednesday, July 20, 2005 NCAA Women's Basketball Champions, Tuesday, July 12, 2005 President Congratulates 2004 and 2005 NCAA Sports Champions, Wednesday, July 06, 2005 Washington Nationals Join America Supports You, Monday, June 27, 2005 White House South Lawn Tee Ball