New model postulates existence of shape-shifting ‘chameleon’ particleMay 30th, 2009 - 12:55 pm ICT by ANI
London, May 30 (ANI): Cosmologists have come up with a model postulating the existence of a ‘chameleon’ particle, which would change its mass depending on its environment, and might be used to explain the accelerating expansion of the Universe.
According to a report in Nature News, a new research has claimed to have spotted signs of this elusive particle, whose existence was first postulated in 2003 to explain the accelerating expansion of the Universe, which has been attributed to some unknown ‘dark energy’.
The changing mass of a chameleon particle would modify the range at which its force can act, thus possibly explaining why whatever causes the Universe’s acceleration hasn’t been detected on Earth.
On Earth, the chameleon would be too heavy to create any noticeable force, but in the tracts of empty space, its effect would be huge.
In theory, photons that travel through magnetic fields can turn into chameleons, reducing the amount of light that reaches Earth from distant sources.
The amount of dimming depends on the light’s frequency.
By comparing light emitted across a range of frequencies from the luminous centres of 77 active galaxies, Douglas Shaw at Queen Mary University of London and his colleagues have found what they call “good evidence” that some photons have gone missing in transit.
“It’s absolutely an interesting way of looking for (exotic) particles, and the results are certainly intriguing,” said Frank Wilczek, a particle physicist at the Massachusetts Institute of Technology (MIT) in Cambridge.
By themselves, the observations of dimmed light by Shaw and his colleagues can’t distinguish between models that rely on chameleons and models in which photons turn into other ‘axion-like’ particles.
Either “would be an interesting discovery,” said Shaw.
However, only the chameleon model predicts that the photons’ polarizations should be aligned with the magnetic fields they traversed.
So far, the team has studied data on light from three stars in the Milky Way galaxy and in each case found the required polarization.
As part of the research into the Chameleon particle, Amanda Weltman at the University of Cambridge, UK, along with the GammeV group at the Fermi National Accelerator Laboratory in Batavia, Illinois, is attempting to shine laser light through a tube with windows at either end that is immersed in a magnetic field.
The chameleon model predicts that some photons should convert to chameleon particles. When the laser is switched off, the chameleons should slowly turn back to photons and create a faint afterglow.
The experiment has completed its first phase without seeing any signs of a chameleon.
However, the team has not yet searched for the chameleons with parameters that match those possibly sighted by Shaw’s team.
The GammeV group is now preparing to test for chameleons in that “interesting range,” said Weltman. (ANI)
- God Particle's discovery 'biggest leap in physics' (Roundup) - Jul 05, 2012
- Electromagnetism and gravity: Are they related? - Sep 20, 2011
- Scientists clear away "cosmic dust" to get better look at youngest supernova remnant - Apr 23, 2009
- Now, nanorods to improve how visual display of information - Mar 15, 2011
- Universal, primordial magnetic fields discovered in deep space - Sep 22, 2010
- Warm ocean currents cause ice loss from Antarctica - Apr 26, 2012
- Black-hole-powered jets create fog of gamma rays - Mar 03, 2010
- Jets streaming from black holes have more complex shape than earlier believed - Feb 18, 2010
- Trigger that sets off pulsating aurorae found - Oct 02, 2010
- Large Hadron Collider sets new beam intensity record - Apr 23, 2011
- First-ever measurement of magnetic field inside Earth's core - Dec 17, 2010
- Scientists unveil secrets of exploding plasma clouds on Sun - Nov 09, 2010
- Scientists produce first-ever, 100 times brighter rare colour of laser light - Dec 22, 2010
- Laser system can see what's behind walls - Aug 07, 2012
- First evidence of magnetic field ejected from a young star - Nov 26, 2010
Tags: axion, chameleon, chameleons, cosmologists, dark energy, distant sources, douglas shaw, elusive particle, exotic particles, expansion of the universe, frank wilczek, magnetic fields, massachusetts institute of technology, massachusetts institute of technology mit, nature news, particle physicist, postulates, queen mary university, queen mary university of london, university of london