What is Dark Matter? New fundamental particle may help
Nobody knows what Dark Matter is, even though 85% of the Universe’s mass is thought to be made up of it. Researchers from the Max-Planck-Institut für Physik in Germany and the University of Southampton in England believe a new fundamental particle may help explain what it is.
Scientists are convinced Dark Matter exists. It has a gravitational effect on stars and galaxies, something is bending light (gravitational lensing), and astronomers are aware of its imprint in the Cosmic Microwave Background (the afterglow of the Big Bang).
Dark matter was first postulated by Dutch astronomer Jan Hendrik Oort (1900-1992) in 1932. It is called Dark Matter because we cannot see (observe, detect) it.
Even though the indirect evidence is there, and compellingly so, to date not one astrophysicist has been able to detect Dark Matter directly.
We are aware of its effects but cannot see or detect it? We call it Dark Matter. But what is it? Nobody knows.
Particle physics (branch of physics that deals with subatomic particles) gives us some clues of what Dark Matter could be. The majority of scientists believe it has a huge mass for fundamental particles, like heavy atoms.
The researchers wrote in the academic journal Scientific Reports that for astrophysical reasons, lighter Dark Matter particles are considered less likely, even though there are exceptions.
This latest study highlights a previously unknown window where it is possible they could exist, and with very general particle physics arguments, derives some startling results.
The particle that the team members are proposing has a mass of 100eV/c^2, i.e. 1/500 or 0.02% of an electron. Unlike Dark Matter, it does not interact with light, but interacts very strongly with normal matter.
Experiments cannot be done on Earth due to the atmosphere
The proposed particle probably cannot penetrate the Earth’s atmosphere, the authors say, so any experiments would have to be performed in outer-space.
The team would like to incorporate searches into a space experiment planned by the Macroscopic Quantum Resonators (MAQRO).
If a nanoparticle is suspended in space and is exposed directly to the Dark Matter flow, it will be pushed by this flow (downstream), meanwhile sensitive monitoring equipment should be able to monitor its position and reveal information about the nature of this Dark Matter – that is of course, if it really does exist.
University of Southampton astrophysicist Dr. James Bateman, a study co-author, said:
“This work brings together some very different areas of physics: theoretical particle physics, observational x-ray astronomy, and experimental quantum optics. Our candidate particle sounds crazy, but currently there seem to be no experiments or observations which could rule it out.”
“Dark Matter is one of the most important unsolved problems in modern physics, and we hope that our suggestion will inspire others to develop detailed particle theory and even experimental tests.”
Co-author, Dr. Alexander Merle, who works at the Max Planck Institute, Munich, Germany, added:
“At the moment, experiments on Dark Matter do not point into a clear direction and, given that also the Large Hadron Collider at CERN has not found any signs of new physics yet, it may be time that we shift our paradigm towards alternative candidates for Dark Matter.”
“More and more particle physicists seem to think this way, and our proposal seems to be a serious competitor on the market.”
Dr. Bateman commented:
“Also from this point of view, the paper comprises a milestone on the history of our department: for the first time there has been a publication involving authors from all three groups in Physics and Astronomy, which shows how valuable it can be to cross boundaries and to look beyond one’s own field.”