Scientists have made their most accurate measurement yet of the mass of a mysterious neutrino particle.
Neutrinos are sometimes known as ghost particles because they interact so weakly with other forms of matter.
Previous experiments had shown that neutrinos have a mass, but it was so tiny that it was very hard to measure.
Using data from the largest ever survey of galaxies, researchers put the mass of a neutrino at no greater than 0.28 electron volts.
This is less than a billionth of the mass of a single hydrogen atom, the scientists say.
Their nickname is fitting: a neutrino is capable of passing through a light-year (about six trillion miles) of lead without hitting a single atom.
The results are to be published in the journal Physical Review Letters and will be presented at the Weizmann UK conference at University College London (UCL) this week.
Back in 2002, we put an upper limit on the neutrino mass of 1.8 electron volts. So this is an improvement by a factor of six, said co-author Professor Ofer Lahav, from UCL.
It is remarkable that the distribution of galaxies on huge scales can tell us about the mass of the tiny neutrinos.
The work resulted from the PhD thesis of UCL scientist Shaun Thomas, working with Professor Lahav and Dr Filipe Abdalla.
Scientists used the largest ever 3D map of galaxies in the Universe, based on data gathered by the Sloan Digital Sky Survey.
Link: http://news.bbc.co.uk/1/hi/science_and_environment/10364160.stm
Neutrinos are sometimes known as ghost particles because they interact so weakly with other forms of matter.
Previous experiments had shown that neutrinos have a mass, but it was so tiny that it was very hard to measure.
Using data from the largest ever survey of galaxies, researchers put the mass of a neutrino at no greater than 0.28 electron volts.
This is less than a billionth of the mass of a single hydrogen atom, the scientists say.
Their nickname is fitting: a neutrino is capable of passing through a light-year (about six trillion miles) of lead without hitting a single atom.
The results are to be published in the journal Physical Review Letters and will be presented at the Weizmann UK conference at University College London (UCL) this week.
Back in 2002, we put an upper limit on the neutrino mass of 1.8 electron volts. So this is an improvement by a factor of six, said co-author Professor Ofer Lahav, from UCL.
It is remarkable that the distribution of galaxies on huge scales can tell us about the mass of the tiny neutrinos.
The work resulted from the PhD thesis of UCL scientist Shaun Thomas, working with Professor Lahav and Dr Filipe Abdalla.
Scientists used the largest ever 3D map of galaxies in the Universe, based on data gathered by the Sloan Digital Sky Survey.
Link: http://news.bbc.co.uk/1/hi/science_and_environment/10364160.stm
