Astronomers use galaxies to reckon a subatomic particles mass.
Astronomers surveyed regions outside our Galaxy to estimate neutrinos mass.
© R. Smith
The spread of galaxies reveals the smoothing effect of invisible neutrinos.
By mapping hundreds of thousands of galaxies, astronomers have estimated the mass of the neutrino. They have also calculated the contribution that this mysterious subatomic particle makes to the total mass of the Universe.
The neutrino weighs no more than one-billionth of the mass of a hydrogen atom, Ofer Lahav of the University of Cambridge told the annual UK National Astronomy Meeting in Bristol today. Yet despite being so small, neutrinos could account for a maximum of about 20% of the mass of the entire Universe.
Small but influential
Neutrinos are unimaginably tiny, carry no electrical charge and can pass through planets unperturbed. But their abundance makes them potentially major players in the Universe.
For a long time it was thought that neutrinos had no mass at all. Recent astronomical observations have suggested that they do, but working out the exact figure "is probably one of the hardest questions [in physics]", says theoretical physicist Stephen King of the University of Southampton, UK.
The new estimate "sounds like a reasonable number", King adds. It broadly agrees with, although does not confirm, other figures produced from studies of radioactive decay earlier this year.
One-billionth of a hydrogen atom is towards the lower end of current estimates. If this value stands up, it shows that neutrinos do not exert enough gravitational tug to have much influence over the evolution of the visible Universe, says King. "Its saying that neutrinos cant play an important part in galaxy formation."
Lahav and his colleagues conclusion is based on gauging the lumpiness of the Universe. Tiny wrinkles in the Big Bang led to matter forming into gigantic clumps - galaxies, and clusters of galaxies - as the Universe aged.
Yet only about 5% the Universes mass is in a visible form. The rest is in a variety of substances known as dark matter, of which neutrinos are one component.
Dark matter is betrayed by its influence on what we can see. Neutrinos, which whizz through space at close to the speed of light, smooth the Universe out by redistributing mass. The heavier neutrinos are, the less clumping we should see in todays Universe.
Lahavs team used a three-dimensional map of 160,000 galaxies that they constructed as part of an Anglo-Australian team. They worked out the mass of the neutrino that best fitted the spread of galaxies they saw.
JOHN WHITFIELD | © Nature News Service
MEMS chips get metatlenses
21.02.2018 | American Institute of Physics
International team publishes roadmap to enhance radioresistance for space colonization
21.02.2018 | Biogerontology Research Foundation
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
21.02.2018 | Life Sciences
21.02.2018 | Life Sciences
21.02.2018 | Materials Sciences