Massive neutrinos solve a cosmological conundrum

Feb 10, 2014 by Emma Rayner
Massive neutrinos solve a cosmological conundrum

(Phys.org) —Scientists have solved a major problem with the current standard model of cosmology by combining results from the Planck spacecraft and measurements of gravitational lensing to deduce the mass of ghostly sub-atomic particles called neutrinos.

The team, from the universities of Nottingham and Manchester, used observations of the Big Bang and the curvature of space-time to accurately measure the of these elementary particles for the first time.

The recent Planck spacecraft observations of the Cosmic Microwave Background (CMB) – the fading glow of the Big Bang – highlighted a discrepancy between these cosmological results and the predictions from other types of observations.

Massive or massless?

The CMB is the oldest light in the Universe, and its study has allowed scientists to accurately measure cosmological parameters, such as the amount of matter in the Universe and its age. But an inconsistency arises when large-scale structures of the Universe, such as the distribution of galaxies, are observed.

Dr Adam Moss, from The University of Nottingham's School of Physics and Astronomy said: "We observe fewer galaxy clusters than we would expect from the Planck results and there is a weaker signal from of galaxies than the CMB would suggest.

"A possible way of resolving this discrepancy is for to have mass. The effect of these massive neutrinos would be to suppress the growth of dense structures that lead to the formation of clusters of galaxies."

Neutrinos interact very weakly with matter and so are extremely hard to study. They were originally thought to be massless but have shown that neutrinos do indeed have mass and that there are several types, known as flavours by particle physicists. The sum of the masses of these different types has previously been suggested to lie above 0.06 eV (much less than a billionth of the mass of a proton).

'Flavours' of neutrinos

Dr Moss and Professor Richard Battye from The University of Manchester have combined the data from Planck with gravitational lensing observations in which images of galaxies are warped by the curvature of space-time. They conclude that the current discrepancies can be resolved if massive neutrinos are included in the standard cosmological model. They estimate that the sum of masses of neutrinos is 0.320 +/- 0.081 eV (assuming active neutrinos with three flavours).

Professor Battye added: "If this result is borne out by further analysis, it not only adds significantly to our understanding of the sub-atomic world studied by particle physicists, but it would also be an important extension to the standard model of cosmology which has been developed over the last decade."

The paper is published in Physical Review Letters and has been selected as an Editor's choice. 

Explore further: Swirls in remnants of big bang may hold clues to universe's infancy

More information: "Evidence for Massive Neutrinos from Cosmic Microwave Background and Lensing Observations." Richard A. Battye, Adam Moss Phys. Rev. Lett. 112, 051303 (2014) [5 pages] DOI: 10.1103/PhysRevLett.112.051303

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indio007
1.4 / 5 (19) Feb 10, 2014
Torbjorn_Larsson_OM
4.7 / 5 (18) Feb 10, 2014
@indio007: The Cosmic Microwave Background, predicted for about a century and measured since about 1/2 century. [ http://en.wikiped...ckground ]
shavera
4.4 / 5 (10) Feb 10, 2014
The more interesting (to me) proposal in the paper is the discussion of limits on a sterile neutrino species, with effective mass 0.450 +/- 0.124 eV and an additional effective degree of freedom of .45+/-.23 (ie, neutrinos oscillate as if they can oscillate to 3.046 types of neutrino + 0.45 of another kind of neutrino that does not interact via the weak force).
rkolter
3.5 / 5 (2) Feb 10, 2014
Is there evidence of neutrinos beyond the three we know about? Could we generate and detect massive sterile neutrinos?
AeroSR71
4.6 / 5 (11) Feb 10, 2014
indio, that is some crackpot nonsense you've linked there
Sanescience
3.4 / 5 (5) Feb 10, 2014
Lets hope that we don't attract the attention of the Photino Birds with our contraptions ;-)
Mimath224
5 / 5 (1) Feb 10, 2014
The quote '...If this result is borne out by further analysis, it not only adds significantly to our understanding of the sub-atomic world studied by particle physicists...' could mean that they are looking for others to confirm/deny. But wasn't these studies made earlier in the search for HDM where massive neutrinos were considered (and which observation apparently shows very little HDM exists)?
axemaster
5 / 5 (4) Feb 11, 2014
Lets hope that we don't attract the attention of the Photino Birds with our contraptions ;-)

Don't worry, the Xeelee are fighting for baryonic life everywhere!
Lex Talonis
3 / 5 (4) Feb 11, 2014
I have ancient cosmic background radiation in my microwave oven.

It's a 1984 model.
matt_roadhouse
1.5 / 5 (4) Feb 11, 2014
There was a time, when speaking against the accepted theories, one would be subjected to censorship, ridicule and excommunication.

There is no limit to man's hubris.

I welcome the links posted to test what one thinks as 'truths'
Nestle
4.8 / 5 (4) Feb 11, 2014
I have ancient cosmic background radiation in my microwave oven
CMB is 100 times higher frequency than microwave oven radiation. The shorter wavelength probably means it is less penetrating so I would imagine that most common liquid or solid material would block it. Your skin probably stops all but a tiny fraction of it - not to say about chasis of your owen. Also, the vast majority of it is blocked by our atmosphere anyway (this is why we have satellites to observe the CMB). Also, the cosmic background radiation is always up to date.
indio007
1 / 5 (9) Feb 11, 2014
indio, that is some crackpot nonsense you've linked there


The only thing you proved is that you didn't read the article or the papers it cites.

Scientific fraud is rampant. Sorry to bust your bubble.

They allowed a faulty instrument to launch and then covered it up by fudging data. I guess that's just unthinkable.

Aliensarethere
4.7 / 5 (3) Feb 12, 2014
Neutrinos must have mass:

They have been seen to fluctuate between different types of neutrinos in flight. If
they were massless, they are forced to travel at the speed of light, but then
according to special relativity, time is frozen as seen by an external observer.

With frozen time, the neutrino cannot change from one species to another, therefore
it has mass.
sirchick
5 / 5 (3) Feb 13, 2014
indio, that is some crackpot nonsense you've linked there


The only thing you proved is that you didn't read the article or the papers it cites.

Scientific fraud is rampant. Sorry to bust your bubble.

They allowed a faulty instrument to launch and then covered it up by fudging data. I guess that's just unthinkable.



What possible evidence do you have to suggest it was faulty?
Maggnus
5 / 5 (3) Feb 14, 2014
What possible evidence do you have to suggest it was faulty?
Just a guess, but it's probably along the lines of "it measured something my theory says can't be out there".
antialias_physorg
4.7 / 5 (3) Feb 14, 2014
With frozen time, the neutrino cannot change from one species to another

The E and M components of a photon seem to do quite well fluctuating - even though time is frozen from its perspective.
axemaster
5 / 5 (3) Feb 15, 2014
In order for an object such as a neutrino to change types, it must be able to send waves parallel to its direction of motion. Photons travel at the speed of light, and thus consist only of waves orthogonal to the direction of motion. Since neutrinos are observed to changes types, they must travel at less than the speed of light, and therefore they must have a nonzero rest mass.
Fleetfoot
5 / 5 (4) Feb 16, 2014
indio, that is some crackpot nonsense you've linked there


The only thing you proved is that you didn't read the article or the papers it cites.

Scientific fraud is rampant. Sorry to bust your bubble.

They allowed a faulty instrument to launch and then covered it up by fudging data. I guess that's just unthinkable.



What possible evidence do you have to suggest it was faulty?


The site quoted is that of Stephen Crothers. The instrument had no problems, he imagines that because water absorbs microwaves, it also emits them and that is what COBE measured. Complete rubbish of course.
barakn
5 / 5 (3) Feb 16, 2014
What CMB?

http://www.princi...ury.html

Crothers appears to be ignorant of the fact that the part of the microwave spectrum in question bears numerous water and oxygen absorption lines as seen from a satellite (yeah, absorption, not emission, which is what one would expect from an atmosphere that decreases in temperature with altitude - at least the part that actually contains water vapor). Were the CMB contaminated with such a signal, the absorption lines would have made it obvious. That Crothers was too lazy or too devious to look for this data is typical of his particular brand of intellectual dishonesty. http://www.boulde...ed_1.png
Remigiusz
1 / 5 (1) Feb 17, 2014
Dear Scientists ! This is like Comedy Club.!! 1st- You do not know what You measure as masses. ? Yes I know. 2nd. If You think You can change mass in energy, You are wrong. You are wrong about Big Bang and what I know 80% do not believe that Big Bang was a beginning of Universe. You are looking for dark matter inside our Planet. Yes ! there are not lamps there.
To inform You, "dark matter" and "dark energy" is the same matter and energy You can see. What You need is to understand Time-Space and electro-magnetic waves. In Universe there is no minus charge or plus. There is charge and we may agree that they are particles / neutrinos, neutrons../ with charge but something neutralize it. To understand it You need to know what we measure as mass. Higgs with his Standard Model and God Particle is wrong. Yes I know what is the base particle ! Quantum Time-Space is the space in which all particles have been build by combinations of base particles. All is in front of Your nose.