In 1912, Austrian physicist Victor Hess was using balloons to measure radiation levels in the Earth’s atmosphere. His innovative and meticulous work required him to travel with the balloon up to altitudes of 5.3 km, monitoring the measuring equipment and checking data.
The danger of traveling to such heights paid off for Hess. Unexpectedly, he found higher levels of radiation as the balloon rose and concluded that radiation was penetrating the atmosphere from outer space. The mysterious radiation was eventually called “cosmic rays”. One hundred years later, the nature of cosmic rays is well known; they are charged subatomic particles raining down from outer space. However, their origin is still a mystery. Two theories predominate: that cosmic rays come from massive black holes at the centers of active galaxies, or from the massive fireball thought to be produced during a gamma ray bursts (GRBs).
Using data from the IceCube Neutrino Observatory, astrophysicists Nathan Whitehorn and Pete Redl searched for neutrinos coming from the direction of known GRBs. And they found nothing.
Their result, appearing today in the journal Nature, challenges one of the two leading theories for the origin of the highest energy cosmic rays.
If gamma ray bursts are indeed the sources of cosmic rays, they must emit neutrinos. The model maintains that neutrinos are produced in the interactions of protons and photons coexisting in the GRB fireball.
Out of the sky and into the ice
Where Hess took his research to the skies, the IceCube collaboration headed in a different direction: deep into the ice.
The IceCube Neutrino Observatory is a high energy neutrino telescope built into the ice under the geographical South Pole. When a neutrino collides with a nucleus in the rock or ice inside or near the observatory, IceCube detects the faint blue light emitted by a secondary particle called a muon.
Neutrinos are of a ghostly nature. They can easily travel through people, walls or the entire planet Earth, rarely interacting with regular matter. IceCube is built on an enormous scale to compensate for the antisocial nature of neutrinos and catch their rare collisions. This ghostly nature allows neutrinos to travel the enormous distances from gamma ray bursts to the detector on the Earth.
One cubic kilometer of clear glacial ice, enough to fit the great pyramid of Giza 400 times, is instrumented with 5,160 optical sensors. IceCube was constructed using a hot-water drill. Eighty-six holes were drilled to 2.5 km deep and a string of sensors was deployed in each hole to complete the array. IceCube construction was finished in January 2011 by a collaboration of 250 physicists and engineers from the USA, Germany, Sweden, Belgium, Switzerland, Japan, New Zealand, Australia and Barbados.
From the National Science Foundation
The most luminous explosions in the universe are explored
Credit: Peter Rejcek, National Science Foundation
Analysis of data from the IceCube Neutrino Observatory, a massive detector deployed in deep ice at the U.S. Amundsen-Scott South Pole Station in Antarctica at the geographic South Pole, recently provided new insight into one of the most enduring mysteries in physics, the production of cosmic rays.
Cosmic rays were discovered 100 years ago, but only now are scientists homing in on how the highest energy cosmic rays are produced.
Cosmic rays are electrically charged particles, such as protons, that strike Earth from all directions with energies up to one hundred million times higher than those created in man-made accelerators.
The intense conditions needed to generate such energetic particles have focused physicists’ interest on two potential sources: the massive black holes at the centers of active galaxies and exploding fireballs observed by astronomers called gamma-ray bursts or GRBs.
“Although we have not discovered where cosmic rays come from, we have taken a major step towards ruling out one of the leading predictions,” said Francis Halzen, a physicist at the University of Wisconsin-Madison and the IceCube principal investigator.
In a paper published in the April 19 issue of the journal Nature, the IceCube collaboration describes a search for neutrinos emitted from 300 gamma ray bursts observed between May 2008 and April 2010 in coincidence with the SWIFT and Fermi satellites.
Surprisingly, the scientists found no neutrinos–a result that contradicts 15 years of predictions and challenges the theory that gamma-ray bursts produce the highest energy cosmic rays.
“The result of this neutrino search is significant because for the first time we have an instrument with sufficient sensitivity to open a new window on cosmic ray production and the interior processes of GRBs,” said Greg Sullivan, a physicist at the University of Maryland and IceCube spokesman.
“The unexpected absence of neutrinos from GRBs has forced a re-evaluation of the theory for production of cosmic rays and neutrinos in a GRB fireball and possibly the theory that high-energy cosmic rays are generated in fireballs,” he said.
IceCube observes neutrinos by detecting the faint blue light produced in neutrino interactions in ice. Neutrinos are of a ghostly nature; they can easily travel through people, walls, or the planet Earth. To compensate for the antisocial nature of neutrinos and detect their rare interactions, IceCube is built on an enormous scale. One cubic kilometer of glacial ice, enough to fit the great pyramid of Giza 400 times, is instrumented with 5,160 optical sensors embedded up to 2.5 kilometers deep in the ice.
GRBs, the universe’s most powerful explosions, are usually first observed by satellites using X-rays and/or gamma rays. GRBs are seen about once per day, and are so bright that they can be seen from half way across the visible Universe. The explosions usually last only a few seconds, and during this brief time they can outshine everything else in the universe.
The IceCube Neutrino Observatory was built under a National Science Foundation (NSF) Major Research Equipment and Facilities Construction grant, with assistance from partner funding agencies around the world.
NSF continues to support the project with a Maintenance and Operations grant co-funded by the Division of Antarctic Sciences and the Division of Physics. IceCube construction was finished in December 2010. A collaboration of 250 physicists and engineers from the Unites States, Germany, Sweden, Belgium, Switzerland, Japan, Canada, New Zealand, Australia and Barbados operate the observatory.
“Building the IceCube Neutrino Observatory at the geographic South Pole was a major effort made possible through many collaborating institutions and the U.S. Antarctic Program,” said Scott Borg, division director for Antarctic Sciences in NSF’s Office of Polar Programs. “The IceCube Collaboration has been busy analyzing data and the finding published in Nature is an early and significant, result. We are pleased with this achievement but we also anticipate many more important discoveries to follow.”
NSF, an independent U.S. government agency, manages the U.S. Antarctic Program, through which it coordinates all U.S. scientific research on the southernmost continent and aboard ships in the Southern Ocean as well as related logistics support.
Improved theoretical understanding and continued data collection from the complete and fully calibrated IceCube detector will help scientists better uncover the mystery of cosmic ray production.
For more information, visit the IceCube Neutrino Observatory Web site.
One hundred years later, the nature of cosmic rays is well known; they are charged subatomic particles raining down from outer space. However, their origin is still a mystery.
Although it is said in the article that the mystery is only about the ultra-high energy cosmic rays, there is a danger that people will misunderstand and think that the mystery extends to ordinary galactic cosmic rays. It does not.
Oh, how I love science.
/smiles happily!
Well at least the physistists are prepared to set aside that which does not work, admit it did not do so and find a new explination, which may be an old one recucled.
So reading that I took it to mean that they have ruled out Neutrinos or cosmic rays coming from GRB’s…… So they are now going to look to see whether cosmic rays and Neutrinos come from the centers of Galaxies.
Very interesting. There is nothing better than science based on observation and measurement. No assumptions divined from models with this research by the looks. How refreshing.
I wonder if they Astronomers are starting to entertain the idea of seeking insight into the architecture of the universe via Plasma principles rather than just gravitational models.
Interesting that the article should mention the Great Pyramid at Giza, known to have small shafts aligned on particular stars. If you got the right detector inside the structure at the terminus of one of those 8″ shafts, you could theoretically isolate the signal from the noise, and measure a certain elusive output of a star. A signal normally lost in the noise from other sources.
Just a passing thought.
I love science too. Especially when a huge experiment is done to try to substantiate a theory and what we get is a nice succinct honest result like: “I don’t know.” That is when you know you are talking to an honest hard working scientist.
Guess that is why I became an engineer. A good formula based on empirical data will do. I don’t need to know why it works, just that it works.
Wayne;
It’s better than that. The conclusion is, “We thought we might know, but now know we didn’t know. What now?” >;-p
Totally off topic, but can’t help noticing that the illustration of the earth at top of the article depicts cosmic rays with an appearance similar to the pattern of sparks and forking made while grinding ferrous metals. Perhaps the artist works with steel and torch, as well as brush and paint to manifest his (her) talent.
The disproof that GRBs cause cosmic rays is based on assumptions in the model of how many neutrinos GRB’s produce, the null detector result could be explained if the number of neutrinos is far less than expected/assumed. Perhaps worth revisiting GRB theory?
IceCube studying neutrinos…it’s nice to see a rapper really contribute something to society.
This is so interesting please keep us posted on further discoveries.
Real scientists doing real science and happy to say we don’t know but we want to find out, not it is settled and the readings are wrong.
James Bull
Tenuk;
Yes, that seems to be rather the crux. GRB speculations and hypotheses are hardly worthy of being called “theory”. SWAGs, one and all!
rbateman says:
April 20, 2012 at 10:14 pm
“Interesting that the article should mention the Great Pyramid at Giza, known to have small shafts aligned on particular stars. If you got the right detector inside the structure at the terminus of one of those 8″ shafts, you could theoretically isolate the signal from the noise, and measure a certain elusive output of a star. A signal normally lost in the noise from other sources.”
Chris Dunn entertains the idea that the shafts are waveguides for microwaves emitted by hydrogen. Google “Giza power plant”.
Looks to me like a perfect illustration of why science is never “settled”.
An old favorite:
But if GRB is the consensus then the experiment must be wrong! Works in climate science /sarc
IceCube experiment at the South Pole. Who knew? Thanks. I recall a similar experiment with photo detectors trained on a salt mine filled with water, looking for the same thing, a flash of light. This flash would have been from electron decay not a neutrino/matter collision.
If both these phenomenon cause a flash of light, how do we know if it’s one cause or the other?
Phenomenon : singular: Phenomena : plural.
Also, It’s good to see solid science coming from Barbados. 🙂
Researchers having difficulty finding “dark matter” in the local vicinity of the sun:
http://www.universetoday.com/94680/the-case-of-the-missing-dark-matter/
Also some comments on this post’s topic:
http://www.universetoday.com/94703/cosmic-rays-they-arent-what-we-thought-they-were/
Well duh! We live in a snap, crackle and pop universe. “big bang” is an anthropogenic conceit. Black holes suck in matter and eject energy that condenses into increasingly stable matter starting with cosmic rays. Red shift simply tells you the age of a galaxy or star, not it’s speed.
( if you’re going to troll, at least troll astrophysicists)
Trolling aside, IceCube is a very elegant engineering solution. A cubic km of pure ice that you don’t have to build or pay to keep frozen.
It is so nice to see real science. Very refreshing after the last few “peer-reviewed” papers posted here at WUWT.
Too bad CAGW was political from the get go. I want to cry when I think of all the billions wasted on psuedo-science and the black eye that real science has taken as a result.
I wonder how big constraints did they put on time difference. After all, GRBs happen on a bit different distance scales than SN1987A and neutrinos are expected to have nonzero mass…
I’m sure there is a reasonable explanation for this but I’m stumped.
The post says:
“IceCube construction was finished in January 2011 …”
and then:
“In a paper published in the April 19 issue of the journal Nature, the IceCube collaboration describes a search for neutrinos emitted from 300 gamma ray bursts observed between May 2008 and April 2010 in coincidence with the SWIFT and Fermi satellites.”
How would you detect neutrinos from events observed >6 months prior to the instrument being completed?
Luther Wu says:
April 21, 2012 at 12:41 am
The diagram is correct. Cosmic rays are also composed of charged particles. This component of cosmic rays can collide with an air molecule and produce a shower of particles. This can happen more than once, forming a cascade of particles.
Time out. I don’t understand how this experiment can prove what they’re saying it proves. The gamma rays travel at the speed of light. Neutrinos have mass (albeit tiny) and thus do not. They may be super close to c, but not exactly. And, more importantly, they presumably do not all travel at exactly the same speed.
Thus, over the vast distances involved they would lose synchrony with the gamma ray bursts and with each other.
Right?
French ANTARES detector was deployed in 2008 at 2475 m depth, 40 km off La-Seine-Sur-Mer, French Mediterranean cost, close to Toulon. From this position ANTARES can observe the Northern Sky, complementing neutrino telescopes at South Pole.
More technical details and preliminary results here:
http://iopscience.iop.org/1742-6596/173/1/012024/pdf/1742-6596_173_1_012024.pdf
Wayne Delbeke says:
April 20, 2012 at 10:28 pm
Guess that is why I became an engineer. A good formula based on empirical data will do. I don’t need to know why it works, just that it works.
“Why” something works is rarely the full story, because our information is always limited. You don’t need to know “why” gravity works to build very useful predictions about its effects.
The reality is that human history doesn’t operate in that fashion. We learned to predict the seasons thousands of years before we learned “why” we had seasons.
First we observe, then we look for a formula that predicts the observation based on something we can already predict. If the prediction proves reliable, then we know where to start looking for the “why”.
Unfortunately, modern science has become all about “why” as the starting point in building a theory. The argument being that if you can’t find the “why” then your formula can’t predict. This has led us to the situation with climate science, where the ‘why” is driving the science, before it demonstrated any skill at prediction.
It has also led to the situations where climate predictions with demonstrated skill have been rejected simply because we have not yet discovered the “why”. Even on this site. By that argument, Newton and Einstein should be rejected, because they couldn’t answer “why”.
Why does Newton’s gravity act instantaneously at infinite distance? Why does Einstein’s gravity curve space when space is empty? There is nothing to curve if space itself is empty. We end up back at the argument for an “ether” if we ask “why”.
We know that gravity, resonance and the shape of the ocean basins causes the tides, but that isn’t how we calculate them. Instead, we calculate the tides in a manner that is almost identical to calculating a horoscope. However, if we apply the same technique to climate prediction, and it demonstrates skill, it is rejected as Astrology.
The cosmic rays are particles traveling slightly below light speed. Neutrinos may travel slightly different speed than the cosmic rays. The result is that if the detection of a GRB is used as a trigger to look for Neutrinos, it may not see it due to different arrival times, which for the huge distances traveled, may be a very long time. In addition, cosmic rays may be deflected by glactic magnetic fields, to appear to come from different directions than the non-deflected Nutrinos. The experiment proves nothing.
beng says:
April 21, 2012 at 6:12 am
Researchers having difficulty finding “dark matter” in the local vicinity of the sun:
http://www.universetoday.com/94680/the-case-of-the-missing-dark-matter/
“Dark” is of course not referring to matter that simply doesn’t shine, such as a cold rock. Dark refers to matter that is completely invisible to all electromagnetic radiation, but necessary if the standard model of the cosmos is correct.
Dark matter is a consequence of assuming that red shift results from motion, which is the basis for our standard model. However, there are other well known mechanisms that causes red shift. If you replace motion with one of the other mechanisms, the standard model falls apart and with it dark matter and dark energy.
Tenuk says:
April 21, 2012 at 1:00 am
“The disproof that GRBs cause cosmic rays is based on assumptions in the model of how many neutrinos GRB’s produce, the null detector result could be explained if the number of neutrinos is far less than expected/assumed. Perhaps worth revisiting GRB theory?”
Great post. In the “old days” (1960’s) we were taught that neutrinos had no mass, no charge, only a “spin”. More recently I have seen information that indicates that they do have a mass but they come in three different “flavors or colors” and transmute from one to the other. Given the potential difference in arrival time from something as heavy as a proton and the different types of neutrinos, I am not sure what this data might mean of if it has any meaning at all depending upon how it was collected and analysed. Very interesting anyway and my personal favorite type of article on this site where no science is “settled”.
Several posters have pointed out that neutrinos do not travel at the speed of light. Over the distances involved – billions of light years – I would assume the difference in arrival time to be significant – probably years.
Another criticism, is how can they detect the direction of travel of the neutrinos? It’s not like looking for the source of EM radiation. You simply point the device at the source. If the device is not pointed at the source, the energy is not collected. But neutrinos are different. You detect them using a huge cube of matter and wait for the collision, revealed by a photon of light. But the neutrinos could have come from any direction, and still give an identical result. How do they know?
Fred berple
“Dark refers to matter that is completely invisible to all electromagnetic radiation, but necessary if the standard model of the cosmos is correct.
” Dark matter is a consequence of assuming that red shift results from motion, which is the basis for our standard model.”
I assume you are refering to the rotational speeds of galaxies, in which it has been found that the orbits of stars at the edge of galaxies are much faster than should occur with the known mass contained within them. Galaxies appear to rotate such that all stars have the same angular velocity, as if the galaxy was a solid object. You suggest that these speeds are determined by measuring red shift, and that the red shift might be caused by other factors: “If you replace motion with one of the other mechanisms, the standard model falls apart and with it dark matter and dark energy.”
However, it is not just the red shifts that indicate that galaxies appear to be rotating as if they were solid. They must in fact be rotating at that speed in order to maintain their structural integrity. Think about it. We observe galaxies with highly organised spiral structures. If stars rotated more slowly the further they orbit from the centre, then the whole galaxy would become a highly unorganised structure.
ferd berple says:
April 21, 2012 at 8:30 am
assuming that red shift results from motion, which is the basis for our standard model.
Not at all. There is no motion involved. The galaxies are not moving [except for small local velocities caused by gravitational influence from nearby galaxies].
There are several important facts not commented on yet. First the ‘penetration’ through “people, walls or the planet Earth” and have energies up to “100 million times higher than man made accelerators”. The inner most Earth core appears to be a ~900 mile cubic Iron crystal [http://news.illinois.edu/news/08/0310core.html] that may well defect or in fact be CAUSED to rotate faster than the mantle & crust [Earth’s Core Rotates Faster than Crust, Live Science, 25Aug2005] due to the deflection vector. See “No Loophole for Your Soul” on this possible cause for Earth’s magnetic filed. We have NO way to measure an incoming and similtaneous outgoing neutrino so the “passing through Earth” hypothesis is below reasoned speculation. If human particle accelerators can cause nuclear fission, it seems plausible that 100 million times this energy may well trigger reactions as well. Our greatest limit on knowledge is what we “know”. Question Authority.
Faux Science Slayer says:
April 21, 2012 at 1:48 pm
We have NO way to measure an incoming and similtaneous outgoing neutrino so the “passing through Earth” hypothesis is below reasoned speculation.
We can easily measure the direction of a moving neutrino: “”Ring-imaging” detectors take advantage of the Cherenkov light produced by charged particles moving through a medium faster than the speed of light in that medium. In these detectors, a large volume of clear material (e.g., water or ice) is surrounded by light-sensitive photomultiplier tubes. A charged lepton produced with sufficient energy typically travels faster than the speed of light in the detector medium (though slower than the speed of light in a vacuum). This generates an “optical shockwave” known as Cherenkov radiation which can be detected by the photomultiplier tubes. The result is a characteristic ring-like pattern of activity on the array of photomultiplier tubes. This pattern can be used to infer direction, energy, and (sometimes) flavor information about the incident neutrino”.
And about your ‘iron crystal’: the average neutrino can pass through a light year of lead without being affected.
Vince Causey says:
April 21, 2012 at 11:24 am
Several posters have pointed out that neutrinos do not travel at the speed of light. Over the distances involved – billions of light years – I would assume the difference in arrival time to be significant – probably years.
The experiments claiming that neutrinos travel slower than the speed of light have been found to be flawed: a cable was not screwed in properly. “Approximately three hours before the visible light from Supernova 1987A reached the Earth, a burst of neutrinos was observed at three separate neutrino observatories. This is likely due to neutrino emission (which occurs simultaneously with core collapse) preceding the emission of visible light (which occurs only after the shock wave reaches the stellar surface)”
Leif Svalgaard says:
Leif,
First, the claim was that Neutrinos traveled FASTER, not slower than light speed. This was found to be an error. The best data shows they travel essentially if not exactly at the speed of light. The problem I an other have stated is not that Neutrinos travel slower than the speed of light, it is the protons and other cosmic ray particles that travel slower. Thus arrival time can be greatly different. Also Neutrinos may not be deflected, but cosmic rays (ions) are deflected by magnetic fields. Passing several billion light years (probably close to some glactic magnetic fields) gives a lot of time for differences to establish.
Thanks Leif for the info of neutrino speed. I suppose it’s possible that over 168,000 light years the neutrinos from Supernova 1987A might have only lost an hour or so but, “It sounds like c to me.” That’s super interesting.
Leonard Weinstein says:
April 21, 2012 at 6:46 pm
The problem I an other have stated is not that Neutrinos travel slower than the speed of light, it is the protons and other cosmic ray particles that travel slower.
Of course, particles travel slower than the speed of light. That is not a ‘problem’. The ICE CUBE experiment is not concerned about protons or cosmic rays, but with gamma rays and neutrinos.
Frederick Michael says:
April 21, 2012 at 7:20 pm
Thanks Leif for the info of neutrino speed. I suppose it’s possible that over 168,000 light years the neutrinos from Supernova 1987A might have only lost an hour or so but, “It sounds like c to me.” That’s super interesting.
They have not lost anything. That the visible light arrived a few hours later is because the shock wave took some hours to reach the surface where we could see the effects, while the neutrinos pass through the star in seconds.
Leif Svalaard says
This pattern can be used to infer direction, energy, and (sometimes) flavor information about the incident neutrin
—————
Neutrinos are not charged so the explanation is either wrong or incomplete.
Also since Cerenkov radiation is an energy loss mechanism and the cross-section of interaction for neutrinos is small you will not see any Cerenov radiation.
I think the some of the questions raised about the speed of neutrinos and how they are detected is valid but I have not seen a valid answer yet.
Don’t know the answer myself.
Iit looks like the article is describing a variation of the well known coincidence detection techniques that require a trigger (detection of a cosmic ray) followed by detection of a possibly related event (a neutrino). This is a statistics-based detection method.
As to the speed of neutrinos I have never heard of neutinos traveling at less than the speed of light. So when neutrinos are said to have mass it sounds like a paradox. Maybe some kind of quantum weirdness is invoked to resolve this.
Leif Svalgaard says:
April 21, 2012 at 8:51 pm
They have not lost anything.
Haste is waste. I should have said that neutrinos don’t travel faster than light as pointed out up-thread as a also implied by my comment about the neutrinos arriving before the light. Apart from that, the rest of what I said is OK.
LazTeenager says:
April 21, 2012 at 9:16 pm
“This pattern can be used to infer direction, energy, and (sometimes) flavor information about the incident neutrino” Neutrinos are not charged so the explanation is either wrong or incomplete.
All simplified explanations are incomplete [a full explanation is given in the 171 pages of http://arxiv.org/pdf/0910.2555.pdf . The IceCube detector detects Cherenkov light from the charged secondary particles resulting from neutrino-nucleon interactions.
And the expected coincidence were not between cosmic rays and neutrinos, but from the timing and direction coincidence of neutrinos with gamma ray bursts measured by other detectors. Unfortunately none were detected.
Vince Causey says:
Another criticism, is how can they detect the direction of travel of the neutrinos? It’s not like looking for the source of EM radiation. You simply point the device at the source. If the device is not pointed at the source, the energy is not collected. But neutrinos are different. You detect them using a huge cube of matter and wait for the collision, revealed by a photon of light. But the neutrinos could have come from any direction, and still give an identical result. How do they know?
Also there are many sources of neutrinos, including the nuclear fusion going on in the majority of stars.
A cube would give you some directionality since the shortest distance to travel through it is perpendicular to each face and the longest distance is through diagonally opposite vertices.
A long, thin, cone or cylinder might make a more directional detector. Though you’d still have the problem of working out which of two possible directions the neutrinos were coming from.
Leif Svalgaard says:
April 21, 2012 at 8:51 pm
They have not lost anything. That the visible light arrived a few hours later is because the shock wave took some hours to reach the surface where we could see the effects, while the neutrinos pass through the star in seconds.
Just to clarify what I meant — I was not saying that the few hour time difference was due to neutrinos traveleing less than light speed. The time difference is in the wrong direction for that.
What I meant is that if the shock wave takes, say, four hours to reach the surface of the star but we see the light only 3 hours later than the neutrinos, that would imply an hour of delay for the nutrinos going slightly less than c.
Thus, while I’m convinced the neutrinos travel at exactly c, I wouldn’t say I’m certain. Do we really know exactly how long that shock wave takes to reach the surface?
“Leif Svalgaard says:
April 21, 2012 at 1:32 pm
ferd berple says:
April 21, 2012 at 8:30 am
assuming that red shift results from motion, which is the basis for our standard model.
Not at all. There is no motion involved. The galaxies are not moving [except for small local velocities caused by gravitational influence from nearby galaxies].
”
IS this correct ?
I thought that the big buzz was that EVERYTHING was receding into the distance at accelerating speeds, and though this will not be a problem for a billion years or more, that it was a major indicator of the purposelessness of everything ( Not that I buy that part)
Seriously, not moving except for local ?
jimash1
“I thought that the big buzz was that EVERYTHING was receding into the distance at accelerating speeds,”
No, not everything. Galaxies are gravitationally bound into clusters, and they are not receding with respect to each other, even though the space between them is expanding. At a larger scale, clusters are grouped into super clusters, which are also gravitationally bound and clusters are not receding within super clusters. It’s when you go to the next higher level – super clusters in relation to other super clusters. They are receding from each other, at speeds that increase linearly with the distance between them.
The physical explanation is that space is expanding everywhere, but the rate of expansion on small scales is quite tiny. This is the reason why gravity predominates on smaller scales. Since each length of space is expanding at the same rate, then it follows that the more such lengths of space you consider together, the higher the expansion speed between two points at each end. At vast distances, the expansion speed between two points at either extreme of that distance becomes large, and at a distance of 13.7 billion light years, approaches light speed.
“The physical explanation is that space is expanding everywhere”
Thank you Vince for explaining that to me.
So I get it they aren’t moving ( except like Andromeda coming this way gravitationally) so much IN space as that the huge amount of space between is expanding and carrying the various superclusters yonder.
Seriously thanks.
Frederick Michael says:
April 22, 2012 at 9:54 am
I was not saying that the few hour time difference was due to neutrinos traveleing less than light speed
The ‘less than’ was a boo-boo on my part [see comments up-thread. I meant ‘faster than’.
Vince Causey says:
April 22, 2012 at 12:03 pm
At vast distances, the expansion speed between two points at either extreme of that distance becomes large, and at a distance of 13.7 billion light years, approaches light speed.
Actually vastly exceeds light speed, but it is hard to make such a comparison because the concept of speed loses its meaning out there. The correct metric to use is the so-called z-parameter, http://en.wikipedia.org/wiki/Redshift#Expansion_of_space
That is a good wikipage there Dr Svalgaard.
Ya know,
I did know that space was expanding etc.
But I had not conceptualized that things aren’t going anywhere but that everywhere is going with them.
And now I understand a little more how the redshift is a cosmological effect and not really
just a speed related doppler shift.
Thanks.
Last I heard it is suspected that neutrinos have a small but non-zero mass which means according to special relativity (vacuum etc.) cannot reach the speed of light as it would take infinite energy to accelerate them to C. I say suspected as I am not aware of anyone coming up with an actual number for that mass. But given this and the fact that they and the photons from the GRB are not in a vacuum, which also complicates the issue of arrival time, who can say what about these results? It would seem to me that neutrinos are quite speculative in nature in that they supposedly transmute form one type to another, have undefined mass & no known charge which makes this entire “insight” also quite speculative.
Also please note that the Big Bang and resultant expansion of the universe are THEORIES requiring an unfound, unproven force, or some unknown property of the 4 known forces causing the expansion. And the entire presently most accepted THEORY of the cosmos also requires the existence of “dark matter” making up the bulk of the universe that we can presently see. If we knew the mass of the neutrino and the quantity of same perhaps we would have part of the answer, err if it reaaly does have a mass. Many here sound a slight bit smug in their “answers” to questions for which we have only theories. We must remember the difference between proven facts and theory or we join the AGW crowd.