Science

GPS satellites to aid in hunt for elusive dark matter

GPS satellites to aid in hunt ...
The orbiting GPS network could be used to detect waves of dark matter that pass between them and the surface of the Earth (Photo: University of Nevada)
The orbiting GPS network could be used to detect waves of dark matter that pass between them and the surface of the Earth (Photo: University of Nevada)
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The orbiting GPS network could be used to detect waves of dark matter that pass between them and the surface of the Earth (Photo: University of Nevada)
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The orbiting GPS network could be used to detect waves of dark matter that pass between them and the surface of the Earth (Photo: University of Nevada)

Dark matter is hypothesized to account for the large amounts of "missing" invisible matter in the universe where visible objects such as stars, gas, and dust are insufficient to explain the total gravitational effects observed. Despite repeated and verifiable observational evidence supporting this hypothesis, the existence of dark matter remains unproven. However, recent research has suggested that the hunt for this elusive substance may be aided by detecting any changes in the synchronization between the individual atomic clocks on-board satellites in the orbiting GPS network and receivers on the ground as waves of dark matter pass between them and the surface of the Earth.

Of the dark energy and dark matter that's believed to make up around 95 percent of all the missing energy and matter in the universe, some 68 percent is dark energy. The other 27 percent is commonly recognized to be dark matter, despite the fact that it is neither visible nor detectable through direct detection and measurement methods.

"Despite solid observational evidence for the existence of dark matter, its nature remains a mystery," said Professor Andrei Derevianko of the University of Nevada, Reno. "Some research programs in particle physics assume that dark matter is composed of heavy-particle-like matter. This assumption may not hold true, and significant interest exists for alternatives. Modern physics and cosmology fail dramatically in that they can only explain 5 percent of mass and energy in the universe in the form of ordinary matter, but the rest is a mystery."

GPS satellites carry several super-precise atomic clocks on board, the time measurements of which are used in combination with transmissions of their position to allow a ground-based receiver to measure the relative time delay between satellites to determine the receiver’s position in relation to the satellites and, therefore, the position of the receiver on the surface of the Earth.

Derevianko, and his associate Maxim Pospelov, of the University of Victoria, Canada, have posited the notion that these satellites could be used to search for dark matter because of the easy access to time signals from the large number of rubidium and cesium clocks contained in the network of GPS satellites encircling the Earth. As such, the researchers assert, these clocks should provide a sufficient array of easily-accessible comparisons to detect any shift in the synchronization of transmitted time signals affected by any passing dark matter field.

As a result, in analyzing clock data transmitted from the 31 GPS satellites currently in orbit, the researchers hope to use the network as a potent, cross-correlated instrument to hunt for the topological defects intrinsic to dark matter. It is hoped that this will be evidenced by initially synchronized clocks becoming de-synchronized.

"Our research pursues the idea that dark matter may be organized as a large gas-like collection of topological defects, or energy cracks," said Professor Derevianko. "We propose to detect the defects, the dark matter, as they sweep through us with a network of sensitive atomic clocks. The idea is, where the clocks go out of synchronization, we would know that dark matter, the topological defect, has passed by. In fact, we envision using the GPS constellation as the largest human-built dark-matter detector."

Using the Geodetic Lab also located at the University of Nevada, Professor Derevianko is analyzing the collected GPS data in collaboration with director of the lab, Professor Geoff Blewitt. The Geodetic Lab is the biggest center of GPS data processing in the world, and is capable of continuously processing information from around 12,000 stations located all around the Earth.

"We know the dark matter must be there, for example, because it is seen to bend light around galaxies, but we have no evidence as to what it might be made of," said Professor Blewitt. "One possibility is that the dark matter in this gas might not be made out of particles like normal matter, but of macroscopic imperfections in the fabric of space-time. The Earth sweeps through this gas as it orbits the galaxy ... As the dark matter blows by, it would occasionally cause clocks of the GPS system to go out of sync ... If the dark matter causes the clocks to go out of sync by more than a billionth of a second we should easily be able to detect such events."

The research was published in the journal Nature Physics.

Source: University of Nevada

5 comments
Robert Woodward
So how would this experiment remove confounding by variations in the Earth's gravity field caused by local variations in density and eccentricities in the satellites orbits? Isn't time dilation a function of both velocity and proximity to mass? Is the magnitude of the dark matter influence expected to be large enough to be noticeable in the presence of these co-factors, which will also be changing? There must be minor variations in altitude (which should vary gravity and velocity slightly), local variations in gravity due to variations in proximity to mass (Himalayas vs. mean sea level), which would influence the measurements? Shouldn't we assume a nearly stable geo-synchronous orbit at different altitudes above MSL (for example) would result in differing velocities of the instruments, therefore different dilations? To be accounted for by cross-corelation, wouldn't the effect measured have to be significantly larger than these components?
Slowburn
Funny how it takes dark matter and dark energy to make big bang cosmology work.
Bob Ehresman
This whole concept seems to presuppose that "Dark Matter" is somehow invisible, that we would not see it in if it was in our immediate neighborhood. All we know about "Dark Matter" is it doesnt glow, it has mass, and there must be a tremendously large amount of it to account for its mass effects. Pretty much anything that is not a star meets that criteria on an astronomical scale. You know, planets, moons, asteroids, KBOs, comets, black holes without accretion disks. Matter in states that dont support some form of nuclear fusion. If "mysterious invisible" "Dark Matter" were available in our immediate neighborhood in any small fraction of the quantities and concentrations that appear to be the norm throughout the universe, then the books would not balance on Kepler's equations. The planets, moons, asteroids, comets, and KBOs (not to mention GPS satellites) would not orbit the way we know that they do. It seems to me if "mysterious invisible" "Dark Matter" were "here" we would already know about it. Just sayin'. And it seems absurd that we would need something as sensitive to gravity as atomic clock noise to locally detect something that is supposed to be that pervasive and intense in the Universe.
Reid Barnes
How much have we really changed when it comes to science establishments? The existence of Dark Matter is hypothesized only in order to support the general theory of relativity, which turned out to be based on self-contradicting non-Euclidean geometry. Think back to the arrest of Galileo or back to Ptolemy and the epicycles. Did the general relativity, quantum road of twentieth century physics and cosmology become a religion masquerading as science? Here is an explanation about the self-contradicting non-Euclidean geometry, which you can understand even if your math education didn't exceed high school geometry: https://www.facebook.com/photo.php?fbid=792800204113180&set=a.132821853444355.21816.100001496224835&type=1&theater&notif_t=like
Bob
I have always thought that IF there was a "big bang" that it happened more like 50-100 billion years ago rather than the current 13.7 billion estimate. This would allow more time for expansion instead of explaining it with the made up inflation theory. It would also allow time for many generations of stars to form, of which, many would never go nova and simply be burnt out cinders by now. If only 20 % of the stars went nova in each generation and there have been at least seven generations of stars, that would leave only the small percentage visible that we now see along with a huge amount of cold mass that could only be detected by its gravitational effects. I also have doubts about many observations of the light that has traveled through clouds of gas(refractive index) and years of gravitational effects. Are we supposed to believe that a black hole can stop or bend light but billions of years of lesser gravity has no effect? I have no problem with theories but I do have a problem when they are presented as proven fact and more imaginary theories are postulated to prop them up. I also agree that there are too many variations in earth's density and gravity for this GPS clock theory to work. It wasn't that long ago that we were reading articles about the fact that the gravitational constant has yet to be determined beyond a few decimal places. When they show me their new computers and software, I often tell my engineer sons that we haven't been back to the moon since scientists and engineers stopped using slide rules. I also told them to look in a chemistry and physics handbook and see what years the values and constants were measured and updated. You will be amazed.