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Is Earth Weighed Down By Dark Matter?
Nerval's Lobster writes "There may be a giant ring of dark matter invisibly encircling the Earth, increasing its mass and pulling much harder on orbiting satellites than anything invisible should pull, according to preliminary research from a scientist specializing the physics of GPS signaling and satellite engineering. The dark-matter belt around the Earth could represent the beginning of a radically new understanding of how dark matter works and how it affects the human universe, or it could be something perfectly valid but less exciting despite having been written up by New Scientist and spreading to the rest of the geek universe on the basis of a single oral presentation of preliminary research at a meeting of the American Geophysical Union in December. The presentation came from telecom- and GPS satellite expert Ben Harris, an assistant professor of mechanical and aerospace engineering at the University of Texas- Arlington, who based his conclusion on nine months' worth of data that could indicate Earth's gravity was pulling harder on its ring of geostationary GPS satellites than the accepted mass of the Earth would normally allow. Since planets can't gain weight over the holidays like the rest of us, Harris' conclusion was that something else was adding to the mass and gravitational power of Earth – something that would have to be pretty massive but almost completely undetectable, which would sound crazy if predominant theories about the composition of the universe didn't assume 80 percent of it was made up of invisible dark matter. Harris calculated that the increase in gravity could have come from dark matter, but would have had to be an unexpectedly thick collection of it – one ringing the earth in a band 120 miles thick and 45,000 miles wide. Making elaborate claims in oral presentations, without nailing down all the variables that could keep a set of results from being twisted into something more interesting than the truth is a red flag for any scientific presentation, let alone one making audacious claims about the way dark matter behaves or weight of the Earth, according to an exasperated counterargument from Matthew R. Francis, who earned a Ph.D. in physics and astronomy from Rutgers in 2005, held visiting and assistant professorships at several Northeastern universities and whose science writing has appeared in Ars Technica, The New Yorker, Nautilus, BBC Future and others including his own science blog at Galileo's Pendulum."
"Any headline which ends in a question mark can be answered by the word no."
It's standard not to write all the technicalities down in a scientific presentation. They usually last 30 to 45 minutes. There is no way, even for a scientific mind, to follow all the technicalities in 45 minutes when it took several months for the speaker to grasp the subject. Nobody in the audience would understand anything aside from the coauthors. Imagine your 20 hours advanced graduate course on physics condensed in 45 minutes with no simplification at all.
Disclosure: I'm a mathematician, not a physicist.
Let's wait for the proceeding or the full paper even though it's true we should be skeptical at this point.
The excess mass is an invasion force of cloaked ships.
> geostationary GPS satellites
A what now?
How was the accepted mass of earth measured? It should at least be consistent with large-scale behavior of our solar system. Now satellites see a harder pull from earth. The same pull should be seen from the sun. It would make sense to me if satellites saw a lower pull than sun, implying that some mass is at earth, but further out than the satellites. This way, not so much.
Is it drag induced by the outer parts (not perfectly vacuum) of the atmosphere?
There are two types of waves in water. Gravity Waves are the ones large enough to be held together by gravity, and capillary waves are held together by surface tension.
If the ring was perpendicular to the orbit of the satellite, it would have an additive effect to the earth's gravity in proportion to how far out of the plane of the ring the satellite is. If the satellite is in the plane of the ring, it would have no effect, as it would pull equally in all directions.
Yo mama!
A house divided against itself cannot stand.
You laugh at the power of Lord Cthulhu, the Great and Glorious One. You try to come up with "scientific" theories and fancy math but the truth will become apparent to you very soon.
Your screams of terror will be like the song of angels to me.
Dedicated Cthulhu Cultist since 4523 BC.
More information complexity creates more entropic potential energy.
http://en.wikipedia.org/wiki/Entropic_force
http://arxiv.org/abs/1207.4803
http://arxiv.org/abs/1001.0785
No, this research wasn't even published, it's a conference talk and a PR release. Go read the actual link, at the bottom of the long post, where Matthew Francis dishes it out. Here it is again in case you missed it:
http://galileospendulum.org/2014/01/02/no-dark-matter-is-not-messing-up-gps-measurements/
The later link from Dr Francis points out that the calculation has yet to be adjusted for the gravitational contributions of the Moon or Sun, and that it also doesn't make any relativistic corrections.
Those omissions puts the dark matter claim on par with "hey guys I haven't looked at it from far away but from right here it looks the Earth is pretty flat, yeah?"
The dark matter ring is merely a hypothesis. In my field (or science, engineering, or mathematics generally) we should follow the scientific method when reporting results at a meeting.
This guy was unfortunately presenting a hypothesis. He should have waited and tried to find more compelling evidence before presenting. New Scientist should be familiar enough with the scientific method to avoid publicizing a radical and unproven hypothesis.
Do NOT burn the goats - they're much better medium rare.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Unless they have peer reviewed papers - however can you trust them?
This statement is inaccurate: "...predominant theories about the composition of the universe didn't assume 80 percent of it was made up of invisible dark matter" 80% of the universe is made up of with Dark Matter and Dark Energy. The theories suggests the universe is made up of about 27% dark matter (not 80%) which is the subject of the article. Dark energy is a sort of negative gravity and is the force pushing galaxies apart faster and not relevant to this article's topic. Dark energy makes up most of the energy mass of the universe at 68%. Taken together they make up 80%, but affect the universe in completely different ways. http://en.wikipedia.org/wiki/Dark_energy
planets can't gain weight over the holidays like the rest of us
Actually they do. It's estimated that the Earth gains at least 164,000 kg per day from meteoric accretion. (Barker, J.L. and Anders, E. "Accretion rate of cosmic matter from iridium and osmium contents of deep-sea sediments." Geochimica et Cosmochimica Acta 32, 627-645 (1968))
You never really know how close to the edge you can go until you fall off.
No one has ever come up with a theory of Modified Gravity that can explain the data we have , but Dark Matter does. http://scienceblogs.com/startswithabang/2013/01/18/why-the-universe-needs-dark-matter-and-not-mond-in-one-graph/
I work with GPS a lot, and there are many MANY people around the world who spend their entire lives making sure that there are very precise measurements of where those satellites are and how good predictions of where they'll be going are. These orbit calculations take into account the pressure of light from the sun on the satellites along with several other very small effects, so if there was some large extra mass in a ring around the earth it would have been noticed many years ago. I think this guy needs to recheck his calculations.
Probably because dark matter doesn't interact with itself. When normal matter hits other normal matter it will be slowed down and eventually the stuff gets bigger and bigger. But dark matter doesnt hit anything, so even though it's gravitationally attracted to other dark matter particles they will fly right through each other. Therefore, i think, it won't be concentrated enough to form black holes.
...and he says to the farmer, I have found a solution to your problem: Imagine spherical cows in a vacuum, uniformly radiating milk in all directions...
I don't trust this whole "theory of gravity." Obviously, this "theory" is just an unknowable guess and therefore doesn't have the full consensus of "science". I say we need to teach the controversy that the reason we stay on the earth is because some supreme being wants us there. Birds and planes only work because when their wings are outstretched they make a holy cross.
Teach the controversy. Don't believe "theories".
Slow Down Cowboy! It's been 1 hour, 47 minutes since you last successfully posted a comment
A ring doesn't make any sense at all given existing ideas about dark matter. Rings and disks form as a result of friction gradually eliminating all rotation except along a single, common axis. Friction is exactly the sort of thing that makes matter non-dark. Where would a ring come from?
Socialism: a lie told by totalitarians and believed by fools.
C'mon, don't reinvent the wheel here. The theory of Intelligent Falling is the go-to parody, and is well-known enough to have a Wikipedia page. You might also find last-Thursdayism amusing.
Socialism: a lie told by totalitarians and believed by fools.
It's not direct detection of gravitational radiation, but observations of PSR B1913+16 have been considered convincing enough proof of the existence of gravitational waves as predicted by general relativity. It's a binary pulsar: a neutron star and another object that might be another neutron star or possibly a black hole, orbiting each other. They're spiraling in together, which could only happen if their orbits were losing energy due to gravitational radiation, and calculations based on their observations conform exactly with the predictions of general relativity for gravity waves. This was convincing enough to have won the 1993 Nobel Prize in Physics for the scientists involved in the discovery and analysis of the pulsar, Russell Alan Hulse and Joseph Hooton Taylor Jr.
Qu'on me donne six lignes écrites de la main du plus honnête homme, j'y trouverai de quoi le faire pendre.
The Moon and Sun would act to counter earths gravity, making it appear lighter not heavier.
If it were a more uniform cloud around the Earth, not a "ring" like Saturns, then it would be hard to find. The effects wouldn't be fully visible until one was beyond it. And I don't know whether any of the probes sent out looked back at Earth for any gravitational changes.
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