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"New Natural Law of the Cosmos" --Challenges Current Theories of Dark Matter

 

NGC_6946

 

A team led by Case Western Reserve University researchers has found a significant new relationship in spiral and irregular galaxies: the acceleration observed in rotation curves tightly correlates with the gravitational acceleration expected from the visible mass only. In a paper accepted for publication by the journal Physical Review Letters and posted on the preprint website arXiv, the astronomers argue that the relation they've found is tantamount to a new natural law.

"The natural inference is that this law stems from a universal force such as a modification of gravity like MOND, the hypothesis of Modified Newtonian Dynamics proposed by Israeli physicist Moti Milgrom," says Stacy McGaugh, chair of the Department of Astronomy at Case Western Reserve. "But it could also be something in the nature of dark matter like the superfluid dark matter proposed by Justin Khoury," McGaugh said. "Most importantly, whatever theory you want to build has to reproduce this."

"The standard model of cosmology is remarkably successful at explaining just about everything we observe in the universe," said Arthur Kosowsky, professor of physics and astronomy at the University of Pittsburgh, who was not involved but reviewed the research."But if there is a single observation which keeps me awake at night worrying that we might have something essentially wrong, this is it."

In spiral galaxies such as NGC 6946 (shown above), researchers found that a 1-to-1 relationship between the distribution of stars plus gas and the acceleration caused by gravity exists. In the late 1970s, astronomers Vera Rubin and Albert Bosma independently found that spiral galaxies rotate at a nearly constant speed: the velocity of stars and gas inside a galaxy does not decrease with radius, as one would expect from Newton's laws and the distribution of visible matter, but remains approximately constant. Such 'flat rotation curves' are generally attributed to invisible, dark matter surrounding galaxies and providing additional gravitational attraction.

"If you measure the distribution of star light, you know the rotation curve, and vice versa," said McGaugh, lead author of the research. "The finding is consistent among 153 spiral and irregular galaxies, ranging from giant to dwarf, those with massive central bulges or none at all. It is also consistent among those galaxies comprised of mostly stars or mostly gas.

An astrophysicist who reviewed the study said the findings may lead to a new understanding of internal dynamics of galaxies.

"Galaxy rotation curves have traditionally been explained via an ad hoc hypothesis: that galaxies are surrounded by dark matter," said David Merritt, professor of physics and astronomy at the Rochester Institute of Technology, who was not involved in the research. "The relation discovered by McGaugh et al. is a serious, and possibly fatal, challenge to this hypothesis, since it shows that rotation curves are precisely determined by the distribution of the normal matter alone. Nothing in the standard cosmological model predicts this, and it is almost impossible to imagine how that model could be modified to explain it, without discarding the dark matter hypothesis completely."

McGaugh and Schombert have been working on this research for a decade and with Lelli the last three years. Near-infrared images collected by NASA's Spitzer Space Telescope during the last five years allowed them to establish the relation and that it persists for all 153 galaxies.

The key is that near-infrared light emitted by stars is far more reliable than optical-light for converting light to mass, Lelli said.

The researchers plotted the radial acceleration observed in rotation curves published by a host of astronomers over the last 30 years against the acceleration predicted from the observed distribution of ordinary matter now in the Spitzer Photometry & Accurate Rotation Curves database McGaugh's team created. The two measurements showed a single, extremely tight correlation, even when dark matter is supposed to dominate the gravity.

"There is no intrinsic scatter, which is how far the data differ on average from the mean when plotted on a graph," McGaugh said. "What little scatter is found is consistent with stellar mass-to-light ratios that vary a little from galaxy to galaxy."

Lelli compared the relation to a long-used natural law. "It's like Kepler's third law for the solar system: if you measure the distance of each planet from the sun, you get the orbital period, or vice versa" he said. "Here we have something similar for galaxies, with about 3,000 data points."

"In our case, we find a relation between what you see in normal matter in galaxies and what you get in their gravity," McGaugh said. "This is important because it is telling us something fundamental about how galaxies work."

Kosowsky said McGaugh and collaborators have steadily refined the spiral galaxy scaling relation for years and called this latest work a significant advance, reducing uncertainty in the mass in normal matter by exploiting infrared observations.

"The result is a scaling relation in the data with no adjustable parameters," Kosowky said. "Throughout the history of physics, unexplained regularities in data have often pointed the way towards new discoveries."

McGaugh and his team are not pressing any theoretical interpretation of their empirical relation at this point.


The Daily Galaxy via Case Western Reserve University

Comments

I have been against dark matter since it first went mainstream. It was and still is a lame excuse for stupid people because they can't think of anything better.

@bil...uh, for all us "stupid people" , would you kindly present some earnest first person research, including your personally observed data, and your extensive math showing the relation between multiple cosmic objects of the order in size of multiple galaxies across both billions of light years and within our own constrained galaxy?

Uh, go ahead, please. Give some solid foundation for your "thinking". That would be what, something you watched on the Sci-fi channel?

And your idea of something "better" is??

If you can do the math, show me...or just STFU. You're a troll without a motorcycle (sorry James Dean).

It's not a proof that there is no dark matter but it suggest only a possibility. A model needs to explain more than the relationship for spiral galaxies. It may indicate a special context of matter vs dark matter needed for the formation of spiral galaxies. In the end, it is an important study because it will help to understand dark matter and the history since the big bang or maybe dark matter will be disproved, though I doubt it.

I think we need evidences that the standard cosmological model is wrong in someways. Not that I think all physics is wrong but I think that the big bang may have only occured in a relation to something exterior to the visible universe, something exterior to the object seen as the entire universe compacted to a point finite in size or not. The thing is why it would expand if it is unitary and self sufficient? The reason for the big bang may only reside in its incompleteness and in its vibrational relationship to something external...

Actually it's not a natural law, its an empirical relationship. What is shows is that the dark matter and the ordinary matter are strongly coupled and strongly correlated. Since dark matter is presumed to be weakly coupled to the standard model and electromagnetism, then it must be gravitational coupling. Since there is little reason to modify gravity to account for this (MONDs and MOGs), then this tells us something about gravitational coupling to electromagnetism and the standard model that we do not understand. Since MACHOs, WIMPs and new particles are nearly excluded, then gravitons, axions and the Higgs boson are implicated in this new strongly coupled scenario. Bosons all. Whether they are composite bosons remains to be seen, but it's appears the Higgs is not composite from what we know so far.

I'm with Bil, but I can provide a little more detail as to my own theories (Not backed by math, mind you). I believe that the movement we observe in galaxies is due to gravitational distortion, nothing more. The center of a galaxy is inhabited by a massive black hole, which as we all know, has incredible gravitational pull. We think about that massive gravity ending at the event horizon, but it doesn't. The black hole makes an impression in spacetime, drawing other objects into itself. Like a bowling ball in the center of a sheet held taut by four people. If you place a marble at the very edge of that sheet, it'll roll down and hit the bowling ball. Add angular momentum and the marble will spiral inward. But gravity also distorts time as well. The closer you get to the galactic core, the slower time will move for you. We don't think about this effect in modern physics often enough because in most cases this dilation of time is almost negligible. But even here on Earth we can measure it. Time moves faster for someone on the top floor of a skyscraper than it does on the ground floor. The apparent "Slowing down" of the stars towards the center of a galaxy can be easily attributed to this due to the enormous gravity possessed by the supermassive black hole. It's clean, and there's no murky, magical, unexplained "Dark Matter" to fall back on. I think this is the great oversight of modern physics, and I really do wish I knew the math to prove it. Maybe someone with more education than I can figure it out.

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