Existence of Dark Matter Challenged

[Xarog]

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.

Now 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.

"If you measure the distribution of star light, you know the rotation curve, and vice versa," said Stacy McGaugh, chair of the Department of Astronomy at Case Western Reserve and 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.

In a paper accepted for publication by the journal Physical Review Letters and posted on the preprint website arXiv, McGaugh and co-authors Federico Lelli, an astronomy postdoctoral scholar at Case Western Reserve, and James M. Schombert, astronomy professor at the University of Oregon, argue that the relation they've found is tantamount to a new natural law.

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.

http://phys.org/news/2016-09-spiral-irregular-galaxies-current-dark.html

And people wonder why I question the validity of the cosmic inflation model.

 

[grok]

Hypotheses should be questioned, as more evidence becomes available the models get refined, even rejected and replaced with a more accurate model that follows the observations more closely. It's how theoretical science works.

 

[Arthur]

This is great news. I've always found the DM hypothesis somewhat troublesome from a Philosophy of Science viewpoint -- that all galaxies and stars make up only 10-25% of the universe (the CERN reckons 5%, btw). If DM is real then it means most of the universe's stuff is inaccessible to our instruments and not susceptible of experimental examination, and that leaves not just physics but all of science in a dead-end. It's why I've also abandoned any support for and interest in superstring/M-Theory, btw - it's a pointless deviation that's keeping us from doing real physics. My own a priori position is that the universe is readily and entirely accessible to reason. Which is why any new research that points to abandoning the DM hypothesis is welcome.

 

[stricken]

Yea. What a relief. Next should be the "big bang"

 

[baasgene]

Yea. What a relief. Next should be the "big bang"

Agreed, even though the universe is continually expanding it doesn't mean that it's because of an explosion. There isn't enough knowledge on earth to determine the reason for it and there probably won't be. The laws outside of the atmosphere differ from earth so reasoning will always be limited, but believing that the universe was compressed and then exploded sounds like something a child would dream up.

 

[Arthur]

The laws outside of the atmosphere differ from earth

Not a single shred of evidence for this whatsoever. Everything we know supports the notion that the laws inside and outside our atmosphere are identical. Atmospheres obey the universal laws of physics, fluid dynamics, etc.

 

[baasgene]

Not a single shred of evidence for this whatsoever. Everything we know supports the notion that the laws inside and outside our atmosphere are identical. Atmospheres obey the universal laws of physics, fluid dynamics, etc.

According to everything we know as you said, it's not proven so it's still just another hypothesis

 

[Arthur]

According to everything we know as you said, it's not proven so it's still just another hypothesis

What we know works so well we can slingshot probes around the solar system with great precision.

 

[Xarog]

Yea. What a relief. Next should be the "big bang"

Believe it or not, but this also indirectly challenges the Big Bang model since it heavily affects the predictions regarding the expansion of the Universe.

Further reading:
https://en.wikipedia.org/wiki/Inflation_(cosmology)

 

[grok]

What we know works so well we can slingshot probes around the solar system with great precision.

Exactly, science has already cracked the laws of say gravity even though we have limited understanding of what exactly causes it. We can for example observe with great accuracy how the universe is expanding, yet only have a hypothesis of what the origin of this expansion is.

Dark matter has always been one of those placeholder theories, something postulated to fill in a gap in another hypothesis, and science's job is to either prove or disprove it. Doesn't make the original model invalid, just unrefined.

 

[azbob]

#DarkMatterMatters

 

[grok]

#DarkMatterMatters

#starlightmustfall

 

[Bobbin]

This is probably a really silly question here but is there a star/galaxy map, of sorts, that "eliminates" relativity or time in its positioning? i.e. every point is precisely mapped according to if you were actually standing there right now. Or where everything is precisely mapped from our POV + simulated to X light years ahead according to its distance from us. I'd be interested to see what this might look like - and if anything if it would look any different, and if spiral shapes would still look spiral and so on.

 

[Ninja'd]

Existence of Dark Matter Challenged

But I just watched an episode this morning.

 

[SykomantiS]

But I just watched an episode this morning.

Even I watched three...

 

[rietrot]

I think we have no idea whats out there it's very limited guess work at best.
We haven't even been able to explore huge parts of the ocean on our own planet.

 

[Moosedrool]

http://phys.org/news/2016-09-spiral-irregular-galaxies-current-dark.html

And people wonder why I question the validity of the cosmic inflation model.

You're confusing the early stages of the universe and the current expansion not to mention dark matter and dark energy.

Back to the article. Science tests theories and hypotheses all the time.

 

[Slootvreter]

Hypotheses should be questioned, as more evidence becomes available the models get refined, even rejected and replaced with a more accurate model that follows the observations more closely. It's how theoretical science works.

Correct, but sadly this will be seen as a win for creationists

 

[Arthur]

Correct, but sadly this will be seen as a win for creationists

Why? It has nothing to do with origins. Someone who tries to make Creationist deductions from this simply doesn't understand science or philosophy.

 

[Nuke]

Damn scientists, how can you trust them? Changing their minds every time new evidence comes along.