Mysterious X-ray Signal Hints At Dark Matter

Astronomers using the Chandra X-ray Observatory and the XMM-Newton have recorded an unusual emission of X-ray light from a remote cluster of galaxies which may turn out to be evidence of dark matter. Astronomers think dark matter constitutes 85% of the matter in the Universe, but does not emit or absorb light like “normal” matter such as protons, neutrons and electrons that make up the familiar elements observed in planets, stars, and galaxies. Because of this, scientists must use indirect methods to search for clues about dark matter. he latest results from Chandra and XMM-Newton consist of an unidentified X-ray emission line, that is, a spike of intensity at a very specific wavelength of X-ray light. Astronomers detected this emission line in the Perseus galaxy cluster using both Chandra and XMM-Newton. They also found the line in a combined study of 73 other galaxy clusters with XMM-Newton. ... The authors suggest this emission line could be a signature from the decay of a "sterile neutrino." (Abstract.) Sterile neutrinos are a hypothetical type of neutrino that is predicted to interact with normal matter only via gravity. Some scientists have proposed that sterile neutrinos may at least partially explain dark matter.

Comments

Why isn't time dark matter?

[Nyder]

Granted I know nothing about such matters, but I wondered why time couldn't be dark matter?

Re:Why isn't time dark matter?

[Jason Levine]

Basically, IIRC, the best models that we have to explain the Universe say the Universe should have X amount of matter in it. When we look at the Universe, though, we see only 15% of X existing. So either our models are wildly off or there is a type of matter out there that we can't currently detect (so-called "dark matter" because we can't see it). In the case of the former, it's possible, but that would toss other theories - with more firm proof for them - out as well. In the case of the latter, it's completely possible that there is sort of a self-selection bias in play. We see normal matter regularly so our detection methods have been geared towards normal matter and miss the dark stuff.

Re:Why isn't time dark matter?

[TWX]

Because time doesn't impact mass.

You should see my sister-in-law...

Re:Why isn't time dark matter?

[Anonymous Coward]

Similarly I'm thinking that length could be magnetism. We should collaborate and revolutionize physics!

Re:Why isn't time dark matter?

[Russ1642]

Time is a four sided square universal time-cube, not dark matter.

Re:Why isn't time dark matter?

[PolygamousRanchKid]

Because time doesn't impact mass.

You should see my sister-in-law...

Marriage impacts mass. Just compare the waistlines of your single and married friends, and you will see what I mean.

At night, a bachelor goes to the refrigerator, looks at what's inside, and then goes directly to bed.

At night, a married man goes to the bedroom, looks at what's inside, and then goes directly to the refrigerator.

Re:Why isn't time dark matter?

[TWX]

I thought marriage was created by mass, at least for most Catholics...

Re:stimulate all of our senses & spirits at on

[kruach aum]

"When the Sun shines upon Earth, 2 – major Time points are created on opposite sides of Earth – known as Midday and Midnight. Where the 2 major Time forces join, synergy creates 2 new minor Time points we recognize as Sunup and Sundown. The 4-equidistant Time points can be considered as Time Square imprinted upon the circle of Earth. In a single rotation of the Earth sphere, each Time corner point rotates through the other 3-corner Time points, thus creating 16 corners, 96 hours and 4-simultaneous 24-hour Days within a single rotation of Earth – equated to a Higher Order of Life Time Cube."

I just realized this reference may be too old, and that made me sad.

Re:This too shall pass

[CaptainLard]

Phlogiston, the luminiferous aether, the Rutherford atom, dark matter, dark energy, the Higgs field... .

Getting closer every day...

Maybe one day we'll explore the idea that the geometry of space-time isn't flat, and that most of our constants aren't.

Whats stopping you?

Doesn't jive for me

[Pro923]

If photons with a frequency in the visible spectrum don't react with "dark matter" than why would photons with a frequency in the xray spectrum?

Re:Doesn't jive for me

[An Ominous Coward]

The hypothesis is not that the X-Rays are interacting with this type of dark matter. It is that the decay of this type of dark matter generates X-Rays.

Re:Doesn't jive for me

[drall.kj]

I get what you are saying but.... if it can decay into a photon isn't that the same as emitting a photon? The first line quoted above is "but does not emit or absorb light like “normal” matter." If it can generate a Photon (by decay or someother means) it can't be dark. I'm not that smart but Dark Mattter/Energy thing just stinks of take a stab in the dark (no pun intended). I think some where we have some constant of the universe calculated wrong, or we are estimating the mass of the galaxies wrong.

Re:Doesn't jive for me

[An Ominous Coward]

It's the ambiguity of language that's at fault here. The key to the sentence you mentioned is "like normal matter". Normal matter absorbs electromagnetic radiation, increasing its energy level, and drops back to lower energy levels by emitting electromagnetic radiation. Thus, normal matter interacts with light. This is a different physical process than the emission of light due to decay of the particle itself.

And while we haven't pinned down dark matter by any means, it's much more than a stab in the dark. For one, there are known particles--neutrinos--that do not interact via the electromagnetic force, so the idea of unknown particles with the same property isn't unrealistic.

Then, there are clues from many different directions that point to something consistent with matter that interacts gravitationally but not electromagnetically. These include calculations concerning the total matter in the universe, galaxy cluster formation, the rotational speed of stars on the out edge of galaxies, etc.

Re:Doesn't jive for me

[Anonymous Coward]

Defining dark matter as having zero interaction with electromagnetism is at best a terse over-simplification and at worst just wrong. Dark matter does not strongly interact with electromagnetism, meaning that it for the most part doesn't interfere with light other than from gravity in places we think there are lots of it. But that doesn't preclude it from having rare or much harder to see interactions, such as decays, or rare interactions with high energy photons, or creating Cerenkov radiation when passing through a detector as some experiments are looking for. For a while, astronomers wondered if dark matter could literally just be chunks of rock or black holes, otherwise normal matter that absorbed but didn't emit light. Although surveys of the sky set upper bounds on the amount of such things to be too low. Further evidence suggests it isn't made out of normal things like protons. But none of that means it can't have weak or rare interactions with light, just that whatever interaction there is has to be weak enough to not have conflicted with previous observations.

Re:stimulate all of our senses & spirits at on

[NoNonAlphaCharsHere]

...Oreo flavored Doritos...

Do you have a newsletter?

What ever happened to Occam's Razor?

[Squidlips]

Why do these crackpot-darkmatter-theories-du-jour all smell like mysticism?

Re:This too shall pass

[wonkey_monkey]

so therefore the speed of light is changing with the expansion of the Universe.

No, it isn't.

Re:This too shall pass

[bill_mcgonigle]

Hey, there's some suggestive evidence that our universe may be discrete and quantized around 10^-27 (and cheats to the Plank length). That's almost aether.

Granted, we should study the skull surface shape of these scientists, just to be sure.

Re:This too shall pass

[Soft]

Bullet cluster, bitches!

What ever happened to Occam's Razor?

[Anonymous Coward]

Because you don't understand them, so you assume they must be hokum.

Re:This too shall pass

[Anonymous Coward]

Also the idea that space it self isn't flat has also been investigated (Not an astrophysicist, but if I remember correctly current verdict is it's flat/nearly flat).

The whole point of General Relativity, about to turn 100 years old next year, is that space is not flat on various scales. Observation suggests on the largest scales it averages out to flat, but physicists have put a lot of effort into understanding non-flat space on smaller scales (and even large scales in case observations are wrong).

Re:stimulate all of our senses & spirits at on

[Vyse of Arcadia]

I dunno about Time Cube, but I feel like the Thyme Cube guy is on to something.

Re:It's always dark matter. Except when it isn't.

[mcelrath]

Let's have some fun. Also remember that luminiferous aether was an idea that was around for a long time as well. Dark matter is a difficult-to-disprove fad, without any real competing ideas. That will not always be the case.

Re:stimulate all of our senses & spirits at on

[ScentCone]

Normal human with average IQ and understands that science is real?

Or

Extremist right wing moron speak?

I was hoping you could translate it into left wing moron speak, perhaps using a metaphor involving healing crystals and/or homeopathy. That'd be super, thanks. If that's too hard, perhaps just translate it into some sort of yoga-energy-manipulation example, or maybe use the interaction of wind turbines killing thousands of bats as an analogy to the sterile neutrons decaying.