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Dark Matter Stars in the Early Universe?
OriginalArlen writes "UniverseToday reports new research which suggests dark matter could have condensed to form 'dark stars' in the early universe. These stars would have been very massive and burned very slowly, fueled by non-fusion reactions, they could still be with us. Astronomers hope to better constrain theories of early galaxy and star formation with observations of gravitational lensing events caused by these ghosts of the primordial universe."
The whole article sounds like a solution in search of a problem. It talks about "Dark Matter" as though the mysterious substance's properties were well-defined, even going as far as positing stars fuelled by "dark matter annihilation, instead of nuclear fusion". And then TFA says "If these dark stars are stable enough, its possible that they could still exist today".
I propose that dark matter is actually composed of jellybeans and M&M's, and that the first massive objects were stars fuelled by the crushing force of the crunchy shells of the M&Ms piercing the relatively soft outer coating of the jellybeans. Gravitational separation eventually turned the masses into giant Cadbury Creme Eggs.
Other than being completely silly, am I making any fewer wild guesses than the Dark Matter Annihilation folks?
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
Dark Star crashes...pouring it's light into ashes...reason tatters...the forces tear loose from the axis...
Just wondering but if they are are massive and burn slowly wouldn't they tend to collapse into black holes? If they don't put out enough heat to counter their gravitational field they should collapse. If so they may be the cores of the super massive black holes at the center of many galaxies. Just and idea since there where no numbers given in the article.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
On \. OriginalArlen reports the news. I look at the linked website, called Universe Today and I see that there is one "publisher" by the name of Fraser Cain. Following the link there, finally, I get to the article on the arxiv, the definitive source of new physics papers. So to get to the source, it takes three jumps. So what has Fraser Cain done for us? Watered down the content? Couldn't OriginalArlen read the article and write a gist himself/herself? Or is Fraser Cain the same person as OriginalArlen? Reading the original article, I find "some" correlation on what ends up on \. and what is in the article. Or is this not the point? If I had to write a review for this article, I would have said that the last sentence of the abstract is what is most important: "A ..star .. detectable via annihilation products (gamma-rays, neutrinos, anti-matter) possibly in combination with hydrogen lines."
The brilliant thing about this article is that these theorists are cooking up something that is actually detectable! Something that can be tested and hopefully will! *Finally* congrats to Douglas Spolyar, Katherine Freese and Paolo Gondolo, who *wrote* the article. (No, I dont know any of them. But isn't it time we cited those whose ideas we regurgitate?)
I can't help but see parallels between dark matter and the (al)chemist's Phlogiston theory. Phlogiston was used to account for quantitative errors in chemical reactions. Funny thing was, every (al)chemist had his own measurements for its properties, until our understanding of chemistry improved. I wouldn't be surprised if the dark matter theory were eventually tossed out the window because our understanding of gravity improved.
The purpose of dark matter is to explain why spiral galaxies can rotate as a fixed plate. Until you can actually observe the particles or somehow conclude that they do indeed exist (and speculative NASA press releases with colorized images do not count), we should avoid further speculation about their role.
We cannot prove that dark matter exists with thought experiments. It requires the construction of equipment or laboratory work, or possibly even careful interpretation of observations. But, regardless of how many astrophysicists need PhD's, we should not encourage any further speculation about dark matter until it is demonstrated to exist -- for everything these new theories touch will themselves turn into speculation, and we will confuse ourselves more than we already have about the level of confidence we can place in our theories. What if we do decide to invest lots of astrophysicists into thought experiments about dark matter's role in the universe? Then, you will have effectively created a group that will lobby for the existence of dark matter even when the weight of the evidence is against it.
In other words, speculations should be based upon some sort of observation. Dropping hints about what a dark matter star might look like is just a clever way of trying to stake out terrain within the astrophysics community.
"A man cannot begin to learn that which he thinks he already knows." --Epictetus, 1st Century A.D.
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The moon--as in, Earth's moon--is just normal matter that doesn't glow. Oh, and Earth is too! Neither are dark matter.
That's not true. Earth does glow, quite strongly, in the infrared. The moon glows too, although at a slightly lower temperature (and thus longer wavelengths) due to lack of greenhouse effect.
However, Earth's infrared glowing is of course due to the sun's fusion output. Ie, Earth is in equilibrium, where it radiates as a blackbody the same amount of energy it that it absorbs from the sun.
So (as far as I know) a dark-matter planetoid at the same distance from the sun as Earth wouldn't have this infrared glow, because it wouldn't absorb solar photons. It would just exert a gravitational pull (or maybe have some other exotic effects). So you are correct, though, about dark matter being different from non-glowing (ie cold) 'regular' matter.
make world, not war
I'm confused, if we don't know what dark matter is, or if it even exists - why do we know that it would burn slowly?
Ace
Some sense at last. I just can't understand why rational people accept dark matter theories at face value, but claim to reject notions like 'ghosts' or 'god'.
Hell, here's my theory: Dark Matter = God. He's everywhere, invisible, and keeps the universe together! See, explains everything really.
The interesting thing about the whole dark matter episode, is that it probably gives an insight as to how religions form. Someone has a wild idea, that someone else expands on, that someone else tries to validate, that someone else uses as doctrine, that someone else teaches, that someone else uses to explain a wild idea...scary really. Eventually you end up with so many layers of analysis and reference that everyone's forgotten that the *original* idea was bunk. It's like an upside down house of cards.
lemonade was a popular drink and it still is
Actually, if all of the dark matter were Dyson Spheres around stars, or star systems, they'd still give off black body radiation, which we can easily detect. This is because black body radiation is independent of everything except temperature, which will be above ambient interstellar temperature (thus producing the radiation) in every case, unless this civilization has found a way to reverse entropy.
Further, recent observations of a pair of colliding galaxies conclusively shows that dark matter absolutely cannot be normal matter, since normal matter interacts with the EM force (which is producing drag on the colliding gas clouds), but dark matter does not (in the collision the dark matter clouds are just sliding past each other). Thus Dyson Sphere-covered stars, or star systems, dark matter is not.