Are 'Immortal Stars' Feasting on Dark Matter in the Milky Way's Core? (gizmodo.com) 62
"Stars very close to the center of our galaxy could be fueled by dark matter in perpetuity," writes Gizmodo, "according to a team of astronomers who recently studied the distant light sources."
The group of stars, known as S-cluster stars, is just three light-years from the center of the Milky Way (for reference, we are about 26,000 light-years from the center of our galaxy, which hosts a supermassive black hole at its core). The stars are surprisingly young for their galactic neighborhood, yet they don't look like stars that simply migrated to this part of the Milky Way after forming in another location...
As reported by Space.com, the research team posits that these weird stars may be accreting dark matter, which they then use as fuel to keep burning. Since models estimate there is plenty of dark matter near the galaxy's core, the stars are "forever young," as study lead author Isabelle John, an astrophysicist at the Kavli Institute for Particle Astrophysics and Cosmology told Space.com. Effectively, the stars have a long, long way to go before they start running low on fuel. The team's paper is currently hosted on the preprint server arXiv, meaning it has not yet gone through the process of peer review.
Dark matter is only "seen" through its effects on other objects, the article points out — leading to lots of theories as to where it's actually located. "Earlier this year, a different team of researchers proposed that neutron stars — extremely dense stellar remnants — could actually be a source of dark matter. Last July, yet another team suggested that the Webb Telescope had detected stars that were powered by dark matter."
As reported by Space.com, the research team posits that these weird stars may be accreting dark matter, which they then use as fuel to keep burning. Since models estimate there is plenty of dark matter near the galaxy's core, the stars are "forever young," as study lead author Isabelle John, an astrophysicist at the Kavli Institute for Particle Astrophysics and Cosmology told Space.com. Effectively, the stars have a long, long way to go before they start running low on fuel. The team's paper is currently hosted on the preprint server arXiv, meaning it has not yet gone through the process of peer review.
Dark matter is only "seen" through its effects on other objects, the article points out — leading to lots of theories as to where it's actually located. "Earlier this year, a different team of researchers proposed that neutron stars — extremely dense stellar remnants — could actually be a source of dark matter. Last July, yet another team suggested that the Webb Telescope had detected stars that were powered by dark matter."
Heat death of Universe (Score:3)
In perpetuity, my ass.
Re: (Score:1)
The premise of TFA is that adding fuel to a star extends its life.
That's nonsense. Adding mass to a star shortens its life.
The luminosity of a star is roughly proportional to M^3.5.
Adding even a little mass makes it burn significantly hotter and faster.
Re: (Score:3)
I believe what they're saying is the the dark matter is absorbed gradually replacing spent fuel so there would be no change in mass. They describe the stars as being kept "young" which certainly implies they aren't obtaining mass beyond their original peak.
Re: (Score:1)
Yes, I understand what TFA said, and it is nonsense. Stars don't work that way.
The additional mass would increase the rate of fusion, causing the buildup of helium and "metals".
High levels of heavy (non-hydrogen) elements are the hallmarks of an aging star.
Additional mass doesn't make the star "young". It makes it age faster.
Our sun loses 4.7M tonnes of mass per second. That's 148 trillion tonnes per year, and about 6e23 tonnes over its 4.5B-year lifetime. That's only 0.03% of its total mass.
Re: (Score:2)
The additional mass would increase the rate of fusion, causing the buildup of helium and "metals".
Maybe I need to be clearer. Stars typically get smaller as they age. If they are staying "young" then they are maintaining mass not gaining.
Re: (Score:2)
Maybe I need to be clearer. Stars typically get smaller as they age.
No, they don't.
They get bigger by volume, and the mass change is negligible.
Re: (Score:2)
Well at least I got my point across this time.
As for the rest, I'm not an expert on this AT ALL but it has always been my understanding the general direction of a star is smaller (especially prior to becoming a red giant) and denser with age (but still less mass due to spent fuel) and this from NASA seems to support that https://imagine.gsfc.nasa.gov/... [nasa.gov] . There are of course phases where it does get larger such as in when stars "briefly" become red giants.
Re: (Score:2)
Yes, I understand what TFA said, and it is nonsense. Stars don't work that way.
I am always surprised when people are so convinced of their views on something as the absolute truth.
Re: (Score:1)
You don't understand. Dark matter is the magical stuff that solved all astronomy questions and mysteries.
Unexplainable phenomenon discovered? Dark matter. Solved.
Re: (Score:2)
As physicists, I'm sure they would never have thought of that in their models. Maybe you could tell them? What from which school did you get your astrophysics degree?
Acreting Dark Matter Hard for Stars (Score:5, Interesting)
I believe what they're saying is the the dark matter is absorbed gradually replacing spent fuel so there would be no change in mass.
This makes no sense. How do the stars acrete Dark Matter when the Dark Matter interaction cross-section has to be small? This matters a lot because, if there is nothing that the Dark Matter can interact with when it passes through the star then it will not slowdown and so will just exit the gravity well again. This is why, on a galactic scale the Dark Matter halo extends out well beyond the ordinary matter and has a spherical distribution not a disk or spiral. Black Holes can acrete DM because nothing can escape them but ordinary stars do not have that kind of gravity.
If there is something that Dark Matter has a large interaction cross-section with and so can exchange momentum and slow down in a star then there are problems with the cosmic microwave background that shows Dark Matter to be decoupled from matter.
Re: (Score:2)
That assumes the usual star composition like mostly hydrogen (or whatever it is "fusion fuel"). Dark matter won't participate in any fusion, it only interacts gravitationally as far as we know (or shall I say "define" as we don't really know what we're talking about).
Re: (Score:3)
That assumes the usual star composition like mostly hydrogen (or whatever it is "fusion fuel"). Dark matter won't participate in any fusion, it only interacts gravitationally as far as we know
Nope. Gravitational interaction is enough to compress the core and vastly[1] increase the rate of fusion.
[1] By a power factor of 3.5.
Cosmetology not Cosmology (Score:5, Funny)
Adding mass to a star shortens its life.
Yes, because it makes it burn hotter and brighter than it should for its age. So perhaps this is an example of cosmetology rather than cosmology: the DM just makes the star look younger?
Re: (Score:3)
Novas and supernovas appear as part of the life cycle of a star during which it exhausts various fuel sources and changes its physical characteristics in response. Massive stars run out of fuel faster because stellar luminosity is proportional to the *fourth* power of mass. So a star that is twice as massive has twice the fuel, but burns it 16 times as fast and therefore lasts 1/8 as long.
Dark matter, however, is a hypothetical phenomena. We don't know what it is, other than that it has mass and so inter
Re: (Score:2)
This may be like the recent serious attempts of physicists to prove a reactionless drive is possible. To hypothesize such a drive is to hypothesize conservation is not always conserved.
Nah those were always cranks. Arguably scammers.
Firstly there's not annoy real difference between a reactionless drive asks a perpetual motion machine, in that given the former you can construct the later.
Second thing that's a terrible smell of bullshit is that it went from zero to a demonstrator drive they just needed to tes
Re: Heat death of Universe (Score:2)
Iâ(TM)m pretty sure theyâ(TM)re saying that the stars accumulate mass from dark matter over time. That allows the star to compress its fuel more, and keep fusion going for longer.
Re: (Score:2)
That allows the star to compress its fuel more, and keep fusion going for longer.
Compressing the core makes fusion go faster and end sooner.
Re: (Score:2)
Steady state cosmology ... sure it needs a ton of kludges, but it's not like inflation isn't a massive kludge too.
Not all Kludges are Equal (Score:3)
sure it needs a ton of kludges, but it's not like inflation isn't a massive kludge too.
Yes, but there is a massive difference in the type of kludge. Inflation is a idea in an area where we have essentially no experimental data: quantum gravity. Steady-state cosmology needs basic laws of physics that are based on exceptionally well known experimental data - like the laws of thermodynamics - to be thrown out the window.
Re: (Score:2)
Dark energy throws the first law of thermodynamics out of the window to begin with.
Inflation has got little to do with quantum gravity. Cosmological structure looks a little like amplified quantum fluctuation, that's its raison d'etre. You can turn enough knobs on QM to make it all seem plausible, it's not like you can ever get near the energy needed for experiment ... it's a wonderful rug, shovel inflationary leptogenesis under it too and it "solves" everything.
Re: (Score:3)
Dark energy throws the first law of thermodynamics out of the window to begin with.
No it does not. A cosmological constant is part of GR and GR does not violate energy conservation if you include the energy of the gravitational field.
Inflation has got little to do with quantum gravity. Cosmological structure looks a little like amplified quantum fluctuation
Hardly - quantum graivty requires us to understand the small-scale structure and behaviour of space-time which is exactly where the fluctuations that inflation potentially expands through some sort of phase change come from. Given that we have no clue about either I suppose it is technically possible that they might turn out to be completely independent eff
The damn satellites are much prettier (Score:1)
And much closer and man made so better.....Thank You, Thank You.
Supposition on supposition. (Score:3)
Bad suppositions (Score:2)
Oort Cloud (Score:2)
Re:Oort Cloud (Score:4, Interesting)
Surprisingly, someone thought of that idea rather a long time ago. Small cold ordinary matter objects like asteroids were excluded as major contributors to dark matter through occultation surveys, IR surveys, and modelling.
Re: (Score:2)
Surprisingly, someone thought of that idea rather a long time ago. Small cold ordinary matter objects like asteroids were excluded as major contributors to dark matter through occultation surveys, IR surveys, and modelling.
The first problem is that Dark Matter is not necessarily any sort of "matter" at all. It is a placeholder for "something's not right here!" It is unfortunately named because these doofuses all demand that it be matter. And a perpetual motion version of Dark Matter just amps up the doofosity to level 11.
Re: (Score:2)
Too many say dark matter is "proven". Proven to be needed by our current crappy equations. I am suspecting that what we think we see is not exactly what is really happening, AND there is something wrong with our current crappy equations.
Right now Webb is detecting large galaxies that exist too early after the big bang, so that makes me suspect that the cosmic distance ladder has something wrong and maybe we simply don't fully understand everything that causes red shift and attribute too much red-shift t
Re: (Score:2)
Too many say dark matter is "proven". Proven to be needed by our current crappy equations. I am suspecting that what we think we see is not exactly what is really happening, AND there is something wrong with our current crappy equations.
Right now Webb is detecting large galaxies that exist too early after the big bang, so that makes me suspect that the cosmic distance ladder has something wrong and maybe we simply don't fully understand everything that causes red shift and attribute too much red-shift to distance and/or expansion of the universe.
There are a lot of magic kludges we seem to have to make the math work and/or explain what we think we are seeing, and that tells me that there is something wrong with the equations and/or what exactly we think we are seeing.
This. All of this. The BB theory is kludge upon kludge and is a tad creaky. Dark matter is a fascinating kludge, just adjust it ao the magickal value and hot diggity - we know what it is, and all is well and perfect.
Except it isn't. It's still as much a placeholder, and as you note about the things Webb is seeing, something simply does not add up.
And that my friends is awesomeness level 10,000, and something new to put our minds to.
Re: (Score:2)
Read the thread. The OP proposed dark matter was asteroids. Those are made out of ordinary matter.
Re: (Score:2)
Read the thread. The OP proposed dark matter was asteroids. Those are made out of ordinary matter.
Umm, I read the thread, and I thought I was actually bolstering your view. Or am I just commenting in a thread you control, and that pisses you off? Relax a little.
We don't see or even think we'll ever see enough non-stellar ordinary matter to create the anomalies that are observed. The standard model is that so called dark matter is 85 percent of the total mass of the universe, and that dark matter plus so called dark energy makes for 95 percent of the total mass-energy content of the universe. And this
Re: (Score:2)
Kind of sounded like you were trying to start a fight. That's fine, but when people like the OP at least give the initial impression that they're being intellectually honest it's worth giving them the benefit of the doubt. Someone who "doesn't see why dark matter can't be asteroids" can be simply ignorant of ninety years of astrophysics.
DM cannot be Atoms (Score:2)
To my mind, dark matter would be sufficiently explained by widely dispersed asteroids floating in space.
Nope. Asteroids are made of "ordinary" matter (atomic nuclei) and, in the early universe this type of matter formed a plasma that cooled and collapsed under gravity to form the galaxies, stars, planets and indeed eventually us. However, we know from looking at the cosmic microwave background that Dark Matter was not part of that plasma since it's gravitational field compressed the plasma thus leading to the non-uniform density that collapsed into what we see today. This means it cannot be made of ordinary
im an internet expert (Score:2)
43 (Score:2)
Dark Matter seems to be a lot like the number 43.
Re: (Score:2)
Say what?
The answer to life, the universe and everything is 42
Re: 43 (Score:2)
Re: (Score:1)
42 was already the wrong answer to the Ultimate Question.
Re: (Score:2)
Not at all.
It just proves that 7=9.
Time dilation (Score:2)
Stars that are right next to a huge black hole would age far slower from our perspective outside its area of influence
Re: (Score:3)
Stars that are right next to a huge black hole would age far slower from our perspective outside its area of influence
The BH at the center of the Milky Way has a Swartzchild radius of 12 million kilometers.
The stars described in TFA are 28 trillion kilometers from the center.
Too near (Score:2)
"Ah, but you forgot about SUPER-super-super-man!" (Score:2)
Re: (Score:2)
Yeah, When the model/explaination gets too complicated then that is often a sign of something wrong with the model/explaination...our solution seems to be to keep piling more crap to make the current model we are invested in work.
PM people rejoice! (Score:2)
Dark matter, immortal forever stars, finally proving that perpetual motion exists, but explains how dark matter is the key to silencing the skeptics.
How could they? (Score:2)
Dark matter doesn't interact with regular matter.
It's a nice thought exercise (Score:2)
Here we go again (Score:2)
Once scientists thought the universe was centered around the earth. After all, that explained everything well and gave pretty convincing results. But it wasn't right. So who is
Good question (Score:2)
Why don't they ask Gillian Anderson?
So now regular and dark matter DO interact? (Score:2)