Phew, galactic accident helps boffins explain dark matter riddle An accidental discovery by a team of astronomers has helped answer one of the burning questions about dark matter and where it came from. Previous studies found that galaxies created over ten billion years ago contained low levels of dark matter. This posed the annoying question of where it all came from since then, as dark …
Neil Barnes,
I think you're utterly wrong. Though I didn't downvote you.
I think you'll find that dark matter isn't there in young galaxies because they're footloose and fancy free. It's when they start to age, that all the existential dread comes in, from children mortgages, fear of impending doom etc. Thus dark matter = existential dread.
I'll take my Nobel grant in beer thanks.
I think Dublin is just an over-priced visitors' centre nowadays - and it's actually made in Cork.
Although perhaps they know something about cosmology that the rest of us don't?
In which case, do Guinness manufacture the dark matter, or is Guinness just made out of it? And given the post-Guinness black poo issue, have we found an area where dark matter directly interacts with normal matter? [Insert your own joke about dropping heavy particles here...]
(I do actually test full 330 watt bi-facial PV modules this way) feed in rather a lot of amps& volts; they glow, a bit, mostly IR, but can be photographed and reveal amorphous or crystalline silicon defects.
Not sure if reverse electroluminescence of a CCD would illuminate much dark-matter, or remote galaxies, but worth a try.
Exactly, isn't this just one aberrant point on the graph - the reading that would normally be regarded as unreliable in a pool of consistency?
Cups of tea are hot. My cup of tea is demonstrably cold. Therefore all cups of tea are cold and all previously measured cups must have been cold...
I would suggest the conclusions as reported are 'excessively optimistic'.
I *think* what they mean is that this is the first old galaxy we've been able to measure in this way (because of the angle), and previous results suggesting low levels of dark matter in old galaxies were using less precise methods (at a guess that'd be something like gravitational lensing, the rotation at the outer edges only, or trying to infer the effects on nearby galaxies).
You may be correct that Accuracy and method may be different but one of the earlier investigations was 240 disks not just the one and they did have the accuracy to measure angular velocity at various radii ... I still think there's more work needed to prove the conclusion based on only one observation.
I opened this article thinking that scientists had finally explained dark matter.
Not at all, they just found an old galaxy with present-day amounts of the stuff.
All well and good, and now it must be asked what measurement error made us misinterpret the data on all the other old galaxies, but this does nothing to explain dark matter.
Our galaxy is one of the younger ones?
We have stars that are almost as old as the universe.
A quick google tells me our galaxy is a mere 300 million years younger than the universe and if the big bang theory is correct, part of the first 300 million years were the dark days of massive inflation.
Well 'part of the first 300 million years' means 'from 10E-36 to about 10E-32 seconds after the big bang' so ... quite a small part.
What you might mean is the surface of last scattering, which is the point where the universe got cool enough for light to propagate -- when it was cool enough for electrons and protons to combine into Hydrogen in other words. This is what we're looking at when we look at the CMB, and it's about 380,000 years after the big bang.
"Galactic Accident" in the title referred to a cosmic prang seen all too often when those in charge of galaxies fail to watch where they are going. Really, really, really! You put them in charge of a galaxy and they think they are rulers of the universe!
All those jokes comparing dark matter to phlogiston and some serious boffins go on and say 'you know what, it is phlogiston!
“The galaxy we found is a clear counter-example of that, where it seems to have dark matter behaving in the normal way, as it does in the present-day universe.”
As I understand it, current theories of galaxy formation need dark matter in the primordial mix to work well, but the earlier studies found DM was lacking in the first three billenia, and this fact is vexxing. The theory has a big hole in it.
Now someone has found a galaxy, almost old enough to be classed in that era, that has plenty of DM. That's very interesting, but how does this discovery negate the problem presented by the other old galaxies they found lacking DM? The article seems to imply this find fixes the DM theory problem, but does it really?
Is it dark matter? Really? We've still to capture or measure any. It sounds like we have come all the way back to the concept of Aether. And that was just a name for "we don't know how the **** this happens". Giving it a new millenial name doesn't change what it is.
Perhaps its just our poor monkey brains trying to make sense of an Ndimensional universe through a 4d set of goggles.
Can we just call it Magic and have done?
It's different than aether, because while we have no idea what it is we can detect it. So, yes, we can measure it: we can look at galactic rotation curves and infer from them how much dark matter must be there. This is essentially the same trick we did to discover Neptune and Pluto: look at some stuff we can see, infer things about the gravitational field from their motion and infer there must be some other thing we can't see. Of course, in the case of Neptune & Pluto we did see them when we looked hard enough. The trouble with aether was that it turned out that there was no way to detect it even in principle, and some smart guy decided that things which you could not detect, even in principle, were not there. He did this trick several times with different things: it's a good trick.
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