Comic Discussion > QUESTIONABLE CONTENT
WCDT 2071-75 (Dec. 5-9, 2011)
VonKleist:
--- Quote from: tjradcliffe on 08 Dec 2011, 03:58 ---
She's caring about possible problems for her, and I'm betting Marten is caring about possible problems for them.
--- End quote ---
Yet they both think "I´m in trouble."
I can't see a "we" in Marten's bubble.
tjradcliffe:
--- Quote from: Loki on 08 Dec 2011, 02:59 ---An Italian scientist recently suggested that dark matter might not in fact exist, by coming up with some complicated formulae which predict movements of spiral galaxies without requiring the existence of dark matter. He has shown his math to work so far for two (according to other sources, four) galaxies, which may or may not be simple luck
--- End quote ---
Rotation curves of spiral galaxies are only one aspect of the Dark Matter problem, and one that can be solved without invoking exotic particles. At larger scales we need exotic Dark Matter to explain the dynamics of the universe: the problem is that we know how much ordinary matter there is in the universe based on the ratio of hydrogen (whose nucleus is just a single proton) and helium (whose nucleus contains two protons and two neutrons.)
Back in the minutes after the Big Bang protons and neutrons condensed out of the quark-gluon plasma, and then neutrons were captured onto protons to create helium. But free neutrons decay into protons and electrons with a lifetime of about fifteen minutes, so the amount of helium created was dependent on the density of the universe at that time (the denser it was the more neutrons would be captured into helium before they had time to decay). We know what the volume of the universe was during that brief interval from other observations, we know the primordial He/H ratio, so we know the mass of the universe in "ordinary matter", and there's enough of it to explain "galactic dark matter", which is what's needed to make spiral galaxy rotation curves work out.
But on larger scales we still see anomalous dynamics that suggest too much mass to be accounted for by the known mass of ordinary particles, so we think there must either be exotic physics or exotic particles (not, unfortunately, exotic dancers.) This new paper explains away the need for exotic particles in galaxies, but that's not where we need them. And the argument doesn't even deal with other galaxy-scale anomalies like the Bullet Cluster, where two galaxies in collision show clear evidence of non-interacting Dark Matter that accompanies the visible mass but is substantially decoupled from it.
Wait, isn't this supposed to be a discussion forum about the shenanigans of a group of 20-somethings in a slightly alternative universe?
ilikefishfood:
From the glowing smile on Padma's face and the way she is looking Marten straight in his eyes in panel two, I think she's rather smitten. Their body language is very relaxed. Like they're comfortable with each other. And then they spoon! That's some pretty intimate stuff.
ASIDE: I'm new at posting here. Long time lurker. Hi everybody.
Throg:
Hi fishfood.
This comic made me happy, if only for the simple reason that Padma is not the stereotypical cold-hearted exotic inscrutable unscrupulous "foreign" bimbo. She may be clueless and come across harsh sometimes, but she's not heartless.
Mr_Rose:
See the thing about Schrödinger's Cat is that yes it's ridiculous—it is intended to be—but only physicists ever get the joke because everyone else wanders off before they get to the punchline. Specifically, that the only 'observer' that is required is the Geiger counter in the box with the cat.
All the superposed cat demonstrates, really, is that physicists should never be allowed to name things and especially should not be allowed to borrow words that everyone else already thinks they know in order to do so.
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