Slashdot Mirror
Dinosaurs Done In By... Dark Matter?
bmahersciwriter writes "Theoretical physicists propose that the Sun periodically crosses into a dense layer of dark matter sandwiching the Milky Way. The gravitational push and pull that this creates disturbs debris in the Oort cloud sending deadly comets and asteroids ricocheting around the solar system. This passage happens, their admittedly speculative model suggests, every 35 million years, which jibes somewhat with evidence on impact craters. Take it with a dino-sized grain of salt."
GO!
seriously how long until someone claims that this happens every 35 million years and the clock is ticking down to Nov 10, 2016.
I understand why they're getting a weak signal here on Earth, where most craters will have long since been erased by erosion and surface remodeling. But I'll bet we could get a much stronger signal from the Moon, particularly the far side. Do we have the ability to get dates for craters there from orbiting probes, or is that something we'd have to collect physical samples to do?
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Real Reason
Visit the Arcade Restoration Workshop @ http://www.arcaderestoration.com
Just remember, dark matter is for explaining why very big things don't fly apart, and dark energy is for explaining why even bigger things do.
If you look over the past 500 billion years, the geological record shows that there is a mass extinction event roughly every 62 million years. Even though there is some give and take, on that timescale it's almost like clockwork. Since this discovery, scientists of many disciplines have been trying to figure out what could be causing it. While I admit that it could be a cosmic coincidence, if not, then somewhere a culprit is lurking. There are also lesser extinction events every 26 - 35 million years.
For more on the 62 million year problem
More on mass extinction events in general
Brought to you by Carl's Junior.
My understanding of the English language isn't complete, but I understood "theoretical physicists" to mean that the physicists themselves were only theoretical -- in much the same way that "garden gnome" is a gnome that lives in a garden.
Everything is science is "theoretical", that doesn't mean it's unlikely to be true.
Dark matter explains both galaxy rotation and the behavior of the early universe quite well. Until the CMBR data, dark matter was just one hypothesis among many for galaxy rotation, but only dark matter explained the observed pattern of mass distribution when the universe cooled enough to become transparent for the first time. And the numbers matched to a couple of significant digits, not in some hand-wavey way.
What dark matter is made of is still an open question, but it's pretty clear that about 4/5ths of the matter in the universe is dark.
Socialism: a lie told by totalitarians and believed by fools.
I have found you can increase gravity locally by slamming down a 12 pack of beer. From this I can deduce that in order to stay together, the galaxies must be totally hammered...
You have the right to remain sentient. If you give up the right to remain sentient, you will be elected to public office
...in case you missed the first three words of the summary: "Theoretical physicists propose..."
I prefer to get my physics from physicists that actually exist, thanks.
Dark matter is not THEORETICAL. There is direct evidence for it. Quoting from the relevant wiki:
In other words, gravitational lensing of light waves - which is 100% direct evidence of matter - shows a region where there is matter that is clearly non-baryonic (i.e. does not interact with the electromagnetic field, a.k.a. "dark"). This is not subject to dispute. The question of what, exactly, is dark matter - is indeed still a subject of scientific research. There are, however, a number of super-symmetric theories which posit super-partners for well known particles, the most stable of which turn out to have the exact characteristics we're noting observationally. It is important to note that these theories were not tailored to account for the dark matter, but seem to fit the observational evidence quite well so far. As with all science however, theories are subject to falsification at any times as soon as new evidence comes on the scene.