Yeah, between Dengue fever, chickenwhatever and now Ziki, plus shitty (literally) water, unfinished transportation, etc. etc., the Rio Olympics are pretty much doomed at this point.
‘The search for dark matter heats up’:
This year, the search for dark matter seems to be dominating the minds of a lot of physicists. It’s quite an intriguing issue. We have a lot of gravitational evidence for dark matter at length scales from single galaxies to galaxy clusters—and even the cosmic microwave background. The variety of evidence is such that it’s difficult to imagine a suitable modification to the laws of gravitation that would satisfy all these constraints.
But actual dark matter remains elusive. I’ll discuss some details in a moment, but my take-home from the dark matter talks is that if it can be detected at all, we should see it relatively soon.
So how do we go about detecting dark matter? Francesca Calore from University of Amsterdam presented results from observations of cosmic and gamma ray production. The idea is that dark matter forms a halo of relatively slowly moving particles around the galaxy where the particles occasionally run into each other. In doing so, they may destroy themselves and generate some high-energy particles of the type that we can detect. Following a number of possible decay paths, we get gamma radiation and/or cosmic rays.
Gamma rays are just a high-energy version of ordinary light, so they travel relatively unimpeded through the galaxy. That means we can turn our detectors to the sky and observe the energy, intensity, and direction of high-energy gamma rays. This data can then be compared to what might be expected from known astronomical sources…
This process is actually a good deal more complicated than you might imagine. First, you need to consider all the other possible gamma ray production processes and subtract those from the signal. Then, you need to create a model of the dark matter distribution and see if any observed excess of signal correlated with expected clumps of dark matter.
Finally, you need to examine the energy spectrum of the gamma rays and see if they have the right energy range and the right intensity at each energy (the shape of the spectrum) to match what might be expected from dark matter destruction.
This all probably sounds a bit strange. We don’t know what dark matter is, so we can’t know what energies the gamma rays should have, right? Well, not quite. For instance, we have a lot of particle physics data and a lot of other observations that have eliminated whole swaths of possible energies. If the excess appears in a region of the spectrum that is known to not originate from dark matter annihilation, we know the signal is spurious.
Taking all of this information into account, there is a signal that looks like dark matter. But—and this is a big but—not all possible background gamma ray production processes have been taken into account yet. It might be possible that there are faint gamma ray producers that just happen to coincide with the observed hot spots. These producers would be astronomical objects like galaxies that have not been cataloged over the course of ordinary observation.
Why the BBC is important, the latest David Attenborough documentary (58mins) ‘Attenborough and the Giant Dinosaur’:
watch it while you can!
My lab (the lab I’m in, not the lab I own) in the NYT today! Schizophrenia research is pretty awesome…
Here is a bike water bottle that uses a hydrophobic condensator to pull water out of the air while you ride your bike.
This is an interesting article about math education, and how traditional western educational practices are doing it wrong.
I absolutely would love to see a great deal more Euclidian plane geometry (done the fun way with actual compass & straight edge) in grade school, but from my experience grading college students, I don’t think there’s much benefit to learning calculus rules early.
Most students don’t have the capacity to understand the actual concepts at the much earlier age the rules are introduced in some cultures. It amounts to rote memorization, which almost hinders those students when they get to the age where they can understand what’s going on.
Baking basic algebra into students’ bones, on the other hand, is the equivalent of forcing students to diagram sentences as they learn their native language. There’s no deeper understanding to be had than what children can comprehend. It’s just something you have to know like the back of your hand to be literate in either context.
I expected the link to lead to a “mathematician’s lament”, rather than to an interesting article about math circles and moebius noodles, whatever they are.
Yeah, it made an interesting point about how we tend to focus on “Simple but hard” stuff, assuming that children can handle it better than the “complex but easy” stuff. When in reality, the human brain is awesome at doing all kinds of ridiculously complex things.
Ultimately, with things like integral calculus, we actually naturally do that stuff in our heads constantly as part of our visual processing. Your brain is good at math, if you simply don’t get in its way with silly crap.
Interesting tidbit: Angela Merkel holds a Ph.D in physics. I did not know that.
Aren’t fusion reactors moving towards a spherical design now, due to their being much smaller and able to generate much higher reaction pressures with a given magnetic field?
Either way, it seems like we are likely to see functional fusion reactors in our lifetime, which will effectively solve humanity’s energy problem.
That’s pretty cool. But when I see that its called the “experimental stellarator” I can’t help but read that in the voice of Dr. Doofenshmirtz.
“Behold, the experimental stellaratinator! You see, back in Gimmelshtump…”
RBF, or “Resting Bitch Face” is real.
Scientists pick a neutral-looking image of a person — one in which they aren’t smiling — and run it through the FaceReader software. The software then registers the face and gives a percentage of underlying emotions it’s picking up.
On an average reading, the software will register a face at 97% neutral. But there’s about 3% of an underlying expression, Macbeth explained. That 3% is made of emotions that show traces of sadness, happiness or anger, for example.
“We see that people who have this RBF expression [have] double the amount of emotionality expressed,” she said. Those afflicted with RBF may show a jump of trace emotions as high as 6% and most of the emotion expressed is of contempt: the feeling that something is worthless or deserving scorn.
I think you’re right: http://www.generalfusion.com/ Fusion has been what, 30 years away for forever, but demostrable progress is getting made. Fusion reactors will change the world as we know it. Almost hard to imagine.
Sounds like huge progress. Still likely to be major scale/economics issues with moving to a feasible commercial scale:
Well, this is actually one of the chief advances being made currently… Various groups are starting to realize that it’s actually easier to do fusion using SMALLER reactors. Some of this comes in the form of the spherical reactors, where shrinking the toroid into a sphere dramatically reduces the size, but also the efficiency of the magnetic field. So the overall effect is an improvement across the board.
Likewise, the High Beta reactor that Lockheed is working on is in the same line of thought… a small, even portable reactor that’s about the size of a tractor trailer, and produces something like 100 megawatts of power. Of course, they are using some novel approaches.
The cool thing about the Lockheed approach is that by virtue of the fact that they’re lockheed… they aren’t faking it. They’re doing this as a business, so they fully intend to actually make a commercial product in the reasonably near future.
This bit did get a chuckle out of me - because that sure is not the Lockheed I grew up around. I’m sure that Lockheed also talked in terms of commercial products - but what they were really making money on back then were top-secret military projects with top-secret, unlimited budgets and cost overruns.
LDRIC the golf-bot smashes the 16th green at TPC Scottsdale.
Oh yeah, I know that… but I don’t believe that their fusion reactor project is a military contract. I believe it’s being funded largely internally, isn’t it?
Presumably, if they were doing it for the military, they wouldn’t be broadcasting its development.