Comments on: Searching for Dark Matter

Searching for Dark Matter

Burhanistan — Sun, 30 Mar 2008 20:55:02 -0800

Scientists at Amundsen-Scott Station at the South Pole have begun searching for the elusive dark matter using the South Pole Telescope.

The Station has been visited here before, but not in this context.

By: porpoise

porpoise — Sun, 30 Mar 2008 20:59:40 -0800

Photographic evidence of theoretical dark matter.

By: not_on_display

not_on_display — Sun, 30 Mar 2008 21:24:53 -0800

One of the first goals of the SPT is to try to confirm the existence of the Dark Energy and find out something about its properties. It likes to disrupt interviews, it seems.*

By: The Card Cheat

The Card Cheat — Sun, 30 Mar 2008 21:27:06 -0800

"Only about 4% of the total energy density in the universe (as inferred from gravitational effects) can be seen directly. About 22% is thought to be composed of dark matter. The remaining 74% is thought to consist of dark energy...It has been noted that the names "dark matter" and "dark energy" serve mainly as expressions of human ignorance, much as the marking of early maps with "terra incognita"." 4%, eh? I'll remember that the next time Roger Penrose or Stephen Hawking try to get all uppity on me.

By: not_on_display

not_on_display — Sun, 30 Mar 2008 21:29:43 -0800

^porpoise: Photographic evidence of theoretical dark matter. No pun intended, but I don't see the evidence you're pointing to. OK, pun slightly intended.

By: intermod

intermod — Sun, 30 Mar 2008 21:35:33 -0800

porpoise, I think you're misunderstanding what dark matter is. I believe that picture simply shows how some regular matter has blocked the light from reaching us. Dark matter (see the "matter" link above) isn't just dark in the sense that it blocks light like your hand in front of the sun, it means it literally can not be seen by any means. It doees not emit nor reflect radiation. Only the gravitional effects of its apparent presence can be observed. Now, if that image had shown effects of gravitational lensing, then sure, it could be captioned as perhaps evidence of dark matter. But that's not what it shows and that' s not how it's captioned. And thanks Burhanistan for helping me burn half an hour digging into all this ... I don't quite understand why a Chilean mountaintop isn't good enough, forcing them to the extremely difficult environment of the south pole. Maybe someone knowledgable (!) can explain.

By: delmoi

delmoi — Sun, 30 Mar 2008 21:45:31 -0800

Dark matter (see the "matter" link above) isn't just dark in the sense that it blocks light like your hand in front of the sun, it means it literally can not be seen by any means. Oy. "Dark Matter" simply means matter that does not emit enough light to be visible on earth. Your hand and everything else on earth is technically Dark Matter, or it would be dark matter if it was on another planet. The "mysterious" stuff is actually a subset of Dark Matter called non-baryonic dark matter. Baryonic dark matter is dark matter which is made out of "normal" particles (protons and neutrons) and includes everything anything made out of atoms which is not emitting light.

By: Balisong

Balisong — Sun, 30 Mar 2008 22:08:57 -0800

I blame Heisenberg.

By: Clave

Clave — Sun, 30 Mar 2008 22:16:42 -0800

I blame Heisenberg. Are you sure?

By: Brian B.

Brian B. — Sun, 30 Mar 2008 22:18:27 -0800

How will this end up in a creationism debate, and what do I need to know to make it go away?

By: Ynoxas

Ynoxas — Sun, 30 Mar 2008 22:28:05 -0800

How will this end up in a creationism debate, and what do I need to know to make it go away? posted by Brian B. at 12:18 AM on March 31 Are you denying that God could make matter that even he couldn't see?

By: Brian B.

Brian B. — Sun, 30 Mar 2008 22:38:35 -0800

Are you denying that God could make matter that even he couldn't see? To look on the bright side (no pun necessary), if God was hiding in that stuff, he could have a PR problem.

By: Tube

Tube — Sun, 30 Mar 2008 22:51:04 -0800

One surprisingly low-tech hitch, however, will keep the telescope from operating at 100% until early 2009. The telescope is designed to nest inside a huge metal shield -- a 75-foot-high, 155-foot-wide bowl-shaped structure that will block ambient light traveling from South Pole buildings two-thirds of a mile away. Even those minute sprinkles of light can be enough to skew the telescope's super-sensitive sensors in certain sectors of the sky. A couple of summers back we were vacationing in Marfa Texas, and decided to visit the nearby McDonald Observatory. With an assembled group we were led by the tour guide into the main room where the huge telescope was kept. The tour guide began to detail how the telescope functioned, then switched on a motorized mechanism that caused the telescope to elevate. Suddenly a metal bolt fell from somewhere on the intricate device. No catastrophe ensued, thankfully, but it must have been rather embarrassing for the tour guide. Even high-tech scientific devices can have low-tech problems...

By: hortense

hortense — Sun, 30 Mar 2008 23:41:15 -0800

Very cold there today * NZSP: Amundsen-Scott Stn, Antarctica [-57°C, -70.6°F]

By: jouke

jouke — Sun, 30 Mar 2008 23:43:41 -0800

Pf, how hard can it be finding that dark matter on all that snow and ice?!

By: teppic

teppic — Mon, 31 Mar 2008 00:11:04 -0800

That headline says South Pole telescope peers heavenward for dark energy, which is different from dark matter, no? Dark energy being some mysterious quality of space, and dark matter being something mysterious floating around in space.

By: hal incandenza

hal incandenza — Mon, 31 Mar 2008 01:58:45 -0800

Huh. I'm a graduate student working on this project. In fact, I spent most of January and half of February at the South Pole working on the SPT camera. First things first: why the South Pole? It turns out that its elevation, temperature, and atmospheric stability conspire to make it an ideal place to do millimeter-wavelength astronomy. But it's obviously not the most accessible place in the world: South Pole Station's ice runway is only open for business from about November to mid-February every year, when the sun is up all day and temperatures range from about -15 to -50 C. This is what passes for summer. I stayed for about six of those weeks, which was about typical for our team of 20 or so scientists and students; but most of the station's support staff, construction crews, maintenance crews, etc. (and even a couple SPT scientists) stayed for the whole season. The station closes each year when the temperature drops low enough that LC-130s can no longer land safely. Just before that happens, the "day shift" bugs out and the "night shift" takes over. For the 2008 winter season, about 60 people--including Keith and Dana, SPT's two intrepid winter-overs--are now holding down the fort, tied to the outside world only via a few hours of satellite coverage and some spotty Iridium service. Anyway, as Burhanistan said, our experiment hopefully will yield some information about dark matter. But we're actually more interested in dark energy; the names may be similar, but they're different things. Dark matter is believed to be some form of non-baryonic matter (i.e. not electrons, protons, neutrons, or any of their heavier siblings, but something more exotic) that interacts only weakly with normal matter. Although nobody has figured out exactly what it is, it's reasonably well understood from a phenomenological standpoint, and the evidence for its existence is very solid. Dark energy is a more mysterious beast. It was discovered due to its most dramatic effect: it causes the universe's expansion to accelerate. One form of dark energy was proposed by Einstein, who included a so-called Cosmological Constant in his formulation of general relativity. But dark energy need not be as simple as Einstein's formulation, and one of the primary goals of the SPT is to try to see if Einstein's model is actually consistent with the universe we live in. We'll do so by mapping out the Cosmic Microwave Background (CMB) to high resolution in a large section of the sky, picking out clusters of galaxies using their distinctive imprint on the CMB, and comparing the statistical properties of their distribution to simulations. There are a number of other experiments working on similar but complementary surveys (such as APEX-SZ, SZA, and ACT), and the data gathered over the next few years should teach us quite a bit about dark energy and cosmology in general. Incidentally, there are some great theories in the dark corners of the internets about the true purpose of the SPT: Planet X. Google it. It's fun. Especially entertaining is the video that purports to be SPT's first observation of Planet X--apparently the camera we've been spending so much time on is actually an Atari 2600. And finally, here are a few pretty pictures from Zak--one of last year's SPT winter-overs--and his friends.

By: Dr. Curare

Dr. Curare — Mon, 31 Mar 2008 03:11:05 -0800

hal, is there a lot of competition to get to work at the South Pole (like becoming an astronaut), or is it just bad luck that whatever you decided to study just happens to be best seen there?

By: geos

geos — Mon, 31 Mar 2008 04:20:44 -0800

previously

By: Devils Rancher

Devils Rancher — Mon, 31 Mar 2008 04:57:21 -0800

I've read that the ice at the pole moves as much as 30 feet per year. Do they pick up all that stuff and move it back annually, or what? Just curious.

By: Skorgu

Skorgu — Mon, 31 Mar 2008 05:17:26 -0800

Man I love science. Between this, the Pioneer gravity anomaly, the LHC and a dozen or iterative steps in robotics and AI (not to mention Mr. Venter and his designer bugs) it's an awesome time to be alive.

By: jmnugent

jmnugent — Mon, 31 Mar 2008 05:20:43 -0800

hal incandenza, Thanks for popping in to share, thats awesome !

By: hal incandenza

hal incandenza — Mon, 31 Mar 2008 07:48:25 -0800

Dr. Curare - It depends on what you want to do there. Many of the crane operators, iron workers, etc. had to apply for several years in a row before they were able to come to Antarctica, despite the fact that the money isn't all that great. For scientists and students, it's more serendipitous; as you might imagine, there are only a few kinds of experiments for which it makes sense to accept the logistical challenge of working in Antarctica. The largest group of scientists and students this year worked for the IceCube neutrino observatory, followed by the SPT, followed by another millimeter-wavelength cosmology project called BICEP. There are a few atmospheric scientists and seismologists down there too, but it's mostly physicists and astronomers. Devils Rancher - Yeah, 30 feet per year sounds about right. Nothing gets moved other than the pole marker, though, so the SPT is further away from the geographic pole today than it was when it was constructed.

By: elfgirl

elfgirl — Mon, 31 Mar 2008 08:39:36 -0800

Dr. Curare -- I know someone who's a winterover this year and she said most of the ~~non-beaker~~ non-science staff are hired through Raytheon. As long as you can pass the psych and physical tests, and assuming you have a skill they're looking for, you're eligible. hal -- Did you meet Sue from Weather Obvs while you were there?

By: Devils Rancher

Devils Rancher — Mon, 31 Mar 2008 09:58:40 -0800

Yeah, 30 feet per year sounds about right. Nothing gets moved other than the pole marker, though, so the SPT is further away from the geographic pole today than it was when it was constructed. I just finished a book on Shackelton's "forgotten" expedition, where they got within 97 miles of the S. pole, man-hauling sledges, and nearly freezing/starving to death. In 1908. Those people where goddam insane. It's amazing what 100 years of progress will get you. I think that's where I saw the stat concerning glacial movement at the pole.

By: By The Grace of God

By The Grace of God — Mon, 31 Mar 2008 14:24:40 -0800

This is a good spot to link Big Dead Place, a now-archived blog full of awesome Antarctica related news and snark by the people that worked there.

By: By The Grace of God

By The Grace of God — Mon, 31 Mar 2008 14:32:59 -0800

hm, looks like it is being updated again! Yay!

By: GrammarMoses

GrammarMoses — Mon, 31 Mar 2008 17:21:30 -0800

I am an Antarctica fanatic -- can't believe it took me this long to find this post. hal incandenza, I envy you beyond words. And Devils Rancher -- if you liked that one, I have two more to recommend: 1) Endurance: Shackleton's Incredible Voyage, by Alfred Lansing, and 2) The Worst Journey in the World, a memoir by Robert F. Scott's crew member Apsley Cherry-Garrard (which has been recommended many times all over MeFi, I do believe).

By: EndsOfInvention

EndsOfInvention — Mon, 31 Mar 2008 21:04:30 -0800

And finally, here are a few pretty pictures from Zak--one of last year's SPT winter-overs--and his friends. Love this comment on one of the Flickr pics: When you were little you always wanted to visit Hoth. You got your wish, now get the hell back. 23 days and counting. Dad

By: Dr. Curare

Dr. Curare — Tue, 01 Apr 2008 17:13:13 -0800

Well, it seems I don't have what it takes to work there. Not a lot of demand for overweight chain-smoking actionscript developers in the South Pole. I just shaved my antarctic explorer beard in dejection. I will have to keep writing code and hope this is not a second dot com bubble, so that one day I can afford a private expedition.

By: freya_lamb

freya_lamb — Sun, 06 Apr 2008 11:53:15 -0800

Great post. BTW, Dr Curare! If you're anywhere London in the next week you could do worse than checking out the Ice Station Antarctica exhibit at the Natural History Museum. It's aimed at the wee nippers, but I loved it. Temperatures below freezing! Penguin vomit! Cabin fever! And I did get a more visceral understanding of just how ill-equipped I'd be out there. No dark matter though, I'll just have to wait for the grown-up version to be installed :)

By: intermod

intermod — Sat, 12 Apr 2008 20:28:48 -0800

Thanks mathowie for putting this in the sidebar so that I got to see all the great comments after I first read this at the time it was posted . Another science nerd envious of hal ...