Large Hardon Collider

[Woozie]

I'm about to dump a few articles here. Probably more than anyone will read in one sitting, but they all seem pretty interesting.

Dark energy on firmer footing

tl;dr: Thirty years ago, a test was proposed to verify that the universe is expanding at an accelerated rate due to dark energy. A recent test as somewhat confirmed it. Nothing new really came from this. They just confirmed something we were already pretty sure of.

http://www.nature.com/news/2010/1011....2010.629.html

Spoiler: show

he claim that mysterious dark energy is accelerating the Universe's expansion has been placed on firmer ground, with the successful application of a quirky geometric test proposed more than 30 years ago.

The accelerating expansion was first detected in 1998. Astronomers studying Type 1a supernovae, stellar explosions called "standard candles" because of their predictable luminosity, made the incredible discovery that the most distant of these supernovae appear dimmer than would be expected if the Universe were expanding at a constant rate.1 This suggested that some unknown force - subsequently dubbed dark energy - must be working against gravity to blow the universe apart.

Since that time, studies comparing variations in the cosmic microwave background radiation — an echo from the Big Bang — with the distribution of galaxies today have allowed cosmologists to trace how the Universe has expanded, supporting the idea of dark energy. They have also suggested that the Universe is 'flat' — that is, it contains just enough matter to keep it delicately poised between collapsing in on itself and expanding forever2.

hese two assumptions have become a fundamental part of cosmologists' understanding of the Universe. Now Christian Marinoni and Adeline Buzzi of the Centre for Theoretical Physics at the University of Provence in Marseilles, France, have independently checked these ideas by analysing the geometry of orbiting pairs of galaxies. Their study is published this week in Nature3.

The researchers used a version of the Alcock–Paczynski test, which relies on identifying symmetrical objects in space and using them as 'standard spheres'. Any distortions in space caused by the expansion of the cosmos would cause the most distant standard spheres to appear asymmetrical. "This provides a similar level of accuracy to supernovae," says Marinoni. "It's a direct proof of dark energy."
Object lessons

For example, if the universe is expanding outwards due to dark energy, distant objects will appear elongated along the line of sight from Earth, because Earth and the objects are being propelled away from one another along that direction.

Several groups have tried to apply the test, for example by considering clusters of galaxies as the standard spheres, but largely failed because they could not measure distant objects with sufficient accuracy.

To get round this, Marinoni and Buzzi instead studied the distribution in orientations of pairs of galaxies that orbit each other. In a Universe without dark energy, that distribution is expected to be spherically symmetrical — in other words, the number of galaxy pairs oriented in any particular direction should be the same.

The researchers found that the farther away the galaxy pairs were, the more asymmetrical the distribution was, with more galaxy pairs oriented along the line of sight from Earth. The pattern matched what would be expected in a flat Universe expanding due to dark energy.

The reliability of the test depends on the assumption that the distribution in orientations of galaxy pairs doesn't change depending on their distance from Earth — an idea that is largely untested. But researchers are still excited by the result.

"It's a very clever idea, it's unexpected, and it's going to take a while to determine whether it's accepted or not," says Charles Alcock, director of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and co-proposer, in 1979, of the test Marinoni and Buzzi used4.

"This is a cool new tool. It's another indication that everything is consistent," says Anthony Tyson, who studies cosmology at the University of California, Davis. Tyson adds that he is sceptical about some of the assumptions underlying theories of dark energy, so he finds independent efforts to confirm its presence extremely valuable. "For those of us who are doubters, it's making us think twice," he says.

Future surveys of distant objects are planned, for example using the European Space Agency's planned Euclid space telescope, and the Wide Field Infrared Survey Telescope, a proposed mission that was the top recommendation of the US National Academy of Sciences Decadal Survey of Astronomy and Astrophysics. Marinoni says he hopes these will find further remote pairs of galaxies that can be analysed to pin down the nature of dark energy, perhaps even enough to overtake the accuracy offered by studies of type Ia supernovae

Early universe recreated in LHC was superhot liquid

http://www.newscientist.com/article/...ot-liquid.html

Doesn't really look like a huge deal, but on the bright side, every single inconsistency with the standard model we find is going to bring us one step closer to finding the appropriate theory to replace the Standard Model (afterall, every particle physicist agrees that the standard model is very limited and at high energies we'll need something new. We just can't agree on what the new theory should look like). I'm still looking forward to the LHC reaching it's full power and hopefully violating some larger parts of the standard model.

Spoiler: show

The experiment to probe the early moments of the universe started up on 7 November, smashing together the nuclei of lead atoms inside the LHC's circular tunnel to produce incredibly dense and hot fireballs of subatomic particles at over 10 trillion °C. The idea behind ALICE is to recreate the exotic, primordial "soup of particles" known as quark-gluon plasma that appeared microseconds after the universe's birth. Gluons and quarks went on to become the constitutive "bricks" of neutrons and protons inside atomic nuclei.

Many models have suggested that the flow of particles from these subatomic fireworks produced in high-energy nuclear collisions should behave like a gas and not a liquid. "These observations keep surprising us," says David Evans of the University of Birmingham, UK, a member of the ALICE team.

A further surprise was the density of subatomic particles created by the smash. One major school of thought suggests there is an upper limit on how many interacting gluons can be packed into a given volume: when this saturation point is reached during a collision, no more new debris particles should therefore be produced.

But to the surprise of the ALICE scientists, the lead ions' mini big bang produced more subatomic particles than expected. "This means that if an upper limit exists, it has not yet been reached at the energies used at LHC," says Evans.
Gold soup

This is especially significant, because ALICE has used the highest energies yet. It used energies 13 times higher those used in similar experiments in 2005 at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in Upton, New York.

The Brookhaven experiments smashed nuclei of gold atoms together to probe the same questions as ALICE. They delivered the puzzling finding that the primordial soup formed after the collision appeared to flow like a near-perfect liquid with almost no viscosity.
Energies up

Some models had indicated that if higher energies were used, viscosity values – resistance to flow of a fluid – would indicate the presence of a gas. "At the time, the RHIC results already surprised us," says Evans. "But our data still seem to show that the quark-gluon plasma flows like a superhot liquid."

He adds, however, that it is too early to draw any new interpretation about the structure of the early universe.

"Those results are impressive," comments John Ellis, a theorist at CERN who was not involved in the experiment. "But these are early days. We knew it would be very difficult to find hints of a gaseous form of quark-gluon plasma. Maybe it all started as a gas, and then its expansion, and therefore cooling, led it to become a liquid."

"We have to look deeper into the details of the collisions to be sure," admits David Evans, who is already looking forward to the LHC's next phase in 2013, when the possible collision energies will be doubled.

Self-affirming essay boosts coeds' physics skills

http://arstechnica.com/science/news/...ics-skills.ars

tl;dr: The performance gap between men and women in math and science are due mainly to people living up to perceived stereotypes. In cultures without such stereotypes, there is no gender gap. A teacher found out that even in America, the gender gap seems to disappear when you make your students write a "Self-Affirming Essay". We're all looking forward to more boobs in our classroom in the near future. Especially those of us who may become professors.

Spoiler: show

For many years, there has been a persistent achievement gap between the performance of males and females in math and the sciences. It has become increasingly apparent, however, that the problem is cultural. The math gap seems to vanish in countries with higher degrees of gender equality, while females exposed to the stereotypical expectation that they'd do worse in a subject tended to live down to these low expectations. These findings, however, don't provide clear guidance as to how to address the problem: if females have already been exposed to these stereotypes, how do you get them to ignore them and perform up to their abilities? The answer, it appears, may be as simple as a short essay.

A study in last week's Science describes a program at the University of Colorado, focused on helping to narrow the achievement gap in an introduction to physics class targeted to science majors. In past years, research had found that a strong background and preparation could account for over half the gender difference in test scores, but that still leaves other, substantial factors to explain the discrepancies.

The authors suspected that stereotypes might account for the remaining differences. "The fear of being devalued based on a group identity, such as becoming aware that one could be seen in light of a negative stereotype about one’s group, has been shown to undermine performance on difficult tests," they explain. "For example, women’s performance on difficult math and science tests can suffer insofar as they worry that their poor performance could be seen to confirm a negative gender stereotype."

Since the problem wasn't physics-based, the solution wasn't either. Instead, it focused on the worries about poor performance by taking an approach focused on self-affirmation. "When they affirm their core values in a threatening environment," the researchers suggest, "people reestablish a perception of personal integrity and worth, which in turn can provide them with the internal resources needed for coping effectively."

The test took place in a class where the efforts to equalize background and preparation for the course. Students, both male and female, were divided into experimental and control groups. In both groups, the students were given a list of things they potentially valued (ie, relationships with family and friends). The experimental group was asked to choose something they actually valued, and write an essay describing its importance, which served to affirm their own values. The control group picked something they didn't care about, and wrote about why they thought someone else might value that.

There were only two essays over the course of an entire semester, and neither of them had anything to do with the course material. Yet the results on the physics exams were pretty significant. The exam scores, which exhibited a significant gender gap in the control group, largely vanished. Women came in slightly behind the men, but the difference was not statistically significant. Men's test scores were largely unaffected. In terms of grades, the difference largely occurred as a large chunk of the women who had been receiving Cs moved up to the B category.

But the improvements weren't limited to performing well in the class' exams. The researchers also gave the students a standardized exam of general physics knowledge (the FMCE). Here, the women's performance in the experimental group was actually slightly higher than that of the men, while a large gender gap existed in the control group. This indicates a generally improved understanding of physics. After controlling for background and pre-course FMCE scores, the authors estimate that the affirmation exercise wiped out over half of the residual gender gap.

In past studies, an affirmation task has been found to work at different ages and with underachieving minority groups. In addition, the task can be completely unrelated to the topic at hand, and the authors suggest that it could probably be widely deployed in different educational contexts.

Black Hole May Offer Clues to Extra Dimensions

http://news.sciencemag.org/scienceno...ex.html?ref=hp

His theory (that if extra dimensions exist, this should lead to the brightening of images of stars on the other side of our galaxy) is still in its baby steps, but if we can somehow get a test for extra dimensions that doesn't require particle accelerators bigger than the freakin' planet, then I consider that progress.

Spoiler: show

Could space have dimensions beyond the three that we all know and love? Some theories in particle physics speculate that it might, although these dimensions would be curled up in loops so small, they could probably be probed only in high-energy particle collisions. Now, however, one theorist suggests that, at least in principle, these hypothesized dimensions might reveal themselves in another subtle way. If there are extra dimensions, then the gravity from the black hole in the center of our galaxy might dramatically brighten the images of stars beyond it. Others see problems in making the scheme work, however.

The idea rests on two assumptions. First, that space has extra dimensions. That's a central tenet of string theory, which posits that every fundamental bit of matter is really an infinitesimal string vibrating in one way or another. According to string theory, space has six extra dimensions that we don't see because they're curled and tangled up at very small length scales.

The second assumption is the warping of space by a black hole. According to Einstein's theory of gravity, matter warps space and time, or spacetime. This warping changes the paths that free-falling objects follow, making, for example, planets orbit the sun when they would otherwise travel at constant speeds in straight lines into space—in other words, creating what we think of as gravity.

In Einstein's theory, warped spacetime even affects light. When light from a star passes near a galaxy, for example, its path bends, changing where the star appears in the sky—the so-called gravitational lensing effect. If a star is just behind a gravitational lens such as a black hole, the effect can produce multiple images of a star or even a so-called Einstein ring that encircles the lens. Just like a telescope does, gravitational lensing also makes stars appear larger and hence brighter.

Now, physicist Amitai Bin-Nun of the University of Pennsylvania argues that gravitational lensing around Sagittarius A*, the supermassive black hole thought to be at the center of the Milky Way, might provide a way to search for extra dimensions. In one version of the extra-dimensions scenario, gravity is much stronger near the black hole than it would be without the extra dimensions, so that images of the stars appear larger and brighter than they otherwise would. Bin-Nun used numerical simulations to show that, in a world with extra dimensions compared with one without, a star known as S2 could be as much as 44% brighter when it reaches its peak brightness in 2018. If S2 were that bright, it could be evidence for extra dimensions or at least evidence that our understanding of gravity should be modified.

Bin-Nun says that the approach, published in Physical Review D, could be a good way to probe black hole properties, but he acknowledges practical and theoretical concerns. Using gravitational lensing to search for extra dimensions "depends on a telescope being able to see a very faint object" at the galactic center, he says, which may be impractical given current technology. Still, if astrophysicists observed the brightness Bin-Nun predicts, it could be a sign that some of those extra dimensions are coiled loosely enough to have a detectable effect.

Harvard University physicist Abraham Loeb says that "overall, it's a good idea to test modifications of gravity" using black holes. But he says Bin-Nun's hypothesis will be hard to validate and that observations of the orbits of planets in our solar system might already rule out such large changes in the strength of gravity. Furthermore, Loeb says, if the black hole is rotating, it would produce effects that could easily be confused with Bin-Nun's predictions.

[Kaylia]

but if we can somehow get a test for extra dimensions that doesn't require particle accelerators bigger than the freakin' planet, then I consider that progress.

This.

I not sure how additional dimension make star shine brighter, but I'm sure it make sense..somehow! Pretty cool experiment.

[Ferion]

As for Ferion, I'll get to your question by this weekend, hopefully. I'm just letting you know that I'm not ignoring it. I'm just too busy. I'll try to get it answered before your finals (which I assume are next week since that's when everyone else's seem to be, including mine).

To be honest I don't even remember what I asked, so don't worry about it. Especially if you have finals next week. If it's what I'm thinking of, it was for my second exam which I took already. I don't have my Advanced Calc final until the 16th so if it causes a problem while studying I'll ask again.

[Kaylia]

I'm surprised it wasnt posted already, but the discovery made by Nasa thing was a super earth with dense water atmosphere.
http://www.eso.org/public/archives/r...47/eso1047.pdf



Im amazed Hubble is powerful enough to get a glimpse of the spectrum (even if the planet is relatively close), and reconfirming once again that water is common is great, but meh, I was really hoping they had detected oxygen somewhere,

Oh well...at the rate thing are moving, I wouldnt be surprised if we find such planet in the next few years.

[Eliseos]

Why did NASA even feel the need to pre-announce this? The only purpose it will serve is to build up hype in people thinking they found little green men on Mars, and now when it's released people are going to wonder why NASA receives any funding at all.

[BerenTebogo]

I'm going to murder everyone in the NASA titled thread. Halp.

[Eliseos]

Might as well just let them do their speculation, since they clearly can't read.

Afterwards we can just be like "told you so.".

[BerenTebogo]

Yeah, between fb and bg i'm going to have an aneurysm.

[zoobernut]

I'm going to murder everyone in the NASA titled thread. Halp.

Lol that thread is a sad excuse for a discussion. People are speculating all sorts of retarded things.

Planet with dense water atmosphere is very cool indeed. I don't think it will be too long before we find a planet with an oxygen based atmosphere. At least this discovery makes it feel like a discovery like that could happen within my lifetime which makes me happy.

[foopy]

I'm going to murder everyone in the NASA titled thread. Halp.

i find it odd that you, a huge proponent of science and discovery, are not more excited about the confirmed and verified alien bacteria they found.

i guess you missed the leaked gizmodo link.

[Ferion]

You haven't heard Sath? NASA is just a subset of gizmodo, they know a thing or two about alien bacteria.

[Cruzizzle]

The big announcement is a microbe found from Mono Lake that is able to substitute arsenate for phosphate in DNA construction.

[Kaylia]

Well my bad. I thought Nasa being able to detect telluric's planet atmosphere was the big step announced lol. I guess not.

[Cruzizzle]

Anyone else that watch the announcement think Felisa Wolfe-Simon must have minored in elementary education? She reminds me of this high school math teacher who started off as a elementary school teacher we had that demanded everyone, teenagers, in unison say "Have a happy sun shiny day" at the bell and wouldn't let us leave till we did.

[BerenTebogo]

I thought this article was one of the coolest I've read all year. Too many pics to quote. http://scienceblogs.com/startswithab...s_how_abou.php

[Eliseos]

That's fucking bad ass.

[Woozie]

Wow, that is pretty awesome.

♫Can we pretend that airplanes in the night sky are like shooting galaxies?

[Shiroikage]

It's not even an alien microbe. Our department chair was pretty skeptical and voiced it at our Christmas party.

[Max™]

Wow, that is pretty awesome.

♫Can we pretend that airplanes in the night sky are like shooting galaxies?

Spoiler: show

http://images1.memegenerator.net/Hay...NICER-TITS.jpg

Those shooting galaxy pics are totally worth posting, Sath.



http://scienceblogs.com/startswithab...sn-galaxy.jpeg
http://scienceblogs.com/startswithab...8_UV_Wake.jpeg

Fuckin' stars and shit, wouldn't that be a trippy spot for life to form, like the reverse of the globular cluster Nightfall story.

[Kaelan?]

Wow, that is pretty awesome.

♫Can we pretend that airplanes in the night sky are like shooting galaxies?

http://www.nytimes.com/2010/12/02/sc...ce/index.jsonp

How Many Stars? Three Times as Many as We Thought, Report Says
(...)
Also inconclusive: whether we now have three times as many wishes.