I take it personally when idiot politicians call me and my fellow scientists evil liars. My latest post at Galileo’s Pendulum explains why:

Broun and his compatriots obviously think very bad things about me, my friends, and the work we do. They don’t just disagree or think we’re wrong, they think we’re literally in league with Satan. The work we do—researching, writing, and teaching others about how the Universe works—is evil in their eyes. Broun’s explicit statements that science education is all built on lies aren’t harmless. I hold education to be one of the most noble undertakings in human society, and here we have an elected official trumpeting ignorance while slandering those who work to knowledge. [Read more….]

You may hate me, but don’t spread your lies to children

Since 1995, a team of astronomers led by Andrea Ghez has been studying the motion of stars near the center of the Milky Way. They just announced the discovery that one of those stars is the closest to the black hole yet, with an orbital period of about 11.5 years—short enough that they’ve been able to track its entire orbit. This could be good news for testing general relativity in a new regime of strong gravity.

One of the earliest identified S-stars was S0-2, with an orbital period of about 16 years. Until the discovery of S0-102, it was the only star with a sufficiently short orbital period to enable a complete three-dimensional reconstruction of its trajectory, which provided the best data on the shape of the black hole’s gravitational influence. [Read more….]

Animation of star motion near the central black hole, based on real infrared observations. [Credit: Andrea Ghez et al./UCLA/Keck]

The darkness at the center of the galaxy

“Must have facts,” said Lord Peter, “facts. When I was a small boy I always hated facts. Thought of ’em as nasty, hard things, all knobs. Uncompromisin’.” (from Clouds of Witness by Dorothy L. Sayers)

My latest post over at Galileo’s Pendulum explains why I won’t be writing a book called “1,001 Mind-Blowing Facts About the Universe” any time soon, even when offered money to do so. Bonus: contains “yo momma” jokes.

Style aside, there’s another reason I’m not a big fan of omnibus fact lists: that’s not a very scientific way to organize knowledge. Facts are some of the least useful things in science, so just dumping a list of them on readers will not generally result in much gain in understanding. [Read more….]

Just the facts, ma’am

(This headline was my original choice for the article, which was understandably rejected by my editors. So, you get to read it here instead.)

Pulsars are rapidly-spinning neutron stars, the very small dense remnants of stars at least 8 times more massive than the Sun. Their pulses are intense beams of light that sweep across our field of view each time the neutron star rotates. A pulsar’s rotation slows down over time, though, and some researchers in the UK have proposed a simple physical model that refines the most widely accepted theory.

Observations of the matter expelled by the initial supernova can be used to estimate the age of the pulsar; those numbers can be compared to age estimates based on its spin slowdown. In some cases, these estimates match reasonably well, but in others, they give wildly different results, differing by thousands of years at the extreme. The researchers’ model began with a different assumption: that the superfluid comprised a higher fraction of the core before things start to cool down. The result is pinning: the vortices in the superfluid stick to one spot relative to each other. That means the superfluid’s rotation rate remains the same, while the rest of the pulsar continues to slow down. [Read more….]

Spinning pulsar, got to slow down

There’s just one word for the ‘teens: plastics photovoltaics. A new experiment may have solved a problem in nanostructured silicon solar cells: a type of photovoltaic cell that uses pores to increase the effective surface area for collection of light.

By separating the contribution by surface and interior recombination effects, the NREL study found that Auger recombination—recombination by these interior charges—was actually more damaging to photocell efficiency. In other words, the very pores that offered advantages also led to problems, which was why nanostructured photovoltaics haven’t lived up to their promises thus far.

The researchers found that etching the silicon material with tetramethylammonium hydroxide (TMAH) greatly increased the efficiency of the photocell. The result was shallower, slightly wider, and more irregularly shaped pores. [Read more….]

Pore, pore, pitiful solar cells