Saturday, January 29, 2011

Polar Ring Galaxies

Polar Ring Galaxies have a large ring of material perpendicular to the main galaxy. See also Polar Disk Galaxy found in Wall between Voids.
 Polar Ring  Galaxy NGC 4650A: A Disk of Red Stars Ringed By Dust, Gas, and More Stars
Source: Hubblesite.org

Another Void Model of Cosmic Acceleration

Supernovae observations published in 1998 surprisingly indicated that the expansion of the universe is accelerating - with the standard explanation being Dark Energy. A very different explanation for this acceleration is the possibility that we are near the center of a gigantic void in the distribution of galaxies. Many such Voids (smaller, but still mind-bogglingly large themselves) have been found. The preprint Reconciling the local void with the CMB elaborates on earlier proposals by relaxing the assumption that the Cosmic Microwave Background (CMB) is scale-invariant.
Here's an earlier blog post on this topic: Void Models of Cosmic Acceleration.

Friday, January 14, 2011

Ghost Imaging

Quantum effects are sometimes very strange and occasionally even useful. Ghost imaging is a particularly bizarre example. It's possible to create an image using pairs of photons. One photon is sent to the subject and the other is sent to the camera. An image of the subject is created using the photon which is received by the camera - even though that photon was never anywhere near the subject! This is possible because of the (weird) quantum nature of photons. Here's a blog post that discusses recent research in which the photon source is classical instead of quantum - supposedly you can even use sunlight. Making ghost images by getting sunlight to act quantum

Wednesday, January 12, 2011

Neandertals Cooked

Neandertals have often been characterized as highly carnivorous but now it appears that they ate a variety of plant foods and even cooked them: Microfossils in calculus demonstrate consumption of plants and cooked foods in Neanderthal diets at PNAS and here's a link to the full paper.

Tuesday, January 11, 2011

Top Quark Asymmetry

There are six quarks in the standard model of physics, the heaviest is the top quark. The Tevatron at Fermilab in Batavia, Illinois had earlier detected an unexpected asymmetry in top quark/antiquark production, but it wasn't overwhelmingly significant statistically speaking. New results in 2011 are more significant - see this preprint: Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark Pair Production . There's a discussion at the R├ęsonaances blog.

Monday, January 10, 2011

Motion Blinds Change Awareness

Motion Silences Awareness of Visual Change

One Way Ticket to Mars

Getting to the planet Mars isn't so difficult, as it turns out - it's coming back that's hard. Are you you willing to permanently relocate? To Boldly Go: A One-Way Human Mission to Mars discusses the possibilities.

Extinctions and Ocean Anoxia

There were a series of massive extinctions during the Cambrian period around 500 million years ago, the period when the first modern animals are found. There is new evidence that the extinctions coincided with dramatic decreases in ocean oxygen levels: Biogeochemistry: Toxic Cambrian oceans in Nature.

Hubble pictures of Hanny

Hubble Zooms in on a Space Oddity has better images of Hanny's Voorwerp.

Sunday, January 02, 2011

The Flood Myth

There's a big flood in the book of Genesis as well as other cultures: Flood myth. One hypothesis is that those stories originated from the time when the Black Sea basin was mainly dry land: Black Sea deluge theory at Wikipedia and The Search for Noah's Flood at National Geographic. Here's another possibility: Lost Civilization May Have Existed Beneath the Persian Gulf. During the last Ice Age the Persian Gulf was dry land and may have been heavily settled. Maybe the flooding there as water levels rose at the end of the Ice Age was the origin of the stories?

Saturday, January 01, 2011

Renormalization

Quantum Field Theory (QFT)is the basic framework for both particle physics and condensed matter physics. However, disturbingly, QFT calculations are plagued by unwanted infinities. All too often, when we use the theory to calculate some observable property - for example, the mass of a particle - our calculation diverges, there is no finite solution. This can't be a good thing, especially when we find in our laboratories that the mass of that particle is indeed finite. Ordinarily, this would seem like a really good reason to throw up our hands and find ourselves a better theory. But theoretical physicists are made of sterner stuff. Whenever they stumble across one of these infinities they simply use the actual observed laboratory value instead. They then proceed with their calculations until they hit another observable infinity and do it again. For certain happy theories, clever people have proved that it's only necessary to resort to the process of kludging in laboratory values a finite number of times. The theory is then said to be renormalizable and the lucky physicist who creates such a theory may well get a Nobel Prize. Steven Weinberg got his Nobel Prize after the theory of electroweak interactions which he helped create was shown to be renormalizable. In the 2009 preprint Living with Infinities Weinberg discusses the problems with infinities in QFT.

Hanny's Voorwerp

Hanny's Voorwerp is mysterious green object found by an amateur during the Galaxy Zoo project, which enlists the public to help classify galaxies over the internet.
http://antwrp.gsfc.nasa.gov/apod/ap080625.html