Saturday, May 30, 2009

The White Tiger

While on a scuba diving trip to Cocos Island last week, I read The White Tiger the 2008 Man Booker award winner, a coming-of-age story about a poor young man in India.

Self Control Studies in the New Yorker

Don’t! The secret of self-control

Wednesday, May 13, 2009

William Blake - Auguries of Innocence

William Blake - Auguries of Innocence
To see a world in a grain of sand,
And a heaven in a wild flower,
Hold infinity in the palm of your hand,
And eternity in an hour.

Joy and woe are woven fine,
A clothing for the soul divine.
Under every grief and pine
Runs a joy with silken twine.

Lepton Oscillations

Do charged leptons oscillate?
The question of whether charged leptons oscillate is discussed in detail, with a special emphasis on the coherence properties of the charged lepton states created via weak interactions. This analysis allows one to clarify also an important issue of the theory of neutrino oscillations.

Tuesday, May 12, 2009

The Fall of the Roman Empire

I just finished reading How Rome Fell by Adrian Goldsworthy. I found the story of the last "pagan" emperor Julian the Apostate most fascinating.

Monday, May 11, 2009

The Cartwheel Galaxy

The Cartwheel Galaxy may be the result of a collision with one of the two nearby galaxies to its right.
Hubble Space Telescope - NASA

Friday, May 08, 2009

Sahara Dust and Atlantic Ocean Temperatures

The Role of Aerosols in the Evolution of Tropical North Atlantic Ocean Temperature Anomalies
Observations and models show that northern tropical Atlantic surface temperatures are sensitive to regional changes in stratospheric volcanic and tropospheric mineral aerosols. However, it is unknown whether the temporal variability of these aerosols is a key factor in the evolution of ocean temperature anomalies. We used a simple physical model, incorporating 26 years of satellite data, to estimate the temperature response of the ocean mixed layer to changes in aerosol loadings. Our results suggest that the mixed layer’s response to regional variability in aerosols accounts for 69% of the recent upward trend, and 67% of the detrended and 5-year low pass–filtered variance, in northern tropical Atlantic Ocean temperatures.

Free Will

The Sources of Human Volition
Every day we make actions that seem to depend on our "free will" rather than on any obvious external stimulus. This capacity not only differentiates humans from other animals, but also gives us the clear sense of controlling our bodies and lives. It therefore forms a key element of our personal identity. However, such voluntary actions are a puzzle for modern neuroscience. Where do they come from? A study by Desmurget et al. (1) on page 811 of this issue reveals how the brain may produce our experience of initiating voluntary action.

Tuesday, May 05, 2009

Edgar Allan Poe - Cosmologist

If the universe is infinite and homogeneous why is the night sky dark? There's an argument that really the entire sky should be just as bright as the sun. That's called Olbers' paradox. Edgar Allan Poe was athe first to suggest a solution to this problem - that perhaps the universe had a beginning in time.

Face Recognition

Symmetry, probability, and recognition in face space
e essential midline symmetry of human faces is shown to play a key role in facial coding and recognition. This also has deep and important connections with recent explorations of the organization of primate cortex, as well as human psychophysical experiments. Evidence is presented that the dimension of face recognition space for human faces is dramatically lower than previous estimates. One result of the present development is the construction of a probability distribution in face space that produces an interesting and realistic range of (synthetic) faces. Another is a recognition algorithm that by reasonable criteria is nearly 100% accurate.

Green Fluorescent Protein

Green glow deciphered - Mysterious jellyfish gene widely used in biology find its place in nature.

Space Clocks

Title: Orbit determination for next generation space clocks
Over the last decade of the 20th century and the first few years of the 21st, the uncertainty of atomic clocks has decreased by about two orders of magnitude, passing from the low 10^-14 to below 10^-16, in relative frequency . Space applications in fundamental physics, geodesy, time/frequency metrology, navigation etc... are among the most promising for this new generation of clocks. Onboard terrestrial or solar system satellites, their exceptional frequency stability and accuracy makes them a prime tool to test the fundamental laws of nature, and to study gravitational potentials and their evolution.
In this paper, we study in more detail the requirements on orbitography compatible with operation of next generation space clocks at the required uncertainty based on a completely relativistic model. Using the ACES (Atomic Clock Ensemble in Space) mission as an example, we show that the required accuracy goal can be reached with relatively modest constraints on the orbitography of the space clock, much less stringent than expected from "naive" estimates. Our results are generic to all space clocks and represent a significant step towards the generalised use of next generation space clocks in fundamental physics, geodesy, and time/frequency metrology

Monday, May 04, 2009


Time as an Illusion
We review the idea, due to Einstein, Eddington, Hoyle and Ballard, that time is a subjective label, whose primary purpose is to order events, perhaps in a higher-dimensional universe. In this approach, all moments in time exist simultaneously, but they are ordered to create the illusion of an unfolding experience by some physical mechanism. This, in the language of relativity, may be connected to a hypersurface in a world that extends beyond spacetime. Death in such a scenario may be merely a phase change.