14 November 2007
Shortly before sunset, on 13 November 2007, there were beautiful patterns of scattered clouds over the Bibliotheca Alexandrina. BA Senior Astronomy Specialist Aymen Ibrahem captured interesting images of the fascinating cloud shadows and crepuscular rays that glimmered in the sky.
12 November 2007
On 3 November 2007, there were clouds of various altitudes over Alexandria, Egypt. BA Senior Astronomy Specialist Aymen Ibrahem pictured colorful views of the beautiful sunset and evening twilight of that day.
10 November 2007
The most promising new treatment for severe depression is not a pill. It is a permanent implant that shocks the brain. Is this what joy looks like?
08 November 2007
RAND paper finds diesel, hybrid vehicles can provide more societal benefits than gas-powered autos
08 November 2007
Mt Ruapehu has a summit plateau which consists of several craters covered under a central glacier. The active vent contains a crater lake. Is is about 400 m wide, 600 m deep and contains highly acidic water, up to 600C warm. The lake drains through an ice cave just off the tip of the wing. The temperature and color changes all the time. The color ranges from green to muddy grey, and earlier this century the water sometimes had frozen or even disappeared.
08 November 2007
The white wagtail is a beautiful small bird, found in Europe and Asia. It migrates to Africa, and is observable in Egypt from October to May. Practicing his favorite hobby of wildlife photography, BA Senior Astronomy Specialist Aymen Ibrahem recently captured interesting images and movies of white wagtails in Cairo and Alexandria.
05 November 2007
We hear a lot these days about how air pollution is changing temperatures on Earth. New evidence from a mountaintop in China now suggests that pollution can also change the amount of rain and snow that fall in some places.
05 November 2007
Koalas are the cutest animals you can ever see in the wild. With fluffy fur, pudgy bodies, round eyes, and wisps of spiky hair sprouting from behind their ears, koalas look like teddy bears with attitude.
01 November 2007
NASA recently published a spectacular image of Tethys, Saturn's intriguing icy moon. The image was acquired by the Saturn-bound Cassini spacecraft. It shows a magnificent surface feature on Tethys, a gigantic impact crater.
31 October 2007
A black hole is a bit like the Invisible Man: You cann't see it directly, but you might be able to catch a glimpse of its footprints. With black holes, however, you must first figure out what these footprints look like. Thanks to Frans Pretorius, we now have a pretty good idea. black holes consume everything, including light, scientists can find them only by searching for their gravitational energy. A collision between two black holes is one of the most powerful events in the universe, a cataclysm equivalent to 500 million supernovae convulsing the fabric of spacetime. Scientists now watch for signs of the resultant ripples—the first gravitational-wave detectors sensitive enough to spot these collisions are already operational, and a handful of others will begin gathering data over the next few decades. To distinguish these waves from background noise, physicists must simulate how the waves will appear when they reach Earth. They do this by solving Einstein's equations of general relativity at millions of points over a 3-D grid of space—the only way the computers can churn through the calculations like a game of Telephone, these translations can introduce minor errors that rapidly accumulate, turning the information into gibberish. Despite 40 years of effort, these errors always crashed the computers of the groups struggling to run the simulations. Some feared the problem was unsolvable. Then Pretorius, at the time a postdoc at the California Institute of Technology, single-handedly solved the problem in a year. His trick was to make the translation—and therefore the simulation—as simple as possible. "I said, 'Well, I might as well give this a shot,' " he recalls, shrugging. "It turned out to work."