Light emission from organic materials occurs through two separate processes: fluorescence – the process by which today’s organic semiconductors produce light – and phosphorescence. In fluorescence, a material absorbs charge carriers such as electrons and electron holes. The opposite charges meet up and combine to form an excited state known as an exciton. The material […]
The team claim to have evidence for: an thin outer layer that is hot; a warm middle layer that is also optically thick; and a “cold” inner layer. The similarity of these layers to that of the corona, chromosphere and photosphere of the Sun suggest that similar physical processes may be at work in both […]
Mara Prentiss and colleagues at Harvard University in the US mounted two short wires on a sapphire substrate (Phys. Rev. Lett. 84 1124). When electric currents flow in opposite directions through the wires, a magnetic field is generated. An external magnetic field can then be used to cancel this field in the region between the […]
Previously is was thought that the result might have been due to some inadequacy in the data for the troposphere. However, Dian Gaffen from the US National Oceanic and Atmospheric Administration and colleagues have analyzed the data carefully and confirmed that although the temperature changes with height, the current average temperature measurements for the troposphere […]
The disagreement stems from a paper Gott published in Nature several years ago and recently discussed in the New Yorker magazine. In this paper Gott proposed a formula that suggests that by knowing how long an object, person, species or event has existed for, you can make a generalised prediction for how long it will […]
The Delft group fabricated the electrodes by making a slit in a silicon nitride film with standard lithography. A series of platinum layers were then sputtered across the slit until the gap was reduced to 4 nanometers. The electrodes were then immersed in a droplet of dilute DNA solution. A voltage applied between the electrodes […]
Molecules are poor candidates for the standard techniques used to create Bose-Einstein condensates because of their complicated internal vibrational and rotational structures. But by creating the molecules from atoms that are already inside a condensate, the Texas researchers have been able to put all the molecules into the same quantum state. The molecules, which have […]
Immediately after humans discovered writing, they must also have discovered that concealing information is almost as important as expressing it. They also learned that there is nothing more fascinating than other people’s secrets. The ancient art of cryptography (code-making) has throughout history been matched against the ingenuity of cryptanalysts (code-breakers), sometimes in very dramatic circumstances. […]
Read article: Coded secrets cracked open
Meanwhile, ESA this week released the first two images from XMM-Newton. One shows the Magellanic Cloud, with hot gas released from supernova explosions and new stars being created in a interstellar nursery. The second image shows the different effects of galactic collisions. “In one collision a black hole shows through a dense cloud of material […]
Read article: X-ray telescope burns-up
In the CERN experiments a 33 TeV lead ion beam was crashed into targets made of lead and gold inside the seven different experimental detectors. The collisions created energy densities twenty times that of ordinary nuclear matter in order to break down the forces that normally confine quarks within protons and neutrons. The collisions produced […]
