Physics and Astronomy

At this week’s First Pan American/Iberian Meeting on Acoustics in Cancun, researchers presented results on acoustic microscopy, a burgeoning technique that could provide new kinds of medically useful information on biological tissue. Unlike many other microscopy techniques, acoustical microscopy can be performed on living tissue and even inside the body, with the use of small ultrasound probes. And unlike optical microscopy of biological specimens, acoustic microscopy does not require tis sue stain

The internal state of an atom can change by absorbing or emitting bits of light. In a warm gas or plasma the electrons are frequently shuttling back and forth from one state to another. Some of these states are longer lived than others, though, because of extenuating circumstances. For instance, many transitions from an excited state to the ground state occur in nanoseconds, but some can last for tens of seconds or longer. Measuring the true lifetime of the longer-lived of these transitions is diff

When it comes to miniature electronics, scientists have seen the shape of things to come — and that shape is a fractal.

People most often see fractals in the familiar, irregular branching shapes of nature — a leaf, or tree, or snowflake. A repeating pattern of ever-smaller branches gives these structures a unique profile that defies classical geometry.

Now a study suggests that magnetic fields can take the form of fractals, too — if a magnet is made of plastic molecules t

An accepted assumption in astrophysics holds that it takes more than 1 million years for gas giant planets such as Jupiter and Saturn to form from the cosmic debris circling a young star. But new research suggests such planets form in a dramatically shorter period, as little as a few hundred years.

The forming planets have to be able to survive the effects of nearby stars burning brightly, heating and dispersing the gases that accumulate around the giant planets. If the process takes too lo

VLT Interferometer Measures the Size of Proxima Centauri and Other Nearby Stars [1] At a distance of only 4.2 light-years, Proxima Centauri is the nearest star to the Sun currently known [2]. It is visible as an 11-magnitude object in the southern constellation of Centaurus and is the faintest member of a triple system, together with Alpha Centauri, the brightest (double) star in this constellation. Proxima Centauri is a very-low-mass star, in fact barely massive enough to bu

What kind of mysteries and scientific intrigue await the European Space Agency’s Venus Express once it has left Earth for its nearest planetary neighbour in 2005? A closer inspection promises to reveal a planet that is hugely different from our own despite a few similarities.

Astronomers often call Venus the Earth’s twin because both are about the same size and have the same mass. In other ways, however, Venus seems to be an altogether different class of planet. Scientists are keen