Scientists have not yet found a way to actually make time run backward, but in the cutting-edge world of recent acoustics research, they have shown a way to make sound waves run backward in a kind of ultra-focused reverse echo. By the technology known as time-reversal acoustics, sound waves – in exact reverse order from the original sound – echo directly and very precisely back to their source point.
The technology promises a wide array of applications, including medical applications such a
The hunt for space rocks on a collision course with Earth has so far been pretty much limited to the Northern Hemisphere. But last week astronomers took the search for Earth-threatening asteroids to southern skies. Astronomers using a refurbished telescope at the Australian National University’s Siding Spring Observatory discovered their first two near-Earth asteroids (NEAs) on March 29. NEAs are asteroids that pass near the Earth and may pose a threat of collision. Si
Home is the place we know best. The Milky Way, our Galaxy, is the exception to the rule, however: Our knowledge of our nearest stellar neighbours has long been seriously incomplete and – worse – skewed by prejudice concerning their behaviour. In the past, stars were selected for observation because they were thought to be ’interesting’ in some sense, not because they were typical of stars in general. Naturally, this gave a biased view of the evolution of our Galaxy – that serves as the prototype of
A rare celestial event was captured by NASA’s Chandra X-ray Observatory as Titan — Saturn’s largest moon and the only moon in the Solar System with a thick atmosphere — crossed in front of the X-ray bright Crab Nebula. The X-ray shadow cast by Titan allowed astronomers to make the first X-ray measurement of the extent of its atmosphere.
On January 5, 2003, Titan transited the Crab Nebula, the remnant of a supernova explosion that was observed to occur in the year 1054. Although Saturn and
Results of 1001 observing nights shed new light on our Galaxy
Unknown history
Home is the place we know best. But not so in the Milky Way – the galaxy in which we live. Our knowledge of our nearest stellar neighbours has long been seriously incomplete and – worse – skewed by prejudice concerning their behaviour. Stars were generally selected for observation because they were thought to be “interesting” in some sense, not because they were typical. This has resulted in
Cornell University researchers already have been able to detect the mass of a single cell using submicroscopic devices. Now they’re zeroing in on viruses. And the scale of their work is becoming so indescribably small that they have moved beyond the prefixes “nano” “pico” and “femto” to “atto.” And just in sight is “zepto.”
Members of the Cornell research group headed by engineering professor Harold Craighead report they have used tiny oscillating cantilevers to detect masses as small
The planet Mars possesses two small moons named Phobos (Fear) and Deimos (Terror). Although their existence has been known since their discovery in 1877 and a number of long-range observations have been made by Earth-based telescopes and spacecraft that have visited Mars, the satellites remain only partially studied, particularly Deimos.
Consequently, a number of outstanding scientific questions remain concerning their origins, evolution, physical nature and composition. A recent study fund
Patterns in nature can be seen every day, yet in many cases, little is understood about how and why they form. Now University of Arizona mathematicians have found a way to predict natural patterns, including fingerprints and the spirals seen in cacti.
UA graduate student Michael Kuecken developed a mathematical model that can reproduce fingerprint patterns, while UA graduate student Patrick Shipman created a mathematical model to explain the arrangement of repeated units in various plants.
Black hole fits inside Earth’s orbit
Thirty years after astronomers discovered the mysterious object at the exact center of our Milky Way Galaxy, an international team of scientists has finally succeeded in directly measuring the size of that object, which surrounds a black hole nearly four million times more massive than the Sun. This is the closest telescopic approach to a black hole so far and puts a major frontier of astrophysics within reach of future observations. The scien
In this week’s issue of Science, a Dartmouth researcher comments about a new experiment that brings us closer to connecting the macroscopic and the microscopic worlds.
Miles Blencowe, a quantum theorist with the Physics and Astronomy Department at Dartmouth, wrote the article “Nanomechanical Quantum Limits” for the “Perspectives” section of the April 2 issue of Science. In it, he explains the problem of reconciling the inherent contradiction between the quantum or atomic world and the
These are exciting times for space exploration. For the first time in a generation, human missions beyond Earth orbit are being seriously considered by space agencies on both sides of the Atlantic. Europe has initiated the Aurora programme, with the ultimate aim of landing people on Mars by 2033, while the U.S. has recently redirected its human space activities towards a return to the Moon.
On Friday 2 April, Dr. Ian Crawford, a planetary scientist based at Birkbeck College, London, will be
At present, we know of no worlds beyond our Earth where life exists. However, primitive organisms on our planet have evolved and adapted over billions of years, colonising the most inhospitable places.
Since life seems to gain a foothold in the most hostile environments, it seems distinctly possible that living organisms could exist in ice-covered oceans on worlds far from the Sun, according to Dr. David Rothery (Open University), who will be speaking today at the RAS National Astronomy Mee
A new survey made with the Anglo-Australian Telescope (AAT) has revealed dozens of previously unsuspected miniature galaxies in the nearby Fornax galaxy cluster. They belong to a class of galaxies dubbed “ultra-compact dwarfs” (UCDs), which was unknown before the same team of astronomers discovered 6 of them in the Fornax cluster in 2000. Now they say the UCDs outnumber the “conventional” elliptical and spiral galaxies in the central region of the Fornax cluster and they have found some in the Virgo
An international group of astronomers led by Dr Jean-Philippe Beaulieu (Institut d’Astrophysique de Paris) and Dr Martin Dominik (University of St Andrews) are about to continue their hunt for extrasolar planets with an enhanced world-wide telescope network in May this year. They are hoping to secure the firm evidence for the existence of Earth-mass planets orbiting stars other than the Sun, which has so far eluded astronomers. Dr Dominik will describe the project, known as PLANET (Probing Lensi
Genetic mutations – sudden, random and usually harmful changes to the structure of a gene – are only one factor that determines the ultimate fate of a cell. Chicago scientists have discovered that a non-genetic molecular process also can play a role, and that experimenters can influence this process in bacteria, they report in the April 1 issue of the journal Nature.
The research team, led by Philippe Cluzel, Assistant Professor in Physics at the University of Chicago, arrived at its finding
Optimizing space missions
Titan, the largest moon of Saturn was discovered by Dutch astronomer Christian Huygens in 1655 and certainly deserves its name. With a diameter of no less than 5,150 km, it is larger than Mercury and twice as large as Pluto. It is unique in having a hazy atmosphere of nitrogen, methane and oily hydrocarbons. Although it was explored in some detail by the NASA Voyager missions, many aspects of the atmosphere and surface still remain unknown. Thus, the existenc
Feedback
