A crayfish’s urine scares off its enemies.

A well-timed blast of urine is the key to winning a crayfish fight, say researchers. The chemical aggression intimidates opponents into backing down.

Ecologist Thomas Breithaupt injected freshwater crayfish with a dye that made their urine glow green. He and his colleague Petra Eger staged fights between blindfolded crayfish ( Astacus leptodactylus ), to replicate the animals’ nocturnal habits1.

The eventual

Satellite sensors operating in the visible wavelength region are now in use for the monitoring of oceanic waters.

For the first time ever, Finnish scientists have demonstrated the practical usability of satellite data for the simultaneous monitoring of water quality in large lake and coastal regions. The project was carried out by the Laboratory of Space Technology of the Helsinki University of Technology in cooperation with the Finnish Environment Institute.

The attached fi

In the past five weeks two asteroids have passed close by Earth, at distances of 1.2 and 3 times the distance to the Moon. Another asteroid has recently been shown to be on course for a collision with Earth in 2880.

Monitoring known asteroids allows astronomers to predict which may collide with Earth. But that is only true for the asteroids we know of. What about those that lie in the asteroid blind spot between the Sun and Earth? The European Space Agency is studying ways in which its miss

Astronomers probing the intimate details of apparently quiescent stellar black holes have discovered that in reality they are dynamic, lively places, subject to flares that briefly illuminate the whole of the gas disc around the black hole. Their observations are helping to build up a picture of precisely where X-rays are generated in the gas as it heats up to extreme temperatures and swirls around under incredible gravitational forces before cascading into the black hole itself. On Friday 12 April,

Long-term exposure to the weightless environment of space has significant effects on astronaut physiology, notably changing the skeleton and muscle. To meet the requirements of long-stay missions aboard the International Space Station, the European (ESA), French (CNES) and Japanese (NASDA) space agencies are jointly conducting ground-based research to evaluate ways of countering the adverse effects.

Countermeasures are tested on the healthy subject using an experimental model reproducing t

Galaxies were once thought of as `island universes` evolving slowly in complete isolation. This is now known not to be the case. By using the world`s most powerful X-ray observatories, UK astronomers are discovering that most of these gigantic star systems interact with each other in a wide variety of ways.

During the UK National Astronomy Meeting in Bristol on Thursday 11 April, Dr. Andrew Read (University of Birmingham) will present new results from the Chandra and XMM-Newton spacecraft ab