Science: Update

"THE ION engine on Deep Space 1 has shut down unexpectedly." This may sound like a line from Star Trek, but in fact it was the latest news from Nasa on a space probe sent to rendezvous next July with an asteroid, 1992 KD. After working for just over four minutes, the futuristic solar- powered engine, which throws out a constant stream of xenon ions to accelerate its payload, turned itself off and failed to restart. The ion engine of Deep Space 1 probe is one of 12 new technologies being tested on the $152m (pounds 91m) mission.

THE US ARMY has teamed up with the American Red Cross to develop bandages and a foam and spray which can stop severe bleeding in seconds. The treatments contain freeze-dried versions of two natural clotting agents - a protein, fibrinogen, and the enzyme thrombin - at concentrations 50 to 100 times greater than in blood. When they touch blood they start forming the sticky lattice of fibrin molecules which becomes a scab. In animal experiments, arterial bleeding - where the blood pumps out of the body - was stopped within 15 to 60 seconds, cutting the blood lost compared with the standard procedure (applying firm pressure and a bandage to the wound) by 50 to 85 per cent. Clinical trials on humans are expected to start within a year. The foam is intended for bullet wounds and similar puncture wounds with deep-seated bleeding.

WHAT HAPPENED in 1250? Astronomers have discovered that people should have seen the light from a supernova which exploded closer to Earth than any other since. It would have been the brightest object in the night sky apart from the Moon, yet records fail to mention it. Either the astronomers were sloppy, or there is a new celestial phenomenon - invisible supernovae.

The discovery by scientists at the Max Planck Institute in Germany was reported in the journal Nature. The supernova turned up when they were scanning the constellation Vela for X-rays and gamma rays, which can be byproducts of a supernova explosion. There, 650 light-years away, they found the supernova's gas cloud - still twice as hot as the Sun's core, and up to 25 light-years across.

Scientists are divided over the explanation: some suggest it was sloppy record-keeping in the Middle Ages, others that little visible light was produced in the explosion, and yet others believe that interstellar dust might have obscured the sight.

A COMMON virus may contribute to "hardening of the arteries", otherwise known as arteriosclerosis, according to new research. Animal studies show that cytomegalovirus (CMV), which causes few symptoms apart from a mild rash or flu-like symptoms, seems to contribute later in life to hardening of the arteries, according to Archana Chatterjee of Creighton University in Omaha, Nebraska. "In most cases CMV is a benign disease... Most people don't even know they've been infected," she said. But depending on the size of the risk, it may be worth vaccinating people against CMV when young to avoid arteriosclerosis later, she suggested.