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Monday, 10 April, 2000, 11:09 GMT 12:09 UK
Star mistaken for planet
The space object announced to the world in 1998 as the first directly detected planet outside our solar system is probably just a faraway star, say Nasa.

It is simply too hot to be a planet, said its discoverer, Susan Terebey. It is most likely a star far in the background, with its light dimmed by interstellar dust. This gave it the appearance of being a planet in a double-star system nearer to Earth.

The Hubble telescope image shows a dot at the end of a long streamer of reflective dust, located 450 light-years away in the constellation Taurus. A light-year is the distance light travels in one year, about 10 trillion kilometres.

However, planet-hunters still believe there are 30 or more so-called extra-solar planets, which have been detected more indirectly by the characteristic wobble their gravity exerts on the stars they orbit.

Hamsters sniff pheromones

Researchers have proved that animals can recognise close relatives purely by smell.

The hamsters in the study apparently used pheromones to do this. These are compounds that are not consciously registered as a smell but are still detected. In humans, pheromones are produced under the arms and the effect is sometimes called the "armpit effect".

Scientists at Cornell University in New York, US, raised newborn hamsters in foster families. All they had ever smelled were the unrelated foster mother and her offspring.

When the hamsters reached sexual maturity, they were presented with a variety of pheromone scents including those of their biological and foster siblings. The hamsters avoided these and were clearly attracted to the scents of unrelated strangers.

Dr Jill Mateo of the research team said: "Because of the way we structured the experiment, there is no other way the hamsters could have known the scent of their family."

This ability may have evolved for two reasons: to avoid unhealthy inbreeding or for nepotism when an animal helps a close relative.

Dinosaur-bird a case of mistaken identity

The fossil hailed last year as proof that birds evolved from dinosaurs was a false alarm say the US National Geographic Society (NGS).

Scientists now believe the Archaeoraptor to be a composite of at least two different animals.

The NGS unveiled the "feathered dinosaur" in October 1999. However the Society decided to review it's diagnosis after questions raised by Chinese palaeontologist Xu Xing.

Dr Xing discovered that the supposed tail of Archaeoraptor matched the tail of a small dinosaur from the same type of rock where Archaeoraptor had been found.

The Society's review panel concluded that the upper part of the fossil represented a species new to science. They said this new find may have implications for the early evolution of birds.

Other evidence exists for the link between dinosaurs and birds and the fossil is still of great interest.

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