A mystery object recently found orbiting the Earth is more likely to be a used rocket booster from an Apollo spacecraft than a tiny second Moon.
NASA scientists have now analysed the object鈥檚 orbit, which 鈥渋ndicates that it could be a leftover Saturn V third stage from one of the Apollo missions, most likely the Apollo 12 mission, launched on 14 November 1969鈥�.
The computer simulations were carried out by Donald Yeomans and Paul Chodas at NASA鈥檚 Jet Propulsion Laboratory. They show that the object鈥檚 orbit is consistent with a booster that circled the Earth in the 1960鈥檚 or 1970鈥檚, was then captured by the Sun and finally returned to Earth orbit in April 2002.
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The object was spotted on 3 September by an astronomer in Arizona and was initially thought to be an asteroid passing the Earth. But further observations revealed that a 50-day Earth orbit at an altitude rising from 300,000 to 800,000 kilometres.
Light reflected by the object suggests that it is between 10 and 50 metres in size. These dimensions led astronomers to suspect that it might be a discarded section of rocket, but they could not immediately link it to any particular mission. Some have speculated that it could be an asteroid and have even dubbed the object a 鈥渟econd Moon鈥�.
Watch this (1.7MB) to see how J002E3 may have been captured by the Earth. Hosted by NASA.
It is still possible the object, dubbed J002E3, will turn out to be a new Moon. But more observations and modelling will be needed to determine if it space rock or space junk.
At its current distance, no telescope can resolve the object clearly, says Robert Massey of the UK鈥檚 Royal Observatory. 鈥淓ssentially it鈥檚 like trying to resolve one of the landers on the surface of the Moon 鈥� no telescope can do it,鈥� Massey told New 杏吧原创.
He suggests that radar observations would be the best way to determine the size and shape of the object. Studying radiation reflected by the object would also let astronomers determine its composition, he says.
Whatever it is, it may not be around for long. Yeomans and Chodas calculated that the object has a 20 per cent chance of smashing into the Moon by the end of 2003.
