Posted on 09/12/2002 3:01:44 PM PDT by blam
Thursday, 12 September, 2002, 11:57 GMT 12:57 UK
Earth's new 'moon' is space junk
Has this rocket returned to Earth?
By Dr David Whitehouse
BBC News Online science editor
So, it looks like Earth does not have a new "moon" after all The latest analysis of the mysterious object called J002E3 suggests it could well be a leftover Saturn V rocket component from one of the Apollo lunar missions.
The suspicious, fast-moving object was discovered on 3 September by Bill Yeung from his observatory in Arizona, US. Initial orbit calculations indicated that it was only about twice as far away as the Moon, and in orbit around the Earth.
At first, astronomers were not sure whether the object was a passing chunk of rock that was captured by the Earth's gravity, or a piece of space junk.
Now the mystery may have been solved thanks to a retrospective analysis of its movement through space. The object is most likely from the Apollo 12 mission, launched on 14 November 1969.
Returned to sender
It seems that the object was in orbit around the Sun until April of this year when it was captured by the Earth's gravity. The capture occurred when the object passed near the Earth's L1 Lagrange point, a region of space where the gravity of the Earth and Sun approximately cancel.
J002E3 is the first known case of an object being captured by the Earth, although Jupiter has been known to capture comets in the same way.
The most recent analysis of J002E3's pre-capture orbit about the Sun shows that it was always inside the Earth's orbit, and that it may have come within the Earth's vicinity in the early 1970s or late 1960s.
This suggests that J002E3 was very likely orbiting the Earth during this period before escaping into solar orbit.
Experts say that it is likely that this object is one of the Apollo Saturn rocket's third stages. The brightness of J002E3 seems to match the expected brightness of such a component.
Analysis of J002E3's orbit suggests that there is a chance of it impacting the Moon in 2003, and an outside possibility of it burning up in the Earth's atmosphere sometime in the next decade or so.
In general a "moon" is naturally occuring, a "satellite" has been placed there by other than natural phenoms. Of course, technically either one is a satellite.
Michael
The most recent analysis of J002E3's pre-capture orbit about the Sun shows that it was always inside the Earth's orbit, and that it may have come within the Earth's vicinity in the early 1970s or late 1960s.
Looks like the rocket scientists (pun intended) have it figured out all right.
16:10 12 September 02
NewScientist.com news service
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's orbit, which "indicates 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".
The computer simulations were carried out by Donald Yeomans and Paul Chodas at NASA's Jet Propulsion Laboratory. They show that the object's orbit is consistent with a booster that circled the Earth in the 1960's or 1970's, was then captured by the Sun and finally returned to Earth orbit in April 2002.
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 "second Moon".
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's Royal Observatory. "Essentially it's like trying to resolve one of the landers on the surface of the Moon - no telescope can do it," Massey told New Scientist.
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.
Will Knight
What's one more? To the people who buy that stuff, nothing matters.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.