Doomsday asteroid page, really great articles!
pw1.netcom.com...
The saga of Asteroid 1997XF
On Tuesday, March 10, 1998, Brian Marsden, Director of the International Astronomical Union's central telegram bureau in Cambridge, Mass., announced
that celestial object 1997XF, a 1 to 2 mile wide asteroid, could pass within 30,000 miles of Earth in October of the year 2028.
One day later, scientists from NASA's Jet propulsion Laboratory announced that the asteroid would instead miss Earth by 500,000 to 600,000 miles.
JPL's Paul Chodas said that the chance of it impacting the Earth was
"...so unlikely as not to worry about." Essentially, zero.
Do you thnk the scientists really know exactly where this asteroid's going to be 1331 weeks from now! How confident are you about them predicting the
exact location of a speeding two mile wide space rock 306 months away?
Think about it.
1997XF isn't the only thing we have to worry about. There seem to be more and more too close encounters all the time. Get to know the near misses,
and see what would happen if one of them doesn't miss us after all...
An asteroid discovered just weeks ago has become the most threatening object yet detected in space. A preliminary orbit suggests that 2002 NT7 is on
an impact course with Earth on 1 February 2019, although the uncertainties are large.
Astronomers have given the object a rating on the so-called Palermo technical scale of threat of 0.06, making NT7 the first object to be given a
positive value.
From its brightness astronomers estimate it is about 2km wide, large enough to cause continent-wide devastation on Earth.
Although astronomers are saying the object definitely merits attention, they expect more observations to show it is not on an Earth-intersecting
trajectory.
It was first seen on the night of 5 July, picked up by the Linear Observatory's automated sky survey programme in New Mexico, in the southern US.
Since then astronomers worldwide have been paying close attention to it, amassing almost 200 observations in a few weeks.
Dr Benny Peiser, of Liverpool John Moores University in the UK, told BBC News Online that "this asteroid has now become the most threatening object
in the short history of asteroid detection".
NT7 circles the Sun every 837 days and travels in a tilted orbit from about the distance of Mars to just within the Earth's orbit. Detailed
calculations of its orbit suggest many occasions when its projected path through space intersects the Earth's orbit.
Researchers estimate that on 1 February 2019 its impact velocity on the Earth would be 28km a second - enough to wipe out a continent and cause global
climate changes.
However, Dr Peiser was keen to point out that future observations could change the situation. He said: "This unique event should not diminish the
fact that additional observations in coming weeks will almost certainly, we hope, eliminate the current threat."
According to astronomers NT7 will be easily observable for the next 18 months or so, meaning there is no risk of losing the object. Observations made
over that period - and the fact that NT7 is bright enough that it is bound to show up in old photographs - mean that astronomers will soon have a very
precise orbit for the object.
Dr Donald Yeomans, of Nasa's Jet Propulsion Laboratory in California, told BBC News Online: "The orbit of this object is rather highly inclined to
the Earth's orbit so it has been missed because until recently observers were not looking for such objects in that region of space."
Regarding the possibility of an impact, Dr Yeomans said the uncertainties were large. "The error in our knowledge of where NT7 will be on 1 February
2019 is large, several tens of millions of kms," he said.
Dr Yeomans told BBC News Online that the world would have to get used to finding more objects like NT7 that, on discovery, look threatening, but then
become harmless. "This is because the problem of Near Earth Objects is now being properly addressed," he said.