We've Had a Close Call!

[eliza_nightvoice]

While discussions were taking place about Planet X, fact of fiction, we've had an a close call with an undetected asteroid. So why worry about Planet X, it's those sneaking little asteroids that are going to get us.

Space Rock's Close Approach
Thursday, 20 June, 2002, 09:57 GMT 10:57 UK

Detection was made by the Linear search program

By Dr David Whitehouse BBC News Online science editor

Astronomers have revealed that on 14 June, an asteroid made one of the closest ever recorded approaches to the Earth. It is only the sixth time an asteroid has been seen to penetrate the Moon's orbit, and this is by far the biggest rock to do so. What has worried some astronomers, though, is that the space object was only detected on 17 June, several days after its flyby.

It was found by astronomers working on the Lincoln Laboratory Near Earth Asteroid Research (Linear) search program in New Mexico. Catalogued as 2002MN, the asteroid was travelling at over 23,000 miles per hour when it passed Earth at a distance of around 75,000 miles. The space rock has a diameter of between 160 - 320 feet. This is actually quite small when compared with many other asteroids and incapable of causing damage on a global scale. Nonetheless, an impact from such a body would still be dangerous.

If 2002MN had hit the Earth, it would have caused local devastation similar to that which occurred in Tunguska, Siberia, in 1908, when 2,000 square kilometres of forest were flattened. Dr Benny Peiser, of Liverpool John Moores University, UK, told BBC News Online: "Our ever increasing observational capacity is now detecting these close shaves from small objects. The probability is actually quite high that a Tunguska-sized object will hit us in our lifetimes."

A major issue of concern centers on how late this object was picked up. Dr John Davies, of the Royal Observatory Edinburgh, has calculated the orbit of the asteroid from the Linear data. He concludes that the asteroid came out of the Sun and was impossible for Linear to see until one hour after its flyby of the Earth on the 14th.

Dr Davies said: "...if an asteroid were to approach close to an imaginary line joining the Earth and the Sun it would never be visible in a night-time sky and would be quite impossible to discover with normal telescopes. Its arrival would come, literally, as a bolt from the blue."

Space-based telescopes, such as Hubble and the future European Gaia spacecraft, are the only means of searching for asteroids in the daytime sky.

[lutefisk]

Fire and Ice
by Robert Frost

Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.

[LisaA]

Excellent crossover poetry, Lutefisk!

To think of it all ending because of an asteroid intrigues me because we have all this biblical mythology wrapped up in our concepts of the end of life on earth. But really, maybe it's just all a matter of a space dirtclod, nothing more or less.

[Cherry Kelly]

They said it was really a fast mover -- and while it was one of the closest it just passed by.....

[eliza_nightvoice]

Just to put things in perspective. That little ole rock was the size of a football field and passed closer between us and the moon. Anyone feel the draft?

[eliza_nightvoice]

Well, there's another possible incoming. If it hits, the ETA is Feb, 2019. Glad that the astronomers are starting to look for these "near earth" objects.

Wednesday, 24 July, 2002, 02:29 GMT 03:29 UK
Space rock 'on collision course'
An asteroid could devastate Earth
By Dr David Whitehouse
BBC News Online science editor

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 (about 1 mile + ), 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.

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".

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."

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.