2947Note to self: do not be in outer space Friday 13th, 2029

[evile]

Feb. 15, 2005

 

 

http://news.independent.co.uk/world/science_technology/story.jsp?
story=611219



A lucky break on Friday the 13th, 2029: giant asteroid will narrowly
miss earth
By Steve Connor, Science Editor
15 February 2005


A giant asteroid the size of three football pitches will make the
closest flyby of Earth in recorded history for an object of its size,
scientists said yesterday.

It will pass between the Earth and the Moon and will even come closer
than the orbit of many telecommunications satellites, although
astronomers insisted that there was little chance of a collision with
the massive rock.

Anxious Earthlings need not worry too much for another 24 years,
however, because asteroid 2004 MN4 is not due to make its closest
approach to Earth until about 10pm London time on Friday 13 April
2029.

The latest calculations of the rock's orbit suggest that it will come
so close that it will probably be visible to the naked eye from
Britain. It will shine in the sky as a dim, fast-moving star - the
first asteroid in modern times to be clearly visible from Earth
without the aid of a telescope or binoculars.

The asteroid was first discovered in June 2004 and calculations of
its orbit made by astronomers last Christmas Eve suggested that there
was a one in 60 chance of it colliding with the Earth. However,
within a week this was revised down to virtually zero probability of
a collision.

If it did collide it would cause an explosion equivalent to about 20
hydrogen bombs being detonated simultaneously, turning vast areas of
land into desert or generating a giant tsunami if it landed in the
ocean.

The latest revisions of the calculations have refined the asteroid's
orbital path to suggest that it will pass our planet by the relative
whisper of 36,000km (22,600 miles) - well within the orbit of
geostationary satellites and about a tenth of the distance to the
Moon. This is by far the largest of the top 10 closest asteroids
recorded by astronomers. Only two others have come closer and both
were much smaller objects - tens of yards wide instead of the 350
yards of asteroid 2004 MN4.

Professor Mark Bailey, director of the Armagh Observatory, said that
there was little danger from the asteroid even though it would come
close enough for its orbit to be directly affected by the Earth's
gravity - causing the path of the space rock to swing away.

"I think everyone is saying that it's going to miss. It'll pass so
close though that you'll be able to see it with a small telescope and
even with the naked eye," Professor Bailey said.

"It's like being on a train station platform and watching an express
train go by three feet away. You're close, but it's not dangerous,"
he said.

Large asteroids have frequently collided with the Earth in the past
and some of the larger ones have caused massive devastation on a
global scale. They can send huge plumes of dust and debris into the
atmosphere, blocking out sunlight for several years and causing the
environmental equivalent of a "nuclear winter".

Last autumn a much bigger asteroid called Toutatis, which is about
2.9 miles long and 1.5 miles wide, made its closest flyby to Earth
but its distance was still four times greater than that separating
the Moon and the Earth.

Unlike asteroid 2004 MN4 and despite its size, Toutatis was not
visible to the naked eye.

Steve Chesley, of Nasa's Jet Propulsion Laboratory in Pasadena,
California, said that asteroid 2004 MN4 was unusual because so much
was known about its orbit before it makes its closest approach in 24
years' time. "All the others in the top 10 were discovered during the
close approach, whereas for 2004 MN4 the close approach is predicted
well in advance," Dr Chesley said.

Scientists estimate that on average an asteroid of this size would be
expected to pass this close to Earth about once in every 1,300 years.

Asteroid 2004 MN4 circles the Sun, but unlike most asteroids that
reside in a belt between Mars and Jupiter, the orbit of this one lies
mostly within the orbit of the Earth, making further encounters
likely. "However, our current risk analysis for 2004 MN4 indicates
that no subsequent Earth encounters for the 21st century are of
concern," said Dr Chesley and his colleagues at the Jet Propulsion
Laboratory.