Nasa coverage of the moment the asteroid passed closest to
Earth
An asteroid as large
as an Olympic swimming pool has raced past the Earth at a distance of just
27,700km (17,200mi) - the closest ever predicted for an object of that size.
It passed far closer even than the geosynchronous satellites
that orbit the Earth, but there was no risk of impacts or collisions.
Its closest approach was at 19:25 GMT.
For regions in darkness, it should have remained visible
until about midnight through good binoculars or a telescope.
The asteroid's arrival was preceded by a damaging meteor
event in Russia on Friday - but indications from the meteor's
path suggest that the two events are entirely unrelated - just a "cosmic
coincidence", as Alan Fitzsimmons of Queens University Belfast told BBC
News.
The asteroid orbits the Sun in 368 days - a period similar
to Earth's year - but it does not orbit in the same plane as the Earth.
As it passes - at 7.8km/s (17,450 mi/hr) - it will come from
"under" the Earth and return back toward the Sun from
"above".
It passed directly over the eastern Indian Ocean, making for
the best viewing in Eastern Europe, Asia and Australia.
But keen viewers everywhere used several live streams of the
event on the internet, including a feed from the Jet Propulsion Laboratory at
Nasa.
2012 DA14 was first spotted in February 2012 by astronomers
at the La Sagra Sky Survey in Spain - once a fairly small-scale, amateur effort
to discover and track asteroids that has in recent years become a significant
contributor to our knowledge of these "near-Earth objects".
They caught sight of the asteroid after its last pass, at a
far greater distance.
From their observations, they were able to calculate the
asteroid's future and past paths and predict Friday's near-miss - which will be
the closest the object comes for at least 30 years.
Prof Fitzsimmons said that it is a scientific opportunity
not to be missed.
"When asteroids come this close, it's very important to
try to learn about them - it's become so bright, so it's so easy to
study," he told BBC News.
"We get an additional insight into these small objects,
which are the most likely impactors on Earth."
No comments:
Post a Comment