Asteroid 2012 DA14 will not hit Earth when it whizzes past us on
Friday - but we may not be so lucky in future, space experts fear.
Although the 150ft (45m) rock will zoom harmlessly by our planet
on its record near approach this week, it is just one of up to a
million "near-Earth objects" which astronomers believe could one
day pose a serious threat.
A program set up by NASA to monitor so-called "NEOs" a decade
and a half ago has so far tracked fewer than 10,000, meaning the
vast majority are still hidden.
Most of the larger specimens, which could have the potential to
wipe out entire continents, have been found but even small
asteroids like 2012 DA14 could be powerful enough to destroy an
entire city if they plunged down to Earth.
Now experts are calling for greater monitoring of small NEOs
measuring less than a kilometre across, and for a contingency plan
in the event of a likely impact.
UK Space Agency engineers travelled to the United Nations this
week to seek a deal with colleagues from around the world and
hope to come to an agreement before Friday.
The first goal is to secure funding for asteroid monitoring from
countries other than America, which is currently the only nation
carrying out such a program.
This would allow new systems to be built specifically to detect
smaller asteroids, and open up more facilities across the world to
help in the search.
Richard Crowther, chief engineer at the UK Space Agency, said:
"Our ability to see objects is limited by the number of telescopes
on the ground and their ability to see objects of particular sizes.
"The current 'survey' is aimed at kilometre-sized objects...the
smaller the object, the more of them there will be but the smaller
the proportion we will see with a system not designed to find them.
"The issue is that this is an infrequent but potentially catastrophic
event which policy frameworks struggle to address."
As well as increasing the monitoring of NEOs, the UN group hopes
to make progress on an emergency plan detailing measures to be
taken if an asteroid does become a threat to Earth, such as
attempting to destroy or deflect it, or reduce damage to a
minimum.
Even if an agreement is reached, experts claim it will be many
years before they have a full idea of which asteroids could threaten
the Earth, and when.
At a press conference last week Lindley Johnson, chief of Nasa's
near-Earth object observations program, said: "It does take quite a
bit of capability, both in sensitivity - the ability to detect these small
objects - and also time.
"It is an effort that will take another decade or two even if we have
the most sophisticated systems that feasible technology will allow
us."
sourcce www.telegraph.co.uk/science/space/9866750/Nasa-cannot-monitor-most-potentially-devastating-asteroids.html