A
May 16 2012 NASA news article sheds some light on the scope of work
to be done in searching for what they term Potentially hazardous asteroids, or PHAs,
which are a subset of the larger group of near-Earth asteroids (NEOs).
In 2010, NASA launched the Wide-field Infrared Survey Explorer (WISE) satellite
into a nearly polar orbit. It used a 40cm aperture telescope with an infrared
detector cooled by cryogens and was always directed 90 degrees away from the Sun.
Part of its mission was termed NEOWISE which was an attempt to assess the
solar system's population of potentially hazardous asteroids.
In particular, WISE's strength was in attempting to detect dark asteroids that
are radiating strongly in the infrared. It attempted to track them for several hours
to try and determine initial orbital elements so that they could then be followed up by
ground based optical wavelength observations.
As stated in the May 2012 NASA news article -
Quote:
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Originally Posted by NASA
The project sampled 107 PHAs to make predictions about the entire population as a whole. Findings indicate there are roughly 4,700 PHAs, plus or minus 1,500, with diameters larger than 330 feet (about 100 meters). So far, an estimated 20 to 30 percent of these objects have been found.
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The article goes on to state -
Quote:
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Originally Posted by NASA
The new analysis also suggests that about twice as many PHAs as previously thought are likely to reside in "lower-inclination" orbits, which are more aligned with the plane of Earth's orbit. In addition, these lower-inclination objects appear to be somewhat brighter and smaller than the other near-Earth asteroids that spend more time far away from Earth. A possible explanation is that many of the PHAs may have originated from a collision between two asteroids in the main belt lying between Mars and Jupiter. A larger body with a low-inclination orbit may have broken up in the main belt, causing some of the fragments to drift into orbits closer to Earth and eventually become PHAs.
Asteroids with lower-inclination orbits would be more likely to encounter Earth and would be easier to reach. The results therefore suggest more near-Earth objects might be available for future robotic or human missions.
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WISE is now in hibernation.
Article here -
http://www.jpl.nasa.gov/news/news.cfm?release=2012-138
So there is still plenty of work to do in the search for PHA's including from dedicated
ground based observations right here in the southern hemisphere.
If you believe that a full-time search for NEO's and PHA's is in the national
interest, you might consider contacting the
Minister for Tertiary Education,
Skills, Science and Research, Chris Evans and/or the
Minister for Industry
and Innovation, Greg Combet. (Thank you Bo for the contact details).
Another possible person to write to is
Nicola Roxon, who is the Attorney General
and Minister for Emergency Management.
One of the outcomes of the 2004 tsunami was a heightened awareness of the
dangers a large tsunami poses and efforts were then put in place to construct
an early warning system network. For example, the Joint Australian Tsunami
Warning Centre (JATWC) is operated by Geoscience Australia and the Bureau of
Meteorology and the Attorney-General's Department contributes to it in
co-ordinating emergency management. In other words, if you feel that a full-time
NEO search program, rather than being a piece of pure scientific research
should become an emergency warning service that could benefit not only
Australia but other nations, then you might like to forward that suggestion to
the Attorney-General's Department for consideration.
The good news is that in recent years, through science shows on television
and through Hollywood, the concept of an asteroid impacting Earth is
not so fanciful in the minds of the population as it once was.
When one then points out the number of recorded recent near encounters such as these -
http://www.lpl.arizona.edu/css/css_news.html , the case for a full-time search becomes
even more compelling.
Apart from the potential for physical damage and loss of life, the world is interconnected
so closely today by commerce and trade that even a small impact could plunge the world
into an economic catastrophe. Something potentially worth hedging against.