From a learned 'Net-friend (25th July 2002)

Well Tom, looks like we baby-boomers won't need to worry that our retirement savings will be insufficient! Seriously though, this is typical of media beat-up and inaccuracy in reporting. Must be a slow news day!

When an asteroid is first discovered, it is difficult to plot its future orbit on just a few measurements. Imagine trying to draw a line on a page by joining two dots. When the dots are very close together, it is difficult to be accurate when extending the line across the page. When the dots are far apart, a more accurate line is drawn. The same applies with predicting the orbit of an asteroid. With just a few measurements, the future orbit possibilities are very broad. As more measurements come in, the orbit prediction narrows down and becomes more accurate.

The usual scenario when a Near Earth Asteroid or Nearth Earth Object (NEA/NEO) is discovered is that there is a very broad range of orbit possibilities and initially this broad range may include impact with the Earth. Usually, as the measurements continue to come in, impact with the Earth is excluded. These kind of discoveries are happening all the time, but every now and again the media picks up on one and hypes it up.

It is interesting to trace the growing extent of inaccuracies as the report goes around. Compare the ABC report with that of the more accurate BBC here:

http://news.bbc.co.uk/1/hi/sci/tech/2147879.stm Compare the BBC with that here: http://www.hohmanntransfer.com/news.htm

Shalom!

Rowland Croucher