Word from the orbit gurus at the Jet Propulsion Laboratory is that the impact watch for Mars is officially "off." On January 9th they announced that the odds of tiny 2007 WD5 crashing into Mars on January 30th have dropped precipitously, to about 1 in 10,000 (0.01%). Instead, the two should come no closer than about 16,000 miles.
This near miss was the likely outcome all along, but uncertainty remained until some big telescopic guns weighed in earlier this week with updated tracking observations. Estimated to be no more than 150 feet across, the asteroid is a dim 24th-magnitude blip and getting fainter as it moves outward from Earth and toward Mars.
Over the past few weeks astronomers have responded to this "will it or won't it?" situation just as they should have. A possible impactor was found, its projected track (though wildly uncertain) showed that a collision couldn't be ruled out, and the call went out for additional observations that eventually settled the matter.
Because the drama surrounding 2007 WD5 played out 50 million miles away, we were all spared the sensational news-media hype that usually surrounds these "killer asteroid" stories.
In discussions among the scientists involved, a few hold the opinion that the public becomes needlessly agitated when they learn that some space rock has a 1-in-XXXX chance of hitting Earth, only to learn later that additional observations have ruled it out. Others say that being able to watch the probability game play out is a good thing, a demonstration of how science actually "works."
What do you think?