"When the Deep Impact probe hit Comet 9P/Tempel, there was almost no change in brightness. … This outburst by Comet Holmes is extreme!"

“What delighted me was that it's 30 years from now — not next week or next year. … That would be totally hopeless; that would be terrifying, in fact. Time is on our side in this one — that's why it's such a wonderful illustration of the process... I say 30 years is a good long time to do something about it if it is a problem … We should be thankful we have this kind of notice.”

“We have to beef up our searches, which are now pretty dismal, so we can find out about these things before we get hit. … It takes a dramatic event to get people's attention, and we thought the comet crash with Jupiter might have done the job. … we tend to ignore an extraterrestrial hazard that could reduce the planet to rubble. … What we really need is a good scare.”

“Man in the News; A Cheery Herald of Fear: Brian Geoffrey Marsden" in The New York Times”

“This is a terrific outburst. And since it doesn’t have a tail right now, some observers have confused it with a nova. We’ve had at least two reports of a new star.”

“It is probably a good idea to search, at some level, for asteroids that come to the Earth's general vicinity. But merely counting the asteroids found is not sufficient. It is desirable to follow up each discovery to examine whether it can or can not be a threat during the next century or so. Objects for which the threat cannot be eliminated should be singled out for special study, notably to the extent of searching for old images in photographic archives. 1997 XF11 was noteworthy for the apathy shown to it prior to the very widespead announcement in March. If proper attention had been given to it earlier, the circumstances that led to the announcement would never have occurred. Sometimes statistics will conspire to draw attention to a problem. Maybe they are trying to tell us something.”