Prabhupada: generally we know when there is comet, there is very bad effect.

There are two comets (ISON & Encke) approaching Earth fast!

What did Prabhupada say about comets?

Here are some nice quotes from Srila Prabhupada about comets:

Prabhupada: generally we know when there is comet, there is very bad effect.
(Morning Walk - January 3, 1974, Los Angeles)

As soon as there is comet, there will be some disaster. Very great disaster. In our childhood we saw the comet, not this like. That was small comet. Still, the first world war was there declared. That we have seen in 1914.
Nara-narayana: Halley's comet.
Prabhupada: Eh?
Nara-narayana: I think they called it Halley's comet. Halley's comet.
Prabhupada: Now the... You can expect at any moment disaster in this material world, but the comet is the sign that there will be some great disaster.
(Morning Walk - January 3, 1974, Los Angeles)

Bali-mardana: There's a comet in the sky and they're saying that some very inauspicious...
Prabhupada: And what is auspicity now? Eh? What is auspicity now? We are describing all inauspicity, even without the comet. (laughter) Where do you find the auspicity? One man said that "He has kicked me, he has beaten me with shoes, and again he has said that 'I shall insult you.' " Where is the scarcity of insult? If he is beaten by shoes and kicked by his leg, and still he's expecting some more insult? You are already in inauspicity. Why you are expecting more inauspicity by the presence of comet? We are already in inauspicity. And therefore these descriptions are there. You have no fixture anything -- where to live, where to take bath, where to eat, where to have sex life -- nothing fixed up. Everything catastrophe, chaos. What more inauspicity you want? Everywhere. Here even one problem, another, in another country, another problem, another problem, another problem. He must be problematic. Daivi hy esa... Because anyone who is not Krsna conscious, he must be punished by the laws of nature.
(Srimad-Bhagavatam 1.16.22 - Hawaii, January 18, 1974)