What was the big disaster in Cormac McCarthy's book The Road?

Answer 1

i think it was a super-volcano because of the reference to an earth movement or after-shock, the orange glow after the event and the ash. If it was a nuclear disaster then the man and his wife would have been irradiated whist standing and watching the glow when the clocks stopped. The darkness, ash and winter conditions also fit with the descriptions of a super-volcano eruption http://www.cambodianonline.net/earthvolcano005.htm

Others claim that the author had an asteroid impact-type event in mind while writing the book, but volcanic ash is said to contain glass particles - which asteroids or their resultant blast would not - which may be the reason for the man's ailment.

In the 2009 movie adaptation, The Man is heard to say in voice over near the beginning of the film that "there was long shear of bright light and a series of low concussions," which is certainly more indicative of an asteroid or comet impact.

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I was thinking either a supervolcano or an asteroid impact, but now I'm leaning towards an asteroid impact. I think this because of the huge amount of ash and how almost everything is burned to the ground. A supervolcano would only burn things down in a relatively limited geographical area (a few thousands of square miles), but a large asteroid impact would cause a global firestorm capable of burning things down across the entire planet. A scientific problem in the story is that the ash is still blocking out the sky after 6 years (the boy was born after the disaster, right?), and in either disaster the sky would have been cleared after this amount of time. The book also mentions the "long shear of bright light", which would be more closely aligned to an asteroid impact. Plus, when the ship was found, The Man noticed that some of the secured items on deck had been sheared off by a tremendous force, which could have been a tsunami, but if it were an asteroid-caused tsunami, the wave would have been so huge the boat would likely have been torn to shreads.

Answer 2

This novel is set after the apocalypse. Scientists have predicted that a large volcanic eruption, collision with another planet or large mass in space, or complications with the sun will cause the apocalypse. No one will know until it comes, however, so it is difficult to be certain.