Various scientific scenarios have been theorized on the effects of an asteroid or comet's collision with Earth. An applicable scenario theorizes a chemical change in the atmosphere due to "heat shock" during entry and/or impact of a large asteroid or comet, reacting oxygen and nitrogen in the atmosphere to produce nitric-acid rain.[7] Acid rain from the heat shock of a large comet or asteroid's impact with Earth is believed by some to fit the Biblical description of the bitterness produced by the Wormwood Star upon a third of the Earth's potable water.[8]