Observers around the world are reporting that Comet ISON brightened sharply last night and is now at the threshold of naked-eye visibility. By some reports, ISON surged in brightness by approximately 2 magnitudes over last 24 hours and is now brighter than comet Lovejoy.
If this trend continues, it will be a faint but easy naked-eye object by the end of the week, SpaceWeather reports.
The sudden uptick in brightness could be caused by a fresh vein of ice opening up in the comet’s nucleus. Rapid vaporization of ice by solar heat is a sure way to boost a comet’s visibility.
ISON’s brush with the Sun on November 28th is very near and many more of these brightening events might happen but all three scenarios for ISON are still open. The first possible scenario is fizzle – ISON evaporates under intense tidal forces and solar radiation. The second scenario is break-up – ISON breaks into smaller chunks.
The third scenario is what everybody hopes will happen – sizzle – ISON survives its brush with the Sun and emerges so bright it becomes visible on Earth in daylight.
