From the October 2013 issue

Comet ISON blazes into glory

This frozen ball of gas and dust puts on a show in the predawn sky before reaching peak brightness in late November as it skims above the Sun’s surface.
By | Published: October 17, 2013 | Last updated on May 18, 2023
Comet ISON captured by Hubble on October 9
Comet ISON appeared perfectly intact when the Hubble Space Telescope captured it October 9.
NASA/ESA/The Hubble Heritage Team (STScI/AURA)

Let’s lay our cards on the table at the outset: No one really knows how bright Comet ISON (C/2012 S1) will get. Lots of people think they know how this comet will perform as it plunges toward the Sun this month. Optimists tout numbers that have many amateur astronomers giddy with excitement. If they’re right, the comet could rival the Full Moon when it passes closest to the Sun at perihelion November 28 and remain as bright as the planet Jupiter for several days around then.