Jimmy Westlake: RIP Comet ISON
December 2, 2013
Steamboat Springs — Comet ISON 2012 S1 made its death-defying plunge into the sun's atmosphere on Thanksgiving Day, and the sun won. The comet was much too close to the sun to be seen with the naked eye from down here on Earth, so I kept my laptop computer nearby all day and watched the drama unfold through the eyes of NASA's fleet of sun-watching spacecraft: SOHO (Solar and Heliospheric Observatory), SDO (Solar Dynamics Observatory) and STEREO A and B (Solar Terrestrial Relations Observatory).
It was a rollercoaster ride that I, personally, will never forget.
When Comet ISON was discovered in September of 2012, astronomers realized that its unusual sun-diving orbit gave it the potential to be a "comet of the century," if it could survive the solar barbeque and emerge victorious. It was to be a classic battle between fire and ice. Many sun-grazing comets crumble and die in the face of such searing heat and crushing acceleration. The ones that do survive even briefly, like 2011's Comet Lovejoy W3, often are spectacular.
I first saw Comet ISON last Jan. 16 and last saw it Nov. 18. It was barely visible to the naked eye in the glow of dawn and headed toward the sun. By Nov. 21, Comet ISON was lost in the glare of the sun but was picked up by the cameras onboard our orbiting spacecraft. The comet sputtered, growing brighter, dimmer and brighter again as it plummeted sunward.
On Thanksgiving morning, there was a sudden brightening, and Comet ISON briefly outshone the brightest stars in the sky. Hopes ran high that it was finally living up to all the hype. Instead, the burst of light was apparently the dying gasp of the comet as its icy nucleus disintegrated. The pieces continued in their prescribed path at nearly one million miles per hour, dragging a long tail of dust and debris.
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Just before noon, the SDO trained its high resolution camera on the spot where Comet ISON was to pass closest to the sun, and it saw… nothing. Absolutely nothing. It appeared that Comet ISON had given up the ghost in the solar heat. I closed my laptop and settled in for a turkey dinner.
Then, by mid-afternoon, something miraculously reappeared on the other side of the sun, a wisp of dust or a puff of smoke. The apparition regained much of its earlier brightness, and, I swear, I heard cheers rising from planet Earth. It appeared that Comet ISON had, indeed, survived!
But, the jubilation was short-lived. Whatever they were, the remains of Comet ISON quickly faded and dissipated in the vacuum of space. Comet ISON is no more.
It is conceivable that a very faint dust cloud might appear in our predawn sky where Comet ISON would have been during the first week of December, but the cloud likely would be visible only in time-exposure photographs. Comet ISON's 5 million-year journey to meet the sun is over. Fire defeated ice. Rest in peace, Comet ISON.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper and his “Cosmic Moment” radio spots can be heard on local radio station KFMU. Check out "Jimmy's 2014 Cosmic Calendar" of sky events on his website at http://www.jwestlake.com. It features twelve of his best astrophotographs and a day-by day listing of cool celestial events that you and your family can enjoy watching in 2014. Proceeds from the sale of Cosmic Calendars help to support the CMC SKY Club.