Hubble Looks but Finds No Trace of Comet ISON

On December 18, the Hubble Space Telescope slewed to Comet ISON’s expected position and found nothing down to the incredibly faint magnitude of 25. According to astronomer Hal Weaver, who planned the ISON search, that limit implies any remaining fragments would have to be smaller than about 500 feet (160 meters) in diameter. 

Composite photo of one of two Comet ISON locations photographed by the Hubble Space Telescope. No trace of the comet is visible. Credit: NASA/ESA

Nothing is visible in any of the images in the photo panel except trailed stars and galaxies, reflections and the occasional zap of a cosmic ray. After ISON was torn asunder by the sun, there existed the possibility that comet’s remains would follow a slightly different orbit. To make sure he was covered, Weaver photographed two separate comet positions, stacking several exposures together.

Comet ISON photographed at a second location. Again, nothing detected. Credit: NASA/ESA

“The images have been combined so that features not at the same place in the various images are suppressed. Any comet fragments would show up more clearly in this composite, though stars still show up as faint streaks”, writes Zolt Lavay, author of the ISONblog at the Hubble site.

Again, nothing shows up in these either. While no one can say that ISON has completely disappeared, we now know that at the very least it’s broken into pieces too small for even Hubble to see. What was once a beautiful sight in binoculars has expanded into a vast cloud of gas and dust thinner than Ebenezer Scrooge’s gruel.

Bob King

I'm a long-time amateur astronomer and member of the American Association of Variable Star Observers (AAVSO). My observing passions include everything from auroras to Z Cam stars. I also write a daily astronomy blog called Astro Bob. My new book, "Wonders of the Night Sky You Must See Before You Die", a bucket list of essential sky sights, will publish in April. It's currently available for pre-order at Amazon and BN.

Recent Posts

An Otherworldly Cloud Over New Zealand

Filmmakers love New Zealand. Its landscapes evoke other worlds, which explains why so much of…

8 hours ago

Early Black Holes Fed 40x Faster than Should Be Possible

The theory goes that black holes accrete material, often from nearby stars. However the theory…

8 hours ago

A Spider Stellar Engine Could Move Binary Stars Halfway Across a Galaxy

Eventually, every stellar civilization will have to migrate to a different star. The habitable zone…

9 hours ago

Scaling Propellant Production on Mars is Hard

Putting humans on Mars has been one of NASA's driving missions for years, but they…

14 hours ago

Is an ‘Off-Year’ Leonid Outburst in the Cards For November?

There are good reasons to keep an eye on the Leonid meteors this year.

15 hours ago

Reaction Engines Goes Into Bankruptcy, Taking the Hypersonic SABRE Engine With it

Rarely does something get developed which is a real game changer in space exploration. One…

20 hours ago