Photo: Hubble Gets First Glimpse of Possible ‘Comet of the Century’

Hubble space telescope snaps detailed view of faraway comet ISON on April 10, 2013. Credit: NASA, ESA, J.-Y. Li (Planetary Science Institute), and the Hubble Comet ISON Imaging Science Team


Hubble has taken its first close-up views of the much anticipated and potential ‘comet of the century’. On the night of April 10th, the space telescope snapped an image in visible light of Comet ISON while it was still at a whopping distance of 394 million miles from Earth (386 million miles from the Sun)- a bit closer than the orbit of Jupiter. (See also: New Comet Found; May Be Visible From Earth in 2013)

While today it is only faintly visible as a fuzzy speck of light in large telescopes,  by end of November this year hopes are that ISON may briefly get as bright as the Moon in the sky.

Using the newly obtained Hubble data, astronomers estimate that the dirty snowball measures 3 to 4 miles wide, while the gas and dust filled coma that surrounds the nucleus stretches out approximately 3,100 miles in diameter – wider than the Australian continent.

Clearly visible on this new Hubble photo is the ghostly dust tail pointing away from the Sun, extending more than 57,000 miles. This iconic, ethereal feature of all comets form from  surface material being ejected at high speeds into space.

As comet ISON heads towards the Sun over the next few months,  the frozen surface of the nucleus will continue to warm up and melt. The Sun’s heat evaporates ices in the nucleus into jets of gases and dust, forming  the snowball-like coma – which, by the way, is slowly getting denser and wider as the comet approaches the Sun.
(Related :New Comet Discovered—May Become “One of Brightest in History”)

Astronomers believe that this may be ISON’s first trip into the inner solar system, coming from the far outer reaches of the solar system, from a frozen reservoir of billions of hibernating comets.  Based on orbital calculations, as the Sun’s gravity pulls in the comet,  it’s trajectory will take it uncomfortably close to the Sun on November 28.  In fact it will plunge within  700,000 miles of the fiery surface of our star before heading back out to the outer solar system and hopefully begin to put on a sky show.

So the big question on everyone’s mind now is – will ISON spectacularly light up our late autumn skies or will it fizzle- out and disintegrate as it dive bombs the Sun?  Time will tell.

Changing Planet

Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.