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

Photo: Hubble Gets First Glimpse of Possible ‘Comet of the Century’
Posted by Andrew Fazekas in StarStruck on April 23, 2013



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.

http://newswatch.nationalgeographic.com/2013/04/23/photo-hubble-gets-first-glimpse-of-possible-comet-of-the-century/

Wow, that's great. Thanks.

"Instead of burning up in a flash of light, they [the particles] will drift gently down to the Earth below," University of Western Ontario meteor scientist Paul Wiegert said in a statement. [See Photos of Comet ISON] The specks of dust will be travelling at a speed of 125,000 mph (201,168 km/h), but once they hit the Earth's atmosphere, they will slow to a halt, according to Wiegert's computer models.
Because of this, observers on the ground probably won't be able to see the meteors as they fall through the atmosphere in January 2014, Wiegert added.

"Don't expect to notice," NASA officials said of the shower in a press release. "The invisible rain of comet dust, if it occurs, would be very slow. It can take months or even years for fine dust to settle out of the high atmosphere."
All hope for a brilliant show might not be lost, however. The dust from ISON could create "noctilucent clouds" — icy night-shining clouds above the Earth's poles that glow blue.
"Electric-blue ripples over Earth's polar regions might be the only visible sign that a shower is underway," NASA officials said.

http://news.yahoo.com/comet-century-could-create-meteor-shower-181547156.html