There is a new object in the sky. Comet ISON is an icy wanderer making its first and probably last last trip into the solar system from its previous home in the Oort cloud. It will graze by the Sun brilliantly and then depart. As it approaches the inner solar system, it is now inside the orbit of Earth, astronomers have been watching its outbursts of ice and volatile materials which then reflect sunlight and make the comet very bright. It is just visible to the naked eye according to some reports now. Comet ISON has increased in brightness many times over in the last few days.
We don’t know how bright it will get. Astronomers generally just don’t know as much about comets as we would like. The comet has undergone outbursts of brightening and dimming, while generally tending to get brighter as it enters in to the inner solar system ISON may become entirely disrupted or get brighter and brighter – the comet of the century. The reason for all this uncertainty is that comets and this object in particular are not well studied. But also it is that comets are not dense rocks, but rather they are loose aggregations of dust, rubble, and ices. Tidal forces and heating of the ices can literally unbind entire comets. I haven’t been able to see it for myself yet, it hasn’t been quite visible because it rises so late I think. Currently, if you want to see comet ISON from North America look east right before dawn as it passes Mercury.
Here is a finding chart for comet ISON (and also for comet Lovejoy) so maybe you can spot it soon. A pair of binocular makes it easy. Currently ISON is swinging by the bright star Spica in Virgo. To find it follow the handle of the big dipper and “arc to arcturus” as they say then follow that arc on the Spica. ISON will be the fuzzy star nearby. Who knows how bright it will be when you look up; it may or may not be visible to the naked eye (last report I read said it was at magnitude 5.5, which is on the edge of visible to the naked eye in clear dark skys). It will look like a lollipop or balloon shape because the tail. It has a central blue-green nucleus and a long narrow tail. It is also currently a full moon, the Frost moon so the sky will look lovely regardless.
This is all just getting started. Comet ISON may dissentigrate at any time. It may fall apart as is grazes by the Sun around Thanksgiving day. Or it may survive and create quite the show in early and mid December after it has swung around the Sun when it will make its closest approach to Earth on December 26th. I have compiled a bunch of useful links if you are interested in learning more. Here is the comet ISON observing campaign. Here is a reddit astro-bot that follows and tags with coordinates pictures of astronomical objects including comet ISON. Here is Sky & Telescope’s continuously updated info on ISON. Here is an interactive 3d orbital diagram of ISON’s orbit. Here is an infographic showing that NASA has over 15 assets that will observe ISON. I will update this post with any good comet finding resources I find in the upcoming weeks and if you find anything helpful please comment below. Finally, here is a little more on about what comets are:
Updates (11.24.2013) and more links:
12 Cool Facts about Comet ISON
ISON’s orbital elements, magnitude graphs, and finding charts
NASA visualization of comet ISON’s path through the solar system
animated infographic of ISON’s path through constellations