Happy Perihelion Day!

When an object in orbit of the sun reaches its closest point to the sun, that is its Perihelion. Even Earth has a perihelion since our orbit is elliptical rather than circular, and the sun is not right in the center of it.

A comet’s perihelion can be much more interesting because of how close they get to the sun at that point.

Today comet ISON reaches perihelion as it rounds the sun. ISON is special in that it’s a “sungrazing” comet and it’s getting so close to the sun that we’re not sure if it will survive the swing around it. It may completely fall apart today.

But if it doesn’t, it’ll come out the other side and head back into space, and will potentially be shining brightly and beautifully in our pre-dawn skies. At least for a few days.

Here’s more about ISONs Perihelion today. [click!]

And here’s more about perihelions in general. [click!]