It's being called one of the largest sunspots in years -- and it just erupted over the sun's northeastern limb a few days ago. The photo above shows how the gigantic sunspot, known as AR1339, looked early Thursday morning, November 3.
The photo shows a group of sunspots measuring 40,000 km wide and at least twice that in length. It's so big, it can easily be seen through a backyard solar telescope. Two or three of the sunspot cores (dark spots) are wider than Earth itself.
Sunspots produce solar flares. Solar flares are tremendous explosions on the surface of the sun. In a matter of just a few minutes, they heat material to many millions of degrees and release as much energy as a billion megatons of TNT.
These flares produce Coronal Mass Ejections (CME). Coronal Mass Ejections are huge bubbles of gas threaded with magnetic energy that are ejected from the sun over the course of several hours. They disrupt the flow of the solar wind and produce disturbances that strike the earth with sometimes very colorful results: the Aurora Borealis, aka: The Northern Lights.
Naturally, the larger sunspots often produce the largest flares and therefore the most notable auroras.
According to Spaceweather.com, "NOAA forecasters estimate a 50 percent chance of M-class solar flares during the next 24 hours."
A large M-class flare could easily produce an large aurora viewable here in Ohio. The sunspot cluster is expected to continue to rotate more in line with earth, so that any weekend flares could easily produce a brilliant display of the Northern Lights! Skies this weekend should be mainly clear, allowing all of us a front row seat for a spectacular show! - Mark Johnson