Experts say there’s a 60% chance this weekend of geomagnetic storms, possibly causing auroras. Plus, over the past couple of days, a lone sunspot has grown rapidly!
By Deborah Byrd
We’re approaching another minimum in the 11-year sunspot cycle, predicted for the years 2019 and 2020, and so the number of visible spots on the sun has been low. But there’s a nice, big, visible spot on the sun now, plus an Earth-facing coronal hole seen by spacecraft. Because this hole in the sun’s atmosphere faces Earth – and because it releases a high-speed solar wind – experts say there’s a 60% chance this weekend of minor G1-class geomagnetic storms, which could causes auroras. The coming full moon, of course, might interfere or might give you an opportunity for some interesting photos. The storms are expected on July 9, 2017 when the solar wind stream should hit Earth’s magnetic field.
As for the sunspot, it appeared on July 6 on the limb of the sun that had just rotated into view, and it was seen to grow rapidly. The animation below shows the sunspot over 36 hours:
This sunspot should be an easy target for backyard telescopes equipped with solar filters. Spaceweather.com commented:
So far the sunspot has not produced any strong solar flares, but this could change if the sunspot’s breakneck growth destabilizes its magnetic field. Amateur astronomers are encouraged to monitor this expanding sunspot.
Of course, the sun is dynamic and changes rapidly, so be sure to check out NASA’s Solar Dynamics Observatory’s The Sun Now page for updates.
Bottom line: There’s a visible spot on the sun now, and an Earth-facing coronal hole might produce some good auroras around July 9, 2017.
Deborah Byrd created the EarthSky radio series in 1991 and EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.