A Stripe Across the Sun

Bad Astronomy
The entire universe in blog form
Feb. 9 2014 8:00 AM

Solar Interloper

contrail on the Sun
Well, I missed my plane.

Photo by Phil Plait

I recently wrote about the ridiculously huge sunspot cluster called Active Region 1967, which has individual spots far larger than Earth. The Sun’s rotation is currently carrying it out of view, away over our star’s eastern edge. It’s possible that it will return in two weeks more, when the Sun’s spin brings it ‘round again.

I say that because it’s happened before: A month ago, AR1967 was actually AR1944! That was the designation given to it when it was first seen in January 2014. Over the course of two weeks the Sun’s rotation swept it across the star’s face. It slipped over to the far side of the Sun, and then two weeks later it came around again, and it was given the new designation of AR1967.


On Jan. 6, during that first apparition, I took my camera out to shoot a few pictures of the Sun using a makeshift filter setup; I wrote about my exploits at the time (I also wrote a description of my setup). A couple of days later it was clear and sunny once again, so on Jan. 8, I went out to take some more pictures. I’m glad I did, because I got a surprise when a far more proximate visitor interrupted my session. I quickly switched modes, and took this brief video:

I must have missed the plane itself passing in front of the Sun by just a few seconds, which is frustrating. However, I take consolation in knowing it takes a fraction of a second for it to cross the entire solar disk, so even if I had known it was coming odds are I would’ve missed it. I’m just glad I got the pictures and video I did.

And it’s a great reminder of the lesson I repeat so many times here on the blog: There’s a lot of cool stuff going on over your head all the time. Look up.

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  


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