Friday, August 12, 2016

A Couple Quick Updates

by Stephanie Osborn

The Sun has definitely awakened for the time. (Finally.) There are currently half a dozen spot groups on the solar near side; 2571 is about to rotate to the far side, but there are also 2573-7 as well, which range from a simple single spot to a multi-spot complex.

Solar Dynamics Observatory imagery
Labeling by
Note how the spots tend to cluster around the equatorial region. This is pretty typical for late in a solar cycle. Sunspots tend to start out at higher latitudes, closer to the poles, then drift equatorward.

Very minor C-class flares are occurring, but there is little chance for anything stronger. A filament did lift, and this may produce a small coronal mass ejection, or CME. We're waiting on LASCO (Large Angle and Spectrometric Coronagraph, an instrument on SOHO, the Solar and Heliospheric Observatory) imagery to determine if it made a CME or not. Such CMEs tend not to be as strong as those associated with large flares, so even if it is Earth-directed, expect pretty aurorae and a few high-latitude effects, but nothing of significance.

There are some coronal holes, but they aren't "geoeffective" (aimed at Earth). Geomagnetic activity is quiet.

Solar Dynamics Observatory imagery
Labeling by

More data as it comes in.

* * *

Well, the night of August 11/12 was the absolute peak of the Perseids. I've just come in from spending about 20 minutes outside, having a look. (It's currently 4am local time.)

I have to say that I was underwhelmed, especially given the hype given to the predictions of "up to 200 meteors/hour." That comes out to be over 3 meteors per minute, or about one meteor every 15-20 seconds. So in 20 minutes, I should have seen around 66 meteors.

I saw about 1/10 that.

Now, granted, I'm in a subdivision and my skies are not the darkest. And we had some light patchy clouds moving through. But  I waited until after the moon had set before I went out, to have the darkest possible skies for my location. And I picked the clearest patches of sky to observe, and ensured I blocked any light sources. Keep in mind that I've observed this shower from this location numerous times before, as well, so I know what I'm looking for. And I've seen the Perseids storm, the year after the parent comet, Swift-Tuttle, came through -- both from a rural dark-sky site, and my yard, where I was tonight.

Bill Cooke, NASA Meteoroid Environment Office,
Huntsville, AL
August 10, 2009

I undoubtedly would have seen more meteors had I been in a dark-sky site. But ten times more? Really?

It's possible, also, that I simply picked a time when, coincidentally, we were going through a sparse patch -- I was busy writing, and lost track of time, or I'd have been out there earlier, for longer. I'll be interested to see what other observers have to say.

As for me -- I love the Perseids; they're gorgeous, bright fireball meteors. But this didn't come anywhere close to the spectacle I remember right after Swift-Tuttle came through. That was one I'll always remember. Tonight, not so much.

If you were out observing the Perseids, I'd love to hear your observations in the comments.

* * *


For more information on solar activity, check out my ebook, The Weather Out There Is Frightful: Solar/Space Weather and What It Means for the Earth and You.

Just a quick promo for me and my fellow scientists, for those of you who are interested in such things: A new anthology will be released in September (we hope!) called Science Fiction By Scientists. Every short story in it is "hard SF" written by an actual scientist, along with a quick primer at the end of each story on the science involved. It's available for preorder now!

~Stephanie Osborn