Shhh! Don’t wake the sun

Contrast these views of the nearly spotless sun on July 16-17, 2014 with a picture taken about two weeks earlier (below). Credit: Giorgio Rizzarelli

Who doesn’t enjoy a nap on a lazy summer afternoon? That’s what the sun’s been up to past few days. Instead of a steady parade of sunspots, it put its pencils away and went to sleep. For a time on July 17 not a singe magnetic blemish marred the entire Earth-facing hemisphere. The last time that happened was nearly 3 years ago on Aug. 14, 2011.

Ten groups including three visible with the naked eye dot the sun on July 8, 2014. Credit: NASA

The solar blank stare lasted but a day; by the 18th two small groups emerged. Today three little spot clusters have emerged but again, they’re on the small side.

I think the reason the sun looks so stark is that only two weeks ago nearly a dozen sunspot regions freckled the disk including three visible with the naked eye with a safe solar filter.

These ups and downs aren’t unusual unless this downturn continues for weeks. Expect more bubbles of magnetic energy to rise from beneath the glaring surface of the sun called the photosphere and spawn fresh groups soon. Because we now have eyes on the farside of the sun courtesy of the dual STEREO solar probes, we know the complete story. There are at least seven spotted regions in hiding there today.

Sunspot numbers are plotted for the last three solar cycles through the present. The double peak of the current cycle is shown. Credit: NASA

Sunspots and flares peak approximately every 11 years. We’re still riding the roller coaster near the top of the arc after the most recent solar maximum in late 2013. Some maxima are strong, others weak. The current max – Cycle 24 – is the weakest since Cycle 14 in February of 1906 and one of the wimpiest on record. Occasionally a cycle will have two peaks like the current one. The first peak occurred in Feb. 2012 and the second just this past June. What makes Cycle 24 even more unusual is that the second peak is higher than the first – the first time this has ever been recorded. Like people, every maximum has a personality of its own.

Doug Bieseker of the NOAA Space Weather Prediction Center has analyzed historical records of solar activity and he finds that most large events such as strong flares and significant geomagnetic storms typically occur in the declining phase of solar cycles—even weak ones, so don’t give up hope for some great auroral displays ahead.

A coronal mass ejection blew off on the farside of the sun early this morning July 20. It appears to envelop Jupiter, but the planet is 490 million miles in the background. SOHO uses an occulting disk to block the brilliant sun. Credit: NASA/ESA

The sun’s got a buddy this week – Jupiter! We can’t see the planet from the ground because it’s swamped by solar glare, but the Solar and Heliospheric Observatory (SOHO) has a great view from space. Watch the sun approach from the right and pass the planet over the next few days. After the 24th, Jupiter will move into the morning sky.

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About astrobob

My name is Bob King and I work at the Duluth News Tribune in Duluth, Minn. as a photographer and photo editor. I'm also an amateur astronomer and have been keen on the sky since age 11. My modest credentials include membership in the American Association of Variable Star Observers (AAVSO) where I'm a regular contributor, International Meteorite Collectors Assn. and Arrowhead Astronomical Society. I also teach community education astronomy classes at our local planetarium.

4 thoughts on “Shhh! Don’t wake the sun

  1. Dr. Ken Tapping, former director of the White Lake DRAO (Dominion Radio Astrophysical Observatory), near Penticton, BC will be giving a lecture about what the Sun is up to at the Mt.Kobau star party ( http://www.mksp.ca ) on August 2nd. The somewhat cooler weather ( 81F/27C ) that we have right now makes me optimistic that the smoke will clear up by then. :)

    • Hi Paul,
      Sure hope it clears soon. It’s been thick over Minn. and Wisconsin for several days now. Tough when the moon’s a crescent and the nights best for viewing.

  2. Thanx Bob for pointing out that the 2nd peak was unusually stronger than the 1st one, I didn’t notice that. Let’s see what shows Sun has still to offer this cycle.

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