A Necklace For Your Milky Way And A Giant Sunspot

This past Wednesday night I dashed off to our local planetarium with zip drive in hand to give a PowerPoint presentation on black holes, but when I arrived, one of the student staffers there gave me a funny look. “Your show’s not till next Wednesday,” she said smiling.

The Necklace Nebula is a planetary nebula 15,000 light years away in the constellation Sagitta near the Northern Cross. The bright knots that resemble jewels in a necklace are dense, glowing pockets of gas. Credit: NASA / ESA

A bonehead move on my part, but two good things came from my error. The first was the sense of relief at now having a show done a full week in advance, a record for me. The second involved my younger daughter Maria. She had dropped by to say ‘hi’ and brought me a candy bar –  a Milky Way, naturally.

One sweet gesture deserves another, so Maria today I offer you the Necklace Nebula as thanks. This pretty bauble resides in the little constellation of Sagitta the Arrow not far from the Northern Cross. A pair of closely-orbiting stars worked in tandem to create the nebula beginning about 10,000 years ago. That’s when the larger, more evolved star bloated up and engulfed its companion. Amazingly, the smaller star remained intact as it orbited inside the giant. Over time the littler one transferred some of its orbital energy to the bigger star which sped up in response. Powerful centrifugal forces caused the big one to slough off  gas along its equator in the form of a ring. The jewels on the necklace are especially dense blobs of gas.

The two stars are only a few million miles apart and appear as a single star in the photo. The innermost planet Mercury’s otherwise rapid 88-day orbital period seems glacial compared to the one day it takes for these two stars to revolve about each other.

The huge sunspot at right, photographed this morning by NASA's Solar Dynamics Observatory (SDO), covers an area 17 times the size of Earth. Credit: SDO/NASA

Speaking of stars, the home star’s cooked up a monster sunspot, one of the biggest in years. Over the past several days, Region 1339 has rotated around the sun’s eastern edge and looks ripe for big flares in the days ahead. One significant flare occurred Thursday but it was not directed toward our planet. We’ll keep a watch on this one as it rotates closer to the sun’s center and alert you when Earth-directed activity might lead to a northern lights show. For the moment, space weather forecasters are calling for a small possibility of an auroral storm for today due to unrelated effects from a coronal hole. Check the latest HERE.

Complex magnetic fields create gigantic loops in the hot plasma above the giant sunspot at left. Photo taken in UV light during yesterday's flare by SDO. Credit: NASA/SDO

6 Responses

  1. Mike

    This class on the black hole, community ed or for something else? Is the public invited, if so what time? On that same note when do the winter community ed classes start. Just can’t get enough Astronomy info in my head really soaking it up these days.

  2. thomas s

    hi bob. a question. I thought that the people who know about such things told us that the sun is now (or soon will be) going thru a “quiet” period. yet, it seems to me that solar activity (at least as far as sunspots are concerned) is increasing. who is right. or am I just uninformed/confused on the matter?

    1. astrobob

      Hi Thomas,
      A lower than usual sunspot maximum has been predicted for 2013 after a very prolonged minimum, the longest in 100 years. However, the sun is now beyond minimum and climbing toward that 2013 maximum, which is why we’re seeing more spots and flares. It’s all part of the cycle, even if this cycle may not reach the heights of say the last one in 2000.

  3. thomas s

    Thanks Bob. Your explanation clears it up for me. wonder what climatologists think about the recent long SS minimum? usually we associate lower SS activity with colder climatic conditions (e.g. the Maunder min). but the last decade or so has seen warmer conditions.

    1. astrobob

      You’re welcome Thomas. I’m guessing global warming from higher CO2 levels have much to do with the warming trend.

Comments are closed.