An Unexpected Surprise During Last Night’s Asteroid Flyby

Last night's circumscribed halo looked like a big eye staring back at Duluth with Jupiter a small "tear" to the left of the pupil. Details: 16mm lens, f/5.6 and 15-second exposure. Photo: Bob King

You can plan, plan, plan for an astronomical event like last night’s asteroid flyby, and finally succeed in seeing something elusive and amazing. While the sense of satisfaction gained from your efforts is keen, the unexpected offers a different kind of joy. Later that evening while walking the dog, I looked up to see the moon ringed by not one but two halos. The delicate rainbow colors at top and bottom were exquisite, and the whole thing didn’t last more than 20 minutes before thicker clouds mussed it up. Striding alongside the moon was the planet Jupiter, much like the dog at my own side. What a sight!

You may have seen the halo, too. The inner circle was the frequently seen 22-degree halo, which refers to the size of the ring’s radius. If you double that number you get 44 degrees for the halo’s diameter. That’s four and a half fists held at arm’s length against the sky. This is what most of us see when we look up and spot a “big ring” around the moon.

Light bent by the prism-like hexagonal ice crystals in high clouds create the rings around sun and moon.

Wrapped around the circular halo was a second or circumscribed halo, which touched the inner halo at top and bottom. That’s where the colors were. Because the outer ring was oval instead of circular, the halo looked very weird – like a giant eye staring back.

Both rings are caused by moonlight bent or refracted by billions of six-sided, pencil-shaped ice crystals in cirrostratus clouds overhead. Each of these tiny prisms contributes to the bending and spreading of light into a ring. Randomly oriented crystals create the 22-degree version, while crystals floating horizontally make the circumscribed halo. I like that as bold and sharp as a halo appears, it’s made of nothing more than light. The color arises from white light being spread into a rainbow spectrum.

The nearly full moon and Jupiter will surely catch your eye in the eastern sky tonight.

If you missed seeing Jupiter close to the moon last night, you have another chance to catch them together this evening. The moon will have moved a fist to the east or left in the interim and shine on the other side of the planet tonight. By tomorrow, the moon will be farther east yet, leaving the planet behind as it travels toward the Seven Sisters Cluster in the constellation Taurus the Bull.

Worrisome news is coming from Russian scientists about the Phobos-Grunt spacecraft. You’ll recall the mission was launched yesterday, but unfortunately, when the probe separated from its rocket stage, it failed to fire its own rockets to leave Earth orbit and head for Mars. The mission’s goal is (was) to retrieve rock samples from Mars’s moon Phobos and return them to Earth in 2014.

Artist rendition of Phobos-Grunt on its way to Mars and its moon Phobos. Credit: Roscosmos

The probe and rocket engines are still intact and ready to go, but engineers have only about three days to figure out and  fix the problem before Phobos-Grunt’s batteries run out of power. After that it will orbit the Earth like another defunct satellite and ultimately burn up in the atmosphere.  There’s also a small Chinese satellite on board that will be sent into orbit to study Mars. Hopefully the troubles will be fixed. If not, it will be Russia’s 4th failed space mission to the Red Planet. I’ll have more information as the story develops.

11 Responses

  1. Debra

    The russians don’t have much luck with Mars do they Bob. Wont this probe be carrying a lot of fuel will this do the earth damage when it re enters. Hope they can sort the problem out Bob it’s such a shame for them and time and money wasted for them.

    1. astrobob

      It really would be a shame. I hope it can be rescued. As for the fuel, I don’t know what would happen if they can’t start the engines.

  2. stephanie

    hi bob I did see that last night it was beautiful lol I even took pictures with my phone and sent them to my father…. who is buying me a telescope for christmas lol I enjoyed the whole night last night!! thanks for everything!! and hope you have a great thanksgiving!!! Keep reaching for the stars Bob lol

    1. astrobob

      Hey Stephanie, thanks very much. How exciting you’re getting a telescope. I hope you share your observations with us, and have a great Thanksgiving, too.

  3. Craig

    Hey Bob. Thanks So Much For Explaining That, I was Looking Everywhere For The Answer And I Thought I Wasnt Gonna FInd It. Much Appreciated (think i spelled that wrong.)

  4. James Camey

    Tuesday evening, my wife and I just got home about 5:20 and she was taking a smoke on the patio (east side of our house) It was super clear and the bright moon was right in our full view. I was looking at it when I observed a small fleck reflecting the same color as the moon move across the very top of the moon. At that time it was almost 5:30. I pointed it out to Nancy and she commented about how fast it was moving. We are on the north side of Dallas TX and were looking east. The ‘fleck’ was moving at what appeared to be slightly north, northwest to the southeast. Could it have been the asteroid? Would have been a random chance if it was. Thanks in advance for any info you may have.

    1. astrobob

      Hi James,
      The asteroid was much too faint to see without a telescope (dim even in my 10-inch scope!) and not near the moon at that time. I’m guessing you saw a man-made satellite. Many satellites move in the direction you described.

  5. Angie Brown

    its was to cloudy in Dayton OH at the time the meteor was to pass and didnt get to se it could you show me a vidoe takn of it passn the earth i just fasnated with astrolligy

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