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The Eye of God

Ed HahnenbergThere are only a few nights that I can image one of the most spectacular nebulae in the sky. I refer to NGC 7293, also known as the Helix Nebula. It has also been referred to as the “eye of God.” Why it has been so difficult to image is because my observatory is situated near trees on the horizon, and unless it is trackable above the trees, I cannot get any image at all.

The Helix has the largest apparent diameter of any planetary nebula. It lies in the constellation Aquarius, which lies low in the southern sky. Looking like a giant circle, the nebula surrounds a dying star that has blown off its outer layers, once its central supply of nuclear fuel was nearly exhausted. The remnant central star is a dense “white dwarf” that can no longer support nuclear reactions. At a distance of 450 light years, it is the closest planetary nebula to earth.

As our sun advances to late middle age, it will expand to a red giant, engulfing the inner planets, including earth. Then, the outer gases will disperse as in the case of the Helix, leaving our sun a white dwarf. The final stage will result in a “black hole” as it dies. Such a fate awaits the star at the center of the Helix.

Below is my image of the Helix with 2 X 2 binning, 35 images stacked, each one minute in length. Be sure to click on it for a larger view.


  • Ed Hahnenberg

    SkyGuide…With our present knowledge of the life cycle of stars the size of ours, black holes, as you say, are reserved to much larger stars. However, since we have no real-time knowledge of what happens to a white dwarf. Read about the experimentation at http://www-news.uchicago.edu/releases/07/070322.explodingstars.shtml.

    As to your spell-check advice, I have seen “earth” and “sun” used without caps. I think it is a fussy point you are making.

    • SkyGuide

      “However, you might find interesting a report about the experimentation as to what some think happens to white dwarfs at the end of their lives”

      The press release you reference is poorly written, and is leading you to the wrong conclusion; there are no astronomers – none – who believe that a white dwarf star like our Sun will ever go supernova unless there is a huge amount of extra mass added to it. This is a rare event, and occurs if the white dwarf is in a binary star system that “steals” gas from its still main-sequence twin. (The technical description is that the white dwarf star exceeds the Chandrasekhar limit, stealing material until it becomes 1.44 times more massive than our Sun; this inevitably leads to a supernova.)

      The press release is referring to a very small subset of all white dwarf stars, and certainly does not what will happen with our Sun.

      “I think it is a fussy point you are making. I am not writing for the League of Famous Astronomers.”

      You write an astronomy column for a newspaper. Proper capitalization is as “fussy” as using the correct form of affect/effect, or their/there/they’re. “Earth” is the proper usage when talking about our planet, “earth” is used to describe dirt. Referring to our planet as earth is as inaccurate as spelling mars, michigan, mesick, or ed hahnenberg without capitalization.

      • Ed Hahnenberg

        Skyguide…Still fussy. Looking at the New Oxford American Dictionary, one finds the definition of planet “earth” this way:

        “The earth is the third planet from the sun in the solar system, orbiting between Venus and Mars at an average distance of 90 million miles (149.6 million km) from the sun, and has one natural satellite, the moon.”

        Wikipedia is chock full of dual use of capitalization and lower case. If you look up “Erotoshenes” for example, you find the following:

        “He was the first person to calculate the circumference of the earth by using a measuring system using stades, or the length of stadiums during that time period (with remarkable accuracy). He was the first to calculate the tilt of the Earth’s axis(also with remarkable accuracy). He may also have accurately calculated the distance from the earth to the sun and invented the leap day.”

        Even though I write for a newspaper, some extraordinarily brilliant folks who read my column have never brought this to my attention. Looking at Latin, terra is not capitalized, nor is the Greek word for earth, except when it refers to the Greek goddess Gaia (Γαῖα). The Germans capitalize all nouns and whatever else comes to their fancy. I learned biblical Hebrew, where caps and lower case are used. However, if you read modern Hebrew, everything is caps, with no diacritic marks used to indicate vowel sounds.

        Language has its rules, but they are not frozen. They change with the times. Our younger generation often omits caps when texting. Search engines like Google and Yahoo don’t give a rip about caps. Will you turn in your grave if no words are capitalized in 50 years or so?

        I recently read Jules Verne’s “From the Earth to the Moon.” Just a snippet:

        “Is it possible to transmit a projectile up to the moon?”

        “Answer.— Yes; provided it possess an initial velocity of 1,200 yards per second; calculations prove that to be sufficient. In proportion as we recede from the earth the action of gravitation diminishes in the inverse ratio of the square of the distance; that is to say, at three times a given distance the action is nine times less. Consequently, the weight of a shot will decrease, and will become reduced to zero at the instant that the attraction of the moon exactly counterpoises that of the earth; that is to say at 47/52 of its passage. At that instant the projectile will have no weight whatever; and, if it passes that point, it will fall into the moon by the sole effect of the lunar attraction.”

        Notice there were no capitalization police running around then. Who sets the rules? Usually common folk in everyday usage, despite purist teachers…and my teaching major was language arts.

      • Bobdisqus

        SkyGuide, it seems to me that Ed has only ever claimed to be an amateur astronomer and has claimed no expertise in astrophysics. The word for people correcting grammar in blogs is pedant. Ed is a grumpy old papist yet, still no pedant.

        If you have a clear and reliable source for the fate of G class stars please link it.
        http://astronomyonline.org/Stars/BlackHole.asp?Cate=Stars&SubCate=OG04&SubCate2=OG0405#Formation_of_black_holes
        http://amazing-space.stsci.edu/resources/explorations/blackholes/teacher/sciencebackground.html#6
        http://en.wikipedia.org/wiki/Black_hole

        Looks to me like only through accretion or merger but, I am no astrophysicist.

  • Ed Hahnenberg

    SkyGuide…I think I have been fairly in line with the various handbooks on capitalization. It is a convoluted issue. There is consensus that planets other than earth are always capitalized, which I have always done. In http://www.eliterateeducation.com/site/capitalization.htm, Solar system names of· . Planets
    · Stars
    · Satellites
    · Not sun, earth, and moon, usually.

    Planets and heavenly bodies can be tricky. Take the word “earth,” for example. First, when you are using the word “earth” to refer just to dirt (as you pointed out), it’s lowercase, of course, but when you’re talking about our planet, it becomes tricky because there isn’t what grammarians consider a strong rule. All the other planet names like Mars and Jupiter are always capitalized because they’re names of specific places, but for some reason, most people treat “earth” (sun and moon as well) differently and don’t capitalize it.

    I’ll call a truce. What I didn’t appreciate is your getting in the “dirt” with your “friend’s fly is down.” Gross and inappropriate example.

    I would have preferred you to have made an observation about the quality of my astrophotograph rather than go the route you did.

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