Supersonic Bullets Etch Tunnels Of Light In Orion Nebula

Supersonic bullets of iron- rich gas tunnel through the outskirts of the Orion Nebula in this photo made on December 28, 2012. The nebula lies about 1,350 light years from Earth. Click to enlarge. Credit: GeMS/GSAOI Team, Gemini Observatory, AURA

If you haven’t seen this picture yet, I’m glad you are now. Amazing, isn’t it? What you’re staring at are blue “bullets” of iron-rich gas shot out from growing stars inside the Orion Nebula. The bullets measure some 70 billion miles across (10x the size of Pluto’s orbit) and create tubular wakes in the nebula’s dust and gas as they plow through hydrogen gas, setting it aglow. Some of traceries are 1/5 of a light year long.

Most stars not only radiate heat but also lose material from their hot surfaces in winds. We’re familiar with the sun’s solar wind, a tenuous stream of protons and electrons that flows away from our star at a speed of around 300 miles per second. The sun loses 1/100,000,000,000,000th (that’s one-trillionth) of its mass per year because of its windy ways.

The massive and clumpy stellar wind blasted by the aging supergiant star in the center of the Crescent Nebula in Cygnus. Click for details and more photos. Credit: NASA/ESA

Massive stars are extremely hot and brilliant. The power of their energetic light accelerates material off the star with gale force winds. While the sun will only lose about .01 percent of its material during its expected 10 billion year lifetime, giant stars, like those powering the bullets, slough off 1/100,000th of a sun’s worth of mass every year. During its brief life, a massive star can lose up to half the material with which it started.

Astronomers used the 8.1-meter (319-inch) Gemini South telescope in Chile to snap the first pictures of the bullets in 2007 and then again on December 28, 2012 with an adaptive optics setup that greatly reduced atmospheric turbulence. The result: super-sharp images. If you study this animation of before and after photos, you’ll see subtle but real changes in the structure and position of the pillars and knots. The universe sits still for no one – everything’s on the move! While we know that intuitively, seeing it is quite another thing. Read more about the photos and science behind the story HERE.

The Orion Nebula is found in a short line of stars called “the Sword” below Orion’s three belt stars. This view shows the sky facing southeast around 8 p.m. local time. Photo: Bob King

While you and I can’t see the bullets through our toddling telescopes, we can see where all the action’s happening – the Orion Nebula. The nebula is faintly visible with the naked eye as a fuzzy spot in Orion’s Sword, a vertical stack of three fainter stars below Orion’s famous belt.

Consisting of a 24-light-year-wide spread of dust and gas arrayed in glowing pink and green tendrils, the Orion Nebula is nothing short of a huge factory cranking out stars like loaves of bread at a bakery.

Denser knots of material with the nebula succumb to the force of gravity and collapse into brand new suns. Many are small and lost in the nebula’s misty folds, but some are supergiants with windy temperaments.

Little more than a wisp to the naked eye, the Orion Nebula easily shows a cocoon-like shape in binoculars from suburban and rural skies.

The Orion Nebula in its full glory. Clouds of hydrogen gas fluoresce red from radiation emitted by the central star cluster (overexposed area) called the Trapezium. Click to enlarge. Credit: NASA/ESA

The real fun comes in the telescope. I’d guess I’ve looked at this cosmic wonder at least 500 times during my life. There’s simply no good reason not to dial it up for a view during fall, winter and even early spring. When it comes to winter deep sky objects, the Orion Nebula’s makes for tasty, low-hanging fruit.

We see the Trapezium in this closeup view. Notice how the small cocoons of dust and gas, which contain developing stars, point away from Theta. Their gases are being stripped off by powerful stellar winds. Credit: NASA/ESA

Not only is it loaded with gaseous detail in the shape of arms, wings, petals and pleats, but at its center shines the exquisite Trapezium, a compact star cluster arranged in a trapezoid. The brightest, largest and most luminous of the quartet is Theta-1 Orionis. Its massive outpouring of ultraviolet light makes it the nebula’s primary illuminator. Take away Theta-1 and there wouldn’t be much left to see. Theta also blasts strong winds into the surrounding nebulosity, stripping away material from stars in the birthing process. These nasty habits guarantee a short life; Theta-1 burns its fuel so rapidly it will likely explode as a supernova in just a few million years.

While it may look like a quiet, fuzzy place on a still winter night, the Orion Nebula is teeming with activity. Have a look sometime and it won’t be hard to imagine those crazy cosmic bullets whizzing about.

15 Responses

  1. Giorgio Rizzarelli

    Fantastic M42. A couple of nights ago I was in country with a friend, weather was exceptional. The sight of M42 in telescope was breathtaking, I never saw it like that before.

    1. astrobob

      Hi Giorgio,
      Thank you! When I saw the clouds, I knew they’d be perfect for safe filtering. Wish I could have seen M42 like you did tonight. It was clear for just a little while – long enough to see comet C/2012 K5. It’s much faded (now about 10 mag.) but still has a fine if faint tail in my 37-cm reflector.

      1. Giorgio Rizzarelli

        We’ve seen the comet too – that was the main target that night. In my scope it was barely visible by eye, and I had to take a 1-minute exposition shot, but it showed the tail. And when, soon after, I took another shot for safety, it was a surprise seeing that the comet had moved! It was very evident because the comet was passing “near” a star in that moment. Then, careless of cold wind, I took about 10 shots to assemble a rough animation of the passage. It’s my first comet shot in a reasonable dark sky. I have to thank that star, New Moon, a rare excellent weather, and you for transmitting your comet passion!

        1. astrobob

          Amazing how rapidly the comet faded after it passed Earth, isn’t it? I last observed C/2012 K5 on the 14th. Everything was there – tail, coma, nucleus – but faint! I estimated an overall magnitude of 10.

          1. Giorgio Rizzarelli

            When we saw it, it was on day 11th and, according to Heavens-above, magnitude had went already down to around 13. I remember it because that is just barely above the limits of the C8 scope (14). In fact we could see the comet just barely.
            I hadn’t chance to see it before, except for a bad photo in city.
            BTW I suspect that the 14 limit magnitude is meant for visual use only (in fact adding to the 6 naked eye limit the amplification term due to the C8 aperture respect eye, I obtain 14), while in photography one can go past that limit, isn’t it? I’d happy if you can clarify this.

          2. astrobob

            The magnitude on H-A is not correct. They’re probably using standard predicted magnitudes, not the real ones based on observation. Comet mags. are tricky because you can have a large, extended object that looks much fainter than an object of the same magnitude but compressed into a small area. Photography through the scope will take you far beyond the visual range. I’ve got a friend with a C14 who reaches nearly to 20th mag. on time exposures. Visually, he can probably get mag. 15.

          3. Giorgio Rizzarelli

            Thank you Bob. I checked H-A more carefully, it indeed gives the last observed magnitude, but often the last observed date is many days behind in time.
            I still have a hope that comet magnitude may be a useful indicator even if comets are spread on angle, just as it’s somehow useful for Messier objects. Do you maybe have a better website to suggest?

          4. Giorgio Rizzarelli

            Great link, great Bob!

            And great M106 galaxy I shot tonight. A modest pic (I still don’t have the accessories or deep sky) but my best so far. It was also visible a bit. Another uncommon good weather winter night here. We went on highland and, although a bit of moisture and snow, had a reasonably dark sky. Cold and lots of frost on the scope didn’t let us see much more, but it was worth the entire night!

  2. H.Bob

    “the Orion Nebula is nothing short of a huge factory cranking out stars like loaves of bread at a bakery”

    AstroBob, I’m curious as to how long the idea of star nurseries (bakeries…!) has been around. Is this considered close to confirmed theory now or is there debate about how stars are formed? It seems there is so much more knowledge and understanding gained in the last 40-50 years, on all matters of astronomy. Is it fair to say that since Hubble and Atacama that astronomical knowledge has grown an order of magnitude? or have those telescopes simply confirmed what was already conjectured?

    1. astrobob

      The debate goes on about the fine details of star formation, but the theory’s been around a while (backed by observational evidence particularly in the infrared) and is sound. I would agree with your assessment of Hubble, Atacama (and others) and especially the many orbiting observatories that have explored stars, galaxies and nebulae in wavelengths of light like X-rays, infrared, gamma radiation and UV that aren’t possible from Earth. Astronomers now know the universe in ALL its colors!

  3. Bob Crozier

    Hey Bob,

    Sorry, but I have another of those, “How can that be?’ questions. From reading your blog entries (always fascinating, btw!) and the links that you (and Giorgio) have been posting for me (and everyone else), I have been trying to get a beginner’s grip on star formation and some of the other cool stuff that goes on ‘out there.’ From these readings, I seem to have gotten the impression that iron forms in stars (BIG, heavy ones!) later on as they are maturing rather than as they are forming and growing. I also got the impression that this iron sinks into the middle (core) of the star rather than floating to surface to be expelled as lighter elements (or even just protons and electrons) would be. If I have understood that correctly, (here it is!) how can this iron be coming from a star that is still just forming and/or growing (a protostar or very young immature star)? If I have not understood that correctly, what did I miss?


    1. astrobob

      All the natural elements up through uranium are present in the sun but in very small amounts compared to hydrogen and helium. That’s because the sun is made of the same materials as Earth but in very different proportions. Iron, calcium, etc. are found in the gas present in the sun’s photosphere as well as its corona. It doesn’t sink to the core because of fierce convection in the sun’s outer layers as well as the tremendous outpouring of radiation from nuclear fusion in the core. LARGE quantities of iron forms in the cores of supergiant stars near the end of a star’s life via nuclear fusion. In that case, the star makes its own iron from simpler elements. The sun will never get hot enough to do that. Good thing, otherwise we’d have to worry about the sun becoming a supernova.

    2. Giorgio Rizzarelli

      Yes, heavy elements originate in heavy stars in late stages, are ejected into interstellar space, and arrived here before Solar System formed. When you’re touching a piece of Iron, that’s “made in supernova” (I refer to the element of course, not the chemistry of mineralogy). To say another one, Carbon of which you’re made, is “made in Carbon star”.. one of those incredible very red stars we can see in telescope. All heavy elements are “made in heavy stars” (at least, until the day when all things will be made in China)

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