Summer Dreams: Glowing Gas and Twisters

The Lagoon Nebula is one of the grandest deep-space objects. Never extending high above the horizon from our vantage point, this patch of nebulosity and stars lurks toward the center of our galaxy in the constellation Sagittarius, best seen in the summer.

It’s so large and bright that in dark skies it can be seen by naked eye as a dim gray patch, if you’re not distracted by the riot of nearby stars and dark patterns in the Milky Way. Through the smallest telescope or pair of binoculars, it shows interesting details. With instruments of larger aperture, the Lagoon that provides its nickname —- which looks more like a dark canal than a lagoon —- is easily visible curving through the nebulosity. So are dark dust clouds and complex folds and rumples of gas.

The nebula is a star nursery where gravity is pulling together gas and compacting it to form new stars. As a Sept. 22, 2010, press release from the Hubble Space Telescope team and the European Space Agency notes, “Clouds of hydrogen gas are slowly collapsing to form new stars, whose bright ultraviolet rays then light up the surrounding gas in a distinctive shade of red.” Hubble experts and ESA say the wispy tendrils and “beach-like features” develop as ultraviolet radiation erodes and disperses gas and dust.

The formal designation is Messier 8, because in the 1770s it was the eighth object that comet-hunter Charles Messier added to his list of fuzzy sky blobs that aren’t comets. But it must have been noticed previously, innumerable times.
M8 is a huge object 5,000 light-years away, 100 light-years across. Because of my telescope’s long focal length and my camera’s small chip, the Lagoon Nebula is far too large for me to take in at one glance. But Tyler Allred’s superb equipment did it on the night of July 2-3, 2011, at Bryce Canyon National Park.

[View of the Lagoon Nebula by Utah astrophotographer Tyler Allred, taken the night of July 2-3, from Bryce Canyon National Park. The so-called “lagoon” is the darker rift curving through most of the central region. For a high-resolution version of this remarkable photograph, click HERE.]

In my view, made the same night, only the central region is visible. My view is approximately 13 light years across, left to right, while the nebula itself covers 100 light-years.

[Photo of Messier 8 that I made the early morning of July 3, 2011, from Bryce Canyon National Park’s Rainbow Point, the same night and location as Tyler’s picture. This is only a small part of the midsection of the vast nebula; the view is about 13 light-years from left to right. A larger image of my photo is posted HERE.]

By zeroing in on the heart of the nebula, we can make out the bright “Hourglass” feature, a little to the right of center. A hot star dubbed “O Herschel 36” makes the Hourglass shine.

“Twisting near the center of the Lagoon,” reads the explanation of NASA’s Astronomy Picture of the Day for Aug. 8, 2010, “the bright hourglass shape is the turbulent result of extreme stellar winds and intense sunlight.” (The APOD information was written and edited by Robert Nemiroff and Jerry Bonnell.)

The Hourglass appears as two separate lobes because this bright area is bisected by something NASA calls a “twister.” On Jan. 22, 1997, the space agency released a Hubble photo that shows the region in unprecedented detail. “This Hubble telescope snapshot unveils a pair of one-half light-year-long interstellar ‘twisters’ — eerie funnels and twisted-rope structures … in the heart of the Lagoon Nebula…” says its release.

[Hubble image released by NASA on Jan. 22, 1997, showing the Lagoon Nebula’s hot central star and “twisters” of dusty material that are swirling around the Hourglass. The agency labeled features in this view.]

If I enlarge my own image of the Lagoon’s heart, rotate it to match the orientation of the Hubble view and work on contrast and brightness to bring out details, I can just barely make out the twisters. Of course, my telescope is no Hubble so the view is fuzzy, with the star O Herschel 36 bloated by my optics, which are astronomically inferior to Hubble’s.

[My picture of the heart of the Lagoon, cropped, enlarged and rotated to match the Hubble view’s orientation. It’s no Hubble picture, but with the proper adjustments to contrast and brightness, it’s just barely possible to make out the “twisters.”]

My image is nothing to brag about — yet I find it satisfying that these mysterious twister features show up in it.

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