Posts Tagged ‘Sagittarius’

Eye of Stars


Set against a starry backdrop, ESO 456-67 glows like a cat’s eye or in the shape of Mas Amedda from Star Wars in this image from the NASA/ESA Hubble Space Telescope.

Explore the planetary nebula ESO 456-67. What shapes do you see? Leave a note in the comments below.

Although called a planetary nebula, these starry objects have nothing to do with planets. In early telescopes of the 18th century, while astronomers were searching for new planets, these small and round nebulae looked like planets. The nebulae are much farther away and much larger than any planet in our solar system. Planetary nebulae are the last stage in the life of a star similar to our Sun in size. As these stars approach the end of their long lives, they run out of hydrogen fuel. They bloat and throw off shells of gas and dust. Sometimes, the bubbles they produce are smooth and round. But other times, they are complex with material shooting away in different directions.

As you explore ESO 456-67, look for the remaining star in the center of the blue area. Astronomers call these stars white dwarfs. They are hot and small. Over billions of years, this star will cool to become a warm cinder. The blue area surrounding the white dwarf is a hot bubble of gas. White dwarfs give off intense ultraviolet radiation that causes the gas of the planetary nebula to glow. Other regions of the nebula contain different elements that glow different colors.

ESO 456-67 is found about 10,000 light-years from Earth toward the rich starfields in the constellation Sagittarius, the Archer. Light from the planetary nebula began traveling toward our eyes on Earth just about the time when humans developed agriculture techniques in Mesopotamia.

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Sam and a Billion Fireflies

ESO/S. Guisard (

Sam, the owl, in hues of pink, yellow and blue glares out of the panorama of a billion fireflies in an image from the European Southern Observatory.

Explore the rich star fields of Sagittarius and Scorpius. What stories or pictures do you see? Leave a note in the comments below.

The owl, to the right in the image, is actually Rho Opiuchi cloud complex and Antares. This nebula, similar to the Great Nebula in Orion, is just over 400 light-years away, making it one of the closest star-making regions to Earth. As gas and dust interact within these nebulae, they begin to swirl and collapse under gravity. When enough material collects, the temperature rises. Sometimes the temperature rises enough so that hydrogen atoms begin to fuse. When this happens a new star is born. some of the stars in these gas-and-dust rich areas are many times more massive and brighter than our Sun. These stars give off strong solar winds that clear out a space around the star. The huge stars also send out a torrent of ultraviolet radiation that excites hydrogen atoms in the nebula causing it to glow.

The bright glow of stars to the left is the center of our Milky Way Galaxy. Between here and there a dusty spiral arm blocks the light. In this image, look for the S-shaped dark nebula near the center of the image toward the top. Astronomers call this Snake Nebula. It is part of a larger structure known as the Dark Horse Nebula. The horse is standing up and down. The Snake Nebula forms its front leg while the back legs are outlined in a dark ribbon of dark dust just below. That leg also forms what’s known as the Pipe Nebula.

As we dive deeper into the dark lane of dust, look for the reddish nebulae, including Trifid Nebula and the Lagoon Nebula. Toward the bottom of the image, look for NGC 6357 and the Cat’s Paw Nebula, or NGC 6334. New stars are forming in all of these nebulae.

This image, taken by astrophotographer Stéphane Guisard, is part of ESO’s GigaGalaxy Zoom project. The mosaic was assembled from about 1200 individual images taken at the observatory at Cerro Paranal in Chile.

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Rosy Nursery

Credit: ESO


Smoky tendrils of dust line the rose-colored gas of the Omega Nebula in this image from the European Southern Observatory.

Explore the detailed cosmic landscape of this stellar nursery. What shapes and stories do you see? Leave a note below.

The Omega Nebula, also known as Messier 17, is a star-making factory. The reddish-colored gas and dark strands of dust are the raw materials for making new stars. Near the bottom center of the image, a blazing blue star lights up this section of the nebula. Intense radiation and strong solar winds stream from the new star born from this nebula. Ultraviolet radiation warms and excites hydrogen atoms in the cloud giving it the red color.

Messier 17 is found about 6,000 light-years from Earth toward the rich star fields in the constellation Sagittarius, the Archer. Swiss astronomer Philippe Loys de Chéseaux first described the nebula in 1745. But it was English astronomer John Herschel, in 1833, who described the nebula as looking like the Greek letter, omega. Other astronomers offered names such as the Horseshoe Nebula, Swan Nebula, Checkmark Nebula and even Lobster Nebula to describe their observations.

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A Swan’s Starry Lake

Credit: ESO/INAF-VST/OmegaCAM. Acknowledgement: OmegaCen/Astro-WISE/Kapteyn Institute

A swan glides in a glowing lake in this image of the Swan Nebula from the European Southern Observatory’s VST telescope.

Explore the plumes of gas that make up the swan’s body and neck. Some observers see the Greek letter omega in the nebula’s dust clouds. Others see a barber’s pole. What images or stories do you see? Tell us by leaving a note below.

The Swan Nebula, also known as Messier 17 or the Omega Nebula, is a vast region of gas and dust near the heart of our Milky Way Galaxy. This region is rich in dust and hydrogen gas making it a perfect place for new stars to form. In nebulae, gravity pulls gas and dust together. If enough dust and gas compresses together, the clump can begin to fuse hydrogen. A star is born producing its own light and heat. Hot, young stars dominate the Swan Nebula. Searing winds from these young stars carve patterns and bubbles in the nebula while scorching ultraviolet light warms and energizes the nebula causing it to glow.

The Swan Nebula is located about 5,000 light-years from Earth toward the constellation Sagittarius the Archer. It takes light zipping along at more than six trillion miles per year more than 15 years to cross the nebula. Swiss astronomer Jean-Philippe Loys de Chéseaux discovered the nebula in 1745. Charles Messier added it to his catalog in 1764.

Merging Y

NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)

Galaxy interactions are always impressive. ESO 593-8 looks like the letter “Y,” swooping eagle or a feather. Explore the NASA Hubble Space Telescope image of these merging galaxies. Do you see any patterns? What stories can you tell?

The two spiral galaxies will probably merge to form a single galaxy in the future. Look for dark lanes of dust and bright blue star clusters at the outer fringes of the galaxies. When galaxies interact, gas and dust are pushed together. The gas and dust can collapse under its own gravity and new stars are formed. However, exist­ing stars them­selves are not really dis­rupted by the merger. After sev­eral mil­lion years, the black holes at the center of these galaxies will merge and the stars will set­tle into new orbits around a new galac­tic cen­ter.

A number of faint background galaxies can be found throughout the image. The bright stars are foreground stars in our own Milky Way Galaxy.

ESO 593-8 lies about 650 million light-years from Earth toward the constellation Sagittarius, the Archer. A light-year is the distance light travels in a year; about 6 trillion miles. When light left this galaxy pair, many geologists believe Earth’s surface was almost entirely covered by ice in what’s known as Snowball Earth or Marinoan Glaciation. But the planet was on the verge of a sudden explosion in the diversity in life. During the later Proterozoic, bacteria and green algae were common in the seas of Earth. Soft-bodied worms swam in these seas. Animals had not yet ventured onto land.


The ancient peoples saw pictures in the sky. From those patterns in the heavens, ancient storytellers created legends about heroes, maidens, dragons, bears, centaurs, dogs and mythical creatures...
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