Category: MainFeature

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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Sparkling Hook


As if waiting for cosmic fish, this hook-shaped galaxy sparkles in a deep image from the NASA/ESA Hubble Space Telescope. Or perhaps you’ve turned your head and you see a galactic smile.

Explore the beautiful galaxy known as J082354.96+280621.6, or J082354.96 for short. Let us know what shapes or stories you see in the comments below.

J082354.96 is a starburst galaxy. These types of galaxies have high rates of star formation. As you explore the image, look for bright blue areas. These are new stars being born. J082354.96 is also warped meaning another galaxy has interacted with it millions of years in the past. As galaxies move near each other, gravity pushes and pulls the stars into unusual shapes. Gravity also pushes gas and dust together where it might collect, collapse and form a new star. You can see the cores and warped arms of the two interacting galaxies at the ends of the hook.

As you zoom across the image, look for faint galaxies far in the dark background. The two bright stars are actually stars in our own Milky Way Galaxy between Earth and J082354.96. The galaxy is found about 650 million light-years from Earth toward the northern constellation Lynx.

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Loops of Stars


A sparkling pink and purple loop floats in a sea of galaxies in this image from the NASA/ESA Hubble Space Telescope.

Explore this image of ring galaxy Zw II 28. What patterns or stories do you see? Leave a note in the comments below.

Galaxies come in many shapes and sizes. Some galaxies have graceful spiral arms. Some galaxies appear as disks with bulges in the center. Other galaxies, called elliptical galaxies, are just giant, milky blobs of stars. Ring galaxies, like Zw II 28, are much rarer. Although the universe seems mostly empty, galaxies do collide. Usually they pass each other and combine leaving tell-tale tails of stars and bursts of star formation. But sometimes, one galaxy will pass right through the center of another leaving behind a ring galaxy.

Interactions between galaxies stir up gas and dust. As gas and dust are pushed together, or compressed, new stars form. In Zw II 28, the outer ring is glowing with pink clouds of gas and dust and will be the home of new stars. Sparkling in these clouds, look for blue patches of light. These are brand new stars. On the right side of the ring, just inside the inner loop, look for a brighter white area. This may be a companion galaxy or perhaps even the galaxy that collided with Zw II 28 to create this rare galaxy.

As you explore the galaxy, look for the dozens of galaxies that dot the background of the image.

Zw II 28, is found about 380 million light years from Earth toward the constellation of Orion.

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A Confused Galactic V


Check out a galactic-sized “flying V in this image of interacting galaxies IC 2184 from NASA’s Hubble Space Telescope.

Explore the two nearly edge-on galaxies as they begin their billion-year-long dance. What shapes or stories do you see in the image? Leave a note in the comments below.

IC 2184 is really two galaxies. Even though space is huge, galaxies graze each other all the time. Gravity is strong with both galaxies. As the galaxies interact, stars, gas and dust are flung out into space forming long tidal tails. Look close for two faint tails. Usually these tails arc far into space but they look straight in this image because we are looking at them from the edge. The tails are arcing toward or away from us.

Also look for bright, fireworks regions. Gravity not only flings stars outward but also it can smash gas and dust. The bright blue and pink bursts are hot regions where new stars are forming, similar to regions in our galaxy such as the Orion Nebula or the Carina Nebula. These areas glow brightly enough that they show up as bright blobs of light in large telescopes.

IC 2184 is found about 160 million light-years from Earth toward the faint constellation Camelopardalis, the Giraffe.

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Ethereal Purple Petals


Purple petals, an eerie purplish eye or tire glow in this image from the European Southern Observatory.

IC 5148, or the Spare Tire Nebula, is a planetary nebula with a diameter of just a couple of light-years. It is one of fastest expanding planetary nebula known to astronomers, growing at more than 50 kilometers per second. Planetary nebulae have nothing to do with planets. In the 19th century, astronomers searching for planets observed objects that looked similar to the outer gas giants Uranus and Neptune. Stars about the same size or slightly larger than our Sun will become planetary nebula at the end of their lives. As these stars burn the last of their hydrogen fuel, they begin to puff up and throw off their outer layers. Blistering ultraviolet radiation from the exposed hot white dwarf excites atoms in the expanding ring of material causing it to glow. While beautiful, planetary nebulae are a short-lived stage in a star’s life. Eventually the glowing shell will fade away.

IC 5148 is found about 3,000 light-years from Earth toward the southern constellation Grus, the Crane.

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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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