Category: Numbers

Galactic Niner

Credit: NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and W. Keel (University of Alabama, Tuscaloosa)

Merging together to form the number 9, two galaxies comprise AM0500-620.

AM0500-620Explore the image from NASA’s Hubble Space Telescope. The foreground galaxy is a highly symmetrical spiral galaxy. If we split this galaxy in half, both sides would appear nearly the same. From Earth, we see this galaxy nearly face-on. Follow the dusty spiral arms to regions of blue clumps of stars. These are new stars, shining hot and blue in the nebulae they were born from. Many of these stars are actually huge star clusters. Astronomers used to consider the background galaxy to be an elliptical galaxy. But with Hubble’s sharp eyes, we can now see that it is a tight spiral galaxy with dusty spiral arms.

AM0500-620 is located about 350 million light-years from Earth toward the constellation of Dorado, the Swordfish. Located in the southern hemisphere, the constellation Dorado was the creation of Petrus Plancius. It first appeared on a celestial globe in about 1597. Dorado is Spanish for mahi-mahi, or the dolphin-fish.

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Credit: The Hubble Heritage Team (STScI/AURA/NASA)

Eight-BurstShaped like the number eight, astronomers in the southern hemisphere call this the Eight-Burst or the Southern Ring Nebula. NGC 3132 is a planetary nebula. The name “planetary nebula” refers to the shape of the nebula. Astronomers in the 17th and 18th centuries found many objects in the night sky that resembled planets. But the expanding shells of gas and dust are all that is left of a star that has reached the end of its life.

Explore the image from NASA‘s Hubble Space Telescope. Two stars clearly show inside NGC 3132’s red and yellow ring. The fainter one, just above and right of the bright star, is actually the star that ejected the nebula. This star is now smaller than our Sun but it is extremely hot. The star also floods space with ultraviolet radiation, causing the cloud to glow. We can see many fine filaments of material within the nebula. One long filament resembles a belt around the middle of the nebula.

The brighter star near the center of the nebula is a younger star but one day, it too may create its own planetary nebula. Our Sun may meet a similar fate one day but not for another 4 to 5 billion years. Material from the nebula will slowly fade as it expands to space. This material, rich in elements such as carbon, will possibly be used in the making of future stars and planets.

NGC 3132 is nearly a half a light year in diameter; about 3 trillion miles across. It would take light six months to travel from one side of the nebula to the other. The gases are expanding from the central star at a speed of 9 miles per second. At about 2,000 light years toward the constellation Vela, NGC 3132 is one of the closest known planetary nebula.

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Mirror 7

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

Forming the number seven, the interacting galaxies that make up NGC 5331 mirror each other as they begin to link spiral arms.

Even though distances between galaxies are immense, NASA‘s Hubble Space Telescope spies many instances of galaxy mergers throughout the universe. Gravity brings together these great groups of stars. As they start to merge, gas and dust is pushed together and pulled into long strands. These new nebulae can collapse under gravity to form new stars. Some of these gas tails get flung out from the main body of the galaxy. We see one of these in the faint, blue trail of new stars to the right.

NGC 5331Explore this image of NGC 5331 from Hubble. What stories can you see in this image? Perhaps the galaxy head is contemplating its belly button lint. Share your stories.

Besides the blue haze to the right, bright blue bursts of new star birth can be seen in both galaxies. It seems likely that the blue smudge to the left is part of the galaxies but it is not entirely clear. Already, the bottom galaxy is warping upward to meet the other galaxy. Gas and dust rise above the galactic center of the bottom galaxy. For the most part, the top galaxy has been able to keep its spiral shape. A number of faint reddish-colored and distant background galaxies are scattered throughout the image. Several hundreds of millions of years in the future, these two galaxies will settle together and become a larger elliptical galaxy. But even though the galaxies are moving together, most stars will remain intact within the new galaxy. There will be no stellar collisions. Some stars, however, through the effects of gravity, will get flung clear of the galaxy. These lone stars will be destined to wander the space between galaxies.

NGC 5331 is located about 450 million light-years from Earth toward the constellation Virgo, the Maiden. A light-year is the distance light travels in one year, a distance of about 6 trillion miles.

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Swirl 6

Credit: NASA, ESA, The Hubble Heritage Team (STScI/AURA)

Locked in a graceful, gravity-induced dance with another galaxy, NGC 3808 appears as a swirling number six.

NGC 3808This pair of interacting galaxies, known as Arp 87, is just one of thousands of merging and colliding galaxies astronomers find when exploring the universe. Even though the dis­tances between galax­ies is great, grav­ity pulls them together with stun­ning effects. Explore the image of Arp 87 in this image from NASA‘s Hubble Space Telescope. The larger spi­ral galaxy on the right, NGC 3808, is nearly face on to us. Its com­pan­ion, NGC 3808A, on the left, is edge on. Fol­low the spi­ral arm of NGC 3808 as it flows toward the other galaxy. Both galax­ies have been warped and stretched by the inter­ac­tion. The stream of stars, gas and dust from the larger galaxy has formed what astronomers call a ‘polar ring. This corkscrew shaped bridge of dust and gas seems to have been pulled off the larger galaxy and now orbits above the plane of the galaxy.

Find the wide areas of blue stars in both galax­ies. When gas and dust get stretched and pushed together, stars can form. Star for­ma­tion is very active in inter­act­ing galax­ies. Arp 87 is found in the zodiacal con­stel­la­tion Leo, the Lion, about 300 mil­lion light years from Earth.

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Spiral 5

Credit: NASA and The Hubble Heritage Team (STScI/AURA)

The swirling arms of NGC 3310 blaze the number five in this image from NASA’s Hubble Space Telescope.

NGC 3310Explore the image of this active starburst galaxy. New stars in most galaxies form at a slow rate. Starburst galaxies churn out new stars at high rates. Redder stars near the galaxy’s core are older stars while hot, young stars glow blue near the middle and edges of the spiral arms. Clusters of these new stars are spread out all the way to the dim edges of the galaxy. Astronomers show that the ages of the stars range from one million to more than 100 million years. Scientists are unsure of what caused the starburst activity to turn on in NGC 3310. They used to believe that galaxy interactions and collisions were involved. But NGC 3310 shows that some other processes might be involved.

NGC 3310 lies about 59 million light-years from Earth toward the constellation Ursa Major. The galaxy is about half the size of our Milky Way Galaxy with a diameter of about 52,000 light-years.

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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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