Posts Tagged ‘galaxy interaction’

A Jellyfish on the Move


A jellyfish, blue tendrils trailing, speeds across this Hubble image of galaxy ESO 137-001. What shapes or stories do you see? Leave a note below.

heic1404b_screenIntense blue streaks trail ESO 137-001 in this composite image from NASA’s Hubble Space Telescope and the Chandra X-Ray Observatory. Wisps of gas stream from hot blue stars as the spiral galaxy ESO 137-001 blasts through the heart of galaxy cluster Abell 3627. Astronomers call this stripping of gas and dust from a galaxy ram pressure stripping. Ram pressure is the drag felt by an object as it moves through a thick fluid, such as your body walking through water. The fluid here though would not be suitable for swimming. It’s superheated gas that lurks near the heart of all galaxy clusters.

Surrounding this galaxy are countless nearby stars in our own Milky Way Galaxy. ESO 137-001 lies near the plane of our galaxy, its light blocked by thick dust and gas. Farther away in the image, look for galaxies of all shapes and pointing in different directions. Most of those galaxies are far beyond ESO 137-001 and are not part of the Abell 3627 galaxy cluster. ESO-137-001 lies about 200 million light-years from Earth. It is part of the Norma Cluster near the center of a region of space called the Great Attractor. This area’s mass is so strong that even The Local Group, containing our galaxy and the Andromeda Galaxy, feel the tug of this strong gravity source.

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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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Lollipops and a Wreckage of Stars

NASA, ESA and the Hubble SM4 ERO Team

Galaxies with twisted arms that resemble swirled lollipops come together in a huge stellar wreck in this image from the NASA/ESA Hubble Space Telescope.

What shapes or stories do you see in this image of Stephan’s Quintet? Leave a note in the comments below.

Stephan’s Quintet, also known as the Hickson Compact Group 92, is a collection of five galaxies. Four of the galaxies are interacting. The galaxy in the upper left, NGC 7320, is actually seven times closer to Earth than the others. Zoom into its blue spiral arms. Bursts of star formation are apparent throughout this galaxy with new blue stars and pink nebulae dotting the scene. These nebulae resemble the Orion Nebula and they are star factories. NGC 7320 is a dwarf galaxy just 40 million light-years from Earth. By contrast, light traveling about six trillion miles per year, has zipped along for more than 300 million years from the redder galaxies in the group. The color of these galaxies is much redder either because the stars are older or because of dust stirred up by the interactions.

Starting at the upper right, NGC 7319 is a barred spiral galaxy. The distinct spiral arms nearly encircle the bar. Huge clusters of stars make red and blue dots surrounding the galaxy. The spiral arms of this galaxy are beginning to show the effects of interactions with the other galaxies.

Moving clockwise, the next galaxy looks like a single galaxy. But zoom in close and you’ll see it has two cores. NGC 7318A and NGC 7318B are trapped in each others gravity embrace. Zoom into this galactic merger’s dark dust bands, bright blue star clusters and pinkish clouds of glowing hydrogen. These clouds of gas and dust are the birthplace of new stars and are less than 10 million years old. To the right of these galaxies lies an area of star cluster formation. Gravity interactions has flung this spiral arm away from the main galaxy.

The bright elliptical galaxy at the bottom is called NGC 7317. Zooming in close to this galaxy and we see that it is fairly normal looking. As the galaxies move closer together, this galaxy will become warped and stretched.

Scattered throughout the image, look deep for dozens of faraway galaxies.

French astronomer Edouard M. Stephan discovered the group in 1877. Stephan’s Quintet resides in the constellation Pegasus, the mythical winged horse. It is the first compact group of many that have been discovered.

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Holy Galacticus

Credit: ESO/Oleg Maliy

Something about this image of the spiral galaxy Messier 96 from the European Southern Observatory has me awestruck.

Explore the glowing core, delicate swirls and dark dust lanes of this off-center galaxy. What stories do you see? Leave a note below.

The spiral arms and core of Messier 96, also known as NGC 3368, are not distributed evenly. The spiral galaxy is about the size of the Milky Way and spans about 100,000 light-years. The warped arms are probably caused by gravity interactions with other galaxies. Other signs of past galactic encounters are the long and looping spiral arms of young blue stars. Gas and dust within the spiral arms gets pushed and pulled like taffy. As nebula get smashed together, new stars can form.

A number of background galaxies peep through the dusty disk of M96. My favorite is the reddish edge-on spiral galaxy above and to the left of M96’s core. The reddish color is due to the thick dust in the spiral arm. We see this effect on Earth as the sun sets. Thick atmosphere and dust scatter the light letting the reddish part of the spectrum through.

Messier 96 is the largest galaxy in the Leo 1 group of galaxies. This group is one of the closest galaxy clusters to our Milky Way Galaxy. It is found about 35 million light-years away toward the constellation Leo, the Lion.

Spectacular Spiral “S”

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

Star clouds sweep around a spectacular spiral “S” in this NASA Hubble Space Telescope image of the heart of M51, the Whirlpool Galaxy.

This image is one of the sharpest views of our near neighbor galaxy M51, also known as NGC 5194. The distinct spiral arms are likely triggered by gravity’s pull of a companion galaxy NGC 5195 (not seen in this image). Explore the spiral arms as they arc away from the bright core. Bright clusters glow in the clouds of reddish hydrogen gas that gave them birth. The interaction with the companion helps give birth to new stars in the galaxy. Dark dust lanes along the spiral arms may one day brighten as new stars form in these areas. Look for dust “spurs” spiking out from the dust lanes. These puzzling features are causing astronomers to rethink how spiral galaxies form. Astronomers believe there may be a huge black hole churning away at the center of the galaxy.

M51 is found toward the constellation Canes Venatici, the hunting dogs of Bootes the hunter. The light from this face-on spiral galaxy has been traveling 31 million years to reach our eyes on Earth. A light-year is the distance light travels in a year; nearly 6 trillion miles.


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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