A close-up view, with the merging galaxies circled. The red data show dust-enshrouded regions of star formation, while green and blue show carbon monoxide gas and starlight, respectively. The blue blobs outside of the circle are galaxies located much closer to us. Image: ESA/NASA/JPL-Caltech/UC Irvine/STScI/Keck/NRAO/SAO

Astronomers have caught two big ancient galaxies in the act of colliding, shedding new light on the role such megamergers played in galactic evolution during the universe’s youth.

The colossal smash up will eventually produce one giant elliptical galaxy, researchers said, suggesting that most such behemoths formed rapidly in this manner long ago, rather than growing slowly over time by gobbling up a series of relatively small galaxies.

“I think at least 90 percent of elliptical galaxies at this mass were formed through this channel,” study lead author Hai Fu, of the University of California, Irvine, told SPACE.com. [Photos of Great Galactic Crashes]

via Rare View of Ancient Galaxy Crash Revealed: Scientific American.

Ligeia Mare, shown here in data obtained by NASA’s Cassini spacecraft, is the second largest known body of liquid on Saturn’s moon Titan. Image credit: NASA/JPL-Caltech/ASI/Cornell › Full image and caption

Saturn’s moon Titan might be in for some wild weather as it heads into its spring and summer, if two new models are correct. Scientists think that as the seasons change in Titan’s northern hemisphere, waves could ripple across the moon’s hydrocarbon seas, and hurricanes could begin to swirl over these areas, too. The model predicting waves tries to explain data from the moon obtained so far by NASA’s Cassini spacecraft. Both models help mission team members plan when and where to look for unusual atmospheric disturbances as Titan summer approaches.

“If you think being a weather forecaster on Earth is difficult, it can be even more challenging at Titan,” said Scott Edgington, Cassini’s deputy project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We know there are weather processes similar to Earth’s at work on this strange world, but differences arise due to the presence of unfamiliar liquids like methane. We can’t wait for Cassini to tell us whether our forecasts are right as it continues its tour through Titan spring into the start of northern summer.”

via NASA – Forecast for Titan: Wild Weather Could Be Ahead.

How many rings do you see in this new image of the galaxy Messier 94, also known as NGC 4736? While at first glance one might see a number of them, astronomers believe there is just one. This image was captured in infrared light by NASA’s Spitzer Space Telescope. Image credit: NASA/JPL-Caltech › Full image and caption

Johnny Cash may have preferred this galaxy’s burning ring of fire to the one he sang about falling into in his popular song. The “starburst ring” seen at center in red and yellow hues is not the product of love, as in the song, but is instead a frenetic region of star formation.

The galaxy, a spiral beauty called Messier 94, is located about 17 million light-years away. In this image from NASA’s Spitzer Space Telescope, infrared light is represented in different colors, with blue having the shortest wavelengths and red, the longest.

Starburst rings like this can often be triggered by gravitational encounters with other galaxies but, in this case, may have instead been caused by the galaxy’s oval shape. Gas in the ring is being converted into hot, young stars, which then warm the dust, causing it to glow with infrared light.

The outer, faint blue ring around the galaxy might be an optical illusion. Astronomers think that two separate spiral arms appear as a single unbroken ring when viewed from our position in space.

via NASA – Galaxy’s Ring of Fire.