10 game-changing space galaxy discoveries

What's hot in space? Galaxies!

A massive amount of new astronomical research and discoveries have been shown at the 219th meeting of the American Astronomical Society recently.  While the new information covers a variety of areas from supernova explosions to dark matter, research on galaxies has been one of the hottest topic areas. Here we take a look at 10 of the biggest galaxy research images presented at the meeting.

Galaxy clusters are the largest structures in the universe, comprising hundreds to thousands of galaxies bound together by gravity. Most galaxies in the universe reside in groups and clusters, and astronomers have probed many mature "galactic cities" in detail as far as 11 billion light-years away. Finding clusters in the early phases of construction has been challenging because they are rare, dim and widely scattered across the sky, researchers say.

An international team of astronomers reports that our Milky Way galaxy contains a minimum of 100 billion planets. That means our galaxy contains a minimum of one planet for every star on average and there should be a minimum of 1,500 planets within just 50 light-years of Earth, according to Kailash Sahu of the Space Telescope Science Institute in Baltimore, Md. Sahu co-founded the Probing Lensing Anomalies NETwork(PLANET) collaboration, which undertook a six-year study of the Milky Way.

A team of University of Pittsburgh astronomers claimed they had come up with the most accurate determination yet of the color of our Milky Way galaxy: "a very pure white, almost mirroring a fresh spring snowfall." Jeffrey Newman, Pitt professor of physics and astronomy, and Timothy Licquia, a Ph.D. student in physics at Pitt. While color is one of the most important properties of galaxies that astronomers study, it has been difficult to make the measurement for the Milky Way, as our solar system is located well within the galaxy.

The cold dust that ultimately grows stars is shown in this image that combines observations from the Herschel Space Observatory, a European Space Agency-led mission with NASA contributions; and NASA's Spitzer Space Telescope. The image maps the dust in the galaxies known as the Large and Small Magellanic Clouds, two of the closest neighbors to our own Milky Way galaxy. The colors in these images indicate temperatures in the dust that permeate the Magellanic Clouds. Colder regions show where star formation is at its earliest stages or is shut off, while warm expanses point to new stars heating dust surrounding them.

The collision of two clusters of galaxies 5 billion light-years away could help astronomers better understand dark matter, the mysterious, invisible stuff that makes up about a quarter of our universe. This image shows the "little universe" which is formally called DLSCL J0916.2+2951. It consists of two clusters of hundreds of galaxies each, in the process of merging into one.

Using NASA's Hubble Space Telescope, astronomers have uncovered a cluster of galaxies in the initial stages of development. The researchers called it the most distant such grouping ever observed in the early universe. The five tiny galaxies are clustered together 13.1 billion light-years away. They are among the brightest galaxies at that epoch and very young -- existing just 600 million years after the big bang.

Astronomers using NASA's Spitzer and Hubble space telescopes spotted one of the most distant galaxies churning out stars at what NASA called a shockingly high rate -- equivalent to about 100 suns per year. The blob-shaped galaxy, called GN-108036, is the brightest galaxy found to date at such great distances.  The galaxy is 12.9 billion light-years away. NASA said our Milky Way galaxy is about five times larger and 100 times more massive than GN-108036, but makes roughly 30 times fewer stars per year.

Researchers said a huge galaxy cluster spotted recently is "the most massive, the hottest, and gives off the most X-rays of any known cluster at this distance or beyond." Nicknamed "El Gordo" ("the big one" or "the fat one" in Spanish) is located more than 7 billion light-years from Earth. Galaxy clusters, the largest objects in the universe that are held together by gravity, form through the merger of smaller groups or subclusters of galaxies.

According to a University of Texas at Austin study, the most massive galaxies present 2 billion to 3 billion years after the big bang differ dramatically from today's. A remarkably high fraction of the massive young galaxies host disk components, making them look like thick pancakes. In contrast, today's most massive galaxies typically have large bulges, and are shaped like watermelons. Additionally, 40% of the young massive galaxies are ultra-compact, compared to fewer than 1% of their massive elliptical and lenticular descendants today.  The University of Texas at Austin group studied 166 of the most massive galaxies that exist only a few billion years after the big bang.

Astronomers said they have mapped dark matter on the largest scale ever observed. The results, written by Dr. Catherine Heymans of the University of Edinburgh, Scotland, and Associate Professor Ludovic Van Waerbeke of the University of British Columbia, Vancouver, Canada, reveal a universe comprised of an intricate cosmic web of dark matter and galaxies spanning more than 1 billion light-years. The researchers looked at about 10 million galaxies in four different regions of the sky. They studied the distortion of the light emitted from these galaxies, which is bent as it passes massive clumps of dark matter during its journey to Earth. This is the first direct glimpse at dark matter on large scales showing the cosmic web in all directions, researchers stated.

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