unknownskywalker:

Citizen Scientists Reveal a Bubbly Milky Way

A huge team of volunteers from the general public has poured over observations from NASA’s Spitzer Space Telescope and discovered more than 5,000 “bubbles” in the disk of our Milky Way galaxy. Young, hot stars blow these shells out into surrounding gas and dust, highlighting areas of brand new star formation.

Upwards of 35,000 “citizen scientists” sifted through the Spitzer infrared data as part of the online Milky Way Project to find these telltale bubbles. The users have turned up 10 times as many bubbles as previous surveys so far.

Volunteers for the project are shown a small section of Spitzers huge infrared Milky Way image (left) that they then scan for cosmic bubbles. Using a sophisticated drawing tool, the volunteers trace the shape and thickness of the bubbles. All of the user drawings can be overlaid on top of one another to form a so-called heat map (middle). Features that have been identified repeatedly by many different users jump out, revealing the overall pattern of bubbles in this part of the galaxy.

At least five volunteers must flag a candidate bubble before it is included in the final catalog (right). The brightness of each bubble in the catalog is determined by its hit rate, or the fraction of users who traced it out. The faintest ones were identified by 10% of the users, while solid white indicates a hit rate of 50% or better.

After identifying all apparent bubbles, volunteers get another of the 12,263 possible image sections to scrutinize. With so much sky to cover, it is clear why so many volunteers are needed to do this kind of science!

thenewenlightenmentage:

Dual Interpretations: Milky Way’s Outer Fringe of Stars Sparks Disagreement

Resolving how the galaxy’s halo of stars was assembled would provide important clues about galactic formation.

It’s well known that the Milky Way is a spiral galaxy, a swirl of stars in an extended, many-armed disk. But the structure of the galaxy is far from two-dimensional. Above and below those familiar spiral arms is a lesser-known feature, a spherical swarm of stars that makes up a halo around the disk.

For decades the presence of the halo has prodded astronomers to ask big questions about its nature: How is it structured? How do stars in the halo compare with disk stars such as our sun, or to stars elsewhere in the halo? And just how did the halo get there? In recent years a group of astronomers has suggested an answer to some of those big questions by drawing on a large telescopic survey of the sky.

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unknownskywalker:

Astronomers determine color of the Milky Way Galaxy

A team of astronomers in Pitt’s Kenneth P. Dietrich School of Arts and Sciences announced today the most accurate determination yet of the color of the Milky Way Galaxy: a very pure white.

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. Because of this, clouds of gas and dust obscure all but the closest regions of the Galaxy from view, preventing researchers from getting the “big picture”.

To circumvent this problem, astronomers set out to determine the Milky Way’s color by using images from other, more distant galaxies that can be viewed more clearly. The team identified galaxies from the Sloan Digital Sky Survey (SDSS) similar to the Milky Way in properties that were able to be determined.

Astronomers described the overall spectrum of light from the Milky Way as being very close to the light seen when looking at spring snow in the early morning, shortly after dawn. New spring snow is the whitest (natural) thing on Earth.

Astronomers divide most galaxies into two broad categories based on their colors– relatively red galaxies that rarely form new stars and blue galaxies where stars are still being born. (The brightest stars are generally blue, but they are very short-lived on cosmic scales and die out quickly.) The new measurements place the Milky Way near the division between the two classes.

This adds to the evidence that although the Milky Way is still producing stars, it is on it’s way out. A few billion years from now, our Galaxy will be a much more boring place, full of middle-aged stars slowly using up their fuel and dying off, but without any new ones to take their place. It will be less interesting for astronomers in other galaxies to look at, too: The Milky Way’s spiral arms will fade into obscurity when there are no more blue stars left.

Hurling through space, I can feel a swelling insignificance.

(via ikenbot)