Monthly Archives: January 2013

american astronomical society, Milky Way, Milky Way Galaxy

Rattling the Galaxy’s Bones

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Dark Cloud in the Milky Way

The galactic “bone” was identified while studying a dust cloud that in 2010 was nicknamed “Nessie” after the Loch Ness Monster. Nessie turns out to be at least twice, and perhaps as much as eight times, longer than originally claimed. Both the original 2010 “Nessie” and the extended structure are outlined and labeled here on a Spitzer infrared image.
Credit: NASA/JPL/SSC

Once in a while a story really grabs my attention, like yesterday’s census of planets in the Milky Way.  It really opened up a galaxy of possible worlds to explore. Today, I was sitting in a press conference, listening to astronomers talking about using radio astronomy to study a cloud of gas and dust that they described as the one of the Milky Way’s “bones”, meaning an important part of its structure.

The structure is nicknamed “Nessie” because it bears a resemblance to the Loch Ness Monster. That right there was enough to grab my attention because as CEO of Loch Ness Productions, I’m quite used to being called one of the “Nessies” by our colleagues in the field. So, I approve of my monstrous namesake in the sky!

It’s a cool name and a memorable mental visual.

So, what’s Nessie all about?

Think about our galaxy. It’s what’s known as a barred spiral galaxy. That means it is a typical spiral — with two principal spiral arms wrapping around, and a bar cutting across the middle.

The central region of our the Milky Way has tantalized astronomers since forever, but it’s tough to see because it’s hidden by clouds of gas and dust. However, if you look at it in infrared light or using radio telescopes, you can make out structures not only in the core but along the plane of the Milky Way.

Astronomers have done that using a variety of techniques. In the case of Nessie, they used the Spitzer Space Telescope to probe along the plane (a line drawn across the central region from edge to edge) and found this cloud feature that got nicknamed Nessie by James Jackson of Boston University.

Alyssa Goodman at Harvard Center for Astrophysics and her team looked at Nessie and analyzed it using various data set. It’s really a long tendril of dust and gas that they called a “bone.”

Goodman gave a talk at the AAS today about Nessie. “This is the first time we’ve seen such a delicate piece of the galactic skeleton,” she said, and pointed out that other spiral galaxies also display internal bones or endoskeletons. Observations, especially at infrared wavelengths of light, have found long skinny features jutting between galaxies’ spiral arms. These relatively straight structures are much less massive than the curving spiral arms.

Computer simulations of galaxy formation show webs of filaments within spiral disks. It is very likely that the newly discovered Milky Way feature is one of these “bone-like” filaments.

Radio emissions from clouds of molecular gas in the center of the Milky Way region show that Nessie is in the galactic plane, and is more than 300 light-years long but only 1 or 2 light-years wide. The amount of mass is enough to make about  100,000 Suns. It’s possible that this odd feature bone is part of a spiral arm, or maybe is part of a web connecting other spiral features. Goodman and her colleagues hope to find more of these bones, and once they have enough data, it will give them enough information to create a cool 3D version of the galaxy and its skeleton.

 

american astronomical society, exoplanets, Kepler mission

AAS: The Firehose of Astronomy

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https://i0.wp.com/www.cfa.harvard.edu/image_archive/2013/2/lores.jpg?resize=369%2C294
This artist’s illustration represents the variety of planets being detected by NASA’s Kepler spacecraft. A new analysis has determined the frequencies of planets of all sizes, from Earths up to gas giants. Key findings include the fact that one in six stars hosts an Earth-sized planet in an orbit of 85 days or less, and that almost all sun-like stars have a planetary system of some sort. (Hat tip to Robert Hurt for inspiring this illustration.)
Courtesy C. Pulliam & D. Aguilar (CfA)

Every January, I journey out to the American Astronomical Society for its annual Winter Meeting. And, every time, I’m amazed at new bit of information about the universe. Today’s revelation (and it’s only Day 1 of the meeting), is that the Milky Way Galaxy is populated with many planets — in fact, one team of scientists estimates that at least one out of every six stars in the galaxy has an Earth-sized planet.

That, my friends, is pretty profound.

If you postulate that the Milky Way has about a hundred billion stars, that means there are at least 17 BILLION Earth-sized planets in our galaxy. Again, that’s pretty profound. Now, the next question everybody will ask is, “How many of those are capable of supporting life?” And to answer that question requires a lot more observation. First, to support life, those planets need to be orbiting close enough to their stars that liquid water will be available to sustain life on them. Then, scientists need to look at the other conditions on the planets, and look for “bio signatures” in the planets’ atmospheres that indicate life could be there. So, even though there could be the potential for 17 billion Earth-sized worlds out there, that doesn’t say they are Earth-like… or that they have life. But, there are 17 BILLION Earth-sized worlds out there. Up until the last decade of the 20th century, we didn’t know of any.

Thanks to the Kepler Mission, which has been cranking out planetary candidate discoveries for some time now, the hunt for planets is now an understood and successful ongoing project.

Want to read more details about how the scientists came up with their numbers? Check it out here. And, stay tuned for more AAS news!