WEBVTT - Why Is Our Galaxy Warped?

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<v Speaker 1>Welcome to brain stuff from how stuff works, Hey, brain Stuff.

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<v Speaker 1>Lauren vogelbam here imagined standing in a dense woodland. How

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<v Speaker 1>would you know the size and shape of that forest

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<v Speaker 1>from your limited viewpoint? Not seeing the woods for the

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<v Speaker 1>trees is a good analogy for what astronomer's experience when

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<v Speaker 1>trying to assess the shape and size of our Milky

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<v Speaker 1>Way galaxy. We occupy a small star system embedded inside

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<v Speaker 1>the Milky Ways disc. It's not like we can fly

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<v Speaker 1>above the galactic plane to peek at our galaxies overall shape,

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<v Speaker 1>although how cool would that be. Researchers, however, were determined

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<v Speaker 1>to figure out the true shape of the Milky Way

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<v Speaker 1>while staying embedded inside of it, and they have. Here's

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<v Speaker 1>how they did it. A team from the National Astronomical

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<v Speaker 1>Observatories of the Chinese Academy of Sciences that's the n

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<v Speaker 1>a o C and Macquarie University in Australia studied the

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<v Speaker 1>one thousand, three D and thirty nine right pulsating stars

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<v Speaker 1>called CEFIAD variables to create a three D map of

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<v Speaker 1>the disc of our galaxy. What they found came as

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<v Speaker 1>a surprise. We live in a warped galaxy. Astronomer and

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<v Speaker 1>research collaborator Richard de Grace said in a statement, we

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<v Speaker 1>usually think of spiral galaxies as being quite flat, like Andromeda,

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<v Speaker 1>which you can easily see through a telescope. But our

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<v Speaker 1>galaxy isn't like Andromeda. It has an S shaped bend

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<v Speaker 1>that gets more twisted the farther you move away from

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<v Speaker 1>the galactic center. At this bend, the galaxy's gravitational pull

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<v Speaker 1>becomes weaker, making it look like an old vinyl record

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<v Speaker 1>that's become warped. The study, which has been published in

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<v Speaker 1>the journal Nature Astronomy, used data from NASA's Wide Field

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<v Speaker 1>Infrared Survey Explorer to precisely determine the locations of the

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<v Speaker 1>cepheids throughout our galactic disc and turned them into a

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<v Speaker 1>powerful tool to cut through the dust, gas, and other

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<v Speaker 1>stars that are ob scaring our view. Cheniadene, a researcher

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<v Speaker 1>at n AOC and the lead author of the study,

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<v Speaker 1>set in a press release it's notoriously difficult to determine

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<v Speaker 1>distances from the Sun two parts of the Milky Ways

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<v Speaker 1>outer gas disc without having a clear idea of what

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<v Speaker 1>the disc actually looks like. However, we recently published a

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<v Speaker 1>new catalog of well behaved variable stars known as classical cepheids,

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<v Speaker 1>for which distances as accurate as three to five percent

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<v Speaker 1>can be determined. Sepheids are young stars that are four

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<v Speaker 1>to twenty times the mass of our Sun, and they

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<v Speaker 1>live fast and die young, consuming all their fuel in

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<v Speaker 1>the span of only a few million years, all while

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<v Speaker 1>burning up to one hundred thousand times brighter than our star.

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<v Speaker 1>But what they lack in lifespan they make up or

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<v Speaker 1>in regular pulses in brightness that can be used by

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<v Speaker 1>astronomers to accurately measure their distances, and in this case,

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<v Speaker 1>they acted as tracers to map out the warped milky

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<v Speaker 1>Way disc. Although the milky Way doesn't conform to the

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<v Speaker 1>standard flat disc exhibited by other spiral galaxies like Andromeda,

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<v Speaker 1>it's not alone. From earlier observations, the researchers identified a

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<v Speaker 1>dozen other galaxies with a similar S shaped bend, which

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<v Speaker 1>have given them a clue as to why our galaxy

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<v Speaker 1>is warped. Blue Chow, co author of the study, said,

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<v Speaker 1>combining our results with those other observations, we concluded that

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<v Speaker 1>milky ways warped spival pattern is most likely caused by

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<v Speaker 1>torques or rotational forcing by the massive inner disc. Basically,

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<v Speaker 1>the orbital motions in the massive central region of the

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<v Speaker 1>Milky Way gravitationally bully the less massive outer regions, causing

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<v Speaker 1>them to buckle and bend out of shape. Ultimately, this

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<v Speaker 1>new finding could help us better understand the dynamics of

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<v Speaker 1>orbital motions inside the Milky Way, thereby providing a glimpse

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<v Speaker 1>of how our galaxy evolved. Today's episode was written by

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<v Speaker 1>Ian O'Neil and produced by Tyler Clang for iHeart Media

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<v Speaker 1>and How Stuff Works. For more on this and lots

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<v Speaker 1>of other warped topics, visit our home planet, how stuff

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<v Speaker 1>works dot com.