The Shape of the Milky Way Is Warped and Twisted (abc.net.au)

Necroloth writes: You probably thought that if you were looking at our galaxy from the outside and at a distance, you would see a thin disc of stars that orbit around a central region, but the further away from the inner regions of the Milky Way you are, the less the pull of gravity. At the outer disc, the hydrogen atoms that make up the Milky Way's gas disc are, as a consequence, warped into an S-like shape, no longer pulled together in a thin plane. A group of astronomers from Australia and China have built their "intuitive and accurate three-dimensional picture" by mapping 1339 classical Cepheids. There's a quick animation of the galaxy on the @NatureAstronomy twitter here. The study has been published in the journal Nature Astronomy.

Comments

And Earth in the bend

[SuperKendall]

An interesting aspect of this is that our solar system I think is in the part where the disc starts to bend, according to this diagram of where our solar system is in the galaxy...

It seems like it would be kind of irrelevant in the grand scheme of things, but maybe for some reason in the places where the gas discs of a universe start to bend, life it more likely for some reason. Or course, with a sample size of one you can't really extrapolate much - just seems like an interesting coincidence.

If I'm wrong about the location I would love to know more exactly where we are.

Re:And Earth in the bend

[Sique]

On a planet with an ocean, you have an environment free from ionizing radiation: under water. On Earth, Life doesn't seem to have moved on land until enough free oxygen was in the atmosphere to create an ozone layer about 400 mio years ago. There has been another period on Earth with at least 10% of oxygen in the atmosphere about 2.1 billion years ago, causing iron in the Earth's crust to oxide and create large layers of reddish stone. It could have give rise to a first development of multicellular life, albeit the nature of the fossils is still in dispute.

torque?

[Anonymous Coward]

"Our Galaxy thus follows Briggs’ rule for spiral galaxies4, which suggests that the origin of the warp is associated with torques forced by the massive inner disk5. "

I assume the force in question being referred to is gravity? Gravity induced torque?

What's the explanation for torque here? The force along the axle where all the spins and forces are in a plane... it's observed sure, its defined in equation form, agreed, but how exactly does the accelerating spin *around* the disc cause torque *along* the axle? When the axle is at 90 degrees to the disc? All the forces and velocities are in the plane of the disc, and yet torque is along the axle?!

Suppose the underlying mechanism is a component of spin across the thickness of the disc, and then rotation would push that component around the circumference of the disc spin, reducing the component in the direction of the axle, i.e. a force across the axle. Slowing it down would push it back into the axis across the disc, a force in the other way also along the axel.

Suddenly torque is simple to understand, as a fairly simple mechanism, but.... not in this context.

Gravity is an attraction only force... so that model of torque wouldn't work if gravity is a simple attraction only force.... how would it also push along the axel?

And then there's the orientation problem again, I said it would push the spin component around the disc, and reduce the component along the axle, and that's true.... but... the two always work in a specific way, acceleration in one direction results in a force in a related direction, a specific orientation rule connects them, and so it must connect the spin. They must be spinning in a particular way, coordinated.

It would be nice if people thought about the magic in Fleming left hand rule too... it's related
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