Scientists Find Doublehelix at Center of Milky Way

An anonymous reader writes "Astronomers report an unprecedented elongated double helix nebula near the center of our Milky Way galaxy, using observations from NASA's Spitzer Space Telescope. The part of the nebula the astronomers observed stretches 80 light years in length."

Light is fast, but not as fast as we think

[BadAnalogyGuy]

It takes light about a second to make a roundtrip from the Earth to the Moon. It takes 8 minutes for light from the Sun to reach the Earth. Light can travel around the Earth 7 times in 1 second.

While it may seem really fast, when broken down into comprehendable units, light is not really that fast. Sure, it's faster than anything else, but that just means that everything else is pretty slow too.

So this new nebula is 40 light years across. That's only 10 times the distance from the Earth to our second-closest star. It's like comparing the distance of the Earth to the Sun vs Pluto to the Sun. It may seem intractable, but it's really not that big.

Re:Light is fast, but not as fast as we think

[techno-vampire]

So this new nebula is 40 light years across.

No, it's 80 light years across. I don't expect anybody here to RTFA, but at least you could read the summary!

Journal link

[brian0918]

Here [nature.com] is the Nature article abtract:

"A magnetic torsional wave near the Galactic Centre traced by a 'double helix' nebula"

The magnetic field in the central few hundred parsecs of the Milky Way has a dipolar geometry and is substantially stronger than elsewhere in the Galaxy, with estimates ranging up to a milligauss (refs 1-6). Characterization of the magnetic field at the Galactic Centre is important because it can affect the orbits of molecular clouds by exerting a drag on them, inhibit star formation, and could guide a wind of hot gas or cosmic rays away from the central region. Here we report observations of an infrared nebula having the morphology of an intertwined double helix about 100 parsecs from the Galaxy's dynamical centre, with its axis oriented perpendicular to the Galactic plane. The observed segment is about 25 parsecs in length, and contains about 1.25 full turns of each of the two continuous, helically wound strands. We interpret this feature as a torsional Alfvén wave propagating vertically away from the Galactic disk, driven by rotation of the magnetized circumnuclear gas disk. The direct connection between the circumnuclear disk and the double helix is ambiguous, but the images show a possible meandering channel that warrants further investigation.

Re:Higher Res Picture?

[edward.virtually@pob]

To answer my own question, here [caltech.edu] is the link.

Re:Latest News

[Welsh Dwarf]

Nop, since looking far is also looking back in time, they probably saw the Big Bang Burger Bar.

Re:The Moon is a bit farther away than that!

[Tango42]

The speed of light in air is only marginally less than in a vacumn (refractive index of air at sea level: 1.0002926, says wikipedia) and the atmosphere drops in pressure very rapidly on a lunar scale. The exosphere starts at, at most 1000km from the earth's surface, and that's the "beginning of the end" of the atmosphere. The moon is around 400000km away. The light is travelling through the atmosphere for only 0.25% of its journey. The difference in light time from the surface of the earth and the exosphere would be a tiny fraction of a second.

Re:Deep thoughts

[qazsedcft]

...we cannot define reality

Well, science defines reality as the set of observables. That's why the post I originally replied to is pure methaphysics.

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Powers of Ten

[murderlegendre]

You're describing a famous film short "Powers of Ten" by Ray & Charles Eames. I'm too lame to make a clicky link, so here is the URL:

http://www.powersof10.com/

Fantastic film, one of the few (good) films that most schoolchildren saw in the 1970's, along with "Our Mister Sun". If there is a better method of presenting The Relative Size of Things in the Universe, I've yet to see it. Ray & Charles were way ahead of their time.

Re:Interesting star or image artifacts?

[CXI]

It's most likely due to the fact that those stars are much, much closer to us in the forground of the shot and therefore are out of focus. Being out of focus means the flaws in the optics are exagerated. Remember, lens, mirrors, beam splitters, etc all need mounting elements and have edges that bounce or block light. That's what you are seeing in the out of focus stars.