Milky Way loses two arms

On the left is an artist's rendition of the revised structure of the Milky Way galaxy; on the right is an earlier sketch, showing the four-armed structure. Since the 1950s, scientists have continued to revise their models of the Milky Way.

(Credit: NASA/JPL-Caltech)

Call it the Milky Way Light, a trimmed-down version of the galaxy we know and love.

Using new infrared imaging from the Spitzer Space Telescope, NASA scientists say our spiraled Milky Way galaxy is actually made up of just two main arms. For years, astronomers have mapped out the galaxy with four primary arms. The two arms on the chopping block--Norma and Sagittarius--haven't disappeared entirely; they've just been demoted to the lowly status of minor arm, according to NASA.

Scientists have studied parts of the galaxy for many years, but say telescopes tuned to detect infrared light give them the best picture of its layout because they can penetrate through dust. Infrared images taken in the 1990s led them to discover the large bar of creamy nougat stars in the center of the galaxy. Spitzer's new infrared shots, coupled with software that measures stellar density, indicate that Norma and Sagittarius aren't as thick as astronomers had thought.

"We will keep revising our picture in the same way that early explorers sailing around the globe had to keep revising their maps," said Robert Benjamin of the University of Wisconsin at Whitewater, who presented the results at a press conference Tuesday.

[bigblatch]

LOL...creamy nougat

[Grem135]

does that meen its less fatting?

[Ramon366]

Is this due to global warming?
Being part of a smaller galactic federation; does that put us at a disadvantage?

[Dalkorian]

To answer the brilliant questions posted: 1. Yes, it's less fattening, but it still tastes great! 2. Yes, this is a direct result of global warming. Heating the planet has excited gasses in the galaxy, which has resulted them into going off to find a good party. 3. Yes, the reduction in galactic size puts us at a disadvantage against other galactic federations. Fortunately it also makes us harder to find, in case those other galactic federations are hostile. I for one find the new galactic "map" to be neater and easier to "read", not that it matters much.

[t8]

Why don't they just send out a space craft to place a mirror in the next galaxy and then point hubble at the mirror?

[OldCabanaGuy]

Anything to make us buy a new "You Are Here" t-shirt

[Ramon366]

This of course may mean that the Romulans have perfected their cloaking device to such an extent that it can hide entire regions of the galaxy - I'm getting a bad feeling about this. First, it was about all of the missing dark matter, now this.

[baldguy61]

Call me crazy but there appear to be two axes of rotation in both pictures- one for the inner galazy and another, 90 degrees different, for the outer. Last time I took any photos of our galaxy, everything appeared to have the same plane of apparent rotation. What changed while I was away?

[morbas]

The Galaxy structure was mapped by VLA Georgelin 1975. There are some artists feactures that appear to contradict the VLA map. Also, the artists has not indicated the diametric quadrant which is not visible from our view. References indicate that stars/systems are rather uniformely distributed within the Galactic plane. Inner Galactic orbit star systems having higher metallic content, and outer stars systems having lighter material content. The impact of the galactic core hydrogen outflow effects star luminosity defining arm structure. We get a measure of this outflow rate from Hercules (satellite) and noted professionals with published datum. This hypothetical structure contradicts previous incontroversial data; It appears to not stand on the shoulders of giants.
IMHO morbas

[morbas]

My error, apologies extended. I have overlaid the Geogelin Hii mapping on the JPL Galaxy and find good congruence. However, an arguable issue remains. JPL has renamed the Crux-Scutum are to Scutum-Centaurus. O that the IAS would bother to settle this issue. Also, the overlay indicates that the Norma arm end point aligns to the Cygnus Arm, resulting in a Norma-Cygnus merge, where JPL designates the Outer Arm. A second discrepancy between the maps places the Scutum-Centaurus at a much greater radius in the JPL version. I have but a couple of questions for any of the parties, was bremsstrahlung Compton read shift accounted for? I ask this because not only do I see a constant increase in radius of the Sagittarius Arm with angular vector, but I also see a rate peaking centered on Sol.

[benjaminstraight]

Poor Milky Way.