Starship Asterisk*

Chris Peterson wrote: ↑Sat Feb 13, 2021 2:06 pm

VictorBorun wrote: ↑Sat Feb 13, 2021 10:53 am

Chris Peterson wrote: ↑Sat Feb 13, 2021 3:16 am Only material that interacts with multiple bodies inside the galaxy has the possibility of being captured.

Can you please give more details?
How can a galaxy or a star form in the first place? How can they manage to drop the energy and the rotation momemtum?
OK, the energy can be radiated to the outer space by photons and neutrinos.
But those particles are ultra-relativistic; they carry more energy than momentum.
To lose its rotation momentum, the proto-galaxy or a proto-star cloud has to kick away some of its hadron matter, does not it?

We don't know how galaxies form. But most likely they start with concentrations of gas and dark matter. Such concentrations can form because the material is dense enough to behave as a fluid, meaning that particles interact often enough that there is extensive transfer of angular momentum. This is the same thing that happens in accretion discs, from which individual stars and planetary systems form.

VictorBorun wrote: ↑Sat Feb 13, 2021 10:53 am

Chris Peterson wrote: ↑Sat Feb 13, 2021 3:16 am Only material that interacts with multiple bodies inside the galaxy has the possibility of being captured.

Can you please give more details?
How can a galaxy or a star form in the first place? How can they manage to drop the energy and the rotation momemtum?
OK, the energy can be radiated to the outer space by photons and neutrinos.
But those particles are ultra-relativistic; they carry more energy than momentum.
To lose its rotation momentum, the proto-galaxy or a proto-star cloud has to kick away some of its hadron matter, does not it?

Ann wrote: ↑Fri Feb 12, 2021 6:31 am Remarkably, I could find only one other reasonably good picture of NGC 1350 on the net, and I didn't much like that picture because I found its colors weird.

The bluish cast of the ESO image may be due to the fact that the exposure through a blue filter was twice as long as the exposures through the other filters. At the same time, the fact that a disk is visible outside the prominent ring of NGC 1350 in ESO's picture, which is not really the case in the Selby/Keller image, may be due to the fact that ESO used an infrared filter to bring out the presence of small cool stars in the disk.

Finally, it's really quite weird that this elegant galaxy is so unknown, and has been photographed so rarely. It must be the galaxy's southern position, and the "northern bias" of astronomy (due to the fact that most of the Earth's astronomers live north of the equator), that is to blame for the snubbing of NGC 1350.

Ann

Chris Peterson wrote: ↑Sat Feb 13, 2021 3:16 am Only material that interacts with multiple bodies inside the galaxy has the possibility of being captured.

Alanh wrote: ↑Fri Feb 12, 2021 8:59 pm Hi. When I look at it I have to wonder because it must be spinning somewhat and the gravity it has do these things attract material from space flying by and get bigger? When I look close at the picture I get the impression that it is spinning. Or is it so big that any spinning motion is lost because of its size. What is it that makes planets spin and galaxies spin so I would assume the whole universe is spinning in a huge circle too.

Chris Peterson wrote: ↑Fri Feb 12, 2021 3:16 pm

Wadsworth wrote: ↑Fri Feb 12, 2021 3:08 pm
When I zoom in on the Galaxy in this image my mind sets it to motion and It starts to spin slowly.
I guess our mind knows how things are supposed to spin.

Although most spiral galaxies have arms that lag, a few have arms that lead. And quite a few we don't really know for sure, because it can be difficult to measure. This probably spins the way your mind expects... but it may not.

• (Almost?) all barred spiral galaxies have arms that lag.

https://en.wikipedia.org/wiki/Black_Eye_Galaxy wrote:

M64: HST of the "Black Eye" or "Evil Eye" galaxy

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<<The Black Eye Galaxy (Messier 64, M64, or NGC 4826) is a relatively isolated spiral galaxy 17 million light-years away in the mildly northern constellation of Coma Berenices. A dark band of absorbing dust partially in front of its bright nucleus gave rise to its nicknames of the "Black Eye" or "Evil Eye" galaxy. M64 is well known among amateur astronomers due to its form in small telescopes and visibility across inhabited latitudes.

The morphological classification in the De Vaucouleurs system is (R)SA(rs)ab, where the '(R)' indicates an outer ring-like structure, 'SA' denotes a non-barred spiral, '(rs)' means a transitional inner ring/spiral structure, and 'ab' says the spiral arms are fairly tightly wound. Ann et al. (2015) gave it a class of SABa, suggesting a weakly barred spiral galaxy with tightly wound arms.

The interstellar medium of Messier 64 consists of two counter-rotating disks that are approximately equal in mass. The inner disk contains the prominent dust lanes of the galaxy. The stellar population of the galaxy exhibits no measurable counter-rotation. Possible formation scenarios include a merger with a gas-rich satellite galaxy in a retrograde orbit, or the continued accretion of gas clouds from the intergalactic medium.>>

https://en.wikipedia.org/wiki/NGC_4622 wrote:

Illustration showing the major components of NGC 4622

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<<NGC 4622 is a face-on unbarred spiral galaxy with a very prominent ring structure located in the constellation Centaurus. The galaxy is a member of the Centaurus Cluster. The spiral galaxy, NGC 4622 (also called Backward galaxy), lies approx. 111 million light years away from Earth in the constellation Centaurus. NGC 4622 is an example of a galaxy with leading spiral arms. In spiral galaxies, spiral arms were thought to trail; the tips of the spiral arms winding away from the center of the galaxy in the direction of the disks orbital rotation. In NGC 4622, however, the outer arms are leading spiral arms; the tips of the spiral arms point towards the direction of disk rotation. This may be the result of a gravitational interaction between NGC 4622 and another galaxy or the result of a merger between NGC 4622 and a smaller object.

NGC 4622 also has a single inner trailing spiral arm. Although it was originally suspected that the inner spiral arm was a leading arm, the observations that established that the outer arms were leading also established that the inner arm was trailing.

These results were met with skepticism in part because they contradicted conventional wisdom with one quote being “so you’re the backward astronomers who found the backward galaxy.” The fact that a pair of arms could lead was not easy to accept. Astronomical objections centered on the fact that dust reddening and cloud silhouettes were used to determine that the outer arms lead. The galaxy disk is tilted only 19 degrees from face-on making near to far-side effects of dust hard to discern and because clumpy dust clouds might be concentrated on one side of the disk, creating misleading results.

While the presence of backward arms in a galaxy may seem like an inconvenient truth to many, two independent methods now indicate that NGC 4622's arms do indeed behave in a very unusual fashion, with the outer arms winding outward in the same direction the disk turns.>>

Wadsworth wrote: ↑Fri Feb 12, 2021 3:08 pm When I zoom in on the Galaxy in this image my mind sets it to motion and It starts to spin slowly.
I guess our mind knows how things are supposed to spin..