APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

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APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by APOD Robot » Thu Apr 05, 2018 4:06 am

Image NGC 289: Swirl in the Southern Sky

Explanation: About 70 million light-years distant, gorgeous spiral galaxy NGC 289 is larger than our own Milky Way. Seen nearly face-on, its bright core and colorful central disk give way to remarkably faint, bluish spiral arms. The extensive arms sweep well over 100 thousand light-years from the galaxy's center. At the lower right in this sharp, telescopic galaxy portrait the main spiral arm seems to encounter a small, fuzzy elliptical companion galaxy interacting with enormous NGC 289. Of course the spiky stars are in the foreground of the scene. They lie within the Milky Way toward the southern constellation Sculptor.

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Ann
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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by Ann » Thu Apr 05, 2018 4:52 am

I'm so glad to see this galaxy as an APOD, and I'm so glad to see Adam Block get an APOD for one of his galaxy pictures! :D :jumping up and down:

NGC 289 is a very, very pretty spiral galaxy. The inner parts of it are very spiral-y and regular and also quite yellow, though with a healthy sprinkling of pink emission nebulas in the arms. The outer arms are blue, relatively faint, and rather irregular.

It is interesting that NGC 289 is interacting with a small companion. Other notable spiral galaxies are also interacting with dwarf satellites, such as NGC 1512 (seen in the link in a photo from NASA/JPL-Caltech) and NGC 6872 (in a photo from NASA/ESA Hubble Space Telescope’s Wide Field Planetary Camera 2 (WFPC2)).

I think that a companion galaxy can help "wind up" the spiral structure of a spiral galaxy. The Whirlpool galaxy is the classic example.

Ann
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bmcdonald@iaa.net.au

Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by bmcdonald@iaa.net.au » Thu Apr 05, 2018 8:30 am

HI I just want some one to clarify something for me, we see all these pictures of galaxies with this major hot massive centres of light.. like huge balls that the galaxy sprilas around.. but what is it and how come we cant see the one in the night sky of our own galaxy.. it should be so bright looking at the pictures of other galaxies.. almost blinding?? just confusing me and what someone to open my eyes up to how all that works/ operates?? if that's not a dumb question??

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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by starsurfer » Thu Apr 05, 2018 8:57 am

bmcdonald@iaa.net.au wrote:
Thu Apr 05, 2018 8:30 am
HI I just want some one to clarify something for me, we see all these pictures of galaxies with this major hot massive centres of light.. like huge balls that the galaxy sprilas around.. but what is it and how come we cant see the one in the night sky of our own galaxy.. it should be so bright looking at the pictures of other galaxies.. almost blinding?? just confusing me and what someone to open my eyes up to how all that works/ operates?? if that's not a dumb question??
From our point of view, the centre of the Milky Way is blocked by lots of clouds of dust. But the rest of it is visible from dark skies. :D

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Ann
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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by Ann » Thu Apr 05, 2018 11:08 am

bmcdonald@iaa.net.au wrote:
Thu Apr 05, 2018 8:30 am
HI I just want some one to clarify something for me, we see all these pictures of galaxies with this major hot massive centres of light.. like huge balls that the galaxy sprilas around.. but what is it and how come we cant see the one in the night sky of our own galaxy.. it should be so bright looking at the pictures of other galaxies.. almost blinding?? just confusing me and what someone to open my eyes up to how all that works/ operates?? if that's not a dumb question??
To our human eyes, galaxies are not nearly as bright as they appear to be in most pictures. In reality, the stars of a galaxy are quite far apart, even in the crowded parts of the galaxy. So there is a lot of dark space between the stars, and therefore the galaxy isn't nearly as bright as you'd think it would be.

Some galaxies do have brilliant nuclei, but these are tiny in size and look star-like. You wouldn't necessarily realize that there is an entire galaxy surrounding that brilliant point of light.

The reason why galaxies typically look bright in pictures is that they look better that way, and very nearly all astrophotographers present their galaxy images to make them look pleasing.

Ann
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Sa Ji Tario

Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by Sa Ji Tario » Thu Apr 05, 2018 12:09 pm

For bmcdonald@iaa.net.au, The "beautiful photos of the sky" ARE NOT, they are made in the words of David Malin who is the first to develop star photography remember an image of the Orion Nebula, they present it to you with beautiful hard and impenetrable colors, it is not like that, if we traveled inside it would see that it is more diaphanous than our atmosphere. What you do is take the "signature" of the elements, filter them and color them then combine the images and you have the beautiful and colorful photo, there is a documentary in Nat Geo of Malin's work of the AAO

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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by neufer » Thu Apr 05, 2018 1:13 pm

https://en.wikipedia.org/wiki/Coriolis_force#Draining_in_bathtubs_and_toilets wrote: .
Click to play embedded YouTube video.
<<In 1908, the Austrian physicist Ottokar Tumlirz described careful and effective experiments that demonstrated the effect of the rotation of the Earth on the outflow of water through a central aperture. The subject was later popularized in a famous 1962 article in the journal Nature, which described an experiment in which all other forces to the system were removed by filling a 6 ft tank with 300 U.S. gal of water and allowing it to settle for 24 hours (to allow any movement due to filling the tank to die away), in a room where the temperature had stabilized. The drain plug was then very slowly removed, and tiny pieces of floating wood were used to observe rotation. During the first 12 to 15 minutes, no rotation was observed. Then, a vortex appeared and consistently began to rotate in an anticlockwise direction (the experiment was performed in Boston, Massachusetts, in the Northern Hemisphere). This was repeated and the results averaged to make sure the effect was real. The report noted that the vortex rotated, "about 30,000 times faster than the effective rotation of the Earth in 42° North (the experiment's location)". This shows that the small initial rotation due to the Earth is amplified by gravitational draining and conservation of angular momentum to become a rapid vortex and may be observed under carefully controlled laboratory conditions.>>
Art Neuendorffer

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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by Chris Peterson » Thu Apr 05, 2018 2:36 pm

bmcdonald@iaa.net.au wrote:
Thu Apr 05, 2018 8:30 am
HI I just want some one to clarify something for me, we see all these pictures of galaxies with this major hot massive centres of light.. like huge balls that the galaxy sprilas around.. but what is it and how come we cant see the one in the night sky of our own galaxy.. it should be so bright looking at the pictures of other galaxies.. almost blinding?? just confusing me and what someone to open my eyes up to how all that works/ operates?? if that's not a dumb question??
If you look at another galaxy in a telescope, you'll see that it looks about the same brightness as what you see when you look towards the center of our own galaxy, where the Milky Way and Sagittarius come together.

Similarly, if you look at a processed long exposure image of the central region of the Milky Way, it will be blazing as brightly as the center of many other galaxies in images.
Chris

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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by Fred the Cat » Thu Apr 05, 2018 4:29 pm

Swirling galaxies are mysterious objects. Who knows the what, why, when, and the how of where the answers will come from. :wink:
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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by MarkBour » Thu Apr 05, 2018 8:11 pm

Fred the Cat wrote:
Thu Apr 05, 2018 4:29 pm
Swirling galaxies are mysterious objects. Who knows the what, why, when, and the how of where the answers will come from. :wink:
A very nice set of links, thanks! And I realized something from the article in your "when" link. Not only can gravitational lensing help us see objects that are too distant/faint to be seen without them, but in the cases where they present multiple images, they are giving us parallax information that is absolutely amazing. I wonder if this has been made use of in any significant way.
Mark Goldfain

Georg B

Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by Georg B » Thu Apr 05, 2018 9:53 pm

I wonder what the dark spot a little below center is.
A black hole? Dark matter? A hole in the sky? An artefact?

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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by Chris Peterson » Thu Apr 05, 2018 10:05 pm

Georg B wrote:
Thu Apr 05, 2018 9:53 pm
I wonder what the dark spot a little below center is.
A black hole? Dark matter? A hole in the sky? An artefact?
I'd guess it might be a dust cloud or molecular cloud. It doesn't really look like an artifact.
Chris

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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by starsurfer » Fri Apr 06, 2018 10:44 am

Georg B wrote:
Thu Apr 05, 2018 9:53 pm
I wonder what the dark spot a little below center is.
A black hole? Dark matter? A hole in the sky? An artefact?
It looks like a dust cloud that is part of the galaxy structure.

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Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by starsurfer » Fri Apr 06, 2018 10:44 am

I love the Chilescope gallery, particularly the one of four planetary nebulae near M46!! :D

sillyworm2

Re: APOD: NGC 289: Swirl in the Southern Sky (2018 Apr 05)

Post by sillyworm2 » Mon Apr 09, 2018 1:04 pm

What a GORGEOUS Galaxy image!