APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

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APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by APOD Robot » Wed Oct 09, 2019 4:05 am

Image NGC 7714: Starburst after Galaxy Collision

Explanation: Is this galaxy jumping through a giant ring of stars? Probably not. Although the precise dynamics behind the featured image is yet unclear, what is clear is that the pictured galaxy, NGC 7714, has been stretched and distorted by a recent collision with a neighboring galaxy. This smaller neighbor, NGC 7715, situated off to the left of the featured frame, is thought to have charged right through NGC 7714. Observations indicate that the golden ring pictured is composed of millions of older Sun-like stars that are likely co-moving with the interior bluer stars. In contrast, the bright center of NGC 7714 appears to be undergoing a burst of new star formation. The featured image was captured by the Hubble Space Telescope. NGC 7714 is located about 130 million light years away toward the constellation of the Two Fish (Pisces). The interactions between these galaxies likely started about 150 million years ago and should continue for several hundred million years more, after which a single central galaxy may result.

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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by Ann » Wed Oct 09, 2019 4:46 am

I found this part of the caption confusing:
APOD Robotr wrote:

Observations indicate that the golden ring pictured is composed of millions of older Sun-like stars that are likely co-moving with the interior bluer stars. In contrast, the bright center of NGC 7714 appears to be undergoing a burst of new star formation.
I wrote the words "the bright center" in almost unreadable, yellow-white letters, because I wanted to say that the center of NGC 7714 looks yellow-white to me. Certainly there might be a starburst going on in there, but if so, the starburst is invisible in this picture. By contrast, the blue "arm" below the center of NGC 7714 looks extremely blue to me.

And which are the interior bluer stars that are not part of the starburst?

Central starburst of NGC 7714. Photo: ESA/Hubble.
At least I found a picture, which is really a part of a video, where the center of NGC 7714 looks starburst-cerulean to me.

Ann

EDIT: One of the links in the caption leads to the video in question! I should have clicked all the links.
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by orin stepanek » Wed Oct 09, 2019 11:30 am

NGC 7714; another great photo presented by APOD! :D 8-)
Ngc7714_HubblePohl_1080.jpg
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by neufer » Wed Oct 09, 2019 12:30 pm

https://en.wikipedia.org/wiki/Sonic_hedgehog wrote:
<<Sonic hedgehog is a secreted protein that in humans is encoded by the SHH gene. It plays a key role in the development of animals, from insects to mammals. In vertebrates, it is involved in organogenesis, including the growth of digits on limbs and the organization of the brain. Sonic hedgehog is an archetypal example of a morphogen as defined by Lewis Wolpert's French flag model—a molecule that diffuses to form a concentration gradient and has different effects on the cells of the developing embryo depending on its concentration. Sonic hedgehog is also active in adults; for example, it controls the proliferation of adult stem cells and has been implicated in the development of some cancers.

The hedgehog gene (hh) was first identified in the fruit-fly Drosophila melanogaster in the classic Heidelberg screens of Christiane Nüsslein-Volhard and Eric Wieschaus, as published in 1980. These screens, which led to them winning the Nobel Prize in 1995 along with developmental geneticist Edward B. Lewis, identified genes that control the segmentation pattern of the Drosophila embryos. The hh loss of function mutant phenotype causes the embryos to be covered with denticles, small pointy projections resembling the spines of a hedgehog.

Investigations aimed at finding a hedgehog equivalent in vertebrates by Philip Ingham, Andrew P. McMahon, and Clifford Tabin, revealed three homologous genes. Two of these, desert hedgehog and Indian hedgehog, were named for species of hedgehogs, while sonic hedgehog was named after Sonic the Hedgehog, the protagonist of the eponymous video game franchise. The name was devised by Robert Riddle, who was a postdoctoral fellow at the Tabin Lab, after he saw a Sonic comic book his daughter owned. In the zebrafish, two of the three vertebrate hh genes are duplicated: SHH a, SHH b (formerly described as tiggywinkle hedgehog, named for Mrs. Tiggy-Winkle, a character from Beatrix Potter's books for children), ihha and ihhb (formerly described as echidna hedgehog, named for the spiny anteater and not for the echidna character Knuckles in the Sonic franchise).
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by sillyworm 2 » Wed Oct 09, 2019 12:38 pm

130 million light years away...merging for a couple more million years...in it's location...it is now nearly merged?

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Go Fish

Post by neufer » Wed Oct 09, 2019 12:59 pm

APOD Robot wrote:
Wed Oct 09, 2019 4:05 am

Explanation: NGC 7714 is located about 130 million light years away toward the constellation of the Two Fish (Pisces).
https://www.grammarly.com/blog/fish-fishes/ wrote:
  • The plural of fish is usually fish.

    When referring to more than one species of fish, especially in a scientific context, you can use fishes as the plural.

    The zodiac sign Pisces is also often referred to as fishes.
https://en.wikipedia.org/wiki/Pisces_(constellation) wrote:
<<Pisces is a constellation of the zodiac. Its name is the Latin plural for fish. Pisces is associated with the Greek legend that Aphrodite and her son Eros either shape-shifted into forms of fishes to escape, or were rescued by two fishes. In the Greek version according to Hyginus, Aphrodite and Eros while visiting Syria fled from the monster Typhon by leaping into the Euphrates River and transforming into fishes (Poeticon astronomicon 2.30, citing Diognetus Erythraeus).[4] The Roman variant of the story has Venus and Cupid (counterparts for Aphrodite and Eros) carried away from this danger on the backs of two fishes (Ovid Fasti 2.457ff).>>
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by Ann » Wed Oct 09, 2019 1:08 pm

It would have been much easier for us ESL speakers if the plural of "fish" hade been fishes!
https://holes.fandom.com/wiki/Armpit_(Theodore_Johnson) wrote about Armpit in the movie Holes:[/url]:

Though a tough guy, he had a somewhat tender side, like when he saw Caveman's fish-fossil, he said in a sing-song voice, "Aww look at the little fishies! Aww... I mean that's cool...".
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by TheZuke! » Wed Oct 09, 2019 1:18 pm

"cerulean"
Thanks Ann, for my new "Word of the Day"!

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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by neufer » Wed Oct 09, 2019 1:40 pm

Click to play embedded YouTube video.
TheZuke! wrote:
Wed Oct 09, 2019 1:18 pm

"cerulean"

Thanks Ann, for my new "Word of the Day"!
:arrow: Ann hath a way with blue.
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by Ann » Wed Oct 09, 2019 5:24 pm

neufer wrote:
Wed Oct 09, 2019 1:40 pm
Click to play embedded YouTube video.
TheZuke! wrote:
Wed Oct 09, 2019 1:18 pm

"cerulean"

Thanks Ann, for my new "Word of the Day"!
:arrow: Ann hath a way with blue.
Was the girl in a cerulean sweater by any chance Anne Hathaway?

Ann
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by DL MARTIN » Wed Oct 09, 2019 6:35 pm

If NGC 7714 is 130 million light years away, then an event 150 million years ago is when?

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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by neufer » Wed Oct 09, 2019 8:22 pm

Click to play embedded YouTube video.
Ann wrote:
Wed Oct 09, 2019 5:24 pm

Was the girl in a cerulean sweater by any chance Anne Hathaway?
Yes, you understand.
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by TheOtherBruce » Wed Oct 09, 2019 9:25 pm

I notice that the caption describes NGC 7715 as "off to the left". Are there any good photos of it? I can't find any; the Wiki pages for 7715 and 7714 both show the same picture, similar to today's. Presumably it's at the end of the "shrapnel" of bluish clusters trailing away from the arms of 7714?
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by neufer » Thu Oct 10, 2019 12:50 am


TheOtherBruce wrote:
Wed Oct 09, 2019 9:25 pm

I notice that the caption describes NGC 7715 as "off to the left". Are there any good photos of it? I can't find any; the Wiki pages for 7715 and 7714 both show the same picture, similar to today's. Presumably it's at the end of the "shrapnel" of bluish clusters trailing away from the arms of 7714?
https://it.wikipedia.org/wiki/NGC_7715 wrote:
<<NGC 7715 is an irregular galaxy located in the direction of the Pisces constellation at a distance of about 130 million light years from the Earth. It has a diameter of about 100,000 light years. It interacts with the nearby barred spiral galaxy NGC 7714, a couple listed as Arp 284 in the catalog of peculiar galaxies . This interaction process started in a period between 100 and 200 million years ago. Both galaxies are strongly distorted due to tidal forces, so much that they lose much of their mass.>>
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by Ann » Thu Oct 10, 2019 3:33 am

neufer wrote:
Wed Oct 09, 2019 8:22 pm
Click to play embedded YouTube video.
Ann wrote:
Wed Oct 09, 2019 5:24 pm

Was the girl in a cerulean sweater by any chance Anne Hathaway?
Yes, you understand.
Yes, I understand. As Chance would have it.

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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by sillyworm 2 » Thu Oct 10, 2019 11:55 am

Can't find an edit here...what I meant to say is..if this merge we are seeing is 130 million light years away...and it will merge for approx 200 million more years...does that mean it is now merged and we won't see that for 200 million more years? Approx..

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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by neufer » Thu Oct 10, 2019 12:37 pm

sillyworm 2 wrote:
Thu Oct 10, 2019 11:55 am

Can't find an edit here...what I meant to say is..if this merge we are seeing is 130 million light years away...and it will merge for approx 200 million more years...does that mean it is now merged and we won't see that for 200 million more years? Approx..
It is pointless to define "now" as referring to anything other than what lies on our past light-cone for anything within about 5 billion light years. General relativity allows us to use whatever space-time coordinates we want to make things the simplest to understand. The physics itself requires enough thinking and there is no need to spend time with these metaphysical arguments.
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by TheOtherBruce » Thu Oct 10, 2019 1:35 pm

Ah, I see what's happened — the English version of the Wikipedia page is the only one that doesn't have the proper photo of NGC 7715.

That's quite a mangled galaxy there, it seems both of them are being chopped into little bitty pieces by each other's gravity. I wonder if galaxies are ever completely disrupted in a single pass by head-on collisions like this, or are they generally held together enough by their own gravity? I remember seeing a previous APOD with an animated simulation of a merger, and it took several passes until I couldn't distinguish between the two blobs of debris.
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by neufer » Thu Oct 10, 2019 1:54 pm

TheOtherBruce wrote:
Thu Oct 10, 2019 1:35 pm

That's quite a mangled galaxy there, it seems both of them are being chopped into little bitty pieces by each other's gravity. I wonder if galaxies are ever completely disrupted in a single pass by head-on collisions like this, or are they generally held together enough by their own gravity? I remember seeing a previous APOD with an animated simulation of a merger, and it took several passes until I couldn't distinguish between the two blobs of debris.
It's like two toy gyroscopes banging into each other...

they generally held together by their own individual momentum: both angular & linear.
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by Chris Peterson » Thu Oct 10, 2019 2:38 pm

DL MARTIN wrote:
Wed Oct 09, 2019 6:35 pm
If NGC 7714 is 130 million light years away, then an event 150 million years ago is when?
150 million years ago.
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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by sillyworm 2 » Thu Oct 10, 2019 4:35 pm

Are we not seeing this merge as it appeared in the past? Are you saying it would look exactly the same if we could suddenly be as close as Adromeda?

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Re: APOD: NGC 7714: Starburst after Galaxy... (2019 Oct 09)

Post by Chris Peterson » Thu Oct 10, 2019 5:08 pm

sillyworm 2 wrote:
Thu Oct 10, 2019 4:35 pm
Are we not seeing this merge as it appeared in the past? Are you saying it would look exactly the same if we could suddenly be as close as Adromeda?
In what way does it matter how it looks from a different location in space?
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