Starship Asterisk*

APOD Robot wrote:

Hydrogen gas surrounding newborn stars glows pink.

Bright infant stars shine blue

Cousin Ricky wrote: ↑Tue Feb 20, 2024 2:21 pm If this isn’t already called the Question Mark Galaxy, it should be.

Ann wrote: ↑Tue Feb 20, 2024 2:40 pm

Cousin Ricky wrote: ↑Tue Feb 20, 2024 2:21 pm If this isn’t already called the Question Mark Galaxy, it should be.

Naaah. The Question Mark Galaxy already exists (and it is hard to beat):

The Question Mark Galaxy behind a very young Milky Way star and its jets. Credit: NASA/ESA/CSA/Joseph DePasquale (STScI)

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Ann

johnnydeep wrote: ↑Tue Feb 20, 2024 7:41 pm

Ann wrote: ↑Tue Feb 20, 2024 2:40 pm

Cousin Ricky wrote: ↑Tue Feb 20, 2024 2:21 pm If this isn’t already called the Question Mark Galaxy, it should be.

Naaah. The Question Mark Galaxy already exists (and it is hard to beat):

The Question Mark Galaxy behind a very young Milky Way star and its jets. Credit: NASA/ESA/CSA/Joseph DePasquale (STScI)

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Ann

I wonder if this is perhaps a pair of colliding galaxies.

The NASA/ESA Hubble Space Telescope has snapped the best ever image of the Antennae Galaxies. Hubble has released images of these stunning galaxies twice before, once using observations from its Wide Field and Planetary Camera 2 (WFPC2) in 1997, and again in 2006 from the Advanced Camera for Surveys (ACS). Each of Hubble’s images of the Antennae Galaxies has been better than the last, due to upgrades made during the famous servicing missions, the last of which took place in 2009. The galaxies — also known as NGC 4038 and NGC 4039 — are locked in a deadly embrace. Once normal, sedate spiral galaxies like the Milky Way, the pair have spent the past few hundred million years sparring with one another. This clash is so violent that stars have been ripped from their host galaxies to form a streaming arc between the two. In wide-field images of the pair the reason for their name becomes clear — far-flung stars and streamers of gas stretch out into space, creating long tidal tails reminiscent of antennae. This new image of the Antennae Galaxies shows obvious signs of chaos. Clouds of gas are seen in bright pink and red, surrounding the bright flashes of blue star-forming regions — some of which are partially obscured by dark patches of dust. The rate of star formation is so high that the Antennae Galaxies are said to be in a state of starburst, a period in which all of the gas within the galaxies is being used to form stars. This cannot last forever and neither can the separate galaxies; eventually the nuclei will coalesce, and the galaxies will begin their retirement together as one large elliptical galaxy. This image uses visible and near-infrared observations from Hubble’s Wide Field Camera 3 (WFC3), along with some of the previously-released observations from Hubble’s Advanced Camera for Surveys (ACS).

Ann wrote: ↑Tue Feb 20, 2024 7:55 pm

johnnydeep wrote: ↑Tue Feb 20, 2024 7:41 pm

Ann wrote: ↑Tue Feb 20, 2024 2:40 pm

Naaah. The Question Mark Galaxy already exists (and it is hard to beat):

The Question Mark Galaxy behind a very young Milky Way star and its jets. Credit: NASA/ESA/CSA/Joseph DePasquale (STScI)

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Ann

I wonder if this is perhaps a pair of colliding galaxies.

Probably. I mean, what else could it be?

Ann

johnnydeep wrote: ↑Tue Feb 20, 2024 8:01 pm

Ann wrote: ↑Tue Feb 20, 2024 7:55 pm

johnnydeep wrote: ↑Tue Feb 20, 2024 7:41 pm

I wonder if this is perhaps a pair of colliding galaxies.

Probably. I mean, what else could it be?

Ann

Well, do they have to necessarily be near enough to each other for a collision to be possible?

Ann wrote: ↑Tue Feb 20, 2024 5:38 am

AM1054: Stars Form as Galaxies Collide. Image Credit: NASA, ESA, STScI; Processing: J. English (U. Manitoba); Science: M. Rodruck (Penn State U. & Randolph-Macon C.) et al.; Text: Jayanne English (U. Manitoba).

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As the Color Commentator, I'm unimpressed with the colors here. The galaxy is all yellow and white.

APOD Robot wrote:

Hydrogen gas surrounding newborn stars glows pink.

There is no pink in the APOD.

Bright infant stars shine blue

There is no blue in this APOD.


Could it be that the filters used for this image made it harder to create a good color picture? I'd say no, because these were the filters: F336W (ultraviolet), F435W (blue), F606W (orange), F814W (infrared).

The assigned colors for the filters were these: Magenta ███: F336W, Cyan ███: F435W, Green ███: F606W, Red ███: F814W.


It shouldn't be impossible to create a picture of a starforming, yellow, pink, blue and white galaxy that looks more than just yellow and white using those filters, should it?

Ann

Chris Peterson wrote: ↑Tue Feb 20, 2024 8:37 pm

johnnydeep wrote: ↑Tue Feb 20, 2024 8:01 pm

Ann wrote: ↑Tue Feb 20, 2024 7:55 pm

Probably. I mean, what else could it be?

Ann

Well, do they have to necessarily be near enough to each other for a collision to be possible?

Collisions are determined not by distance, but by orbits. (In theory you could have two galaxies that aren't gravitationally bound collide, but I think that's very rare.) And "collision" is a special case of "interaction". The latter is much more common, where two galaxies alter each other's morphology, which does not require anything we'd likely call a collision.

johnnydeep wrote: ↑Tue Feb 20, 2024 10:22 pm

Chris Peterson wrote: ↑Tue Feb 20, 2024 8:37 pm

johnnydeep wrote: ↑Tue Feb 20, 2024 8:01 pm

Well, do they have to necessarily be near enough to each other for a collision to be possible?

Collisions are determined not by distance, but by orbits. (In theory you could have two galaxies that aren't gravitationally bound collide, but I think that's very rare.) And "collision" is a special case of "interaction". The latter is much more common, where two galaxies alter each other's morphology, which does not require anything we'd likely call a collision.

Ok, then are they "gravitationally bound enough" to be affecting each other? (Yes, I know the reach of gravity is infinite so no matter the distance, everything is technically affected by everything else.) Andromeda is 25 Milky Way diameters away, and we will eventually collide wit it, but would you say it is affecting us enough to significantly distort the Milky Way's shape? Could the two galaxies in the "Question Mark" be 25 or more diameters (of the larger one) apart? True, they are a very similar shade of red, and might have a similar redshift, but is there any reason to think they are "close" to each other?

AVAO wrote: ↑Tue Feb 20, 2024 8:55 pm

Ann wrote: ↑Tue Feb 20, 2024 5:38 am

AM1054: Stars Form as Galaxies Collide. Image Credit: NASA, ESA, STScI; Processing: J. English (U. Manitoba); Science: M. Rodruck (Penn State U. & Randolph-Macon C.) et al.; Text: Jayanne English (U. Manitoba).

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As the Color Commentator, I'm unimpressed with the colors here. The galaxy is all yellow and white.

APOD Robot wrote:

Hydrogen gas surrounding newborn stars glows pink.

There is no pink in the APOD.

Bright infant stars shine blue

There is no blue in this APOD.


Could it be that the filters used for this image made it harder to create a good color picture? I'd say no, because these were the filters: F336W (ultraviolet), F435W (blue), F606W (orange), F814W (infrared).

The assigned colors for the filters were these: Magenta ███: F336W, Cyan ███: F435W, Green ███: F606W, Red ███: F814W.


It shouldn't be impossible to create a picture of a starforming, yellow, pink, blue and white galaxy that looks more than just yellow and white using those filters, should it?

Ann

Well, I don't know if it's legitimate to borrow the colors from the Legacy Surveys DR10, but at least it gives you an idea of what direction "true colors" could go. In addition to the blue galaxy, the second yellow galaxy can also be seen here, which is also involved.

Click to view full size image

close up:

Click to view full size image

Original data: HST/LS-DR10 jac berne (flickr)

Chris Peterson wrote: ↑Tue Feb 20, 2024 11:04 pm

johnnydeep wrote: ↑Tue Feb 20, 2024 10:22 pm

Chris Peterson wrote: ↑Tue Feb 20, 2024 8:37 pm
Collisions are determined not by distance, but by orbits. (In theory you could have two galaxies that aren't gravitationally bound collide, but I think that's very rare.) And "collision" is a special case of "interaction". The latter is much more common, where two galaxies alter each other's morphology, which does not require anything we'd likely call a collision.

Ok, then are they "gravitationally bound enough" to be affecting each other? (Yes, I know the reach of gravity is infinite so no matter the distance, everything is technically affected by everything else.) Andromeda is 25 Milky Way diameters away, and we will eventually collide wit it, but would you say it is affecting us enough to significantly distort the Milky Way's shape? Could the two galaxies in the "Question Mark" be 25 or more diameters (of the larger one) apart? True, they are a very similar shade of red, and might have a similar redshift, but is there any reason to think they are "close" to each other?

Gravitationally bound means they are in orbit around each other (or in complex orbits within a larger cluster). Absent interaction with a third body, they will be forever together. Distortion is mainly a tidal effect: when the distances between them is only a few times their sizes, they stop seeing each other as point masses and exert different forces on the closer parts than the more distant... hence distortion.

johnnydeep wrote: ↑Wed Feb 21, 2024 2:20 pm

Chris Peterson wrote: ↑Tue Feb 20, 2024 11:04 pm

johnnydeep wrote: ↑Tue Feb 20, 2024 10:22 pm

Ok, then are they "gravitationally bound enough" to be affecting each other? (Yes, I know the reach of gravity is infinite so no matter the distance, everything is technically affected by everything else.) Andromeda is 25 Milky Way diameters away, and we will eventually collide wit it, but would you say it is affecting us enough to significantly distort the Milky Way's shape? Could the two galaxies in the "Question Mark" be 25 or more diameters (of the larger one) apart? True, they are a very similar shade of red, and might have a similar redshift, but is there any reason to think they are "close" to each other?

Gravitationally bound means they are in orbit around each other (or in complex orbits within a larger cluster). Absent interaction with a third body, they will be forever together. Distortion is mainly a tidal effect: when the distances between them is only a few times their sizes, they stop seeing each other as point masses and exert different forces on the closer parts than the more distant... hence distortion.

Alright. My conclusion here is that we still don't know how close the two parts of the "question mark" are and if they are distorting each other. Their evocative juxtaposition from our point of view may just be pure happenstance.

Chris Peterson wrote: ↑Wed Feb 21, 2024 2:27 pm

johnnydeep wrote: ↑Wed Feb 21, 2024 2:20 pm

Chris Peterson wrote: ↑Tue Feb 20, 2024 11:04 pm
Gravitationally bound means they are in orbit around each other (or in complex orbits within a larger cluster). Absent interaction with a third body, they will be forever together. Distortion is mainly a tidal effect: when the distances between them is only a few times their sizes, they stop seeing each other as point masses and exert different forces on the closer parts than the more distant... hence distortion.

Alright. My conclusion here is that we still don't know how close the two parts of the "question mark" are and if they are distorting each other. Their evocative juxtaposition from our point of view may just be pure happenstance.

Absent any other information (which may or may not exist), there is no way to tell with certainty from the image alone what's going on. Certainly the two components may be unrelated and simply in line of sight. But interacting galaxies seems the most likely explanation.

johnnydeep wrote: ↑Wed Feb 21, 2024 2:36 pm

Chris Peterson wrote: ↑Wed Feb 21, 2024 2:27 pm

johnnydeep wrote: ↑Wed Feb 21, 2024 2:20 pm

Alright. My conclusion here is that we still don't know how close the two parts of the "question mark" are and if they are distorting each other. Their evocative juxtaposition from our point of view may just be pure happenstance.

Absent any other information (which may or may not exist), there is no way to tell with certainty from the image alone what's going on. Certainly the two components may be unrelated and simply in line of sight. But interacting galaxies seems the most likely explanation.

Why is that the most likely explanation? Similar sizes, similar redshift (maybe), no other things "nearby"... other factors?

Chris Peterson wrote: ↑Wed Feb 21, 2024 2:42 pm

johnnydeep wrote: ↑Wed Feb 21, 2024 2:36 pm

Chris Peterson wrote: ↑Wed Feb 21, 2024 2:27 pm
Absent any other information (which may or may not exist), there is no way to tell with certainty from the image alone what's going on. Certainly the two components may be unrelated and simply in line of sight. But interacting galaxies seems the most likely explanation.

Why is that the most likely explanation? Similar sizes, similar redshift (maybe), no other things "nearby"... other factors?

Well, we're almost certainly seeing a galaxy distorted by tidal interactions. As Ann says, what else? We see a great many of those, almost always with the two galaxies involved apparent. How many examples do we have of deformed galaxies visually paired with unrelated galaxies?

johnnydeep wrote: ↑Wed Feb 21, 2024 5:18 pm

Chris Peterson wrote: ↑Wed Feb 21, 2024 2:42 pm

johnnydeep wrote: ↑Wed Feb 21, 2024 2:36 pm

Why is that the most likely explanation? Similar sizes, similar redshift (maybe), no other things "nearby"... other factors?

Well, we're almost certainly seeing a galaxy distorted by tidal interactions. As Ann says, what else? We see a great many of those, almost always with the two galaxies involved apparent. How many examples do we have of deformed galaxies visually paired with unrelated galaxies?

Ok. I'd say that past examples might predict future similar looking phenomena, but don't preclude exceptions. Still, science is all about probabilities I suppose.

Chris Peterson wrote: ↑Wed Feb 21, 2024 5:23 pm

johnnydeep wrote: ↑Wed Feb 21, 2024 5:18 pm

Chris Peterson wrote: ↑Wed Feb 21, 2024 2:42 pm
Well, we're almost certainly seeing a galaxy distorted by tidal interactions. As Ann says, what else? We see a great many of those, almost always with the two galaxies involved apparent. How many examples do we have of deformed galaxies visually paired with unrelated galaxies?

Ok. I'd say that past examples might predict future similar looking phenomena, but don't preclude exceptions. Still, science is all about probabilities I suppose.

I'd just say that understanding objectively derived probabilities is an important tool for guiding scientific investigation. If you're going to conduct an investigation, it makes sense to start with the most probable hypotheses.

johnnydeep wrote: ↑Wed Feb 21, 2024 5:24 pm

Chris Peterson wrote: ↑Wed Feb 21, 2024 5:23 pm

johnnydeep wrote: ↑Wed Feb 21, 2024 5:18 pm

Ok. I'd say that past examples might predict future similar looking phenomena, but don't preclude exceptions. Still, science is all about probabilities I suppose.

I'd just say that understanding objectively derived probabilities is an important tool for guiding scientific investigation. If you're going to conduct an investigation, it makes sense to start with the most probable hypotheses.

Agreed. Thanks.

Ann wrote: ↑Wed Feb 21, 2024 5:59 pm

johnnydeep wrote: ↑Wed Feb 21, 2024 5:24 pm

Chris Peterson wrote: ↑Wed Feb 21, 2024 5:23 pm
I'd just say that understanding objectively derived probabilities is an important tool for guiding scientific investigation. If you're going to conduct an investigation, it makes sense to start with the most probable hypotheses.

Agreed. Thanks.

The pair that make up Arp 256 are two of my favorite galaxies. They are interacting, not colliding. If we saw them from another perspective, they might even look like a question mark.

Interacting galaxies Arp 256. Credit: NASA and the Hubble Heritage Team

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Ann

Ann wrote: ↑Wed Feb 21, 2024 5:59 pm

johnnydeep wrote: ↑Wed Feb 21, 2024 5:24 pm

Chris Peterson wrote: ↑Wed Feb 21, 2024 5:23 pm
I'd just say that understanding objectively derived probabilities is an important tool for guiding scientific investigation. If you're going to conduct an investigation, it makes sense to start with the most probable hypotheses.

Agreed. Thanks.

The pair that make up Arp 256 are two of my favorite galaxies. They are interacting, not colliding. If we saw them from another perspective, they might even look like a question mark.

Interacting galaxies Arp 256. Credit: NASA and the Hubble Heritage Team

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Ann

AVAO wrote: ↑Sat Feb 24, 2024 6:27 am

Ann wrote: ↑Wed Feb 21, 2024 5:59 pm

johnnydeep wrote: ↑Wed Feb 21, 2024 5:24 pm

Agreed. Thanks.

The pair that make up Arp 256 are two of my favorite galaxies. They are interacting, not colliding. If we saw them from another perspective, they might even look like a question mark.

Interacting galaxies Arp 256. Credit: NASA and the Hubble Heritage Team

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Ann

ThanX Ann

I like galaxies dancing together too, and there is actually a nice star bridge between them.
Here is my version - Unfortunately the original data are quite noisy.
Jac

Click to view full size image