APOD: Andromeda over the Alps (2023 Nov 13)

[APOD Robot]

Andromeda over the Alps

Explanation: Have you ever seen the Andromeda galaxy? Although M31 appears as a faint and fuzzy blob to the unaided eye, the light you see will be over two million years old, making it likely the oldest light you ever will see directly. The featured image captured Andromeda just before it set behind the Swiss Alps early last year. As cool as it may be to see this neighboring galaxy to our Milky Way with your own eyes, long duration camera exposures can pick up many faint and breathtaking details. The image is composite of foreground and background images taken consecutively with the same camera and from the same location. Recent data indicate that our Milky Way Galaxy will collide and coalesce with Andromeda galaxy in a few billion years.

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[shaileshs]

I've never been fan of such artificial mixture of different compositions with different settings and processing.. What's the purpose ? Why make something appear so incorrect from physics and reality perspective.. it's not like we are here at APOD to watch a Sci-fi movie with CGI effects.. It's images like these, can be misused and misunderstood for various reasons. Today, at least the creator is accepting that they have mixed 2 compositions, tomorrow, with AI, it'd be absolutely misleading (and be part of "misinformation" or "disinformation"). No ? Sorry, just my personal opinion. Others can agree/disagree as they like.

[Ann]

I've never been fan of such artificial mixture of different compositions with different settings and processing.. What's the purpose ? Why make something appear so incorrect from physics and reality perspective.. it's not like we are here at APOD to watch a Sci-fi movie with CGI effects.. It's images like these, can be misused and misunderstood for various reasons. Today, at least the creator is accepting that they have mixed 2 compositions, tomorrow, with AI, it'd be absolutely misleading (and be part of "misinformation" or "disinformation"). No ? Sorry, just my personal opinion. Others can agree/disagree as they like.

Andromeda over the Alps Image Credit & Copyright: Dzmitry Kananovich

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I rather like it. In a few billion years, Andromeda really will be that large in the sky over the Earth. Of course, Chris would probably tell us that Andromeda will definitely not be that visually striking or impressive in the sky when it comes close to us, because the "surface brightness" of Andromeda is not very high at all outside the bright inner bulge of it.

A more realistic picture of what Andromeda looks like in the sky. Credit: Telok Keman Observatory, Malaysia.

---

In any case, by the time when Andromeda comes close to us our dear old Sun has probably acted up so that life has become impossible on the Earth anyway. So we, or any descendants of ours, will have no chance to check out what it really actually looks like when Andromeda looms humongously large in our skies.

Ann

[sc02492]

I've never been fan of such artificial mixture of different compositions with different settings and processing.. What's the purpose ? Why make something appear so incorrect from physics and reality perspective.. it's not like we are here at APOD to watch a Sci-fi movie with CGI effects.. It's images like these, can be misused and misunderstood for various reasons. Today, at least the creator is accepting that they have mixed 2 compositions, tomorrow, with AI, it'd be absolutely misleading (and be part of "misinformation" or "disinformation"). No ? Sorry, just my personal opinion. Others can agree/disagree as they like.

This type of image has value in appreciating the size of various deep sky targets in relation to more familiar objects on the horizon, for instance. A boxed insert of the Moon (just for illustrative purposes) in the corner, or perhaps a scale marker at the bottom, might serve as a size reference (although doing so would ruin the aesthetics of the image). M31 spans about 3 degrees in angular diameter, whereas the moon is only about 0.5 degrees in angular diameter, so the size difference would have been impressive. Nonetheless, the image is well done and described accurately.

Steve


Steve Cannistra
www.starrywonders.com

[Maxedwell7]

IF we had a telescope that was powerful enough to see all the way into the Andromeda galaxy, and powerful enough to zoom into a planet that harbored some type of life, would we be seeing images from 2 million years ago or current?

[Chris Peterson]

I've never been fan of such artificial mixture of different compositions with different settings and processing.. What's the purpose ? Why make something appear so incorrect from physics and reality perspective.. it's not like we are here at APOD to watch a Sci-fi movie with CGI effects.. It's images like these, can be misused and misunderstood for various reasons. Today, at least the creator is accepting that they have mixed 2 compositions, tomorrow, with AI, it'd be absolutely misleading (and be part of "misinformation" or "disinformation"). No ? Sorry, just my personal opinion. Others can agree/disagree as they like.

There is nothing incorrect in this image from a physics standpoint. And "reality"? Well, we can't see this with our eyes. But it accurately captures a bit of reality that goes beyond our eyes. Like most astronomical images. And most astronomical images involve composites of different exposures.

[johnnydeep]

For the record, this is the description from the photographer at Astrobin

I took this image over a year ago, on 12 January 2022. I used a Samyang 135 mm lens @ f/2.8 and a ZWO ASI 2600MC camera (gain 100, bin 1, -10 °C). The setup was mounted on an SW AZGTi mount operating in equatorial mode and was controlled by ASIAIR Pro. I had only about 20 minutes to capture the Andromeda Galaxy before it hid behind the mountain. The data (40x30 s) was collected between 22:40 and 23:02 UT. Once captured, I turned off the tracking and proceeded with capturing the foreground (10x10 s). The foreground mountain was conveniently illuminated by a waxing gibbous moon that night. Both the background sky and the foreground images were calibrated, stacked, and processed in PixInsight, followed by blending and final polishing in Adobe Photoshop. The final image was resized to 40% and cropped.

So, I gather that Andromeda really would appear this large in the sky if our eyes were sensitive enough to detect its full extent.

In other news, this link to "virial mass" from the Wikipedia page about M31 quickly lost me in a thicket of formulas - yikes! - https://en.wikipedia.org/wiki/Virial_mass

In astrophysics, the virial mass is the mass of a gravitationally bound astrophysical system, assuming the virial theorem applies. In the context of galaxy formation and dark matter halos, the virial mass is defined as the mass enclosed within the virial radius r_vir of a gravitationally bound system, a radius within which the system obeys the virial theorem. The virial radius is determined using a "top-hat" model. A spherical "top hat" density perturbation destined to become a galaxy begins to expand, but the expansion is halted and reversed due to the mass collapsing under gravity until the sphere reaches equilibrium – it is said to be virialized. Within this radius, the sphere obeys the virial theorem which says that the average kinetic energy is equal to minus one half times the average potential energy, ⟨T⟩ = ½ ⟨U⟩, and this radius defines the virial radius.

And that's as far as I got.

[Christian G.]

This image gives a sense both of sublime beauty and looming disaster!

[Chris Peterson]

For the record, this is the description from the photographer at Astrobin

I took this image over a year ago, on 12 January 2022. I used a Samyang 135 mm lens @ f/2.8 and a ZWO ASI 2600MC camera (gain 100, bin 1, -10 °C). The setup was mounted on an SW AZGTi mount operating in equatorial mode and was controlled by ASIAIR Pro. I had only about 20 minutes to capture the Andromeda Galaxy before it hid behind the mountain. The data (40x30 s) was collected between 22:40 and 23:02 UT. Once captured, I turned off the tracking and proceeded with capturing the foreground (10x10 s). The foreground mountain was conveniently illuminated by a waxing gibbous moon that night. Both the background sky and the foreground images were calibrated, stacked, and processed in PixInsight, followed by blending and final polishing in Adobe Photoshop. The final image was resized to 40% and cropped.

So, I gather that Andromeda really would appear this large in the sky if our eyes were sensitive enough to detect its full extent.

There's no way of comparing how Andromeda would look to our eyes and how it looks in an image. Its apparent size in the image depends upon the distance between the camera and the mountains. By changing that, Andromeda could appear the size of a boulder on the mountaintop or the size of the entire mountain range.

[johnnydeep]

For the record, this is the description from the photographer at Astrobin

I took this image over a year ago, on 12 January 2022. I used a Samyang 135 mm lens @ f/2.8 and a ZWO ASI 2600MC camera (gain 100, bin 1, -10 °C). The setup was mounted on an SW AZGTi mount operating in equatorial mode and was controlled by ASIAIR Pro. I had only about 20 minutes to capture the Andromeda Galaxy before it hid behind the mountain. The data (40x30 s) was collected between 22:40 and 23:02 UT. Once captured, I turned off the tracking and proceeded with capturing the foreground (10x10 s). The foreground mountain was conveniently illuminated by a waxing gibbous moon that night. Both the background sky and the foreground images were calibrated, stacked, and processed in PixInsight, followed by blending and final polishing in Adobe Photoshop. The final image was resized to 40% and cropped.

So, I gather that Andromeda really would appear this large in the sky if our eyes were sensitive enough to detect its full extent.

There's no way of comparing how Andromeda would look to our eyes and how it looks in an image. Its apparent size in the image depends upon the distance between the camera and the mountains. By changing that, Andromeda could appear the size of a boulder on the mountaintop or the size of the entire mountain range.

Ok, but wouldn't it look the same if our eyes were positioned exactly where the camera was (and were just as sensitive)?

[shaileshs]

IF we had a telescope that was powerful enough to see all the way into the Andromeda galaxy, and powerful enough to zoom into a planet that harbored some type of life, would we be seeing images from 2 million years ago or current?

From over 2 million years ago. What we "see" is what light shows us and light emitted from stars/planets/life on planets in same galaxy is all same. It takes 2+ millions years for light to reach us from there. So, no one knows what happened later (during those 2+ million years when light was travelling to us) .. whether life on planet lived long or even if galaxy is still there or not.. we'll come to know each passing day.. for next 2+ million years.. if we (our future generation is still around)

[Chris Peterson]

For the record, this is the description from the photographer at Astrobin



So, I gather that Andromeda really would appear this large in the sky if our eyes were sensitive enough to detect its full extent.

There's no way of comparing how Andromeda would look to our eyes and how it looks in an image. Its apparent size in the image depends upon the distance between the camera and the mountains. By changing that, Andromeda could appear the size of a boulder on the mountaintop or the size of the entire mountain range.

Ok, but wouldn't it look the same if our eyes were positioned exactly where the camera was (and were just as sensitive)?

Not really. The field here is 6.8 degrees wide. So basically, this is what it would look like if you were using binoculars from the camera location and had super sensitive eyes.

[VictorBorun]

IF we had a telescope that was powerful enough to see all the way into the Andromeda galaxy, and powerful enough to zoom into a planet that harbored some type of life, would we be seeing images from 2 million years ago or current?

From over 2 million years ago. What we "see" is what light shows us and light emitted from stars/planets/life on planets in same galaxy is all same. It takes 2+ millions years for light to reach us from there. So, no one knows what happened later (during those 2+ million years when light was travelling to us) .. whether life on planet lived long or even if galaxy is still there or not.. we'll come to know each passing day.. for next 2+ million years.. if we (our future generation is still around)

Some parts of Andromeda's disk are more distant from us than others.
We maybe get a beam message THE EMPIRE FLEET IS AFTER YOU EARTHLINGS from a distant part and, in the same time, another beam message SORRY FOR THE BASTARDS WHO MANAGED TO SEND EMPTY THREATS BEFORE THE DEMOCRACY PREVAILED

[johnnydeep]

IF we had a telescope that was powerful enough to see all the way into the Andromeda galaxy, and powerful enough to zoom into a planet that harbored some type of life, would we be seeing images from 2 million years ago or current?

From over 2 million years ago. What we "see" is what light shows us and light emitted from stars/planets/life on planets in same galaxy is all same. It takes 2+ millions years for light to reach us from there. So, no one knows what happened later (during those 2+ million years when light was travelling to us) .. whether life on planet lived long or even if galaxy is still there or not.. we'll come to know each passing day.. for next 2+ million years.. if we (our future generation is still around)

Some parts of Andromeda's disk are more distant from us than others.
We maybe get a beam message THE EMPIRE FLEET IS AFTER YOU EARTHLINGS from a distant part and, in the same time, another beam message SORRY FOR THE BASTARDS WHO MANAGED TO SEND EMPTY THREATS BEFORE THE DEMOCRACY PREVAILED

But that second message would still always arrive on Earth after the first one. The two events' relative sequence in time won't change. But maybe I'm not understanding what you meant.

[johnnydeep]

There's no way of comparing how Andromeda would look to our eyes and how it looks in an image. Its apparent size in the image depends upon the distance between the camera and the mountains. By changing that, Andromeda could appear the size of a boulder on the mountaintop or the size of the entire mountain range.

Ok, but wouldn't it look the same if our eyes were positioned exactly where the camera was (and were just as sensitive)?

Not really. The field here is 6.8 degrees wide. So basically, this is what it would look like if you were using binoculars from the camera location and had super sensitive eyes.

Alright. I guess that's what I was getting at: if our eyes WERE in fact optically equivalent to the the optics that took this photo, we would "see" (or perceive) exactly what the photo shows. But that's pretty much a useless tautology.

[orin stepanek]

I always thought Andromeda was a lot like the MW

I like this!

Kitty cat and kitty cat; what are yuu too looking at?

[nam888id]

I like the bigger view inasmuch it gives me more of a sense that the halos may already be touching.

https://science.nd.edu/news-and-media/n ... alo-shows/

[Rainer Beck]

Good news: Andromeda will NOT collide with our Galaxy. A few years ago, the GAIA space observatory measured proper motions of many stars in M31 and found that is does not head exactly towards us. Instead, M31 and our Galaxy will start dancing around each other in a few billion years. Much nicer!

[johnnydeep]

Good news: Andromeda will NOT collide with our Galaxy. A few years ago, the GAIA space observatory measured proper motions of many stars in M31 and found that is does not head exactly towards us. Instead, M31 and our Galaxy will start dancing around each other in a few billion years. Much nicer!

Perhaps. I think you must be referring to the study from 2019 discussed here - https://www.sciencealert.com/we-now-kno ... -andromeda ?

Astronomers have known for some time that the Milky Way and the Andromeda galaxies will collide on some future date. The best guess for that rendezvous has been about 3.75 billion years from now.

But now a new study based on Data Release 2 from the ESA's Gaia mission is bringing some clarity to this future collision.

...

The study also revealed more of what's in store for the Milky Way and Andromeda. Rather than a collision (which is more accurately called a tidal interaction since no stars or planets were ever likely to collide), there's going to be more of a glancing blow.

And rather than taking place in about 3.75 billion years, it'll be in about 4.5 billion years. Phew!

The new paper, and the new data from Gaia, also shed some light on how galaxies like Andromeda and Triangulum form and evolve.

And from the study paper itself:

The new measurements imply that the M31 orbit toward the MW is less radial than implied by the HST measurement alone. This too is in good agreement with cosmological expectations. This implies that the future collision with the MW will happen somewhat later, and with larger pericenter, than previously inferred

My conclusion is that the MW and M31 will probabaly still merge, just with more mutually tidally destructive encounters, and ever closer orbital passes.

[Chris Peterson]

Good news: Andromeda will NOT collide with our Galaxy. A few years ago, the GAIA space observatory measured proper motions of many stars in M31 and found that is does not head exactly towards us. Instead, M31 and our Galaxy will start dancing around each other in a few billion years. Much nicer!

They're already dancing around each other.

[VictorBorun]

From over 2 million years ago. What we "see" is what light shows us and light emitted from stars/planets/life on planets in same galaxy is all same. It takes 2+ millions years for light to reach us from there. So, no one knows what happened later (during those 2+ million years when light was travelling to us) .. whether life on planet lived long or even if galaxy is still there or not.. we'll come to know each passing day.. for next 2+ million years.. if we (our future generation is still around)

Some parts of Andromeda's disk are more distant from us than others.
We maybe get a beam message THE EMPIRE FLEET IS AFTER YOU EARTHLINGS from a distant part and, in the same time, another beam message SORRY FOR THE BASTARDS WHO MANAGED TO SEND EMPTY THREATS BEFORE THE DEMOCRACY PREVAILED

But that second message would still always arrive on Earth after the first one. The two events' relative sequence in time won't change. But maybe I'm not understanding what you meant.

honestly I failed to remember what I was trying to say.
Now I think a closer point of Andromeda may send a message 100 kiloyears later and we get it on the same day

[johnnydeep]

Some parts of Andromeda's disk are more distant from us than others.
We maybe get a beam message THE EMPIRE FLEET IS AFTER YOU EARTHLINGS from a distant part and, in the same time, another beam message SORRY FOR THE BASTARDS WHO MANAGED TO SEND EMPTY THREATS BEFORE THE DEMOCRACY PREVAILED

But that second message would still always arrive on Earth after the first one. The two events' relative sequence in time won't change. But maybe I'm not understanding what you meant.

honestly I failed to remember what I was trying to say.
Now I think a closer point of Andromeda may send a message 100 kiloyears later and we get it on the same day

True. But any sequence of events in Andromeda will still always arrive in the same sequence and with the same time separation here.