Explanation: What would it look like to fly through the distant universe? To find out, a team of astronomers estimated the relative distances to over 5,000 galaxies in one of the most distant fields of galaxies ever imaged: the Hubble Ultra Deep Field (HUDF). Because it takes light a long time to cross the universe, most galaxies visible in the featured video are seen when the universe was only a fraction of its current age, were still forming, and have unusual shapes when compared to modern galaxies. No mature looking spiral galaxies such as our Milky Way or the Andromeda galaxy yet exist. Toward the end of the video the virtual observer flies past the farthest galaxies in the HUDF field, recorded to have a redshift past 8. This early class of low luminosity galaxies likely contained energetic stars emitting light that transformed much of the remaining normal matter in the universe from a cold gas to a hot ionized plasma.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 4:53 am
by Javachip3
To travel through a field of a thousand galaxies, each tens of thousands of light-years across and separated by hundreds of thousands of light-years, in only one minute, the camera would have to travel billions of times the speed of light, causing all sorts of relativistic issues. A cool video nevertheless.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 5:53 am
by Iksarfighter
Why are some objects more red shifted but closer than some others pls ?
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 6:14 am
by Boomer12k
Amazing... a trip to nearly the edge of the Universe.
:---[===] *
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 9:06 am
by heehaw
So, those dim galaxies, in the last few frames, emitted enough ionizing radiation to ionize all the hydrogen in the universe. Yeh, right! Tell me another one!
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 9:11 am
by Alex_515
modern galaxies
Funny line.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 11:34 am
by orin stepanek
I've often wondered what was at the end of the known universe! There can only be one answer;--more space! but what is there?
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 12:17 pm
by Tszabeau
“Nothing” is the biggest the biggest aspect of the multiverse... otherwise, we’d bump into everything.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 2:26 pm
by johnnydeep
Tszabeau wrote: ↑Sun Jul 26, 2020 12:17 pm
“Nothing” is the biggest the biggest aspect of the multiverse... otherwise, we’d bump into everything.
Yeah. Space is the universe’s way of keeping everything from being in the same place. Just like time is the universe’s way of keeping everything from happening all at once.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 2:30 pm
by johnnydeep
orin stepanek wrote: ↑Sun Jul 26, 2020 11:34 am
I've often wondered what was at the end of the known universe! There can only be one answer;--more space! but what is there?
What’s at the end of the known universe you ask? Why, the unknown universe of course!
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Sun Jul 26, 2020 2:48 pm
by Chris Peterson
Iksarfighter wrote: ↑Sun Jul 26, 2020 5:53 am
Why are some objects more red shifted but closer than some others pls ?
We need to be careful in reckoning redshift from apparent color. Redshifted objects don't necessarily appear more red to our eyes.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Iksarfighter wrote: ↑Sun Jul 26, 2020 5:53 am
Why are some objects more red shifted but closer than some others pls ?
We need to be careful in reckoning redshift from apparent color.
Redshifted objects don't necessarily appear more red to our eyes.
It is not clear to me that the "Flight through the Hubble Ultra Deep Field" isn't simply
slowly readjusting the redshift to be the redshift from the local observer's viewpoint.
(If I had nailed the distances that's certainly what I would have done.)
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Iksarfighter wrote: ↑Sun Jul 26, 2020 5:53 am
Why are some objects more red shifted but closer than some others pls ?
We need to be careful in reckoning redshift from apparent color.
Redshifted objects don't necessarily appear more red to our eyes.
It is not clear to me that the "Flight through the Hubble Ultra Deep Field" isn't simply
slowly readjusting the redshift to be the redshift from the local observer's viewpoint.
(If I had nailed the distances that's certainly what I would have done.)
Not sure what you mean. I don't see anything to suggest that the redshift is being adjusted in any way. (Of course, the redshift can't be determined reliably from this data, only a ratio of intensities between data from two or three broadband filtered channels, which is a weak indicator of redshift at best.)
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Chris Peterson wrote: ↑Sun Jul 26, 2020 2:48 pm
We need to be careful in reckoning redshift from apparent color.
Redshifted objects don't necessarily appear more red to our eyes.
It is not clear to me that the "Flight through the Hubble Ultra Deep Field" isn't simply
slowly readjusting the redshift to be the redshift from the local observer's viewpoint.
(If I had nailed the distances that's certainly what I would have done.)
Not sure what you mean. I don't see anything to suggest that the redshift is being adjusted in any way. (Of course, the redshift can't be determined reliably from this data, only a ratio of intensities between data from two or three broadband filtered channels, which is a weak indicator of redshift at best.)
In the first image the "ratio of intensities between data from two or three broadband filtered channels" is used to accurately determine the wide variety of colors. Any zoomed in version of this first image would simply repeat the same colors (along with the same 2D arrangement of galaxies).
Spectrally determined redshifts allow for a repositioning of everything into a 3D arrangement of the galaxies.
In passing through this 3D arrangement of the galaxies it would seem to make sense then to also vary the "ratio of intensities between data from two or three broadband filtered channels" to simulate the apparent variety of colors for the displaced observer.
The final images should all contain very faint distant red galaxies were it not for the fact that the intensity of the longest wave channel has been both intensified & (blue)shifted into all white galaxies in order to best simulate the view of the displaced observer.
Our attention is primarily on the nearby brighter galaxies whizzing by for which the readjusted (blue)shifted color change is too subtle to notice.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
neufer wrote: ↑Sun Jul 26, 2020 3:15 pm
It is not clear to me that the "Flight through the Hubble Ultra Deep Field" isn't simply
slowly readjusting the redshift to be the redshift from the local observer's viewpoint.
(If I had nailed the distances that's certainly what I would have done.)
Not sure what you mean. I don't see anything to suggest that the redshift is being adjusted in any way. (Of course, the redshift can't be determined reliably from this data, only a ratio of intensities between data from two or three broadband filtered channels, which is a weak indicator of redshift at best.)
In the first image the "ratio of intensities between data from two or three broadband filtered channels" is used to accurately determine the wide variety of colors. Any zoomed in version of this first image would simply repeat the same colors (along with the same 2D arrangement of galaxies).
Spectrally determined redshifts allow for a repositioning of everything into a 3D arrangement of the galaxies.
In passing through this 3D arrangement of the galaxies it would seem to make sense then to also vary the "ratio of intensities between data from two or three broadband filtered channels" to simulate the apparent variety of colors for the displaced observer.
The final images should all contain very faint distant red galaxies were it not for the fact that the intensity of the longest wave channel has been both intensified & (blue)shifted into all white galaxies in order to best simulate the view of the displaced observer.
Our attention is primarily on the nearby brighter galaxies whizzing by for which the readjusted (blue)shifted color change is too subtle to notice.
It would make for an interesting video to actively adjust the colors to approximate their actual appearance based on the changing distance. But I don't think this was done here.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
orin stepanek wrote: ↑Sun Jul 26, 2020 11:34 am
I've often wondered what was at the end of the known universe! There can only be one answer;--more space! but what is there?
What’s at the end of the known universe you ask? Why, the unknown universe of course!
Ya; but I like to imagine!
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
neufer wrote: ↑Sun Jul 26, 2020 7:08 pm In the first image the "ratio of intensities between data from two or three broadband filtered channels" is used to accurately determine the wide variety of colors. Any zoomed in version of this first image would simply repeat the same colors (along with the same 2D arrangement of galaxies).
Spectrally determined redshifts allow for a repositioning of everything into a 3D arrangement of the galaxies.
In passing through this 3D arrangement of the galaxies it would seem to make sense then to also vary the "ratio of intensities between data from two or three broadband filtered channels" to simulate the apparent variety of colors for the displaced observer.
The final images should all contain very faint distant red galaxies were it not for the fact that the intensity of the longest wave channel has been both intensified & (blue)shifted into all white galaxies in order to best simulate the view of the displaced observer.
Our attention is primarily on the nearby brighter galaxies whizzing by for which the readjusted (blue)shifted color change is too subtle to notice.
It would make for an interesting video to actively adjust the colors to approximate their actual appearance based on the changing distance.
But I don't think this was done here.
Then how do you explain that the video ends on all white galaxies rather than very faint red galaxies
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
orin stepanek wrote: ↑Sun Jul 26, 2020 11:34 am
I've often wondered what was at the end of the known universe! There can only be one answer;--more space! but what is there?
What’s at the end of the known universe you ask?
Why, the unknown universe of course!
Ya; but I like to imagine!
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
neufer wrote: ↑Sun Jul 26, 2020 7:08 pm In the first image the "ratio of intensities between data from two or three broadband filtered channels" is used to accurately determine the wide variety of colors. Any zoomed in version of this first image would simply repeat the same colors (along with the same 2D arrangement of galaxies).
Spectrally determined redshifts allow for a repositioning of everything into a 3D arrangement of the galaxies.
In passing through this 3D arrangement of the galaxies it would seem to make sense then to also vary the "ratio of intensities between data from two or three broadband filtered channels" to simulate the apparent variety of colors for the displaced observer.
The final images should all contain very faint distant red galaxies were it not for the fact that the intensity of the longest wave channel has been both intensified & (blue)shifted into all white galaxies in order to best simulate the view of the displaced observer.
Our attention is primarily on the nearby brighter galaxies whizzing by for which the readjusted (blue)shifted color change is too subtle to notice.
It would make for an interesting video to actively adjust the colors to approximate their actual appearance based on the changing distance.
But I don't think this was done here.
Then how do you explain that the video ends on all white galaxies rather than very faint red galaxies :?:
My assumption would be that the most distant, dimmest galaxies have only a single channel of data- either collected through no filter, or summed from several, in order to get a reasonable signal-to-noise.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Chris Peterson wrote: ↑Sun Jul 26, 2020 7:27 pm
It would make for an interesting video to actively adjust the colors to approximate their actual appearance based on the changing distance.
But I don't think this was done here.
Then how do you explain that the video ends on all white galaxies rather than very faint red galaxies
My assumption would be that the most distant, dimmest galaxies have only a single channel of data- either collected through no filter, or summed from several, in order to get a reasonable signal-to-noise.
A very (infra)red single channel of data...
so why all white galaxies if they stuck to a fixed balancing of channels to get realistic color
It would be silly to go to all the effort to correct the perceived galaxy positions for a distant observer
and not to also correct the perceived colors for that same observer.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
neufer wrote: ↑Sun Jul 26, 2020 9:18 pm
Then how do you explain that the video ends on all white galaxies rather than very faint red galaxies :?:
My assumption would be that the most distant, dimmest galaxies have only a single channel of data- either collected through no filter, or summed from several, in order to get a reasonable signal-to-noise.
A very (infra)red single channel of data...
so why all white galaxies if they stuck to a fixed balancing of channels to get realistic color :?:
It would be silly to go to all the effort to correct the perceived galaxy positions for a distant observer
and not to also correct the perceived colors for that same observer.
I don't follow. They didn't do anything to the color. Each galaxy image was isolated from the deep field, with whatever color it had based on the filters used, assigned a distance based on redshift measurements (from some other dataset), and plugged into a 3D model, which was then flown through. If the most distant galaxies lack any color information because they only have a single channel, they'll show as white.
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Mon Jul 27, 2020 1:36 am
by rwlott
Ahead! Warp factor 9 gazillion, Mr. Sulu!
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
Posted: Mon Jul 27, 2020 3:11 am
by neufer
rwlott wrote: ↑Mon Jul 27, 2020 1:36 am
Ahead! Warp factor 9 gazillion, Mr. Sulu!
The warp factor : 250,000
https://en.wikipedia.org/wiki/Warp_drive wrote:
<<The warp drive velocity in Star Trek is generally expressed in "warp factor" units, which—according to Star Trek Star Fleet Technical Manual—corresponds to the magnitude of the warp field. Achieving warp factor 1 is equal to breaking the light barrier, while the actual velocity corresponding to higher factors is determined using an ambiguous formula. According to the Star Trek episode writer's guide for The Original Series, warp factors are converted to multiples of the speed of light by multiplication with the cubic function of the warp factor itself. Accordingly, "warp 1" is equivalent to the speed of light, "warp 2" is eight times the speed of light, "warp 3" is 27 times the speed of light, etc. Several episodes of The Original Series placed the Enterprise in peril by having it travel at high warp factors. However, the velocity (in present dimensional units) of any given warp factor is rarely the subject of explicit expression, and travel times for specific interstellar distances are not consistent through the various series.
In The Original Series, warp factor 6 was established as the common speed of the USS Enterprise NCC-1701. In some cases, the starship traveled at warp 7 or above, but with risk of damaging the ship or the engines. Warp 9 in The Original Series was the "never exceed" speed for the hulls and engines of Constitution-class starships, equivalent to the aircraft VNE V-speed. Warp 6 was the VNO "Normal Operation" maximum safe cruising speed for that vessel class. Only five stories in the original Star Trek series involved the Enterprise traveling beyond warp 9. In any instance, it was a result of the influence of alien beings or foreign technology. The warp 14.1 incident in That Which Survives was the result of runaway engines which brought the hull within seconds of structural failure before power was disengaged.>>
Re: APOD: A Flight through the Hubble Ultra... (2020 Jul 26)
rwlott wrote: ↑Mon Jul 27, 2020 1:36 am
Ahead! Warp factor 9 gazillion, Mr. Sulu!
The warp factor : 250,000
https://en.wikipedia.org/wiki/Warp_drive wrote:
<<The warp drive velocity in Star Trek is generally expressed in "warp factor" units, which—according to Star Trek Star Fleet Technical Manual—corresponds to the magnitude of the warp field. Achieving warp factor 1 is equal to breaking the light barrier, while the actual velocity corresponding to higher factors is determined using an ambiguous formula. According to the Star Trek episode writer's guide for The Original Series, warp factors are converted to multiples of the speed of light by multiplication with the cubic function of the warp factor itself. Accordingly, "warp 1" is equivalent to the speed of light, "warp 2" is eight times the speed of light, "warp 3" is 27 times the speed of light, etc. Several episodes of The Original Series placed the Enterprise in peril by having it travel at high warp factors. However, the velocity (in present dimensional units) of any given warp factor is rarely the subject of explicit expression, and travel times for specific interstellar distances are not consistent through the various series.
In The Original Series, warp factor 6 was established as the common speed of the USS Enterprise NCC-1701. In some cases, the starship traveled at warp 7 or above, but with risk of damaging the ship or the engines. Warp 9 in The Original Series was the "never exceed" speed for the hulls and engines of Constitution-class starships, equivalent to the aircraft VNE V-speed. Warp 6 was the VNO "Normal Operation" maximum safe cruising speed for that vessel class. Only five stories in the original Star Trek series involved the Enterprise traveling beyond warp 9. In any instance, it was a result of the influence of alien beings or foreign technology. The warp 14.1 incident in That Which Survives was the result of runaway engines which brought the hull within seconds of structural failure before power was disengaged.>>
I think that's too fast. Warp 250000 would be 15.625e15 (15.625 quadrillion) times the speed light. That's a light year in about 2.02 nanoseconds, or a Gly in 2 seconds, or 27 secs to cover 13.8 Gly. Since the length of the video is 58 seconds, we'd only need to go about half the effective speed of warp 250000, which, by the magic of cubes is "only" about warp 198000
A Flight through the Hubble Ultra Deep Field
Ya; but I like to imagine! 
