Starship Asterisk*

by **johnnydeep** » Sat Nov 11, 2023 3:33 pm

Chris Peterson wrote: ↑Sat Nov 11, 2023 3:22 pm
johnnydeep wrote: ↑Sat Nov 11, 2023 3:17 pm
Chris Peterson wrote: ↑Sat Nov 11, 2023 3:01 am

Nit. Science never proves anything, and never requires proof. Only evidence. Or disproof.
Hmm, so science can't prove that the Earth is spheroidal, or that the Earth orbits the Sun, or that the speed of light in a vacuum is between 299,000,000 and 300,000,000 m/s? All science can do is provide oodles of evidence for these things, but that no matter how much evidence is found, it's still not definitive? I suppose that's right. After all, Carl Sagan said that "extraordinary claims require extraordinary evidence", and not "extraordinary claims require proof"!
No. We have tools to measure the shape of the Earth to a certain degree of precision, but that isn't even a scientific question. We certainly can't prove anything about the speed of light, we can only note that we haven't made a contradictory observation yet. None of which is to say that when the weight of evidence becomes sufficiently large, we don't accept things as true beyond reasonable doubt. But technically, not proven. Scientific exploration has two primary goals: collecting supporting evidence, and disproving hypotheses/theories.

by **Chris Peterson** » Sat Nov 11, 2023 3:22 pm

johnnydeep wrote: ↑Sat Nov 11, 2023 3:17 pm
Chris Peterson wrote: ↑Sat Nov 11, 2023 3:01 am
ErasmusRoterodamus wrote: ↑Sat Nov 11, 2023 2:05 am Just magnificent what the mind of man can do when motivated!! While science requires evidence and proof to explain observations, "some" religionists interpretations of scripture leave them unsurprised at the magnificence of science, requiring no proof, but with tremendous respect for the observations, AND the observer!!
Nit. Science never proves anything, and never requires proof. Only evidence. Or disproof.
Hmm, so science can't prove that the Earth is spheroidal, or that the Earth orbits the Sun, or that the speed of light in a vacuum is between 299,000,000 and 300,000,000 m/s? All science can do is provide oodles of evidence for these things, but that no matter how much evidence is found, it's still not definitive? I suppose that's right. After all, Carl Sagan said that "extraordinary claims require extraordinary evidence", and not "extraordinary claims require proof"!

No. We have tools to measure the shape of the Earth to a certain degree of precision, but that isn't even a scientific question. We certainly can't prove anything about the speed of light, we can only note that we haven't made a contradictory observation yet. None of which is to say that when the weight of evidence becomes sufficiently large, we don't accept things as true beyond reasonable doubt. But technically, not proven. Scientific exploration has two primary goals: collecting supporting evidence, and disproving hypotheses/theories.

by **johnnydeep** » Sat Nov 11, 2023 3:17 pm

Chris Peterson wrote: ↑Sat Nov 11, 2023 3:01 am
ErasmusRoterodamus wrote: ↑Sat Nov 11, 2023 2:05 am Just magnificent what the mind of man can do when motivated!! While science requires evidence and proof to explain observations, "some" religionists interpretations of scripture leave them unsurprised at the magnificence of science, requiring no proof, but with tremendous respect for the observations, AND the observer!!
Nit. Science never proves anything, and never requires proof. Only evidence. Or disproof.

Hmm, so science can't prove that the Earth is spheroidal, or that the Earth orbits the Sun, or that the speed of light in a vacuum is between 299,000,000 and 300,000,000 m/s? All science can do is provide oodles of evidence for these things, but that no matter how much evidence is found, it's still not definitive? I suppose that's right. After all, Carl Sagan said that "extraordinary claims require extraordinary evidence", and not "extraordinary claims require proof"!

by **Ann** » Sat Nov 11, 2023 7:01 am

Chris Peterson wrote: ↑Fri Nov 10, 2023 6:16 pm
Jim Armstrong wrote: ↑Fri Nov 10, 2023 6:11 pm A bit of a mind-boggler APOD.
I might help me some to know if it was 13.2 billion (!) light years away then, how far is it now.
Thanks
It wasn't that far away then, either. Distance is complex. Given z = 10.1, the two easiest to understand metrics are the light travel time, which is 13.2 billion years, and the comoving disance (how far away it is now, given the expansion of the Universe over the last 13.2 billion years), which is 31.6 billion light years.

Thanks, Chris. I am of course aware that things that existed in the very early Universe have moved away from from us due to the expansion of the Universe. So, yes, a galaxy whose light reaches us after 13.2 billion years is much farther away than 13.2 billion light-years, because the galaxy has moved away from us because of the expansion of the Universe while its light has been traveling to us.

I have read, too, that the actual diameter of the observable universe is some 96 billion light-years (I should google, but I'm lazy), even though the lookback time to the Big Bang is "only" some 13.6 billion light-years. But I wouldn't know how to calculate how far away a galaxy is if the light that reaches us from this galaxy was emitted 13.2 billion years ago.

Explaining how to calculate it is probably wasted on someone like me, but others may find the explanation interesting.

Ann

by **Ann** » Sat Nov 11, 2023 6:32 am

johnnydeep wrote: ↑Fri Nov 10, 2023 9:36 pm Speaking of redshift and values of Z, the XKCD comic has a funny take in the most recent comic. From https://xkcd.com/2853/

Redshift
Title text: So do you have any plans for z=-0.000000000000045?

If you want a detailed explanation, that I think is pretty accurate (Chris, please comment if it's not!), see https://www.explainxkcd.com/wiki/index. ... :_Redshift

Johnny, that's just wonderful!!!

I took one look at yesterday's APOD, didn't appreciate the colors, and decided against commenting. But your post, with the XKCD illustration, is just priceless! I love the caption, too. A redshift value of z=0.00000000038, given that we live in a "flat Lambda CDM cosmology, with H₀ = 69.32 km / (Mpc s), a value of Ω₀ of 0.2865, a cosmic background temperature of 2.725 K", corresponds to circa 1960 days, or about five and a half years!

And the follow-up question, "So do you have any plans for z=-0.000000000000045?", means, "Do you have any plans for five and a half hours from now?".

It's priceless!

Ann

by **Chris Peterson** » Sat Nov 11, 2023 3:01 am

ErasmusRoterodamus wrote: ↑Sat Nov 11, 2023 2:05 am Just magnificent what the mind of man can do when motivated!! While science requires evidence and proof to explain observations, "some" religionists interpretations of scripture leave them unsurprised at the magnificence of science, requiring no proof, but with tremendous respect for the observations, AND the observer!!

Nit. Science never proves anything, and never requires proof. Only evidence. Or disproof.

by **ErasmusRoterodamus** » Sat Nov 11, 2023 2:05 am

Just magnificent what the mind of man can do when motivated!! While science requires evidence and proof to explain observations, "some" religionists interpretations of scripture leave them unsurprised at the magnificence of science, requiring no proof, but with tremendous respect for the observations, AND the observer!!

by **orin stepanek** » Fri Nov 10, 2023 11:12 pm

Kinda looks like there is more to learn about the universe than any
one man can absorb! It's a good thing we have computers!

by **johnnydeep** » Fri Nov 10, 2023 9:36 pm

Speaking of redshift and values of Z, the XKCD comic has a funny take in the most recent comic. From https://xkcd.com/2853/

Redshift

: Title text: So do you have any plans for z=-0.000000000000045?

If you want a detailed explanation, that I think is pretty accurate (Chris, please comment if it's not!), see https://www.explainxkcd.com/wiki/index. ... :_Redshift

by **Pastorian** » Fri Nov 10, 2023 6:35 pm

shaileshs wrote: ↑Fri Nov 10, 2023 3:21 pm When the black hole which is supposed to be at the center of galaxy is shown bigger than entire galaxy.. I'm sure it's got to do with different (and digital) zooms of Chandra and JWST just to make it easier for viewers ? It is beyond my capability of understanding how the telescopes and then processing are able to even distinguish 2 galaxies (which are no bigger than dots at such long distances, figuring out core (black hole) of a spot is even more unimaginable. I' wonder how much we are really able to caliberate and distinguish no matter what technique and science we have today. Maybe 50 years down the road some new findings with newer techniques will falsify all today's data (currently calibrated galaxies, red shifts, age of galaxy, distance of galaxy, size of galaxy, gravitational lensing..) and tell us something totally new unheard of ? Who knows (until it really happens)..

The "UHZ1 is identified in the insets" link in today's APOD description (URL here -- https://chandra.si.edu/photo/2023/uhz1/) explained some things relevant and interesting about that:
"The small object in the Webb image is the distant galaxy UHZ1 and the center of the Chandra image shows X-rays from material close to the supermassive black hole in the middle of UHZ1. The large size of the X-ray source compared to the infrared view of the galaxy is because it represents the smallest size that Chandra can resolve. The X-rays actually come from a region that is much smaller than the galaxy."

The article also talks about the image processing (or some of the processing) involved.

by **Chris Peterson** » Fri Nov 10, 2023 6:16 pm

Jim Armstrong wrote: ↑Fri Nov 10, 2023 6:11 pm A bit of a mind-boggler APOD.
I might help me some to know if it was 13.2 billion (!) light years away then, how far is it now.
Thanks

It wasn't that far away then, either. Distance is complex. Given z = 10.1, the two easiest to understand metrics are the light travel time, which is 13.2 billion years, and the comoving disance (how far away it is now, given the expansion of the Universe over the last 13.2 billion years), which is 31.6 billion light years.

by **Chris Peterson** » Fri Nov 10, 2023 6:12 pm

Chris Alex wrote: ↑Fri Nov 10, 2023 6:10 pm
Chris Peterson wrote: ↑Fri Nov 10, 2023 4:19 pm
The black hole is not visible in the Chandra image. What we're seeing is x-rays from a region surrounding the black hole.
Coud what we see be a quasar? (the wikipedia entry for UHZ1 emphasizes the quasar discovery)

Maybe. But even so, we're not seeing anything resolved. Any actual body is much smaller than a single pixel here.

by **Jim Armstrong** » Fri Nov 10, 2023 6:11 pm

A bit of a mind-boggler APOD.
I might help me some to know if it was 13.2 billion (!) light years away then, how far is it now.
Thanks

by **Christian G.** » Fri Nov 10, 2023 6:10 pm

Chris Peterson wrote: ↑Fri Nov 10, 2023 4:19 pm
The black hole is not visible in the Chandra image. What we're seeing is x-rays from a region surrounding the black hole.

Coud what we see be a quasar? (the wikipedia entry for UHZ1 emphasizes the quasar discovery)

by **Chris Peterson** » Fri Nov 10, 2023 4:19 pm

shaileshs wrote: ↑Fri Nov 10, 2023 3:21 pm When the black hole which is supposed to be at the center of galaxy is shown bigger than entire galaxy.. I'm sure it's got to do with different (and digital) zooms of Chandra and JWST just to make it easier for viewers ? It is beyond my capability of understanding how the telescopes and then processing are able to even distinguish 2 galaxies (which are no bigger than dots at such long distances, figuring out core (black hole) of a spot is even more unimaginable. I' wonder how much we are really able to caliberate and distinguish no matter what technique and science we have today. Maybe 50 years down the road some new findings with newer techniques will falsify all today's data (currently calibrated galaxies, red shifts, age of galaxy, distance of galaxy, size of galaxy, gravitational lensing..) and tell us something totally new unheard of ? Who knows (until it really happens)..

The black hole is not visible in the Chandra image. What we're seeing is x-rays from a region surrounding the black hole.

by **Joe 23** » Fri Nov 10, 2023 3:34 pm

LOL - and I presuppose you can accurately tell me how many Black Holes can dance on the head of a pin !

by **shaileshs** » Fri Nov 10, 2023 3:21 pm

When the black hole which is supposed to be at the center of galaxy is shown bigger than entire galaxy.. I'm sure it's got to do with different (and digital) zooms of Chandra and JWST just to make it easier for viewers ? It is beyond my capability of understanding how the telescopes and then processing are able to even distinguish 2 galaxies (which are no bigger than dots at such long distances, figuring out core (black hole) of a spot is even more unimaginable. I' wonder how much we are really able to caliberate and distinguish no matter what technique and science we have today. Maybe 50 years down the road some new findings with newer techniques will falsify all today's data (currently calibrated galaxies, red shifts, age of galaxy, distance of galaxy, size of galaxy, gravitational lensing..) and tell us something totally new unheard of ? Who knows (until it really happens)..

by **Christian G.** » Fri Nov 10, 2023 2:17 pm

A few days ago there were complaints here that some eclipse image seemed too little "scientific", well it sure is not the case with today's APOD!
One of the links mentions that while smbh in the local universe are roughly 0.1% of the stellar mass of the host galaxy, this one would be of a mass EQUAL to the entire stellar mass of the host galaxy! To me this falls in the category not of the supermassive but the hypermassive black hole! (or the host galaxy is considerably less massive than local ones)
In any case, awesome picture, awesome science! Pandora's cluster is stunning.

by **APOD Robot** » Fri Nov 10, 2023 5:05 am

UHZ1: Distant Galaxy and Black Hole

Explanation: Dominated by dark matter, massive cluster of galaxies Abell 2744 is known to some as Pandora's Cluster. It lies 3.5 billion light-years away toward the constellation Sculptor. Using the galaxy cluster's enormous mass as a gravitational lens to warp spacetime and magnify even more distant objects directly behind it, astronomers have found a background galaxy, UHZ1, at a remarkable redshift of Z=10.1. That puts UHZ1 far beyond Abell 2744, at a distance of 13.2 billion light-years, seen when our universe was about 3 percent of its current age. UHZ1 is identified in the insets of this composited image combining X-rays (purple hues) from the spacebased Chandra X-ray Observatory and infrared light from the James Webb Space Telescope. The X-ray emission from UHZ1 detected in the Chandra data is the telltale signature of a growing supermassive black hole at the center of the ultra high redshift galaxy. That makes UHZ1's growing black hole the most distant black hole ever detected in X-rays, a result that now hints at how and when the first supermassive black holes in the universe formed.

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