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View Full Version : Forget 400 million - How about a 200 million year old (young) galaxy..?



gfellow
2016-Feb-27, 09:46 PM
Hi,
I just recently got a chance to read the replies to a post I made about a month or two ago, (now closed (http://cosmoquest.org/forum/showthread.php?159754-Space-Time-and-the-Mystery-of-Spontaneously-generated-Galaxies&highlight=gfellow),) being puzzled that a galaxy near the cosmic event horizon was a mere 400 million years old; roughly the time it takes the Sun to do two laps around the Milky Way galaxy, or the time between now and back when our distant fish cousins were busy evolving teeth. As I mentioned in that post, I don't know that much about galactic evolution, but I know they are a teensy bit bigger than our Billions year old Sun, and that nature was doing a rather rushed propagation job on this rather larger galactic object.

So yesterday, a friend sends me this article (http://www.space.com/11386-galaxies-formation-big-bang-hubble-telescope.html), data suggesting that galaxies formed a mere 200 million years from the Cosmic Event Horizon. That's hardly one lap around the Milky Way, or the time not so far back into a past when fairly sophisticated animals had figured out how much fun it is to be on land. If observers keep finding galaxies and they are even closer, do we then have to conclude that the Comic Event Horizon is churning them out a la spontaneous generation? Please advise.

*First Galaxies Born Sooner After Big Bang Than Thought (http://www.space.com/11386-galaxies-formation-big-bang-hubble-telescope.html)


Best,

Stephen

slang
2016-Feb-27, 10:45 PM
Moved to Astronomy to allow discussion on the finding. gfellow, posting this in ATM makes it look suspiciously like you tried to shoehorn in your previous ATM topic, which is not allowed without previous permissions from the moderator team. We'll give you the benefit of the doubt, but the other side of that decision is that if you decide to pursue your ATM in this thread anyway the infraction will be heavier.

Squink
2016-Feb-28, 12:44 AM
I'm quite happy with not being able to tell whether it's spiral or globular.

01101001
2016-Feb-28, 03:20 AM
Better reference: ESA/Hubble (spacetelescope.org): First galaxies were born much earlier than expected (https://www.spacetelescope.org/news/heic1106/)


“When we looked at the spectra, two things were clear,” explains co-author Eiichi Egami. “The redshift placed it very early in cosmic history, as we expected. But the Spitzer infrared detection also indicated that the galaxy was made up of surprisingly old and relatively faint stars. This told us that the galaxy was made up of stars already nearly 750 million years old — pushing back the epoch of its formation to about 200 million years after the Big Bang, much further than we had expected.”

01101001
2016-Feb-28, 03:31 AM
If observers keep finding galaxies and they are even closer, do we then have to conclude that the Comic Event Horizon is churning them out a la spontaneous generation?

If. If. If. Why should we accept your hypothetical?

Reformulate your question.

Cougar
2016-Feb-28, 03:31 AM
...So yesterday, a friend sends me this article (http://www.space.com/11386-galaxies-formation-big-bang-hubble-telescope.html), data suggesting that galaxies formed a mere 200 million years from the Cosmic Event Horizon.... If observers keep finding galaxies and they are even closer, do we then have to conclude that the Comic Event Horizon is churning them out a la spontaneous generation? Please advise.

I'd advise restraint. :) Here is the actual paper (http://mnrasl.oxfordjournals.org/content/414/1/L31.short). I note* the lensed images of the galaxy are figured by redshift to be at ~950 million years post big bang, i.e., after the beginning of the expansion. ("Cosmic event horizon" is kind of a nonstandard term for this, isn't it?) Then it is the stars that are spectroscopically estimated to be about 750 million years old, thus concluding the initial conglomeration of stars, whatever its form or cohesiveness, must have arisen at about 200 million years after the beginning. Apparently this is plenty of time for gravity to gather up gobs of H and He and fire them up. Plus, dark matter could start coalescing during the first 300,000 years when all the baryons were in thermal equilibrium and unable to respond to gravity.

________________
* I also note this article is 5 years old.

gfellow
2016-Feb-28, 02:40 PM
I'd advise restraint. :) Here is the actual paper (http://mnrasl.oxfordjournals.org/content/414/1/L31.short). I note* the lensed images of the galaxy are figured by redshift to be at ~950 million years post big bang, i.e., after the beginning of the expansion. ("Cosmic event horizon" is kind of a nonstandard term for this, isn't it?) Then it is the stars that are spectroscopically estimated to be about 750 million years old, thus concluding the initial conglomeration of stars, whatever its form or cohesiveness, must have arisen at about 200 million years after the beginning. Apparently this is plenty of time for gravity to gather up gobs of H and He and fire them up. Plus, dark matter could start coalescing during the first 300,000 years when all the baryons were in thermal equilibrium and unable to respond to gravity..

OK, Cougar, I'll take your advice on restraint. I think we can count on more data to be forthcoming on objects close to the cosmic event horizon in the coming years. As improved instruments better resolve detail of that barrier, I will be very surprised if whatever detail can be discerned, will not largely be comprised of a mass of streaks brought about by gravitational lensing.


* I also note this article is 5 years old.
True, but data is data. Didn't stop Isaac Newton using Johannes Kepler's calculations long after he was dead.

Eclogite
2016-Feb-28, 02:49 PM
Then it is the stars that are spectroscopically estimated to be about 750 million years old, thus concluding the initial conglomeration of stars, whatever its form or cohesiveness, must have arisen at about 200 million years after the beginning. Is it possible that stellar evolution could have been more rapid in this early epoch, so that the 750 m.y. age estimate is faulty? For example, could the (presumably) very low metallicity have an influence. I imagine this would have been taken into account, but seek confirmation.

Cougar
2016-Feb-28, 03:11 PM
Is it possible that stellar evolution could have been more rapid in this early epoch, so that the 750 m.y. age estimate is faulty? For example, could the (presumably) very low metallicity have an influence. I imagine this would have been taken into account, but seek confirmation.

A valid question. I generally give these well educated researchers a presumption of cleverness, moreso than me!

I also wonder about whether an adjustment is needed for a redshift measurement of light that curved around a very large mass. The graphic in the paper of the lensed path and other possible images from the lens that are not observable from our location is very cool!

gfellow
2016-Feb-29, 02:18 PM
Better reference: ESA/Hubble (spacetelescope.org): First galaxies were born much earlier than expected (https://www.spacetelescope.org/news/heic1106/)

Thanks for the reference. In it you point out,

"...made up of stars already nearly 750 million years old — pushing back the epoch of its formation to about 200 million years after the Big Bang, much further than we had expected...”
Wait. How can that be? Could it be a misprint, or perhaps I am misinterpreting the statement? How can there be 750 million year old stars in a galaxy 200 million years from the Big Bang?

Cougar
2016-Feb-29, 02:53 PM
Wait. How can that be? Could it be a misprint, or perhaps I am misinterpreting the statement? How can there be 750 million year old stars in a galaxy 200 million years from the Big Bang?

The galaxy we see is 950 million years old. We're not seeing the "galaxy" when it was 200 million years old. We don't know what it looked like then.

gfellow
2016-Feb-29, 04:46 PM
The galaxy we see is 950 million years old. We're not seeing the "galaxy" when it was 200 million years old. We don't know what it looked like then.

Thanks Cougar. That would ceartainly seem more reasonable. It does still leave us with a galaxy 400 million years old (https://www.sciencedaily.com/releases/2015/12/151203142416.htm) (published in 2015, mentioned in the earlier postings,) an age one might equate with two solar laps around the Milky Way Galaxy. To scale, that seems pretty fast for something that big to pull together. I am intrigued by an earlier respondent suggesting a time dilation close to the cosmic event horizon, but data on that has got to be pretty shaky, yes?

01101001
2016-Feb-29, 06:47 PM
It does still leave us with a galaxy 400 million years old (https://www.sciencedaily.com/releases/2015/12/151203142416.htm) (published in 2015, mentioned in the earlier postings,) an age one might equate with two solar laps around the Milky Way Galaxy. To scale, that seems pretty fast for something that big to pull together.

Pretty fast? How long should it take? All you seem to be asking is why you cannot conceive of galaxies forming so early.

The news article about your cited galaxy at 400 million years post Big Bang (https://www.sciencedaily.com/releases/2015/12/151203142416.htm) says:


This finding suggests that the very early universe will be rich in galaxy targets for the upcoming James Webb Space Telescope to uncover. Astronomers expect that Webb will allow us to see the embryonic stages of galaxy birth shortly after the big bang.

Why is that boggling your mind?

Squink
2016-Feb-29, 08:39 PM
Pretty fast? How long should it take?When I pull the plug on the drain in my sink, it takes some seconds for the bulk of the water to start circling the drain hole, and still more seconds till a gurgly vortex forms in the center. I've not measured it, but 5 or 6 orbits at least, not one or two.

gfellow
2016-Feb-29, 09:03 PM
Pretty fast? How long should it take? All you seem to be asking is why you cannot conceive of galaxies forming so early.

The news article about your cited galaxy at 400 million years post Big Bang (https://www.sciencedaily.com/releases/2015/12/151203142416.htm) says:
This finding suggests that the very early universe will be rich in galaxy targets for the upcoming James Webb Space Telescope to uncover. Astronomers expect that Webb will allow us to see the embryonic stages of galaxy birth shortly after the big bang.


Why is that boggling your mind?

Because a galaxy forming in 200 - 400 million years complete with stars is pretty darn fast, unless one believes in spontaneous generation.

Hornblower
2016-Feb-29, 09:40 PM
Because a galaxy forming in 200 - 400 million years complete with stars is pretty darn fast, unless one believes in spontaneous generation.

200 million years is a mind-blowing long time compared to a human lifetime or even recorded human history. As has been pointed out, massive stars can form from the primordial gas and reach the main sequence in a million years or so. What is your basis for calling 200 million years "pretty darn fast"?

gfellow
2016-Mar-01, 12:00 AM
200 million years is a mind-blowing long time compared to a human lifetime or even recorded human history. As has been pointed out, massive stars can form from the primordial gas and reach the main sequence in a million years or so. What is your basis for calling 200 million years "pretty darn fast"?

400 million years back, fish were already evolving teeth. Our planet is 5 something billion years old. As to massive stars forming from primordial gas and reach main sequence in a million years, yes, impressive - but perhaps not hard observable data. Have we observed such an event?

I guess it's all subjective at the moment. Personally think it a stretch to believe an entire galaxy can evolve in that timespan - but hey, let's wait and see if the ever improving instruments find galaxies even closer to the cosmic event horizon. :)

01101001
2016-Mar-03, 08:42 PM
400 million years back, fish were already evolving teeth.

Fish teeth! I knew it.

See topic z=11.1 (http://cosmoquest.org/forum/showthread.php?160360-z-11-1)

gfellow
2016-Mar-06, 02:44 PM
As Hornblower pointed out, theory holds (although yet to be observed) that massive stars can form from the primordial gas and reach the main sequence in a million years or so. Well, perhaps, perhaps not (http://goodfelloweb.com/nature/cgbi/stars001.html). Hornblower asks, "what my basis for calling 200 million years "pretty darn fast"?

Comparisons? As I mentioned earlier it is estimated that it takes our Sun some 200 million years to orbit our Milky Way galaxy. That would make a galaxy forming in 200 million years the equivalent of "Pop!" - suddenly there. Coincidentally, two articles appear in by news search this morning, both in DailyGalaxy.com:

NASA: "It's Amazing That a Galaxy So Massive Existed So Early in the Universe" (http://www.dailygalaxy.com/my_weblog/2016/03/nasa-its-amazing-that-a-galaxy-so-massive-existed-so-soon-in-the-universe.html),
...so it is not mere laymen such as myself who are rather taken aback by the speed of galactic evolution.

The other, Quantum Time --"The Key to the Origin of the Universe" (http://www.dailygalaxy.com/my_weblog/2016/03/quantum-time-the-key-to-the-origin-of-the-universe-weekend-feature.html)
which directly relates to my earlier (now closed down, posting), "Space, Time and the Mystery of Spontaneously generated Galaxies" (http://cosmoquest.org/forum/showthread.php?159754-Space-Time-and-the-Mystery-of-Spontaneously-generated-Galaxies&highlight=gfellow), suggesting that time dilation may be a significant factor when considering distance and the weight of space.

Shaula
2016-Mar-06, 03:26 PM
Comparisons? As I mentioned earlier it is estimated that it takes our Sun some 200 million years to orbit our Milky Way galaxy. That would make a galaxy forming in 200 million years the equivalent of "Pop!" - suddenly there.
How does comparing two only loosely related timescales give you basis for comparison?

It takes the Earth a year to orbit the Sun - does that mean it is infeasible that aurora vary from night to night?

gfellow
2016-Mar-06, 06:18 PM
How does comparing two only loosely related timescales give you basis for comparison?

It takes the Earth a year to orbit the Sun - does that mean it is infeasible that aurora vary from night to night?

Not quite sure that is an apt comparison; the streaming solar wind takes at most mere days to reach us over a relatively short distance, and is an electromagnetic event. The Earth annually orbiting the Sun is a more lengthy gravitational phenomenon.

My comparison is more akin to the ditty:

Mary had a little lamb
The doctor was surprised
But when Old McDonald had a farm
The doctor damn near died

The time it takes an incoherent mass sizable enough to gravitationally compress sufficiently in order to generate stars on a galactic scale, then gravitationally organize these stars into a coherent galactic entity - all this on the same time-scale it takes our Sun to make one solitary lap around our own galaxy - now that is quite a tall order.
It would seem that at least some real good to honest professional astronomers (see my post and link (http://www.dailygalaxy.com/my_weblog/2016/03/nasa-its-amazing-that-a-galaxy-so-massive-existed-so-soon-in-the-universe.html) preceding this one,) are as surprised as I am.

Shaula
2016-Mar-06, 06:38 PM
Not quite sure that is an apt comparison; the streaming solar wind takes at most mere days to reach us over a relatively short distance, and is an electromagnetic event. The Earth annually orbiting the Sun is a more lengthy gravitational phenomenon.
Neither is your comparison. Which makes mine a very apt comparison in context!


The time it takes an incoherent mass sizable enough to gravitationally compress sufficiently in order to generate stars on a galactic scale, then gravitationally organize these stars into a coherent galactic entity - all this on the same time-scale it takes our Sun to make one solitary lap around our own galaxy - now that is quite a tall order.
It would seem that at least some real good to honest professional astronomers (see my post and link (http://www.dailygalaxy.com/my_weblog/2016/03/nasa-its-amazing-that-a-galaxy-so-massive-existed-so-soon-in-the-universe.html) preceding this one,) are as surprised as I am.
The point is that you have presented absolutely no evidence that this timescale is relevant. If you had done much digging you would have found that it is not. The timescales you should be considering are the freefall rate for a cloud of gas, sound crossing time and the cooling timescale.

So as it stands your incredulity is based on a comparison of two things that are not particularly related.

Cougar
2016-Mar-06, 11:56 PM
The time it takes an incoherent mass sizable enough to gravitationally compress sufficiently in order to generate stars on a galactic scale, then gravitationally organize these stars into a coherent galactic entity - all this on the same time-scale it takes our Sun to make one solitary lap around our own galaxy - now that is quite a tall order.

Well, you've got to imagine what the universe was like at 300,000 years after the beginning of the expansion. It was not exactly "incoherent," as we can see on the CMB. Small variations, but enough to get things started. But it's really the dark matter that did the "heavy lifting," since it could begin interacting gravitationally before 300,000 years, unrestricted by all the charged particles otherwise filling space. )This model matches what we see better than any other. Unfortunately, there's no corresponding "baryogenesis" theory for dark matter (that I know of). I guess that results from not knowing exactly what it is!)

I wouldn't call that z=11.1 galaxy exactly coherent, either. It's in the process of coalescing, and still small.

And you don't seem to appreciate the extraordinary length of time for a round trip around the nucleus of our galaxy. 240 million years? How is that not a good long time?

gfellow
2016-Mar-07, 04:29 AM
And you don't seem to appreciate the extraordinary length of time for a round trip around the nucleus of our galaxy. 240 million years? How is that not a good long time?

Putting the Universe in some kind of scale perspective, imagine our galaxy as a small grain of sand. Let's say that to scale, the Virgo Cluster is six inches away, each inch representing a million light years. Walk about eighteen feet in any direction, and you hit the Cosmic Event Horizon. Now back away a mere two inches from that event horizon and we find a 200 million year young, developed galaxy.

So yes, if you're waiting in a dentist's office for 240 million years, that would seem a good long time, but if you are waiting for a galaxy to form, it is as close to instantaneous as you can get.

One needs to be imbued with a considerable suspension of disbelief to even contemplate something the size of a galaxy coming together in that infinitesimal short period of time.
With continually improving instruments and their greater sensitivity, I will be curious to see if astronomers find galaxies even closer to the Cosmic Event Horizon. If they do, will there be a clearer explanation as to how galaxies can form even faster than 200 million years? I suspect we won't have long a wait.

Shaula
2016-Mar-07, 06:31 AM
One needs to be imbued with a considerable suspension of disbelief to even contemplate something the size of a galaxy coming together in that infinitesimal short period of time.
Which tells me immediately that you have not bothered to look at the freefall time scale but instead are happy to keep on making the same claims based on a misplaced sense of incredulity.

It doesn't matter how many irrelevant visualisations or comparisons you come up with - the physics of gas clouds remains the same. We cannot model everything in detail yet but the approximate calculations we can make show that the timescales are not impossible.

Cougar
2016-Mar-07, 12:48 PM
Well, you've got to imagine what the universe was like at 300,000 years after the beginning of the expansion.

I forgot to add that the density of matter in the universe at that time would have been 1,100 times what it is now, if I've figured correctly. This is not a small difference with respect to early structure formation.

antoniseb
2016-Mar-07, 01:30 PM
... the density of matter in the universe at that time would have been 1,100 times what it is now, if I've figured correctly. ...
You mean perhaps 1100 cubed (about a billion) times denser (measuring in mass per unit volume)

Squink
2016-Mar-07, 01:44 PM
You mean perhaps 1100 cubed (about a billion) times denser (measuring in mass per unit volume)
10^6 atoms per cubic meter or so? Aren't we getting dangerously close to the range where regions of space larger than a few billion km in diameter would form black holes and wink out of normal spacetime?

Cougar
2016-Mar-07, 03:17 PM
You mean perhaps 1100 cubed (about a billion) times denser (measuring in mass per unit volume)

Now, I should have figured that, considering the 1100 pertains to "things closer together," which is a single dimension.

01101001
2016-Mar-07, 03:43 PM
10^6 atoms per cubic meter or so? Aren't we getting dangerously close to the range where regions of space larger than a few billion km in diameter would form black holes and wink out of normal spacetime?

Like a Wikipedia: Primordial black hole (https://en.wikipedia.org/wiki/Primordial_black_hole)?


A primordial black hole is a hypothetical type of black hole that is formed not by the gravitational collapse of a large star but by the extreme density of matter present during the universe's early expansion.

Shaula
2016-Mar-08, 04:39 AM
Now, I should have figured that, considering the 1100 pertains to "things closer together," which is a single dimension.
And since the free fall time is inversely proportional to the square root of the density of the gas cloud free fall times in the early universe were smaller.

gfellow
2016-Mar-08, 04:35 PM
Which tells me immediately that you have not bothered to look at the freefall time scale but instead are happy to keep on making the same claims based on a misplaced sense of incredulity.

It doesn't matter how many irrelevant visualisations or comparisons you come up with - the physics of gas clouds remains the same. We cannot model everything in detail yet but the approximate calculations we can make show that the timescales are not impossible.

A lot of speculation there, Shaula.
To apply free-fall equations one would have to punch in some reliable mass/energy/time numbers which, if I am not mistaken would be at best highly speculative, somehat like applying Reynolds numbers of turbulent gases in order to define the relationship between the solar interior and photosphere. In other words, not necessarily compatible.
So I ask you, by what magnitude do you feel your poorly applied physics trump my irrelevant visualisations? :)

Shaula
2016-Mar-08, 07:53 PM
A lot of speculation there, Shaula.
To apply free-fall equations one would have to punch in some reliable mass/energy/time numbers which, if I am not mistaken would be at best highly speculative, somehat like applying Reynolds numbers of turbulent gases in order to define the relationship between the solar interior and photosphere. In other words, not necessarily compatible.
So I ask you, by what magnitude do you feel your poorly applied physics trump my irrelevant visualisations? :)
Given that numerical simulations based on actual physics produce reasonable results whereas your irrelevant comparisons don't I'd say they were accurate enough to highlight that your claims are based on faulty logic.

And you are wrong about what you have to put into the free fall time to get a result. I am not sure why you think we need to put in time when time is what we want out. Energy doesn't come into it - that is captured by the other time scales and by conservation laws. Free fall time is simply proportional to density. So I really don't know why you are making these claims about poor physics when you don't seem to know what the physics you are dismissing is.

gfellow
2016-Mar-09, 03:17 PM
Given that numerical simulations based on actual physics produce reasonable results whereas your irrelevant comparisons don't I'd say they were accurate enough to highlight that your claims are based on faulty logic.

And you are wrong about what you have to put into the free fall time to get a result. I am not sure why you think we need to put in time when time is what we want out. Energy doesn't come into it - that is captured by the other time scales and by conservation laws. Free fall time is simply proportional to density. So I really don't know why you are making these claims about poor physics when you don't seem to know what the physics you are dismissing is.

Even in a fairly local humdrum part of our Universe, the interactivity between small grains of matter near large scale objects is a lot more exciting than was originally thought. As an instance, take the data we have on this stellar object and see how well plugging free fall equations work:

NASA | Voyager Finds Magnetic Bubbles at Solar System's Edge (https://www.youtube.com/watch?v=5HbJiY1wATQ)

Plainly, matter interactions are a lot more complex than free-fall equations allow for. Charitably, these equations are at best an intellectual exercise and at worst, rather meaningless.

Shaula
2016-Mar-09, 07:11 PM
Plainly, matter interactions are a lot more complex than free-fall equations allow for. Charitably, these equations are at best an intellectual exercise and at worst, rather meaningless.
As I have said, several times now, the free fall timescale (not the free fall equations, by the way) is one of several timescales that characterise behaviours of gas clouds.

Yes, the real behaviours are more complex. You'll note that I have acknowledged that from the get go. What you are getting away from is this: You are arguing from incredulity based on a completely meaningless comparison. A simplified (but likely to be order of magnitude correct) assessment of the timescales involved shows that your incredulity is misplaced.

I suggest you go and read some of the literature out there. Find the gaps. Work out what you think the extra effects that have not been accounted for will do. Then come back here and present some actual physics based evidence for your stance. Stop presenting strawmen, stop presenting false assertions. Show us that your stance is justified.

gfellow
2016-Mar-10, 03:04 PM
As I have said, several times now, the free fall timescale (not the free fall equations, by the way) is one of several timescales that characterise behaviours of gas clouds.

Yes, the real behaviours are more complex. You'll note that I have acknowledged that from the get go. What you are getting away from is this: You are arguing from incredulity based on a completely meaningless comparison. A simplified (but likely to be order of magnitude correct) assessment of the timescales involved shows that your incredulity is misplaced.

I suggest you go and read some of the literature out there. Find the gaps. Work out what you think the extra effects that have not been accounted for will do. Then come back here . Let usand present some actual physics based evidence for your stance. Stop presenting strawmen, stop presenting false assertions. Show us that your stance is justified.

Your well practiced dismissals aside, lack of data is of course the root of most meaningless discussions.
Let us sit back on our haunches and await additional data from the very lip of the Cosmic Event Horizon. Should the timeline for galaxy evolution so close to this boundary be cut even shorter, it will be interesting to see what mechanisms experts will suggest for such seemingly rapid galactic growth.