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Hubble Discovers Ancient Galaxy Far, Far Away
For anyone interested.
//"The discovery of GN-z11 shows us that our knowledge about the early Universe is still very restricted. Probably we are seeing the first generations of stars forming around black holes?"//
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//"The discovery of GN-z11 shows us that our knowledge about the early Universe is still very restricted. Probably we are seeing the first generations of stars forming around black holes?"//
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Oops, forgot to set out that the basic premise is that the universe expands at (nearly) the speed of light.
Also, (hope to be corrected) it kind of extrudes out of everywhere.
space (as it was yesterday)
s-p-a-c-e (today) e recedes 4 units from s; p only by 1 (e more redshift than p)
where {-} are newly formed stretches of space (just dimensions, no actusl substance created)
Also, (hope to be corrected) it kind of extrudes out of everywhere.
space (as it was yesterday)
s-p-a-c-e (today) e recedes 4 units from s; p only by 1 (e more redshift than p)
where {-} are newly formed stretches of space (just dimensions, no actusl substance created)
@jomifl
/you can't see photons from side-on./
you can't see photons but you can see with them.
13:49 Fri 04th Mar 2016
A bit cryptic. Humour?
On a point of pedantry, we do not emit photons so it's not so much "see with" but "see because we've received" them. You cannot see them from the side because they haven't hit you. Mere passers by.
:0)
/you can't see photons from side-on./
you can't see photons but you can see with them.
13:49 Fri 04th Mar 2016
A bit cryptic. Humour?
On a point of pedantry, we do not emit photons so it's not so much "see with" but "see because we've received" them. You cannot see them from the side because they haven't hit you. Mere passers by.
:0)
-- answer removed --
@divebuddy
matter cannot travel faster than life. Pure energy might be able to (I *will* be corrected on this, if wrong)
"space" as in "just dimensions expanding" is massless and can do as it pleases.
Trouble is, because of what's going on (expansion) I am not sure whether "travelling" is a meaningful description of what it's doing.
Expanding foam might be a good visualisation. Each bubble might be tiny but if there is loads of them and they each double in size the foam blob expands by a macroscopic amount.
matter cannot travel faster than life. Pure energy might be able to (I *will* be corrected on this, if wrong)
"space" as in "just dimensions expanding" is massless and can do as it pleases.
Trouble is, because of what's going on (expansion) I am not sure whether "travelling" is a meaningful description of what it's doing.
Expanding foam might be a good visualisation. Each bubble might be tiny but if there is loads of them and they each double in size the foam blob expands by a macroscopic amount.
How about this - does it make sense ?
At the big bang the universe expanded at a rate far exceeding the speed of light .
The earth was formed at a distance , some 13+ billion light years from the position of this galaxy .
With the universe still expanding , the light from this galaxy has thus taken 13+ billion light years to reach us
At the big bang the universe expanded at a rate far exceeding the speed of light .
The earth was formed at a distance , some 13+ billion light years from the position of this galaxy .
With the universe still expanding , the light from this galaxy has thus taken 13+ billion light years to reach us
We don't see anything as (or where) it is. We can only see things as (and where) they were by virtue of the light they emitted from where they were when that light began its journey to our eyes.
For example; we never see the Sun exactly as it is now (or where it is now). What we see when we look towards the Sun is how and where it was over eight minutes ago when the light from the Sun began its journey. In the meantime the Sun has since moved by about two degrees (about four solar diameters) to the west from where it appears in Earth's sky.
As if that illusion isn't enough to cause some confusion, when we observe more distant objects we have to also take into account the expansion of the universe that has taken place since the light they emitted back when began its journey.
Finally, for the most distant objects we can see we have to take into account that the current rate of expansion is increasing from what it was back when the light we observe now began its journey. Observations indicate that expansion began to accelerate again when the universe was roughly two/thirds its current size, about the time our solar system began to take form, about five billion years ago.
https:/
For example; we never see the Sun exactly as it is now (or where it is now). What we see when we look towards the Sun is how and where it was over eight minutes ago when the light from the Sun began its journey. In the meantime the Sun has since moved by about two degrees (about four solar diameters) to the west from where it appears in Earth's sky.
As if that illusion isn't enough to cause some confusion, when we observe more distant objects we have to also take into account the expansion of the universe that has taken place since the light they emitted back when began its journey.
Finally, for the most distant objects we can see we have to take into account that the current rate of expansion is increasing from what it was back when the light we observe now began its journey. Observations indicate that expansion began to accelerate again when the universe was roughly two/thirds its current size, about the time our solar system began to take form, about five billion years ago.
https:/
As I understand it, it doesn't need things to be travelling faster than the speed of light in a vacuum. The point is that space is being created given the impression that things are moving away at speed.
Consider a long enough distance and the ends will be parting at greater than light speed even if you could prove they weren't actually moving. This is because space is being created that fast between the ends that the distance grows as if the ends were moving at greater than light speed.
No information is moving at greater than light speed, and I'm unaware if we have found a limit on how fast space can be created.
Consider a long enough distance and the ends will be parting at greater than light speed even if you could prove they weren't actually moving. This is because space is being created that fast between the ends that the distance grows as if the ends were moving at greater than light speed.
No information is moving at greater than light speed, and I'm unaware if we have found a limit on how fast space can be created.
@jomifl
//emitting photons wasn't stated or implied.//
Ants feel their way around *with* their antennae.
I [do something] to [object] *with* [device]
With, in the sense of 'using'. "We see, using photons" is structured in a way suggesting that the photons are a tool, unintentionally implying we send them out.
I don't know if avec or mit are used in an equivalent way?
//emitting photons wasn't stated or implied.//
Ants feel their way around *with* their antennae.
I [do something] to [object] *with* [device]
With, in the sense of 'using'. "We see, using photons" is structured in a way suggesting that the photons are a tool, unintentionally implying we send them out.
I don't know if avec or mit are used in an equivalent way?
@all
I am struck by the fact that, despite fresh space coming into existence everywhere, all of the time, gravitation nevertheless keeps the solar system intact (and onwards up to to the scale of clusters of galaxies). In other words, they (sun, planets etc.) are 'attached' to each other but not to the expanding fabric of space. Fabric is the wrong word, anyway; it has no substance and I see no reason why it shouldn't pass through matter.
I am struck by the fact that, despite fresh space coming into existence everywhere, all of the time, gravitation nevertheless keeps the solar system intact (and onwards up to to the scale of clusters of galaxies). In other words, they (sun, planets etc.) are 'attached' to each other but not to the expanding fabric of space. Fabric is the wrong word, anyway; it has no substance and I see no reason why it shouldn't pass through matter.
@jomifl
//
Hypo, perhaps I should have said that if parts of the universe are receding from us at speeds greater than light speed we won't know because we won't be able to see them. Is there any reason to believe that this is not the case? //
I take that question in two senses:-
i) The fact that we would not be able to see them is unquestionable. I cannot say that this is not the case (but that might be only down to my ignorance).
ii) Whether they exist is unknowable.
I cannot even postulate that they do not exist. It is a binary yes/no situation.
If they are out there then it certainly exercises the mind in terms of deciding whether their gravitational influence on the rest of the universe. Gravitons would not be received but space-time curvature effects might still apply (give or take enormous dilution by inverse square law).
//
Hypo, perhaps I should have said that if parts of the universe are receding from us at speeds greater than light speed we won't know because we won't be able to see them. Is there any reason to believe that this is not the case? //
I take that question in two senses:-
i) The fact that we would not be able to see them is unquestionable. I cannot say that this is not the case (but that might be only down to my ignorance).
ii) Whether they exist is unknowable.
I cannot even postulate that they do not exist. It is a binary yes/no situation.
If they are out there then it certainly exercises the mind in terms of deciding whether their gravitational influence on the rest of the universe. Gravitons would not be received but space-time curvature effects might still apply (give or take enormous dilution by inverse square law).
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