This ancient quasar may be the remains of the first-gen star that started us all Scientists taking a look at the second-most distant observed quasar believe it's actually the remnants of one of the universe's earliest stars – the so-called Population III stars that seeded the early universe with material that eventually formed life. Working with the National Science Foundation's Gemini North Telescope in …
"Why do they do things backwards here ?"
Because you are looking at an old issue from a modern, orthogonal perspective.
When this particular classification system was invented, there were only two "populations". All we really knew was that one population was yellower, and closer to the galactic center, and the other bluer and tended to live in globular clusters. Seeing as we live near a yellower one, obviously that was the most important (or so the thinking of the time went), so that group became Pop. I, leaving Pop. II for the other ones. It wasn't until later that we postulated the Pop. III group.
If Astronomers ever learn to count properly, they may rename it Pop. 0 ...
"Why do they do things backwards here ?"
Because you are looking at an old issue from a modern, orthogonal perspective.
The Star Wars movies had the same problem. The original parts 1, 2 and 3 later became parts 4, 5 and 6 when they made the first three "prequels", and since then the numbering may have to be revised again as more of them are made going further and further back into the "history".
It was known as "Episode IV" (not episode 4!) before it was even released. Seems Lucas had been thinking about it for a long, long time. He had the plots in mind, but not the technology for the effects he wanted. I remember talking about with my friends it while standing in line for the first showing at the Century 21 theater across from the Winchester Mystery House ... Lucas had hyped the movie at the Varsity Theater in Palo Alto, during a showing[0] of The Andromeda Strain and THX 1138 a weekend or two before the Star Wars release. Not that he needed to.
I was much more of a nerd back then than I am now ...
[0] Midnight double feature, no less :-)
It was called just "Star Wars" - all the contemporary posters called it that, the magazine articles, TV reviews etc. The UK ones as well as the US imports and "from our Hollywood correspondent".
The on-screen text crawl at the beginning described it, as it still does, as "Episode IV", titled "A New Hope", before giving what is basically a "previously on the mind of Mr Lucas" recap of the story so far. Which gave it the feel of one of the old serialised story shows and the sense that there was a great big galaxy we were about to jump into.
From interviews and articles at the time, Star Wars was meant to stand alone as a single film, with a happy ending (except for Chewie being left out of the medals).
Then it all became a tad more successful than anyone really expected, definitely more than the studio did, and a sequel came about. But still without a clear plan - Leia kissing Luke was just a bit cheeky at that point (and for those of us who'd read the officially-sanctioned tie-in novel "Splinter of the Mind's Eye" surprisingly restrained - had they gone off each other?) - other than that there were going to be two sequels. So we get an unresolved story, far more than just a simple sequel hook.
By the time "Return of the Jedi" came out - and you could go to an all-day triple play, still starting with just plain old "Star Wars", Lucasian interviews were including the "I think of it as three trilogies" blurb and the comment that Vader and Kenobi had last met in a fight on a volcano (which I recall at the time was taken with a pinch of salt, another call back to the worst excesses of the old swashbuckling fantasy stories, fisticuffs on the crater's edge).
Even for the 20th Anniversary CGI-fest special edition releases, the posters still called the first film just "Star Wars". It was only with the release of the prequels, 1999 onwards, that the retcon rot really started to set in and saying "Episode IV" or "A New Hope" was heard outside of the pretentious set: "Phantom Menace" was very explicitly referred to as "Episode I" on the posters and advertising.
Next week:
In episode eleven of "When Nerds Collide" we will be explaining away the discrepancies in the Y-wing fighter/bombers; good night.
Actually the Sun is a Population I star together the white-bluish ones, because all are younger stars (and thereby more "metallic"), why Population II stars are older and thereby mostly reddish.
Stars in globular clusters are also old, and reddish too - it's open clusters that have younger, bluish stars.
Back then it was just the discovery there were different "types" of stars, the reason why was only discovered later.
Indeed.
To say nothing of the Sex Pistols, the Clash and the Vibrators as the first wave of Punk. They weren't. They were part of the second wave (some would say third). That is not to bad-mouth the doors they opened. I have many, many happy memories of the British music scene from that era :-)
So just H, He, an Li to start off with? But that time when the neutron stars crashed into each other something like 3x Earth masses of gold was vomited out of the confusion. How come this postulated Big Bang couldn't produce all types of elements? It's still just masses of subatomic particles leaving the scene at great speed.
A very *small* amount of Li (in fact the percentage of Li is a sensitive indicator to the conditions during the Big Bang. Nothing heavier was created because there simply was not enough time before the initial universal fusion reaction shut down due to the pressure dropping (as a consequence of the universe expanding).
All these early universe observations fascinate me. But also confuse me.
They always say that we can see back in time because it's taken x billion years for the light to get here. But we're here so how did we get here x Billion years before that light?
They never explain that bit- and it's strange.
The Universe has expanded. So "here" and "there" were in two different (much closer together) places back then. The expanding universe has moved "here" to where it is now, and all the photons from "there" are now hitting us. And the photons are red-shifted (stretched) by the expansion.
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Well assuming your not joking.
By definition, if you can see something, then the light you are seeing has reached you. Things will appear as if they did when they emitted the light. That is, as far as your concerned, some time in the past, as the light has taken time to reach your eyes, as light travels at a speed, it is not instantaneous. The longer the light took to reach your eyes, the further back in time they will seem.
Since it takes time for light to reach your eyes from an object, then that equates to some distance, as light propagate at a speed. Objects further away will be appear as they did before objects that are closer, as it has taken longer for the light to reach your eyes.
Light travels at a sort of set speed. So, given a few assumptions you can take a guess at how long in the past the light started its journey to your eyes, and therefore how far away an object might be. It's almost as if there is a close relationship between space and time, with the speed of light as a determinant.
So how did you get in front of the light? You didn't. You are always here and the object is always there. When the light left the object, your relationship to it meant that a finite time would pass before the light would reach your eyes. Indeed, light leaving you would also take the same finite time to reach back to the object. When the light left the object you were older by the same amount of time that the light takes to propagate to you. From your perspective anyway, others may have differing opinions.
Now, I guess you thinking something along the lines of, well I didn't exist x billions of years ago. Well that doesn't matter. The bit of space time that you occupy now did. It's relationship to the object then was such that it has taken x billion years for light to propagate from the object to your eyes which just happen to occupy it in your now.
That's one way of thinking about it anyway.
Well put, and if we add this;
Expansion includes both 'in'1 and 'of'2 the space that's between any two points. (Don't expect to get your head around all of this properly until after a lot of thinking time. I find alcohol helps after a while).
1 Things moving apart (us perceiving object 'x' where it 'was' not 'is')
2 The space between things moving apart is also expanding, this is cumulative with time and distance, so there's no upper limit to the relative expansion rate between two points in space-time (they're really really not fixed points). nothing can travel faster than light.
"nothing can travel faster than light" With the possible exception of bad news, which obeys its own special laws. The Hingefreel people of Arkintoofle Minor did try to build spaceships that were powered by bad news but they didn't work particularly well and were so extremely unwelcome whenever they arrived anywhere that there wasn't really any point in being there...
as light travels at a speed, it is not instantaneous
This often hurts my head. From the light's point of view, is it not instantaneous? Doesn't distance shrink to zero at the speed of light? And so doesn't a photon know its destination when it starts its journey? (i.e. you can't intercept a photon) So how did that photon from the past know I was here?
Gentle answers please.
A photon's motion is predictable at macro scale, if it wasn't then we couldn't make lenses.
If you were to assume its motions are oscillatory motions, then all those little motions at tiny 'quantum' scale must add up to that motion at macro scale. Then it must also be well defined at 'quantum' scale too.
Those oscillatory motions are not its wavelength or polarization or circular polarization, they are the components of its motion. Look at the apparent wavelength for example, that depends on the motion of the observer. Two observers, one moving towards and one moving away from a reference point can perceive the photon as red or blue. The photon is not a 'red photon' nor a 'blue photon' it is only red relative to a given observer, and blue relative to another.
i.e. the Schroedinger mistake, you are not setting the properties of a photon by observing it, you are selection which observer you measure NET properties relative to. Select one observer, and the photon is red, select the other and it is blue. It is neither red nor blue, these are NET properties of the observer and observed photon.
So our observers must have an oscillatory component in the axis of motion of the photon for red/blue shift to work, which must also be predictable and repeatable, and since they are not in motion, their patterns must repeat, overall cancelling out. i.e. observers are also oscillating motions, also predictable, in the case of matter it must cancel out to be stationary.
And by extension to other net oscillatory motions. It's polarization is also a net property.
And by extension the speed of light is relative to an observer. A 3 axis NET waddle that defines space. But its a motion relative to the observers field. So not a constant, only an apparent constant relative to a given observer.
And since each observes a different motion, so each observes a different instantaneous location. i.e. superposition.
The above is not accepted physics (well its partly accepted in String Theory).
The issue there is the FASTER THAN LIGHT expansion of space (aka inflation theory) affects the matter of the star but not the light of the star. The light travels at some fixed speed in that theory, and the matter making up the star expands with space FASTER THAN LIGHT.
But it would have to affect both matter+light, if it didn't the star would leave behind its light (and all similar energy) , effectively it would snuff itself out. Leaving the energy it needs for fushion behind as the star is moved due to expansion. And the light would be stretched/smeared out so it could only ever be viewed in one direction only.
i.e. inflation theory requires a suspension of disbelief.
"It's almost as if there is a close relationship between space and time, with the speed of light as a determinant"
Flip that over for a second, you measure the speed of light by comparing it against the scale of matter. 'Space' to you is the scale of matter. If space was uneven in 3 axis, then matter would have a different scale in 3 axis and the measurement of the speed of light, against that matter, would be uneven in 3 axis.
So what you're actually saying is that the size/scale of matter is related to the speed of light.
You could assume that our location is special and space is even in all directions here.... I would say, there's nothing special about us or our location, or our universe.
So then speed of light is no longer a constant, it simply is affected the same way matter is affected. Leading to the apparent constant when you compare one against the other.
Not quite. Over the lifetime of stars (diameter measured in light seconds or minutes), expansion of the space it occupies would only increase it's actual* size by a very small amount. The FTL aspect of expansion requires a distance of many billions of light years between two points to manifest and at this distance you will indeed see nothing beyond it.
Simple analogy, you have a cluster of partially inflated balloons (space) each with a marker point on the surface (star). They all then simultaneously inflate at a steady rate, the rate of change in the distance between any two markers will be relative to the distance between them because the steady rate of expansion is cumulative over distance. The marker points would also be slightly larger due to expansion.
* to measure the before & after actual size would require a fixed reference distance outside of space-time.
Since the entire universe came into existence at the same time, "here" and "over there" have always been "here" and "over there". The position within the (probably infinite) universe for either position hasn't changed since the big bang. Just the distance between the two points as measured by the time required for a photon traveling near the maximum velocity of a photon in vacuum to get from "over there" to "here"
Because of the expanding universe "over there" has been getting further and further away (or we've been getting further and further away from "over there", or both have been moving away from a point in between depending on reference frame as everything is moving away from everything else at the same time.
I am waiting for one of the tabloid paper to call this object the Genesis Star.
Anyway, in astronomy, any element other than hydrogen or helium is regarded as a 'metal' (yes, I know it's a bit bonkers) so a low metallicity star is likely to be an older generation star and younger generation star is likely to be a higher metallicity star.
The first stars in the universe were huge monsters that blew themselves up after a few million years so creating heavier elements* and so the cycle continued.
*It appears that there were small traces of lithium and beryllium created at the start of universe in the Big Bang.
That Pop III stars were far far larger than any we observe now (and there are some stars in the hundreds of solar masses range out there, though few in number since they live such short lives)
There was speculation they would be 10,000 solar masses at a minimum, with lifetimes of less than a million years, because the density of matter in the universe was so much higher then - due to the much smaller size of the universe.
Hadn't seen those before, that's an interesting possibility to explain where quasars came from. It would seem their size would have no practical limit, so long as increasing amounts of fresh hydrogen and helium are drawn in by the increasing gravity to generate an increasing outward pressure to balance the increasing gravity. In a galaxy consisting of many of those quasi-stars born in the densest center regions, eventually they will no longer be able to collect increasing amounts of material, as it has been drawn in by another nearby quasi-star. Gravity wins, and leaves behind a 10k or 100k solar mass black hole.
It has long been a mystery how we observe truly monstrous billion plus solar mass black holes when the universe was less than a billion years old, since the radiative pressure can't support that much growth in such a "short" amount of time. But a galaxy with Pop III 'quasi-stars' born in the dense center regions might create thousands and thousands of 10k or 100k solar mass black holes at their centers that over millions of years eventually merge.
Improved gravitional wave detection capability, like LISA should provide, may allow us to see those mergers if that was happening...
The question would be what happens to the 10k solar mass black holes created in less dense outer regions in fewer numbers that are too far away to merge with the supermassive central black hole? Does the big black hole eventually eject them out of the galaxy, or are they pulled in? What happens to them in a galactic merger? i.e. shouldn't we see evidence of at least one in our galaxy? (though our galaxy may have had a rough history, as it seems we may have lost our original supermassive black hole at some point given how puny ours is)
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