The quasar, according to the 'adsorption disk theory' is an extremely massive black hole that resides in the center of a galaxy and attracts and swallows all the gases that are near it
At the end of World War II, many radar systems were left in the hands of the superpowers. Instead of throwing these systems in the trash, astronomers were able to convert a significant portion of them into telescopes that pick up radio frequency radiation. Soon the researchers discovered that the universe is very active in the radio field - much more active, it turns out, than can be seen in visible light. In the early XNUMXs, a number of point but very strong sources of radio wave radiation were discovered. This radiation was constant and continuous, similar to the light emitted by the stars. This discovery raised a lot of questions for astronomers: stars, which are also point sources of radiation, do not normally emit such large amounts of radio radiation. The name given to these mysterious radio sources was 'quasar' - Quasi Stellar Radio Source, a quasi-stellar radio source.
Additional measurements conducted in the sixties found that quasars also emit radiation at other frequencies: visible light, X-ray radiation and infrared radiation. This discovery further complicated the researchers: ordinary stars do not emit their energy over such a wide range of frequencies across the spectrum. Each star has a certain type of radiation that suits it, usually according to the temperature of that star. The fact that quasars emit radiation over such a wide range of frequencies was very strange - it's as if they have no temperature at all, or are at all temperatures at the same time.
In 1963, an astronomer named Martin Schmidt sat down to write a scientific paper about a newly discovered quasar. This quasar, named 3C 273 (a catchy name, we must admit) was exceptionally bright. To make sure his paper would be accurate, Schmidt decided to check the measured fluorescence spectrum of 273 one more time, just to be sure. He did the necessary calculations, but for some reason he made a mistake in the calculation and got a wrong result. Schmidt was a bit nervous, and decided to abandon the previous calculation and try a completely different calculation. The new calculation also took into account the so-called 'redshift': the frequency change in the observed radiation as a result of the star's rapid motion. Much to Schmidt's surprise, his calculation indicated that quasar 273 was moving away from us at nearly one-fifth the speed of light. Such fast objects exist only at the edges of the known universe, i.e. very, very far from Earth. As in the case of the gamma ray burst, here too the meaning was that if 273 shines with a strong enough intensity that we can see it from the other end of the universe - it must emit an unimaginable amount of energy, a trillion times that of our sun. In fact, if we could get closer to 273, it would appear to us as bright in the sky as the Sun already 33 light years away. For comparison, the Earth is 8 light minutes from the Sun. An upset Schmidt left the room. In the corridor he met an academic colleague of his, and told him about his impossible discovery. The friend retrieved astronomical observations of another quasar, 3C 48, and the two performed the same calculation on it as well. The result was even more dramatic: 48 is moving away from us at 37 percent of the speed of light - that is, it is even farther than 273.
The other scientists did not agree to digest this information easily. It's not that they didn't believe that such distant objects existed - it was already a known and recognized fact. The problem was completely different. The most efficient mechanism for producing energy known to them was nuclear fusion, which converts 0.7 percent of matter into pure energy. This is enough to explain the energy emission of ordinary stars, but does not even come close to explaining the amounts of energy emitted by quasars - which, as I recall, emit this tremendous energy over a long period of time. This means that there is a new and unknown energy process in the universe, more efficient than nuclear fusion, and that was already hard for them to swallow. There have been scientists who have proposed alternative mechanisms for the quasars' energy: perhaps matter and antimatter merging and annihilating in a massive burst of energy, or perhaps a quasar is a so-called 'white hole': the other end of a black hole. None of these theories made much sense.
There was also another problem, no less serious. Some of the quasars exhibited variable luminosity - sometimes they shone brightly and sometimes less so. These changes occurred within a very short period of time, sometimes within minutes. This meant that a quasar could not be larger than our solar system, for example, because if it were larger it would not be able to change at such a speed: after all, the information about the change in luminosity from one end of the quasar to the other end cannot move faster than the speed of light.
The solution came only in the seventies, with the development of a completely new theory called the 'adsorption disk theory'. The quasar, according to this theory, is an extremely massive black hole - with a mass several million times greater than that of our sun - which resides in the center of a galaxy. The black hole attracts and swallows all the gases that are near it. As these gases approach the black hole, they arrange themselves in the form of a flat disk and begin to swirl around it. The particles move around the black hole at a tremendous speed, almost at the speed of light, and the collisions between them cause them to emit energy. The calculations show that this process is much more efficient in creating energy than nuclear fusion: up to ten percent of the matter becomes pure energy. This efficiency could explain the unfathomable amounts of energy emitted by quasars, which are unquestionably the brightest objects in the universe.
The accretion disk has since been accepted as a very stable and reliable theory that explains a wide range of astronomical phenomena, so it seems that the quasar puzzle has been solved quite satisfactorily. Also at the center of the Milky Way, our galaxy, there is a supermassive black hole. It may also have been a quasar at one point, until this black hole swallowed all the gas that was in its vicinity and then died - in other words, it ran out of fuel. This is why quasars are only discovered at the farthest reaches of the universe. Light takes billions of years to reach us from those distant galaxies, so we are actually watching events as they happened a long time ago - very close, relatively, to the big bang and the creation of the universe. Since then, the black holes have had enough to swallow all the matter near them. This is why we do not discover quasars close to us, in old, sleepy galaxies.
[The article is taken from the program Making history!', a podcast about science, technology and history].
More on the subject on the science website
30 תגובות
Thanks for the correspondence.
Can someone explain to me what is meant by the article that says that at some point the black holes in the center of the quasars "ran out of fuel" and stopped working? After all, black holes absorb mass due to the force of gravity, if the black hole in the center of the quasar is so powerful and has absorbed so much matter to it that it suddenly "stops working", it is expected that on the contrary, it will continue to suck everything around it, forever! I would appreciate it if someone could explain this point to me...
And more: so to conclude the quasar matter is a galaxy with a black hole in the middle?
For some reason this discussion wandered between several threads, so I will give two links (which if you want to understand in what context they were written - you should also read before them and in any case you should also read what was written after them):
https://www.hayadan.org.il/gama_ray_blust_0311098/#comment-254296
https://www.hayadan.org.il/rare-supernoba-dovi-poznanski-0610091/#comment-254343
Michael Rothschild:
Give the link of your words to the point. Thanks.
Eddie:
I don't get your point.
I have already said that the past is inaccessible and we don't even have absolute certainty that it existed.
After all, this uncertainty is relied upon by all those who claim that the world was created less than 6000 years ago, but, as mentioned, to the same extent and on the basis of the exact same logic, it could be that everything was created less than a second ago and yet we are talking about the past.
And the future?
The future even less exists because we have never been there.
In short - it is equally legitimate to talk about the distant future.
Since I am starting to repeat myself I will end the discussion at this point.
Michael Rothschild:
I did not find your discourse with a point.
In any case, as far as I understand, we are talking about the past that was in a certain existing 'place', - 'existing' in the sense that we had/have a connection of information from it to us. Therefore it is legitimate to talk about this 'past'.
Not so for a space that is beyond the observable universe.
To refine a little more:
Suppose you are on the last planet in the observable universe (say - 14 billion light years away). You 'look' around you - you see an observable universe 14 light years away, will you see the same universe that you would see if you viewed it from Earth?
Now - assuming that the universe as a whole has the geometry of a four-dimensional supersphere, not a universe with a three-dimensional flat space (and as many good people believe):
I think the answer is negative. The universe is finite and limitless. There is no directionality in this universe - there is no point that is superior to another, there is no point that is a 'center' and there is no point that is an 'edge'. The 'universe beyond' meaning that which lies beyond a radius of 14 billion light years, does not 'exist' with respect to any place in the observable universe.
Therefore, seemingly, it is easy to say that the space beyond will exist in the 'future' and can be seen as theoretical entities that we treat as mathematical entities, which are ontologically fictions.
But on the other hand, this simple statement seems strange: after all, we claim that the universe beyond will not appear out of nowhere in the future, but will only be revealed in the future, and it already 'exists', and has a past and a present that we are able to think about in our 'now' . It is not a purely computational fiction, but a reference to a space-time that has an ontological meaning in our 'now'.
According to this view, it is a different concept of space-time than the familiar one.
The result will vary to a varying extent if we assume that the geometry of the universe is not that of a four-dimensional supersphere, but rather - a 'saddle' geometry (and then there will be areas in the universe where the space will even be depicted as flat) or as a 'trumpet' (or a kind of 'funnel').
Eddie:
As I answered the point, if we treat it as non-existent it will be difficult to explain why we allow ourselves to talk about the past time and the space at this time as existing when they are even less accessible than the same space and time we are talking about here.
For my part, it is possible to see this space and time (of the past, of the future, and also of the very distant future) as theoretical entities that are necessary for us to present a complete picture and formulate predictions regarding the future. Like all the elements of the theory, the existence of these entities receives more and more confirmations as more time passes and we manage to verify some of their predictions and we do not manage to disprove any of them (and the future of 46 billion years will come one day and we just have to make sure we exist until then to watch it - a task that seems beyond our abilities - unless we invent a time machine that allows us to watch events without being harmed by them - although there will certainly be those who will claim that the machine is just showing us a movie that there is no certainty that it describes the true future).
Michael Rothschild,
The question is whether the second type of time (and in any case – of space) exists at all or is it justified to treat it as existing, or is it possible from a relativistic logic point of view (!) to even talk about it, 'before' it enters (or is included, as space) into the space of time inside our cone?
I'm also afraid that if we buy unitary legitimacy into everything that 'exists' outside the cone, we could easily end up with an infinite series of types of 'time' other than the 'normal' time contained in the cone.
I don't know if the phrase "over time" is appropriate.
In time space there are points that are outside our cone of influence (and at the same time - we are outside their cone of influence).
The restaurant at the edge of the universe is currently in this type of spot.
Michael Rothschild,
The arguments you brought about the orders of magnitude of the universe 'now' are very convincing.
But I am a little disturbed by the fact that two types of time are apparently obtained from this: normal 'time' (it is measured as approximately 14 billion light years, and is a function of transmitting a message at speed c) and what can perhaps be called 'on time' (which measures a state at a distance that exists in Now' of any kind, without receiving a signal about this situation).
What do you think?
Read here:
http://www.astro.ucla.edu/~wright/cosmology_faq.html#DN
the following explanation:
If the Universe is only 14 billion years old, how can we see objects that are now 47 billion light years away?
When talking about the distance of a moving object, we mean the spatial separation NOW, with the positions of both objects specified at the current time. In an expanding Universe this distance NOW is greater than the speed of light times the light travel time due to the increase of separations between objects as the Universe expands. This is not due to any change in the units of space and time, but just caused by things being farther apart now than they used to be.
What is the distance NOW to the most distant thing we can see? Let's take the age of the Universe to be 14 billion years. In that time light travels 14 billion light years, and some people stop here. But the distance has grown since the light traveled. The average time when the light was traveling was 7 billion years ago. For the critical density case, the scale factor for the Universe goes like the 2/3 power of the time since the Big Bang, so the Universe has grown by a factor of 22/3 = 1.59 since the midpoint of the light's trip. But the size of the Universe changes continuously, so we should divide the light's trip into short intervals. First take two intervals: 7 billion years at an average time 10.5 billion years after the Big Bang, which gives 7 billion light years that have grown by a factor of 1/(0.75)2/3 = 1.21, plus another 7 billion light years at an average time 3.5 billion years after the Big Bang, which has grown by a factor of 42/3 = 2.52. Thus with 1 interval we got 1.59*14 = 22.3 billion light years, while with two intervals we get 7*(1.21+2.52) = 26.1 billion light years. With 8192 intervals we get 41 billion light years. In the limit of very many time intervals we get 42 billion light years. With calculus this entire paragraph reduces to this.
Another way of seeing this is to consider a photon and a galaxy 42 billion light years away from us now, 14 billion years after the Big Bang. The distance of this photon satisfies D = 3ct. If we wait for 0.1 billion years, the Universe will grow by a factor of (14.1/14)2/3 = 1.0048, so the galaxy will be 1.0048*42 = 42.2 billion light years away. But the light will have traveled 0.1 billion light years further than the galaxy because it moves at the speed of light relative to the matter in its vicinity and will thus be at D = 42.3 billion light years, so D = 3ct is still satisfied.
If the Universe does not have the critical density then the distance is different, and for the low densities that are more likely the distance NOW to the most distant object we can see is bigger than 3 times the speed of light times the age of the Universe. The current best fit model which has an accelerating expansion gives a maximum distance we can see of 47 billion light years.
In this article:
http://www.space.com/scienceastronomy/mystery_monday_040524.html
Write:
All the pieces add up to 78 billion-light-years. The light has not traveled that far, but "the starting point of a photon reaching us today after traveling for 13.7 billion years is now 78 billion light-years away," Cornish said. That would be the radius of the universe, and twice that — 156 billion light-years — is the diameter. That's based on a view going 90 percent of the way back in time, so it might be slightly larger.
The same text also appears here:
http://www.msnbc.msn.com/id/5051818/
And here:
http://news.bbc.co.uk/2/hi/science/nature/3753115.stm
And if you read here:
http://en.wikipedia.org/wiki/Size_of_the_universe
Among other things, we find that:
The age of the Universe is about 13.7 billion years, but due to the expansion of space we are now observing objects that are now considerably farther away than a static 13.7 billion light-years distance. The edge of the observable universe is now located about 46.5 billion light-years away
This response and the two following it are extensions of the answer to Tzemach (copied from another discussion in which the subject came up again):
http://www.cbc.ca/health/story/2006/03/16/cosmos-expands060316.html
http://www.astronomycafe.net/qadir/ask/a11167.html
Are those black holes in the middle of the quasar the same size as the holes in the centers of the galaxies?
Why are there only once today quasars and today there are none? Is the universe calming down?
Are those black holes gone? They calmed down and today they are normal galaxies for everything?
The power of these phenomena is amazing. Truly the most destructive phenomenon there was.
N. Zemach
Usually - all the reports about the distance at which a certain object was observed in space talk about its distance at the moment when the light (or other radiation) coming from it came out.
In my opinion (although we claim otherwise) - this is also the case with the stars we observe.
Beyond knowing that this is the usual practice, I think so because reporting the current distance takes into account additional assumptions (some of which constitute an approximate answer to your other questions) but these assumptions are less tested.
One of the assumptions that must be taken into account in calculating the current position is the "escape" rate of the star from the moment the radiation went out towards us until it arrived here.
It is possible to do this but, as mentioned, it is based on our current assumptions (which may change) about the rate at which the stars move away throughout the period.
And what are our assumptions regarding this rate?
Various measurements and calculations showed that it actually increases as the star moves away!
That is to say - not only is there no sign of slowing down, but there is evidence of acceleration which is apparently due to the continued expansion of the universe!
It must be emphasized that we do not know anything for sure, but there is another reason to think that a collapse has not begun.
This reason is also based, of course, on certain assumptions, but if we accept the assumption that space itself is changing, then if it were to start collapsing we would feel a change in wavelength immediately because we would experience a Doppler effect in relation to the radiation that had already been emitted in the past and this effect would appear to be due to "our movement" We are in relation to it because of the contraction of space.
And another small addition - the cosmological red shift (Hubble's constant) is not really due to the movement of the galaxies but to the expansion of space itself.
You look up at the sky and see all the galaxies moving away from you at the same speed. If all the galaxies are moving away from you at the same speed, according to common sense it means that you are in the center and everything is running away from you. But even if you were in another galaxy, you would see as if all the galaxies were moving away from you and that you were in the center.
All this is due to the expansion of space that gives galaxies a redshift. Therefore, when you get a certain redshift, you can analyze it and understand how many "stretches" of space that photon went through and from that deduce the distance.
Besides the offset that results from the expansion of space, there are 2 other offsets: one is due to the actual movement of the galaxies, and the other is due to processes dealing with gravitational forces.
N. plant,
When you do the Doppler calculation, you are already calculating its current position, not its historical position at the moment of sending the photons. Therefore, when you receive signals from a galaxy that according to Doppler is 10 million light years away, it means that its current location (if it still exists) is 10 million light years away from you (even though the image of the galaxy that is received is an image from the past).
Yael and Michael, thank you for your answers.
But I still haven't received a full answer to my question. I know the Doppler phenomenon, and also the imaging for a reduced raisin cake.
But one of the most famous is that we are always reminded that when we look at a star or a galaxy, we are actually looking at the past. Right? I mean
If we look at a galaxy that is 100 million light years away, we see how it looked 100 million years ago. That is, 100 years ago
0 million years ago it was "there", the light it produced was like that and its speed was like that. The same goes for the recent news that Hubble picked up a galaxy located at a distance of 13 billion AU. That means 13 billion years ago it was "there".
My question is where is that galaxy "today"? Why is there never any reference to the "today" fate of very distant galaxies that are written about from time to time?
Is there even a possibility to calculate their distance in real time from us?
And another question. If 10 million years ago (or two billion years ago)
The universe began to collapse back (oh my...), how can we know
Not so if the galaxy is closest to us
2 million years away?
She was moving away from us at speed X and the intensity of the light she produced was Z, but if half a billion years ago she "changed" her mind and started "returning" how would we know this?
In short, what I claim about this point is that we are absolutely not
"Up-to-date" about the behaviors of distant galaxies and what their situation is today.
What is wrong with the assumptions I made?
Fascination.
And on a completely different topic:
I ignored one response.
Second - I ignored it again.
But the third time is too much:
What part of the article did I miss, from which it is implied that we are in danger?
N. Zemach:
Even though you are not a scientist - your interpretation seems correct to me.
Your conclusions are not inconsistent with the age of the universe.
Since the expansion of the universe at the time of inflation was faster than the speed of light - it is no wonder that today there are parts of it that are separated from each other by such a great distance that light could not pass during the entire existence of the universe until now.
IMA CHARGING MAH LAZOR
IMA FIRING MAH LAZOR
N. plant,
Astronomers determine the distance of a galaxy from us using its redshift. According to Doppler's law, if you move quickly from an object you will see it redshifted (shifted along a longer wavelength), this is because the light is stretched because the same wave has to travel a greater distance. On the same principle, when you move towards some body you will see it shifted to blue, which is a shorter wavelength.
All the galaxies in the universe are moving away from all the other galaxies as the universe continues to expand, and the space between the galaxies is also expanding. This spread looks uniform from every vantage point and in every direction.
The distance from here to some galaxy is calculated by its redshift divided by the Hubble constant.
It's a bit confusing because the speed of the galaxy's own movement in space (the movement that is not due to the expansion of the universe) is also inferred based on redshift and blueshift.
If so, it is the red shift that results from the expansion of the universe that determines the distance between us and the galaxy today and not as it used to be. And when we conclude about the actual movement of the galaxy in space, which looks like a mass of different deviations of different parts within the galaxy itself, then it is a movement that it had a long time ago when the photons came out.
A very "questionable" question: it is noted in the article that the Koisar C 3-48 is moving away from us
at a speed of about a third of the speed of light, and because only the galaxies that are
Farthest from us, moving at such a speed, it can be assumed that the aforementioned quasar is at a distance of about 10 billion light years and more than us. Right?
If so, my question, which is never referred to when it comes to bodies that are at the ends of the visible universe, is this: this quasar was "there",
In the place where it is seen today, about 10 billion years ago. Where is "today"??? If he moves away from us at a speed of about 100 thousand km
in a second?
The answer I give myself is that he is at least 3 or more away
A billion light years away.
Would it be correct to say that all the galaxies at the edge of the visible universe (today it is about 13 billion light years), are "today" actually much further away?
How much further? Assuming that the universe didn't start collapsing at some point, and the calculations show that those galaxies are much further away today, maybe
16-18 billion light years How does this fit with the current estimate that the universe is about 13-14 billion years old?
I am not a scientist and I would be happy to hear intelligent answers from the knowledgeable people of this interesting site.
So are we in danger????
Dawn
The intensity decreases as the square of the distance, if the distance increases by 2168100 times, the intensity (energy) should have decreased by the square of this number, about 4 trillion
Something doesn't make sense to me in the numbers of the coffins.
You noted that the quasar's energy returned so much that if we stood at a distance of 33 light years it would actually be equivalent to the amount of energy we receive from the sun, which we are only 8 minutes light from. But if you calculate the ratio, you find that the energy is greater in a ratio of 2,168,100:1 and not "a trillion times that of our sun" as written.
So are we in danger?:S
If you are already building a melting pot, I wonder if it is possible to imitate
(at least experimentally) the mechanism of the quasar
to create energy.
Anyway, great article.
Excellent article for the general public 🙂
To think that there are black holes walking around outside and we feel protected in our homes.
It's all an illusion.