 and also ejects hot gas (<em>blue streams</em>) back into intergalactic space. The galaxy ends up with only a small fraction of the raw material.
The author and his colleagues generated this image using a state-of-the-art cosmological simulation code.)
In the throes of formation, a galaxy like our Milky Way pulls in dense, cold gas (red streams) and also ejects hot gas (blue streams) back into intergalactic space. The galaxy ends up with only a small fraction of the raw material.
The author and his colleagues generated this image using a state-of-the-art cosmological simulation code.
Image: Graphic by James E. Geach and Rob Crain
In Brief
- Forget dark matter: even the supposedly normal matter of the universe is mysterious enough. Why does only a small fraction of it reside in galaxies? Where did the rest go?
- The current best guess is that the bulk of the normal matter is trapped in giant gaseous filaments. This so-called warm-hot intergalactic medium, or WHIM, is hard to detect directly.
- Galaxy formation is evidently rather inefficient. As material falls into a galaxy, the galaxy tends to shoot much of it straight back out again—a process known as feedback.
- The atoms in your body have probably been cycled through intergalactic space. Indeed, galaxies and their contents are not fixed structures but the bright tips of a wider sea of gas.
I have always been startled and fascinated by the sandlike abundance of galaxies sprinkled across the night sky. The most sensitive optical image ever made by human beings, the Hubble Ultra Deep Field, captures some 10,000 galaxies in an area about 1/100th the size of the full moon. Scaled up to the whole sky, such a density implies a total of 200 billion or so galaxies. And those are just the most luminous ones; the true number is probably much larger.
How did all those galaxies come to be? This question inspired me to become an astronomer and has been the focus of my research career. Over the years my naive way of looking at galaxies has changed. To judge by their sheer numbers, nature appears to be quite good at producing galaxies. Not so. If you add up all the visible matter in galaxies today, you get only about a tenth of the total endowment created by the big bang. Where is the rest, and why did it not end up in galaxies? These are two of the biggest puzzles in astronomy today.
This article was originally published with the title The Lost Galaxies.
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17 Comments
Add CommentThe gravity calculations should take into account the presence of dark matter both at the galactic centre. There is an apparent rise of the efects of gravity which produce the effect of dark matter at the galactic centre.
Reply | Report Abuse | Link to this1] Advances in black hole gravitational physics and cold dark matter modelling. The Open Access Astronomy Journal 4: 6-13 (2011).
Or copy and paste the link
http://www.benthamscience.com/open/toaaj/openaccess2.htm
and go to volume 4.
Is there an error in the article . On the opening page J.E. Geach states "the observable universe contains 200 billion galaxies". On page 49 Geach states " When we add up all the baryons we can see in galaxies, clusters and elsewhere in intergalactic space, they account for roughly HALF THE TOTAL , leaving the equivalent of at least 500 BILLION galaxieswaiting to be found"
Reply | Report Abuse | Link to thisClarification of 200/500 ?
Jaded JJ
Beautifull animations, you can almost feel it happening.
Reply | Report Abuse | Link to thisI was just thinking a little bit :
1. suppose that the baryonic particles (4% of our universe), had a quite different origin as the so called Dark Matter (matter that we cannot experience).
2. At the Origin "planck time after zero" the basis for the baryonic particles emerge from the dimension before the Planck time (because there we are no longer in the causal deterministic universe), inflation does not exist in our time flow but in the non causal universe before 10^-43sec.
3. At that "time" black matter and dark energy are already "existing" (so before what people call today the Big Bang), they have their own origin long before time zero.
4. this could account for the extra inflation that our universe is experiencing 6 billion years ago, because the so called dark matter has his own evolution.
5. The standard model of cosmology indicates that galaxies which have a red-shift of 1,5, this means that their wavelength of light equals 150% of the one we measure in the laboratory, they move away from us at the speed of light.
Right now we know about 10.000 galaxies with a red-shift greater as 1,5. this objects are moving away from us with a recession speed faster as the speed of light.
6. The cosmic background radiation has covered a much longer road, its cosmological red shift is about 1100 !!!. So when the hot plasma that radiated the waves that we observe today, it is probable that we move away from it at a speed of 50 times the speed of light.
7. The emitted photon 380.000 years ago has his local speed of light, so it looses distance compared with its origin (like someone trying to go up on a fast moving down staircase ) her we meet the Hubble Constant .
The Hubble constant right now is 70Km/sec/Mpc (one Mpc=3.262.000light years). In this view also the speed of light is variable and without its limit as indicated by Einstein and it also means that :
THE UNIVERSE IS OLDER AS WE THINK. which is in accordance with the idea that I posed above.
keep on thinking
Wilhelmus
(wilhelmus.d@orange.fr)
Hi everybody,
Reply | Report Abuse | Link to thisI thought it over this night and I want to add :
1. Dark matter and energy need not to have a different beginning as the baryonic material, they can begin at the same moment (but it is not neceverry).
2. If their emergence is at about the same moment (in our 4-d causal deterministic universe) then also the what they call "dark energy", is present at the same time and the origin of the so called "inflation".
3. Dark matter and energy can have a diffrent geometry, not a euclidian but a spherical, so that after for example 8 billion yeras the dark matter is going to rebond on itself, and therefore the origin of the extra inflation thet we observed by now, so our baryonic material has a hyperbolic geometry and the two curves meet each other , before the crosspoint there is the normal inflation and after that it becomes greater...
keep on thinking
Wilhelmus
Hm. I guess I've always considered a big fraction of the mass from the Big Bang to have been converted to energy, and expended in the expansion of the remaining mass. I have zero numbers on this tho. Just seemed to be the way nature works.
Reply | Report Abuse | Link to this
Reply | Report Abuse | Link to thisIf you take the volume of an average individual galaxy (including its dark matter halo) and multiply that volume by 200 billion, you get the volume of the U composed of galaxies.
If you compare that value with the total volume of the observable universe, you discover unambiguously that the galaxies are crammed together with not a lot of wiggle room. As Hoyle or Burbridge put it; "the galaxies are cheek-to-jowl".
That is why there is so much mergering going on, relative to galactic time scales.
So, why are there not more galaxies? Because there would be little room to squeeze them in.
Dark matter = stellar-mass "primordial" black holes, which are very, very hard to detect electromagnetically, but give away their presence gravitationally.
Robert L. Oldershaw
http:/www3.amherst.edu/~rloldershaw
Discrete Scale Relativity; Fractal Cosmology
I'd have to guess that we can only observe a small fraction of all galaxies.
Reply | Report Abuse | Link to thisIf it's assumed that galaxy formation began in a simple, radially expanding spherical universe, perhaps the only galaxies we can observe are those that are or once were near our own relative position.
Many other galaxies could have developed in that early spherical universe that have been receding away from us just as fast as we have been receding away from them for all this time. By the time their light might reach us it could be so disperse that it could never be detected.
In this case, we might simply only be capable of observing an ever diminishing sliver of the ever expanding universe of galaxies.
This may or may not precisely describe the conditions of our developing universe, but there are likely many possible conditions that could severely restrict our ability to observe the entire universe. I wouldn't presume to be able to know how many galaxies there are.
We are looking into the past by means of our technique.
Reply | Report Abuse | Link to thisSo as a matter of fact from the point of 380.000 years after the "ORIGIN" we can go forward in our history, this means that we cannot loose any masses, if so ...
yes if so ... our baryonic material could be changed in ...dark matter, changing could mean being transferred to a "FAMILY" Universe so NO paralel Universe please.
This is a thought a "WHAT IF" that I don't like very much because I also fall into the trap of the scientific thought that all material is like our byrionic matter, so we have to explain everyting like we could explain 4% of our vieuable universe, soif you like it take it.
What I mean to say is that you can TRY to explain everything in a the way that it is favorable of the theory you prefer.
Personnally I prefer MOND.
keep on thinking
Wilhelmus
Sorry for Byrionic it should be BARYONIC.
Reply | Report Abuse | Link to thisThe problem you pose is really a matter of perspective, isn't it? The sample you refer to and the implication that arises from the limits of the sample are only a part of a larger picture. You said as much yourself. I suggest the greater part you say is 'missing' remains in the areas beyond the reach of human technology. Your real question may be about the limits of human perception. The articulation of science takes the shape and limitation of its tools.
Reply | Report Abuse | Link to thisYes Didonai (why not Adonai?), we are all humans with our five (six?) senses, our limitations are here, they are personnel, but all together (joining them in for example the net) perhaps our consciousness as a whole can be more, and 1+1 can be 3. Human "technology" will proceed, so our senses, but never we will araive at a so called theory of everything that is described in words or formula's because everything is different, and this last sentence "everything is different" is the maximal TOE we will have.
Reply | Report Abuse | Link to thiskeep on thinking
Wilhelmus
The last time I checked, science had identified 23 discrete senses. Perhaps if we keep up to date our limitations of perception may not be so severe. I really don't care how many galaxies there are or how big space is. Until we can get off of our mudball in a meaningful way it doesn't really matter much.
Reply | Report Abuse | Link to thisEach night that you have dreams you get of the mudball, the same when your phantasy brings you new thoughts , our mud ball perception may be limited, but our consciousness is not imprisoned in 4 dimensions and 5(6) senses, it is faster then light, which all together is hopefull.
Reply | Report Abuse | Link to thisWilhelmus
I suspect that the fraction of the universe that we can observe diminishes in time, with the expansion of spacetime.
Reply | Report Abuse | Link to thisFor example, light emitted in the in the necessarily smaller earlier universe may reach us today regardless of its relative location within the universe at the moment of light emission.
However, light emitted 1 billion years ago from an object that is now more than 1 billion light years away cannot have yet been detected; if it is more that 2 billion light years away we may never detect it.
These examples apply to any emission source, but can best be understood for the intense light emissions from supernova that can be observed for only a few days. Those gamma ray bursts from the early universe could have been anywhere in the universe. There may be a yet undetected GRBs that are only a million light years away...
The vast majority of the universe has been unobservable for billions of years - the fraction of the universe that is observable is diminishing every day.
Hi Jim,
Reply | Report Abuse | Link to thisOf course we are all just observing the past , we will never be able to observe the what we call "actual" state of the objects , you don't have to go away 1 billion lightyears, this is already true for ven the moment that you are reading this post.
For the limit of our observations we are bound to the Hubble radius, each moment indeed objects are leaving this radius, and with the accelaration of cosmic inflation, the for us observable univesre is becoming more and more empty, it is the apocalyps of knowledge.
Wilhelmus.d@orange.fr
"Dark Backward And Abysm"
Reply | Report Abuse | Link to this-- James Ph. Kotsybar
We can see fourteen billion light years out.
For those still here a million years from now,
more light will have traveled to them, no doubt,
the million light years that space will allow.
Distant descendants may not see much more,
however, than what we can now observe.
Despite larger radius to explore,
their view won’t be a sight they can conserve,
because space itself goes faster than light,
as it expands relatively through time.
This perspective's loss is ever the plight
throughout our universe's known lifetime.
We daily lose ability to see
the things furthest back in our history.
STICK THEORY
Reply | Report Abuse | Link to this-- James Ph. Kotsybar
If God wanted us to know everything,
the universe would have stopped expanding,
or, at least,
its speed should be lessening,
allowing us to gain understanding.
If we are limited to speed of light,
while God stretches the fabric far faster,
then as long as we’re here,
try as we might,
we’ve got a horizon –
past, it’s vaster.
We’ll never reach the end of what we see,
so how can we accurately surmise
God’s unlimited creativity?
We can’t ever grasp
the whole enterprise.
We follow carrots of conjecturing,
beyond our “branes,”
attached to superstring.