Nitpick. The Bing Bang started in 1928 when as one of the Rhythm Boys he and the Paul Whiteman Orchestra had his first number one hit, a jazzy version of “Ol’ Man River”.
If the known universe were to be printed on a A5 sized page planet earth would be the size of less than a photon. Within that photon grow infitisimally small earthlings who have not even moved out out of that photon to the next photon.
They are speculating on what the whole A5 page is about. Therein lies the problem for me.
What is the problem with that exactly?
They are very clear that it all relies on a fundamental postulate that the universe is essentially the same everywhere you look. Everything else follows from that. If it were to turn out that the universe was not the same everywhere then we would have to revise things. For now there has been no evidence to suggest that this postulate is wrong though.
The limits of our ability to test the circumstances of the Big Bang, both in terms of space and time, are well-known and in fact have already been covered fairly thoroughly in this thread. But we do know quite a lot despite those limitations, so dismissing the current working model as “speculation” is not particularly accurate.
On a lighter note, your comment reminded me of this.
While you got off on the wrong foot (or worse) with your earlier posts, this observation does bring up something I agree is quite amazing: that one species of animal on one little planet in one ordinary galaxy has managed to learn SO MUCH about such a a HUGE portion of the universe – and quite a bit about the universe overall – without physically traveling more than a tiny distance. Humans themselves have only gone a piddling 300,000 miles out, and their machines only a couple of billion miles out…like you say, a tiny step in a giant universe. And yet we know so much quite directly (how great to be alive during the First Age of Exoplanet Discovery!), and a whole lot more through ingenious observations and experiments.
It’s rather as if Columbus had mapped the entire Western Hemisphere – some of it in detail, other parts of it rather fuzzily – while merely sailing across the Guadaquivir River in Seville, Spain.
Imagine few ants in a vast carpeted room. They work out that most of the carpet threads are equidistant from each other and have the same rise in pile. They call them laws. They also work it out that they are the same colour and viola they know a lot about the carpet. They are well chuffed that they know their world.
Its an office block, with computers in the other room and elevators, wifi, coffee machines etc etc.
You get the drift?
Yes. The drift is that you still don’t seem to understand how science works. Quite a lot of it is counterintuitive. Quite a lot of it involves some fiendishly complicated mathematics. A surprising amount doesn’t require direct and immediate observation, as noted in the post immediately above yours
We may be ants in the carpet but we can calculate which building floor we’re on by measuring air pressure. We can detect Wifi signals and air currents and the hum of the lights and the smell of the coffee and a thousand, thousand other things and begin to build a model of the universe we live in. And then we test that model by more observations and detections and mathematical extrapolations, and we adjust it and add to it and get rid of bits that don’t match the evidence, and little by little we learn more and more.
No one is remotely saying that we understand even a fraction of what’s out there. But to say that we can only understand what’s under our feet is to ignore the vast amount we already know, and can hope to know.
The other point to our understanding and modelling of the universe is parsimony. We do not add complication where none is needed.
It isn’t just that we assume that the universe we see is the same as the universe further away. We assume that the rest of the universe obeys the same laws as our corner does. So all the physical laws as we understand them should continue to apply. Your ants in the carpet can work out how all the stuff they can observe works to a fine understanding. Gravity, chemistry, atomic physics, and so on. They posit that the rest of the universe works the same way. Those unseen coffee machines, elevators and computers still obey those same laws. There is no new law of gravity in the office next door, chemistry still works the same in the coffee machine, quantum electrodynamics still operates those computers. When we see the furthest reaches of the universe we can mange, we see a universe that has the same laws as here. Not just much the same, but as well as we can tell, exactly the same. And we see absolutely no variation across the entire observable universe in these laws. Further, everything we can see needs no alteration of those laws. They are consonant with what we see, and they predict new things that we go on to find as actually so.
Adding new complications to those laws with no evidence that they are needed is psuedo-science. Worse, it starts to make a case that our corner of the universe is in some way special.
Excellently put, Francis Vaughan. That post is a keeper.
Yes, that you’re not very good at analogies.
The evidence speaks for itself. You are free to propose a different interpretation of that evidence, or look for new evidence that invalidates existing theories. Dismissing an entire world view because you refuse to look up from the carpet doesn’t win many points.
Saying that “we *assume *that the rest of the universe obeys the same laws” is an overstatement. We may be limited to occupying a tiny fraction of the universe, but we can see things that are quite far away. Observations of those objects can verify that the speed of light is more or less the same in distant galaxies. Observations of spectral lines can show that chemistry works more or less the same in distant galaxies.
These “assumptions” about the homogeneity of the universe have in fact been actively tested.
It may actually be true that beyond the observable universe physical laws are different. But we can see really far into the universe, and it seems that as far was we can see the physical law is the same everywhere. So what would make it different farther away than we can see? Maybe it is, but we have no reason to think it would be, why are we in an isotropic region of the universe and just outside that region there’s a region we can’t see and can never interact with that has different physical laws? Why is the basis of that change?
I mean, maybe if the universe is infinite physical laws do vary, they just vary so slightly that we’re unable to detect the difference in the 40 billion light year sphere of the observable universe. But even if that is the case, it doesn’t seem to matter because we could never interact with those parts of the universe that are so distant they are no longer causally connected to our part of the universe. So it is parsimonious to just say that physical law is the same throughout the universe, even though we will never know for sure. If we just mean “the observable universe” when we say “universe” then we’re on pretty firm ground to say that physical law is the same everywhere.
And the difference between us and the ants on the carpet is that we really can observe things billions of light years away. If we lived in an ocean on a planet like Europa where there was an thick opaque ice layer over us, we’d know a lot less about the universe. But even that ice layer isn’t opaque to all forms of electromagnetic radiation, and we wouldn’t have evolved sense organs to detect what earth humans call “visible light” because that ocean would be pitch black. But we would know there was a roof…and burrowing through the ice of the roof would be the equivalent of Columbus’s voyage for that species.
In a way, we do live on such a planet. On the surface of the Earth it really seems like there is a law of physics, “everything gets pulled down”. And it really seems like the sun is a fundamentally different type of object than the stars, and that the planets are very similar to stars, and the the moon is like nothing else in the universe.
Through careful observation we have determined that none of these are actual universal truths, but only features of our limited vantage point. If there were different laws of physics in different (observable) parts of the universe, we could certainly determine that just as well.
Right, it took us centuries to figure out some simple fundamental laws of physics, because in a 1 gee field with air around it seems like it takes work to make things keep moving. I throw the ball, and it moves, and then it hits the ground and stops moving. So it must take work to make things keep moving, and if you don’t keep adding work they come to a stop. Totally wrong idea that most people can’t help but believe.
And it is possible that there’s some other portion of the Universe, off in some other office, where the carpet is a different color and has a different pile. We can’t rule that out. But if you had two of those ants, and one said “I’ve never seen the carpet over there, but I know it’s maroon instead of beige, and has a pile depth of three millimeters instead of five”, and another ant said “The carpet over that way is probably about the same as the carpet here”, which of those two ants would you believe?
You sound like my sister. She seems to think that scientists think they know literally everything and she imagines them as bespectacled dogs paddling in an ocean of smug superiority while sniffing each other’s bums. She is thus very eager to deflate their conceits and never passes on an opportunity to lob a throwaway such as yours.
Any decent scientist is already well aware that it is easily likely that we effectively know sweet FA about anything at all and that it is perfectly possible that the next leap in knowledge could destroy all that came before while also being impossible to know as the last. They get it.
So, given that, what are we supposed to do? Just sit here with bones through our noses and fear the scary-dark-dark? Nah, you poke it with a stick.
All that science is is the remaining factual knowledge we are forced to conclude despite every conceivable effort we have made to destroy it through the application of the only legitimate tool that will ever exist in the acquisition of factual knowledge: Reason. And that’s the best we can do.
Why is it so difficult for so many to understand and accept something so definitively simple, elegant, and beautiful?
It is not really true that we can only see the carpet in one room of our cosmological office block. Thanks to inflation, we can see the carpet in dozens, perhaps hundreds of adjacent rooms, and they all look the same, although nobody can understand why.
This is the so-called Horizon Problem, which I’m sure other people on this board can explain better than I.
Here’s a nice illustration of the problem;
https://inspirehep.net/record/1222779/files/fig_horizon_problem.png
looking back in time, the furthest we can see is the surface of the Cosmic Microwave Background Radiation; if you take any two areas (A and B) on that surface, they can only have been affected by events in their own past light cones - but those light cones are separate as well, all the way back to the hot big bang era. These widely separated locations are like separate rooms, that cannot know anything about each other - yet they are apparently identical in our skies, down to a few percentage points.
Going back to the carpet analogy, it looks like the carpets in our office block, or at least our sector of it, are effectively identical. If the carpets in other buildings are different then we won’t ever get to know about it.
The carpet analogy was proposed to highlight a few things. The ants cannot understand the concept of wifi. They cant see it. They dont see the riad below and the cars and vehicles. They dont know about internal combustion, monetary unions and daily commute. None of these things they can understand or even begin to think about. We are those ants. We make a big deal of the big bang and postulate grandiosely about dark eneregy and dark matter. As someone said few posts earlier it could be all wrong. Scientists know that. I dont think some on here are humble enought to appreciate it.
So now the issue isn’t current cosmological theory, it’s our humility?
Certainly some of us ants aren’t humble enough to appreciate it. These conceited ants tend to think things like that all of the answers can be found in one single ant-book, or in the words of one particular very wise ant. The humble ants, however, go into science to appreciate just how much more there is that they don’t know.