We’re just really lucky to live in a universe where complex carbon chemistry is possible.
The universe might have been much simpler, with no atoms bigger than helium being stable. A perfectly valid universe… We just wouldn’t observe it.
The earth formed but 4.6 billion years ago or 9 billion years after the universe formed. It took many generations of stars to even produce the elements needed for life, this was not a fast process at all.
It is critical to realize that the tendency to minimum total potential energy is actually due to the second law of thermodynamics.
Chemical bonds like those in organic molecules are actually at a lower energy state. It is a common misconception to think that energy is stored in chemical bonds but the bonding processes release energy (and some times can take large amounts of energy to break too).
Even our main energy “transmitter” ATP has the waste products of carbon dioxide and water which have a much lower potential energy than ATP. It is confusing because we think of ATP or sugars as having “energy” but the the energy is from the formation of chemicals bonds with a lower potential energy.
Unfortunately english is not the best tool for these concepts and I am avoiding math which people will just ignore anyway.
But think of thermite which is a mixture of iron oxide and aluminum powders. aluminum oxide has a lower potential energy level than iron oxide so at a particular temperature the aluminum will pull the oxygen atoms from the iron and in the process releases a bunch of heat.
Now actually life is quite amazing and may be common but it is a byproduct of the second law of thermodynamics and not an exception.
The system will try to maximize it’s entropy, and in an over simplified fashion it does this by trying to convert all of the energy into thermal energy (heat) thus increasing the macro entropy. If this requires local “complex” chemical bonds it will do so.
Obviously this entire post is a gross over simplification but the technically wrong idea that braking chemical bonds is what release energy causes much confusion even among scientists.
The premise of this thread is nonsense; human beings see organization in random patterns; it is the way our brains work. The universe “obeys” certain rather mysterious laws, such as gravity, and this leads to things being the way they are, but the main reason there is not utter chaos is things are so big and there is so damn much space between things.
The various constants are what they are because that is what they are, and trying to draw conclusions from this at this point is silly. It is probably like sand in a sand dune; things just fall out within a certain statistical range for background reasons. Various multi-universe proposals, some of which select in favor of things that lead to life, are also possible.
Agreed.
If we’re going to say the universe is organized or complex or whatever…compared to what? I could trivially conceive of a more organized universe (e.g. one where every celestial body hosts life). Why should this particular level of complexity be surprisingly good?
Yeah, I can conceive of a universe with nothing in it–that would be organized. Perfect.
In some philosophies a perfectly empty universe is impossible (cannot exist); change is necessary for there to be existence.
It depends on what is meant by “empty”.
Even removing all energy and matter, we’d be left with the medium of spacetime which is teeming with virtual particles (but perhaps it wouldn’t be if all energy/matter were removed).
But if we remove spacetime and gravity, what are we talking about other than absolute nothingness, which begs the question to begin with. Is absolute nothingness even really possible, and if it is, how could something arise out of an absolute nothing? Which is a philosophical conundrum that’s been mulled over and debated since antiquity.
Nevertheless, here’s the universe as we know it, and it is ordered in a way I do not find as nonsense. Sure, the very underlying fundamental principles of nature cause energy and matter to sift through and fall out into orderly forms from an otherwise chaotic sea of recombined hydrogen atoms, until we get to you and I typing these words on the internet 14 billion years later. Yet, given the initial conditions, something beyond inert*, non-living matter arising seems astoundingly against all odds, and yet… is probably inevitable considering how fast life did arise, once all the necessary elements and conditions fulfilled some minimum threshold.
*inert; not necessarily in the chemical reaction sense, but rather in the sense of self-reproduction, heredity and evolution.
I sorta disagree. Things like sand dunes can be analyzed statistically, and have a definite informational content. I can make predictions, with a reasonably high level of accuracy, about what the next sand dune will look like. (Very much like the previous three hundred…) “Order” exists in an objective, mathematical sense. The repetitive pattern of sand dunes is not a perceived pattern, such as the constellation Ursa Major, which only coincidentally looks rectangular. If you were to observe a representative sample of stars, you wouldn’t find many rectangles.
When you get to living creatures, the degree of order really piles up. The organization of the human brain is astonishing.
One of the more interesting early Einstein/Mach debates was over this point. If you had an entire cosmos that consisted of only one planet, and “nothing else,” can that planet possible rotate? What is it rotating with respect to? If it rotates, does it have an equatorial bulge?
One view was that “spacetime” itself provides a metric, and so, yes, the planet can rotate, and would have an equatorial bulge. The other view was that, no, the planet cannot meaningfully be said to rotate, as there is no frame of reference possible.
(I can never remember which view Einstein took, which view Mach took, or which view is most commonly subscribed to today.)
A universe with only one planet in it—wouldn’t angular momentum at least still hold (despite nothing else in the universe existing, there’d still be inertia)?
According to current theory empty actually requires massive amounts of energy to create and is highly unstable. What people consider “empty” is actually filled with “stuff” that just is not perceived as “stuff” by us. This is mostly because electrons and photons do not interact with them.
http://www.physics.adelaide.edu.au/theory/staff/leinweber/VisualQCD/Nobel/index.html
However as odd as these concepts are to us and our minds there is no indication that any of these actions are anything but natural and deterministic as far as the second law of thermodynamics goes.
What is “Newton’s Law of entropy”? Is this the same Newton who died about 150 years before the term entropy was first used by Clausius?
I don’t like nitpickers. So he has Newton mixed up or maybe just misspoke. The point is accurate – the earth is not a closed system.
That’s the heart of the question: would angular momentum function if it has nothing to function in relationship to? If there is no way to point to a fixed direction in space – we use the earth’s orbit’s ascending node as our “Greenwich Longitude” – then is the planet actually rotating or not? How can it be known?
Now, yeah, you could tell by ocean currents if Coriolis forces operated. But that’s kind of altering the principle of the thought experiment. The minimal cosmos has only one object in it: a planet. By expanding it to “a planet and an ocean” you complicate things.
(Arthur C. Clarke famously attacked Einstein’s equivalence principle by noting that gravity falls off with distance, but the force of acceleration doesn’t. So, you can tell if you’re on a planet or in an upwardly accelerating elevator. But that’s nitpicking, and doesn’t serve to undermine the serious meaning of Einsteinian equivalence.)
You could get similar results by putting a satellite up into orbit around the lonely planet – but, again, that’s introducing a second “object” into the minimal “one object universe.”
Some planets have oceans. The thought experiment should be stated more clearly if we were supposed to begin with a homogenous solid sphere.
There’s a difference between reducing a model to the minimum complexity, and ad hoc removing anything from a hypothetical that would make an observational difference (in the process making it a purely philosophical question).
Sure, but the question of an “empty universe save for one rotating object” is side-stepped if you allow it to be solved trivially by introducing other objects. It doesn’t help answer the original question: what does “empty” mean?
Does space itself have an intrinsic metric…or doesn’t it? Putting a satellite into orbit around the lonely planet doesn’t answer the question; instead, it introduces a new, separate metric, by which the mechanics of the question are answered…but not the core question.
In any case, I’m well past my own limits in this specific exploration, and I can’t remember which views were held by Einstein and/or Mach, or what the current thinking is on the matter. I know the whole suite of GR equations have been solved for certain limited kinds of universes – such as a cosmos entirely filled with perfectly fine-grained “matter” of a given overall density – sort of as if matter could be infinitely divisible, instead of having clumps like atoms. An interesting abstraction, but not our universe!
What I do not know is how much farther than that GR modeling has come in the last thirty (or more) years since I was in college and took cosmology classes.
(Sheesh, such classes. Half the students were creationists! The professor was seriously shaken by the level of stupidity!)
It isn’t introducing other objects. It is using only the objects in the original hypothetical. Real planets have oceans through which it actually is trivially easy to answer the question.
Even if we rephrase the hypothetical as “only one planet with no oceans”, that will still have an atmosphere through which it actually is trivially easy to answer the question.
So then you rephrase rephrase the hypothetical as “only a homogenous solid iron sphere”. but that will rapidly produce an atmosphere formed through sublimation that will allow us to answer the question with sufficiently sensitive equipment.
So then you rephrase it is “only a homogenous solid unobtainium sphere with no sublimation”. But that will produce an atmosphere from radioactive decay because no heavy element is truly stable.
So then you give Unobtainium the property of being perfectly radioactively stable. And it will be pointed out that quantum level teleportation will produce distant objects. So you define Unobtainium as lacking that property as well. Then you need to imbue it with the property of being immune to the photoelectric effect ans so on and do forth. Until Unobtainium ceases to *be *matter in any sense that we understand it.
As Mijin pointed out, the hypothetical actually requires the *ad hoc *removal anything that would make an observational difference. It simply doesn’t work in the real universe. As a result, you have reduced it to a purely hypothetical question.
You have gone from:
“If you had an entire cosmos that consisted of only one planet, and ‘nothing else,’ can that planet possible rotate?”
to
“If you had an entire cosmos that consisted of only one mass that does not permit any possible way of detecting rotation, and ‘nothing else,’ can that mass be said to rotate?”
Those are two totally different questions. The first is a scientific thought experiment that is trivially easy to answer.
The second is a philosophical/semantics question, and no different to “If a tree falls in a forest…” and “Can God create a rock so large…”
Blake: I disagree with what you’re saying, but I am not equipped to address it further, because the GR math is light-years beyond my pay grade. I don’t agree with what you say – but I can’t go any further with it.
(Hey, give me credit for not suffering Dunning-Krueger disease and thinking that my knowledge exceeds that of all historical physicists!)
I only note that, at one point, many decades ago, Einstein and Mach (both light-years beyond my pay grade!) disagreed over the answer to the question. So…take it up with them!
Or, more properly, update me. What is the current status of thinking in this matter. Is it held that the “sea of virtual particles” gives an intrinsic “dimension” to empty space?
I have no idea. I’m just addressing the issue being discussed here.
The fact that two big names argued about an issue decades ago doesn’t really impress me. Big names decades ago argued about how many angels could dance on the head of a pin.
I have no idea what the exact terms of the Einstein and Mach argument were or what conditions they were arguing in. But as far as the proposition presented here, I have to agree with Mijin. It’s only arguable if it’s reduced to a philosophical position without reference to reality.
It actually seems self evident. If the cosmos consists of a single mass and some method that allows rotation to be detected, then it must be possible to detect whether it rotates. And if it is possible to detect whether it rotates, then there can be no *argument *over whether it rotates. It either does or it does not.
It can only be possible to argue this if there is no way to detect whether it rotates.
But that isn’t the way the real universe works. In the real universe there will always be some way to detect rotation because mass in the real universe never holds together in a perfectly coherent unit. If there is enough energy available to permit the detection of rotation, then the mass will be incoherent enough for us to detect rotation. You don’t need any “sea of virtual particles”. You can measure the real particles that will split off any mass in the real universe above 0^oK.
It might be interesting to debate what might happen in a cosmos where the physics is so different that the particles in solid matter remain perfectly coherent regardless of the amount of energy applied. But that’s not our universe, or anything like it. You can’t just say the hypothetical universe is identical to ours except that matter is perfectly coherent because that modification requires a rewrite of a dozen of other physical laws which require a rewrite of dozens of others and so forth. It’s a universe where all the laws of physics have been rewritten from the instant of the Big Bang. It permits any answer at all depending on how you choose to rewrite them.
IOW, it’s a purely philosophical/sematic question with no reference to real physics.
Have to disagree. It’s a “one of two choices” question, the two answers to which have consequences that might be observable in the real world. That leads to a valid reductio ad absurdum proof, if one of the two consequences is contradicted by real observations. And that’s called real science.
(Unless, of course, some third possibility pops up, knocking over the whole apple-cart. Not unheard of.)
No, there is only one answer, because the consequences *are *observable in the real world. And that is “Yes”. In the real world, if we were on planet with nothing else detectable we would be able to tell if it was rotating because the particles that constantly leave that planet would be readily observable.
It’s not real science because reaching one conclusion requires that we ignore other evidence that we know exists, rather than incorporating it.
Aristotle concluded logically that women have fewer teeth than men. That didn’t make his conclusion scientific. It simply meant that he constructed his hypothesis and the went looking for evidence that supported it.
Real science requires that we *first *look at the observations of the real world, and *then *construct a hypothesis to explain them and *finally *attempt to falsify it. If we construct a hypothetical which expressly *prohibits *observations of the real world and then reach a conclusion based on the hypothetical world and finally seek observations of the real world consistent with the hypothetical, that is about as far from real science as we can get.