Ever heard of eternalism/block universe theory? Basically, there's no past nor future but an eternal present where everything exists now. People are terrified by premonitions because of that; you see something, knows it will happen, try to avoid it and end up failing or even causing it. The answer to "what lies after death?" is much easier to find than you think. Your dreams are allegorical images created by yourself to understand how to live, thus can be considered your own life. When you die in your dreams, you wake up. You die in your life to find yourself there again. Also, is proven that several particles can exists in more than one place simultaneously, so...if you're formed by such energies, where are you now?
*rephrase that - Because in measuring you see one answer, so your consciousness must be in a universe (on a thread) where that is the answer.
Let me confirm.
The universe is 13.8 billion years old, and its supposed future to heat death might extend to a
googol years.
"I" never existed before and only have a few decades of existence before returning to nonexsitence, yet it is happening RIGHT NOW. Gee, what are the chances?
Even this generously assumes that time and space are what they appear to the human mind, and that "I" am whatever my conditioned thoughts say I am.
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I don't know of any good evidence for a perpetual universe, but I still keep my mind open to it.
Heat death matches what we currently know, but so does "the big rip" (if dark energy increases over time). The big crunch is not ruled out, but would take new physics.
The universe might be eternal to the past, as well as to the future. The simplest theory for that is described in "Steady state eternal inflation", formulated by Anthony Aguirre and Steve Gratton, and available free online: It is compatible with observations of the Cosmic Microwave Background, and is centered on a Cauchy surface from which time extends in opposite spatial directions. A similar but somewhat more elaborate cosmology, by Carroll and Chen, is analyzed, together with the Aguirre-Gratton one, by Vilenkin, in his online paper "Arrows of time and the beginning of the universe".
The Borde-Guth-Vilenkin Theorem is usually construed as preventing the "past eternality" of inflation by requiring a balancing of universal expansion by universal contraction, but the references in the last (2003) formulation of that theorem by its three authors include a footnote exempting the Aguirre & Gratton theory from its strictures. Also, the BGV Theorem does not rule out a start of the universe at arbitrarily long times before the start of inflation (quasi-exponential expansion), as hypothesized in Martin Bojowald's 2010 book titled "Once Before Time: A Whole Story of the Universe", which utilizes Loop Quantum Cosmology. Some of the "bouncing" cosmologies, of which the Wiki "Big Bounce" provides an overview, also imply past eternality, and substitute a repetition of "bounces" for the "Big Bang".
What these cosmologists, as well as the three mentioned in the last of my comments below, are trying to do is resolve that contradiction of infinite density in the zero volume of the singularity at which General Relativity has been considered to break down: Because densities in "negative time" might cancel densities in"positive time", the densities of the objects duplicated in either version of the temporal dimension might cancel each other, thereby replacing that contradiction with zero density in zero volume, which makes sense.
I believe that a widespread misconception leading to the belief that the universe, or its massive and energetic contents, are finite is the fact that their limitation to some finite amount would provide the simplest explanation for the fact that the sky is dark at night: However, because of the fact that expansion is different from speed or velocity, and is (consequently) NOT limited to a rate no higher than the speed of light, such accelerations as were witnessed by the Supernova 1A observations in the late 1990's are entirely permissible in General Relativity. The simplest explanations do not necessarily provide the best explanation of scientific phenomena.
youtube.com/watch?v=gfYYkC-TO4k, Guth gives a 2018 lecture supporting a past- and future-infinite multiverse based on the possibility of entropy being infinite, with details being worked out in collaboration with Sean Carroll. As in BGV's exemption of Aguirre's past- and future-infinite proposal, the BGV Theorem would apply separately. in each of the two directions outward from a Cauchy surface. Both of these theories resemble the mathematician Barbour's "Janus universe". The astronomical facts detailed by Pela would apply in whichever of the two halves we find ourselves.
The consensus for more than 40 years is that inflation happened before the Big Bang. There was this rapid expansion of space-time but the Big Bang is more actually like the dumping of energy into this place. Plank-order seconds after the Big Bang all of this was happening. The Big Bang doesn't have much to do with the expansion of the universe. It has a lot more to do with the dumping pf energy. Mass and energy are fundamentally related and they come from quantum fields. The expansion was already happening and we know the universe is expanding due to dark energy. The Big Bang is just the moment of creation in the sense of the stuff in this place that we know of. Before the Big Bang we know there was only inflation. We can only say from what we currently understand, what happened at the end stages of inflation. Before those final stages of inflation we don't know what happened. Some people think the universe might have started in a singularity. Before those final stages of inflation the universe was very small so people just jump to the logical conclusion of maybe it started in a singularity. Presumably quantum fields also existed before the Big Bang, so we don't know where they came from. It makes sense to say that outside of space-time itself there may not be time because time is part of this thing and its interwoven with space in some weird way. But that would be looking at General Relativity and taking what it says very seriously so it all gets very tricky.
Let me confirm.
The universe is 13.8 billion years old, and its supposed future to heat death might extend to a
googol years.
"I" never existed before and only have a few decades of existence before returning to nonexsitence, yet it is happening RIGHT NOW. Gee, what are the chances?
Even this generously assumes that time and space are what they appear to the human mind, and that "I" am whatever my conditioned thoughts say I am.
View attachment 131222
Firstly, we think space and time are deeply connected, and objects that are at high energies partially rotate through space-time. See the great interactive explanations here:
Inside Einstein's head
To unify relativity and quantum pictures, we know there is a conceptual conflict between the quantum picture where time is treated externally from the models, and relativity where time varies depending on observer dynamics. The limits of 'quantising' relativity are shown by
canonical quantum gravity. But 'relativising' quantum theories has also been limited to combining special relativity. It is currently impossible to measure gravity at small scales appropriate to quantum behaviour, so where general relativity and quantum scales collide, in blackholes and in the early universe for instance, we don't have a clear account. Loop-quantum gravity, and Twistor theory, are examples of approaches with a more fundamental layer from which spacetime is emergent.
It's important to think about what space does. Noether's theorem shows us that conservation laws are directly equivalent to continuous symmetries under transformation. That is, we link it's shape to the paths objects will take with no forces acting on them, where momentum is conserved.
The other crucial property of space is expressed as
the principle of locality: that an object is influenced directly only by its immediate surroundings, and signals are fundamentally limited by spatial seperation. This is another way of talking about the expectation there will be no action-at-a-distance, which has been a very useful guideline in developing and distinguishing physics from non-physics. Entanglement challenges locality, with the Bell Theorem showing if hidden variables lead to entanglement correlations they must be non-local. That has led to the EPR = ER hypothesis, the idea entanglement information travels down Einstein-Rosen bridges, often dubbed wormholes.
put more eloquently, a space in physics and math is just a way of ordering things. It's common to say causality makes the spacetime ordering the necessarily correct or fundamental one, but from the symmetry-conservation laws point, we can see that in line with Hume's Problem of Induction, what we have is not necessary connections, but
Real Patterns. Discussed here:
Is the idea of a causal chain physical (or even scientific)?
But, our intuitions that give rise to the symmetries we base our shared use of math on, relate to the necessarily shared experiences of space we have, in order for our chemistry and biology to behave the way they do. Discussed here:
The Unreasonable Ineffectiveness of Mathematics in most sciences So space doesn't seem to be fundamental to the universe, but it does seem to be fundamental to how minds work, with '
Flatlanders' or higher-dimensional beings having radically fundamentally different phenomena to those we experience, and our language and learning is rooted in intersubjectivity and common experiences.
A mathematical space is any ordered arrangement of different properties. As long as you have some properties, you can order them into a space, and there's nothing in principle more fundamental about any particular set of properties or scheme of ordering them.
However, geometrical distance-space is special in that:
- there are a small finite number of dimensions worth of similar properties, which makes 'computing' translations and rotations in the space trivial in places where those dimensions are approximately orthogonal
- the dimensions are approximately orthogonal most places in the universe - that is, you can change x position without significantly changing y, z, and (if you're using 4-space) ct position as they would be measured from the original position. (Or change radial position without changing polar and azimuthal angle, or whatever other coordinate system you prefer to use to represent spatial dimensions.)
- disruptions in this approximate orthogonality (gravity) are themselves spherically symmetrical, which preserves the approximate orthogonality across vast extensions of these dimensions
- information about the positioning of processes in geometric space is easy to get (from electromagnetic interactions, which exhibit symmetry in the way they propagate in any direction in distance-space)
- information about distance-space is especially salient to the survival and reproduction of machines that run on electromagnetic interactions
- because of the above symmetries, ability to obtain and act on information about distance-space remains salient across large displacements in distance-space and time, often even when environment changes.
We want your input, my friend
I'm dead
. It's just razzing because he(?) always posts cat related memes and his avatar is a cat. Doesn't he also run the cat mega thread? Btw Pluto, I sincerely apologize if you're actually a girl 
you're so funny lol
(just for you @sserafim) I used the male emoji
en.wikipedia.org
