I have a question about laws of physics

[Loren Pechtel]

Type I SNe are regular enough to be used as standard candles out to cosmological distances.

Can we tell the difference between a normal type 1 and the white dwarf eating a star in one gulp (collision with another star, not nibbling on a companion) and going over the limit while eating? The type 1 energy assumes the star is right at the limit.

 

[Elixir]

Lots of people say utterly stupid shit like "It is theory, not fact" or "It is not proven", as though these were insightful revelations that give us carte blanche to place any wild speculation we like on an equal footing, rather than being statements of the obvious that serve only to highlight the speaker's lack of understanding of science as an epistemology.

I see some qualitative difference between “theory” as in theory of evolution vs “theory” as in Big Bang theory.
We can observe current increments of evolution that allow us to reconstruct aspects of the past, explaining galaxies of currently available data points. But what do we have other than CMBR to evidence the nature of a BB?

 

[bilby]

Lots of people say utterly stupid shit like "It is theory, not fact" or "It is not proven", as though these were insightful revelations that give us carte blanche to place any wild speculation we like on an equal footing, rather than being statements of the obvious that serve only to highlight the speaker's lack of understanding of science as an epistemology.

I see some qualitative difference between “theory” as in theory of evolution vs “theory” as in Big Bang theory.

I don't. They are exactly the same kind of theory.

We can observe current increments of evolution that allow us to reconstruct aspects of the past, explaining galaxies of currently available data points. But what do we have other than CMBR to evidence the nature of a BB?

All of current cosmology.

If anything, the evidence in cosmology is more accessible than the evidence in biology.

Biologists can infer past ecologies and past genetic trends from studying existing populations and the ways in which they evolve. But they can't look back in time to see things as they were.

Cosmologists can look at existing stars and galaxies in near real time (the last few million years); But they can also look at stars and galaxies as they were 13 billion years ago, in real time - by looking at objects 13 billion lightyears away.

 

[steve_bank]

The way it works as I remember it.

Out to a limit parallax is used to measure distance to stars. Knowing distance to a star we can calculate the radiated energy by the inverse square law for different star types. A calibration.

Beyond the parallax limit knowing the total radiated energy of a star type distance can be calculated by the inverse square law.

Star types determined by spectroscopy.

Inverse-square law - Wikipedia

en.wikipedia.org

 

[Elixir]

If anything, the evidence in cosmology is more accessible than the evidence in biology.

I question that.
Cosmology and evolutionary biology are very similar as you point out. One of the most glaring similarities is that regressing either leads to an unknown. In cosmology there’s the BB or singularity of indeterminable origin, in evo-bio there’s the origin of life.
In the latter case, empirical evidence of pathways to life continues to accumulate. Evidence of what causes Big Bangs doesn’t seem so abundant or accessible, even “in theory”.

 

[bilby]

Cosmology and evolutionary biology are very similar as you point out. One of the most glaring similarities is that regressing either leads to an unknown.

Yes.

In cosmology there’s the BB or singularity of indeterminable origin, in evo-bio there’s the origin of life.

FTFY.

In the latter case, empirical evidence of pathways to life continues to accumulate.

Indeed, but it is not a part of the Theory of Evolution.

Evidence of what causes Big Bangs doesn’t seem so abundant or accessible.

Indeed not, but it is not a part of the Big Bang Theory (the current model being Lambda-CDM).

 

[bilby]

By the way, just like evolution, the "Big Bang" isn't an event in the past; It is still going on all around us.

 

[Bronzeage]

By the way, just like evolution, the "Big Bang" isn't an event in the past; It is still going on all around us.

It will be in syndicated reruns for another decade or two.

 

[Shadowy Man]

By the way, just like evolution, the "Big Bang" isn't an event in the past; It is still going on all around us.

The phrase has been turned into some kind of event at the extrapolated t=0 time in layman discussions. As in the commonly heard “…after the Big Bang…”

We don’t know what happened at t=0, because the mathematical singularity that arises from the extrapolation is an indication of the breakdown of the physics.

It’s an area of active research. One day maybe we will have a better understanding but I suspect it will be extremely challenging to get good data.

 

[GenesisNemesis]

the BB model assumes that at a sufficiently high energy density (way above what we can do even with the LHC) the laws were different.

Why you imagine anyone would take your unsupported word for this eludes me.

Do you have a citation for this claim?

I've only ever heard or read that the laws "may have" been different because we don't really know what happened initially at t=0. Not that we know they were different and have never heard a cosmologist claim they were different. Also I highly recommend this podcast (and this episode especially) on the subject:

Cool Worlds Podcast #26 Will Kinney - Before the Big Bang, Inflation, Infinity of Worlds

 

[steve_bank]

Yup, in a dynamic system of any kind dt or t can not go to zero, you end up typically with a divide by zero or an infinite limit.

in velocity = ds/dt dt can not go to zero.

The only thing that makes sense to me is an infinite universe with no beginning and no end.

To start the whole thing the theory needed to have a starting point and mechanism to get it started.

A hot dense uniform something or other. The BB started by quantum fluctuations.

There is a diffidence between TOE and BB.

While abiogenesis has not been demonstrated, experiments have shown how basic building blocks could have been created.

Simulated lightning strikes into seawater. Micro evolution and natural selection can be observed.

 

[lpetrich]

Type I SNe are regular enough to be used as standard candles out to cosmological distances.

Can we tell the difference between a normal type 1 and the white dwarf eating a star in one gulp (collision with another star, not nibbling on a companion) and going over the limit while eating? The type 1 energy assumes the star is right at the limit.

The eater star's outer layers would likely make this supernova a Type II one, or otherwise different from a typical Type I one.

 

[lpetrich]

I've found some research into variations of fundamental physical constants, like observations of spectral lines of quasars. It was hard for me to find out how they derived variations in the fine structure constant from those lines.

If they said something like "We observed these electronic lines and these fine-structure lines, and that's why we were able to estimate the variation in the FSC", I would have been happy. But they didn't.

 

[Shadowy Man]

I've found some research into variations of fundamental physical constants, like observations of spectral lines of quasars. It was hard for me to find out how they derived variations in the fine structure constant from those lines.

If they said something like "We observed these electronic lines and these fine-structure lines, and that's why we were able to estimate the variation in the FSC", I would have been happy. But they didn't.

If you read my post #29 you’ll see that I looked into this and give some citations. The best observations I could find are consistent with the null hypothesis for variations of the fine structure constant.

 

[Elixir]

By the way, just like evolution, the "Big Bang" isn't an event in the past; It is still going on all around us.

Just as evolution requires abiogenesis (or poofery), BB requires a mathematical singularity at the front end. The difference is that abiogenesis is more likely/hypothetically replicable (by humans) than a BB.

 

[Shadowy Man]

By the way, just like evolution, the "Big Bang" isn't an event in the past; It is still going on all around us.

Just as evolution requires abiogenesis (or poofery), BB requires a mathematical singularity at the front end. The difference is that abiogenesis is more likely/hypothetically replicable (by humans) than a BB.

In what way does the big bang theory *require* a mathematical singularity?

 

[bilby]

https://www.smbc-comics.com/comic/beyond

 

[Elixir]

In what way does the big bang theory *require* a mathematical singularity?

By way of my very possibly flawed understanding, born of continual references of a "singularity" that would have once contained all the energy in the universe, now existing in various forms of matter and energy.
So maybe it wasn't a zero-dimensional point singularity, but rather something the "size" of a breadbox or a galaxy; does that matter to the notion of a "big bang"? It still requires an aggregation of "everything in the universe". Whatever level of compression is required to reduce everything to homogeneous primal energy, that would be what was required. Or no?
On further consideration, the idea of anything being "mathematical" at that point, probably wouldn't apply.

 

[Shadowy Man]

In what way does the big bang theory *require* a mathematical singularity?

By way of my very possibly flawed understanding, born of continual references of a "singularity" that would have once contained all the energy in the universe, now existing in various forms of matter and energy.
So maybe it wasn't a zero-dimensional point singularity, but rather something the "size" of a breadbox or a galaxy; does that matter to the notion of a "big bang"? It still requires an aggregation of "everything in the universe". Whatever level of compression is required to reduce everything to homogeneous primal energy, that would be what was required. Or no?
On further consideration, the idea of anything being "mathematical" at that point, probably wouldn't apply.

In my opinion, the Big Bang theory only need go back as far as a hot, dense state. The extrapolation to a t=0 singularity is just that, an extrapolation, and the mathematical density singularity just points out the limitation in the extrapolation. We will need new physics to understand what happened at the so-called "beginning". But I don't think the Big Bang theory and the current lambda-CDM model of cosmology *requires* there be an actual mathematical singularity at t=0.

 

[steve_bank]

My philosophical take is it comes down to conservation and causality.

Unless you posit something fro nothing like Creationism there has to be an initial condition and a spark that starts the BB.

The BB does not start at tine zero and does not explain what led up to the initial conditioj assumed in the theory.


For me the only thing that makes sense is an infinite universe with no beginning or end.