What is the Universe expanding into..

Do you think there was anything before the big bang?

  • I don't think there was anything before the Big Bang

    Votes: 56 12.5%

  • I think something existed before the Big Bang

    Votes: 200 44.7%

  • I don't think the big bang happened

    Votes: 54 12.1%

  • I think the universe is part of a mutiverse

    Votes: 201 45.0%
  • Total voters
    447
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Galu

Galu

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Pete, I was rather hoping that the new dark matter map would elicit a reaction to the suggestion that the observation appears to stray from Einstein's theory of general relativity.

The disparity between models based on Einstein's physics and the new observations is only a few percent, but it could mean that we are on the way to finding out something new about the way the Universe really is.
 
Bonsai

Bonsai

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Ethan Segal has a good discussion in this here:-

No serious physicists doubt it all started with a bang (or ‘rapid inflation’)

Why Isn’t Anyone Seriously Challenging The Big Bang?

An excellent book on this is (although now c. 40 yrs old) is Steven Weinberg’s ‘The first three minutes) that looks at the big bang from a particle physicists vantage.
 
system7

system7

Member
Joined 2008
There's some interesting ideas about the Big Bang:

The Country Gentleman of Physics - Issue 100: Outsiders - Nautilus

In 1772, the French mathematician Joseph-Louis Lagrange made an extraordinary discovery. Approximately, it’s this: Imagine there are three particles moving around and interacting only via Newton’s law of gravity. Lagrange showed that the size of this total system—the diameter of an imaginary circle that encloses all three particles—will vary in a very odd way. The diameter will shrink to a minimum at some moment in time, then grow again—forever. The whole three-particle system never returns to that minimum size.

Amazingly, Lagrange’s result works for any number of particles. And when Barbour read about it, he thought it might work for an entire universe; after all, what is a universe but a load of particles swirling about? If true, this would mean that the universe hit a minimum size at some point, and then grew ever afterward. And that minimum is what we think of as the moment of the Big Bang. In Barbour’s Janus-headed universe, time runs in two directions, away from that point of minimum size. Lagrange’s proof of a minimum size, he said, gives us a cause for the arrow of time. Why do we experience time only running forward? Because we’re moving away from Lagrange’s minimum, and a mathematical law says we can never return there.

“I’ve been interested in the arrow of time for almost as long as I can remember, and nobody has ever come up with a suggestion that a law of the universe says there must be one,” Barbour said. “It’s extraordinary that it has been sitting there for four centuries.”
Click to expand...

So it seems our sense of time starts with the minimum size... the point of inflation from the minimum, if I follow.

Dark matter seems necessary. But it is very elusive:

Is the Search for Dark Matter an Act of Faith? - Issue 77: Underworlds - Nautilus

Didn't that Dutch physicist think maybe it's gravity that works differently from inverse square over long range instead?

We missed the Blood Moon lunar eclipse on Wednesday in the UK, but I noticed the tide was exceptionally low yesterday evening. Seaweed popping up all over the shoreline. Will take a snap tonight.

We then get a partial solar eclipse on June 10 about 11AM:

Annular Solar Eclipse on June 10, 2021

Should be more total in North America, so Discopete might see something. Never look directly at the sun though.
 
D

Disco-Pete

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system7 said:
There's some interesting ideas about the Big Bang:

The Country Gentleman of Physics - Issue 100: Outsiders - Nautilus



So it seems our sense of time starts with the minimum size... the point of inflation from the minimum, if I follow.

Dark matter seems necessary. But it is very elusive:

Is the Search for Dark Matter an Act of Faith? - Issue 77: Underworlds - Nautilus
Click to expand...
From what I'm gathering it seems the entire model is an act of faith since it all depends on a conjecture.
 
system7

system7

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Joined 2008
Tonight's snap turned out to be less interesting than I hoped. :mad:

But thankfully I have fixed Bonsai's criticisms of the lamentable "Soft Focus" criticisms of my 640x480 images, Turns out my idiot Nikon Coolpix A100 camera does not reset to default on reset. It was set to "Soft Focus". :eek:

Here my latest image of low tide at 7 PM Portsmouth Beach. Taken on Hewlett-Packard Photosmart 433 two days after the low tide.

Bit boring IMO. Clearly, I must recalibrate my Instruments. :D
 

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system7

system7

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Joined 2008
Very few people "pull the wool" over our Portsmouthian Eyes.

If you ask me, this Vessel is deeply suspicious!

842735d1589123914-universe-expanding-clouseau-png


A mere 500-1000 tons. What's it supposed to be carrying? Not Bananas.

955616d1622240827-universe-expanding-flat-calm-portsmouth-jpg


No, it's drugs. I'd be ripping it apart if employed in that Border Force Function. Happily I'm retired, so I don't care. :)
 
system7

system7

Member
Joined 2008
This is a more detailed look at the Dark Energy Survey currently mapping about a fifth of the Universe for Dark Matter distribution using telescopes:

Dark Energy Survey releases most precise look yet at the universe’s evolution

Fermilab is building a better detector for Gravitational waves and Dark Matter called Magis-100:

MAGIS-100: The quantum search for dark matter and gravitational waves - YouTube

The whole thing might be Hooey if the MOND theory holds water. Modified Gravity in which the Inertial Mass is different from the Gravitational Mass:

New evidence AGAINST dark matter?! - YouTube

All quite baffling, IMO.
 
Galu

Galu

Member
Joined 2018
TNT said:
I think one of you know what the "dark matter" is? Spill!! Or at least an educated guess.
Click to expand...
Every test we've thrown at General Relativity, like gravitational time dilation, points towards it being correct under every known circumstance. It's a well tested theory.

However, certain observations, like the rotational speeds of galaxies, show a mismatch between the amount of normal matter present and the effects of gravity.

Physicists hypothesise that everything can be brought into line with General Relativity if the Universe contains extra mass in the form of 'dark matter'.

There is a minority camp which suggests that the mismatches can be solved by modifying gravity - MOND for MOdified Newtonian Dynamics - but that also introduces something that looks suspiciously like dark matter!

The introduction of dark matter allows the theory of General Relativity to predict how the Universe will behave and evolve.

The problem is comprehending the required properties of dark matter.

It must be matter, in the sense that it has mass and gravitates, but at the same time it must be transparent to radiation as well as being unable to collide and exchange momentum with either itself or normal matter.

Dark matter is currently the boffins' best "educated guess" and they're better educated than me! ;)

Ask Ethan: Could Dark Matter And Dark Energy Be The Same Thing?
 
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