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The Spontaneous Beginning of Spacetime
#11
RE: The Spontaneous Beginning of Spacetime
(April 27, 2015 at 10:12 am)Pyrrho Wrote: There are lots of possibilities (which really means that we don't know).  Think about the future of the universe.  The last I read on the subject, the universe was believed to be presently expanding (for the latest, you might want to ask Alex K, the rocket scientist who we are depending on to solve our mineshaft-gap problem).
The fuck is a mineshaft-gap problem?
Quote: It could conceivably continue expanding forever.  Or another possibility is that gravity will slow everything down, and eventually pull everything back toward each other, which would result in a rather large bang when everything crashes into everything else.  If that is what will happen, perhaps that is what the "Big Bang" was all those years ago, and maybe this has been going on over and over forever.
The simplest way to have Dark Energy is by simply adjusting the cosmological constant to an appropriate value. From a modern perspective that is a very conservative assumption since the cosmological constant basically has to be there as a free parameter anyway. In that case, the main mystery about dark energy is why the value of the cosmo constant is so tiny compared to the Planck scale.

So far, the fit of astrophysics observations to the so-called lambda-CDM model, where there's cold dark matter and a simple cosmological constant, looks good enough that there's not really a good reason to think that dark energy is more complicated than that.

If dark energy indeed has this simple form, which currently is the most parsimonious explanation, the universe will likely keep expanding forever since matter and radiation keep getting diluted but the dark energy doesn't, until one ends up with basically a universe that only contains dark energy. In such a universe, the expansion is exponential with a factor a = e^Ht, where H is a Hubble constant which is actually constant and proportional to the square root of the cosmological constant, and t is the time.

There are however alternative proposals of a dynamic dark energy where it comes from the cosmological constant as well as something similar to the Higgs field, and can thus vary with time. In such models, the universe could re-collapse if dark energy is reduced in value over time. One other crazy thing that could change this fate is if the Higgs field turns out to be unstable, for which there are speculative indications. If the Higgs field tunnels to a different value, the value of dark energy will change drastically and strange things will happen, first and foremost the violent destruction of everything.
Quote:Of course, we don't know if that is what is going on or not, or, at least, the last time I bothered reading anything on this, we did not know. Certainly, you are right that not knowing the answer to something does not justify the claim that God did it.

Some things, you just don't know, and pretending to know does not alter that fact.

If you invoke God, you're doing it the hard way...
The fool hath said in his heart, There is a God. They are corrupt, they have done abominable works, there is none that doeth good.
Psalm 14, KJV revised edition

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#12
RE: The Spontaneous Beginning of Spacetime
(April 27, 2015 at 11:17 am)Alex K Wrote:
(April 27, 2015 at 10:12 am)Pyrrho Wrote: There are lots of possibilities (which really means that we don't know).  Think about the future of the universe.  The last I read on the subject, the universe was believed to be presently expanding (for the latest, you might want to ask Alex K, the rocket scientist who we are depending on to solve our mineshaft-gap problem).
The fuck is a mineshaft-gap problem?
...

You seem to have forgotten the details of the documentary in which you are featured:

http://www.amazon.de/Seltsam-lernte-Bomb...0026L8MHE/

(I see in the German version, they mistranslate the name.)

The phrase "mineshaft gap" is used by Gen. 'Buck' Turgidson in the War Room, but it is obvious that you are the man to solve it, as it was your idea to use mineshafts as places of safety.


Oh, and thanks for helping us put a man on the moon.

"A wise man ... proportions his belief to the evidence."
— David Hume, An Enquiry Concerning Human Understanding, Section X, Part I.
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#13
RE: The Spontaneous Beginning of Spacetime
(April 27, 2015 at 12:03 pm)Pyrrho Wrote: The phrase "mineshaft gap" is used by Gen. 'Buck' Turgidson in the War Room, but it is obvious that you are the man to solve it, as it was your idea to use mineshafts as places of safety.

Oh right... I haven't seen it in a while Smile
The fool hath said in his heart, There is a God. They are corrupt, they have done abominable works, there is none that doeth good.
Psalm 14, KJV revised edition

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#14
RE: The Spontaneous Beginning of Spacetime
Given that you did not remember that detail, it is rather surprising that you did not also say something about me saying that you were a rocket scientist. But I guess you remember what you studied a bit better than some conversation you had in the War Room.

"A wise man ... proportions his belief to the evidence."
— David Hume, An Enquiry Concerning Human Understanding, Section X, Part I.
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#15
RE: The Spontaneous Beginning of Spacetime
(April 27, 2015 at 12:11 pm)Pyrrho Wrote: Given that you did not remember that detail, it is rather surprising that you did not also say something about me saying that you were a rocket scientist.  But I guess you remember what you studied a bit better than some conversation you had in the War Room.

To quote Sheldon Cooper - Rocket scientist?? You told them I was a rocket scientist!
The fool hath said in his heart, There is a God. They are corrupt, they have done abominable works, there is none that doeth good.
Psalm 14, KJV revised edition

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#16
RE: The Spontaneous Beginning of Spacetime
(April 27, 2015 at 12:13 pm)Alex K Wrote:
(April 27, 2015 at 12:11 pm)Pyrrho Wrote: Given that you did not remember that detail, it is rather surprising that you did not also say something about me saying that you were a rocket scientist.  But I guess you remember what you studied a bit better than some conversation you had in the War Room.

To quote Sheldon Cooper - Rocket scientist?? You told them I was a rocket scientist!

Thanks again for helping us put a man on the moon.

"A wise man ... proportions his belief to the evidence."
— David Hume, An Enquiry Concerning Human Understanding, Section X, Part I.
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#17
RE: The Spontaneous Beginning of Spacetime
I always though so long as our science still requires us to use rocket to get to space, we don't have good enough scientists.
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#18
RE: The Spontaneous Beginning of Spacetime
(April 27, 2015 at 2:24 pm)Chuck Wrote: I always though so long as our science still requires us to use rocket to get to space, we don't have good enough scientists.

Just be patient. The nano-wire space elevator is coming.
The fool hath said in his heart, There is a God. They are corrupt, they have done abominable works, there is none that doeth good.
Psalm 14, KJV revised edition

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#19
RE: The Spontaneous Beginning of Spacetime
And when it does finally come, it'll be able to fire off huge loads up into the sky.
At the age of five, Skagra decided emphatically that God did not exist.  This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair.  Only Skagra responded to it by thinking, 'Wait a second.  That means there's a situation vacant.'
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#20
RE: The Spontaneous Beginning of Spacetime
(April 27, 2015 at 2:32 pm)Stimbo Wrote: And when it does finally come, it'll be able to fire off huge loads up into the sky.

I'm pretty sure when they invented the theory of panspermia, that's not what they had in mind.
The fool hath said in his heart, There is a God. They are corrupt, they have done abominable works, there is none that doeth good.
Psalm 14, KJV revised edition

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