21

Physics, Astronomy & Cosmology / Re: What happened before the Big Bang?

« on: 27/01/2019 17:45:36 »

One can only guess there can never be any evidence.

This is true, but the absence of any real explanation of how something could come from nothing, must be a fairly strong argument for there having been "something" before the BB.

22

Physics, Astronomy & Cosmology / Re: Where did the big bang come from?

« on: 24/01/2019 14:48:21 »

https://www.thenakedscientists.com/forum/index.php?topic=52368.0

JeffreyH started this thread a few years ago.  It might be worth a look when time permits.

23

Physics, Astronomy & Cosmology / Re: What is the difference between astronomy and cosmology?

« on: 23/01/2019 17:50:06 »

 Astrology was a fanciful study of the “heavens”.
 
Astronomy developed from astrology and is a scientific study of the observable Universe.

Cosmology developed from astronomy, and is a fanciful study of what the universe might be like.

Nihil sub sole novum. 
 

24

Physics, Astronomy & Cosmology / Re: Where did the big bang come from?

« on: 23/01/2019 17:46:10 »

Hi Infinityparadox.  Welcome to TNS, and to the ranks of those who try to think beyond the purely mathematical interpretations of infinity.

Your post echoes many of the lines of thought I have wrestled with for a long time.  There are several points to which I hope to return when time permits, and when others have had a say.

Something that doesn’t have a beginning or end is infinity (or infinite possibilities as some put it), it has always existed, time doesn’t flow on it  and it doesn’t reside in space. Then out of it came the universe. The problem as you will see below is that infinity occupies everything that is, there is literally nowhere to put the universe. 

There are two thoughts I would proffer for your consideration.

1.  If “time doesn’t flow” (i.e. there is no time) in infinity, there can be no change; so how could the Universe, or anything else, “come out” of infinity?
2.  If “infinity occupies everything that is, [and] there is literally nowhere to put the universe”; doesn't it follow that the Universe is still included in infinity?

BTW; good luck with this one.  It’s the subject that earned me my first “crackpot certificate”. 

25

Physics, Astronomy & Cosmology / Re: Negative Energy is here? There? Where???

« on: 11/01/2019 17:06:14 »

I’ve had a quick look through the paper, and my initial impression is that they make a good argument for the Universe having arisen from a quantum fluctuation.  I think this is weakened by the (IMO) unnecessary introduction of the “free lunch” idea.  Could it have been a ruse to give them an eye-catching title?

Their assertion that “ The meaning of “nothing” is somewhat ambiguous here” is significant.  How can “nothing” be ambiguous?

If you drop a ball from rest (defined to be a state of zero energy), it gains energy of motion (kinetic energy) as it falls.

Surely, if you can drop the ball from rest, it must be in a position in which it already has GPE?  If you define this as “a state of zero energy”, this may be valid in terms of whatever theoretical point you are making, but has little relevance to “reality”

26

Physics, Astronomy & Cosmology / Re: How remiss is our attitude towards entropy?

« on: 08/01/2019 16:30:07 »

I’m confident that your maths will be flawless, and your reasoning impeccable, but are you talking about entropy or order?

Perhaps you are taking John von Neumann’s advice:  “You should call it entropy…..[because] no one knows what entropy really is, so in a debate you will always have the advantage.”

27

Physics, Astronomy & Cosmology / Re: Does time stand still in the quantum world?

« on: 04/01/2019 12:30:47 »

I like a good debate but the concept of time seems to be flogged to death for no reason.

“Flogged to death” – Yes.    “For no reason” - No.

I think the reason that the subject of time, in a variety of guises, keeps appearing is twofold.

1. We tend to be with St. Augustine, when he said: “What then is time? If no one asks me, I know;
if I wish to explain it to someone who asks, I know not.”

2. We easily lose sight of the point that you make:

It is simply a mechanical means of measurement of change in one form or another.

   
A major factor is the way in which we talk and think about time.  For example: we talk of time passing, when what we probably mean is something along the lines of: change occurs continually, and therefore, we see a progression in time, which is what we use to measure that change.

I doubt that even the most inveterate pedant would suggest that the protracted version would be preferable.  As long as our thinking is adjusted appropriately, the “shorthand” version is fine.  Taking “analogies” too literally, though, tends to lead to confused thinking.

Some examples from this thread include:

  "Change" tells you that time exists.

Change tells us that change exists.  We add the concept of time.

But "change", by itself, doesn't explain the other major characteristic of time: That it seems to travel in only one direction.

The idea that time travels is, in itself, an analogy that should not be taken too literally.

For this you have to look at entropy: Time flows in the direction where entropy increases.

Doesn’t the second law of thermodynamics state that in a closed system, entropy tends to increase, or to remain constant.  In spite of the presence of the word “tends”, the assertion “it never decreases” can still be found attached to many explanations.  Could this be a source of confused thinking?  Even in a closed system, can “time progress” in the direction of decreasing entropy?

28

Physics, Astronomy & Cosmology / Re: What does the term 'time' relate to in time dilation?

« on: 10/12/2018 22:35:57 »

And talking of death! If I die and no longer observe time passing and experience change no longer, does time still exist?

Yes, otherwise your body would not decompose.

29

Physics, Astronomy & Cosmology / Re: What does the term 'time' relate to in time dilation?

« on: 10/12/2018 11:56:16 »

Hi, Set fair; it's always good to look back to the OP when thread drift has moved the discussion away. Mea culpa

If I said time is the measured rate of 'change' then does change happen much slower away from the force of gravity throughout the whole universe?

My “layman” thought is that time is, as you suggest, a measure of rate of change. It becomes convenient to talk of changes in the rate of time’s flow, or of the rate of our passage through time, and to treat time as though it were an entity with existence that was independent of the things being measured and those doing the measuring; which may not be the case.  It certainly streamlines scientific thought and discussion. 

Thinking along those lines suggests that change does happen at different rates in different gravitational situations; however, reference frames and observer dependence must not be overlooked.

30

Physics, Astronomy & Cosmology / Re: What does the term 'time' relate to in time dilation?

« on: 09/12/2018 15:17:45 »

A “timely” thought experiment

“In a galaxy far away”, there exists a star identical to our sun, with an identical “solar system”.
Earth is planet A with physicist A (PA) and clock A (CA).
Earth’s twin is planet B with physicist B (PB) and clock B (CB).
Each physicist can see his own clock and the other’s with no time delay for information transfer.

Three assumptions:

1.  PA and PB each sees time passing at 1 sec per sec on his own clock.

2.  Each physicist sees the rate of time on the other’s clock as unaffected by gravity.

3.  Any difference between the perception of the rate of time between CA and CB, observed by either physicist, will be due to the degree of relative motion between the two galaxies; or relative motion resulting from differential motion within the individual galaxies.

31

Physics, Astronomy & Cosmology / Re: Do photons have mass?

« on: 04/12/2018 22:13:26 »

I’m just trying to get my head round the idea of proper mass, inertia etc, in another thread; so I’m going to have a go at this, to see how I’m doing.

I may be confusing “rest mass” with “proper mass” (possibly they are the same), but let’s start with rest mass.

This is the mass of an object as measured by an observer who sees that object as stationary. We can never observe a photon as being stationary, so we cannot assign it a rest mass. 

However, the photon has inertia, so it adds to the inertia of any system of which it is a part.  Because of the relationship between inertia and mass, the photon must, therefore, contribute mass to that system.

32

Geology, Palaeontology & Archaeology / Re: Can wind weather limestone?

« on: 06/11/2018 11:46:51 »

Hi Jacob, welcome.

It is probably important to distinguish between weathering and erosion.  Weathering is the process by which rocks are weakened and/or broken down, or dissolved.  Erosion is the process by which material, once subjected to weathering, is removed.

In the case of aeolian (wind) effects the picture may be blurred by the fact that the wind itself is generally not what does the weathering, rather, it is material carried by the wind that weathers the rock.  The wind may then do the transporting (erosion) of the weathered material.

Did you have a specific instance in mind?

33

Just Chat! / Re: Would it be wrong to try to get somebody kill themselves?

« on: 13/10/2018 19:17:59 »

Anyone particular in mind?

34

Geology, Palaeontology & Archaeology / Re: What is the name for this form of arch-like geological structure with fractures?

« on: 24/08/2018 22:43:36 »

Hi Geo4dood, welcome.

The left side of the arch looks as though it has parallel surfaces, which could be bedding planes.  This would suggest it is a sedimentary rock that has been folded.  Having said that, I've seen weathered granite domes that have shown quite similar features. Some more details would be valuable.  Where is it?

The fractures at right-angles to these "planes" are likely to be stress fractures.

The structure is an anticline.

I'm only an amateur, and it's a long time since I dabbled in any geology, so hopefully the experts will chip in.

35

Physics, Astronomy & Cosmology / Re: False Vacuum; Who, What, Where, When, Why?

« on: 24/07/2018 23:50:06 »

I’ve found some things that seem to conflict, (surprise!).

One image is that of a scalar field resting with stability in the lowest valley.

Contrast this with statements like: “the bottom of the valley into which the sphere rolls is considered to be the true vacuum, and this is where the scalar field discharges its energy.”

There seems to be a dichotomy between resting in the bottom of the valley, and that “fireball” of elementary particles, mentioned earlier.

The most sensible way round this, that I could see, was that the unstable quon came to rest in the bottom of the valley, discharged its energy and became a stable, expanding, universe.   Does that seem reasonable?

36

Physics, Astronomy & Cosmology / Re: False Vacuum; Who, What, Where, When, Why?

« on: 24/07/2018 20:46:41 »

I would view the higher valleys as tarns - lakes cut off from lower areas.

So far, so good.  Considering a landscape in which a false vacuum state is represented by a valley at an elevation higher than the true vacuum; this would provide the necessary stability. 

What is it that is stable in these valleys?
This necessitates looking at the “inhabitants” of the landscape; often depicted in Pop Sci books as little spheres that can roll about on the hilly landscape.  The best identification of these spheres I have found is that they are scalar fields.  Their energy is dictated by the vertical position they occupy, at any given instant, on the landscape. 

How big are these scalar fields? 
This is a question that is commonly ignored, possibly with good reason, but in developing his argument about the origin of the universe, Vilenkin treats them as quantum objects.  Presumably, this is how we should see them in order to progress to your comment on quantum tunnelling.   

37

Physics, Astronomy & Cosmology / Re: False Vacuum; Who, What, Where, When, Why?

« on: 23/07/2018 20:17:35 »

  The current understanding is that our vacuum has a positive energy equivalent to the mass of three hydrogen atoms per cubic metre, not a lot, but enough to have an enormous impact. 

    In theory, a false vacuum is a higher-energy version, and is characteristically unstable.  Typically, it decays into true vacuum in a small fraction of a second, and its energy is released in a “fireball” of elementary particles.   
 
    In trying to establish a non-technical image of the vacuum, and its energy, the best analogy I found was that of an irregular surface of waves and troughs representing this energy, and considered as a “landscape”.  The bottom of the lowest valley is considered to be the “true vacuum”, that in which our Universe exists.  Crests of waves, and the slopes linking them to the valleys, represent “false “vacuum” states in which the vacuum energy is higher.  Essentially, these are very unstable states. 

38

Physics, Astronomy & Cosmology / Re: Can time emerge?

« on: 16/06/2018 13:32:11 »

A related concept (looking through the other end of the telescope): Can time disappear?

This is subject to the same proviso as is the original question; namely, how do you define time?

If time is just a measure of change, the question should be: can change "disappear"?

39

Physics, Astronomy & Cosmology / Re: Is Einstein Wrong?

« on: 14/06/2018 12:08:32 »

http://www.ewh.ieee.org/soc/pes/switchgear/presentations/tp_files/2010-1_Lunch_Montillet.pdf

I've not read this, and I'm not sure I intend to, but if you're interested it Einstein's mistakes, it could be a good place to start.

It's worth remembering, though, that Einstein had a disconcerting habit of being "right" even when he was "wrong"

40

New Theories / Re: Was a white hole the source of the Big Bang?

« on: 01/06/2018 21:47:56 »

  A zero energy universe requires that the sum total of energy is zero.

That’s an interesting concept.  Surely there are two interpretations of a zero energy universe.

1. A universe that contains no energy.

2. A universe which contains equal quantities of -ve and +ve energy, so the net is zero.

There must be a distinction (?)