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originally posted by: dragonridr
we learned there is no universal time and how something experiences time is dependent on its point of view.

What do you mean by 'universal time'; if there was 'universal time' what would that mean?

originally posted by: ImaFungi

originally posted by: dragonridr
we learned there is no universal time and how something experiences time is dependent on its point of view.

What do you mean by 'universal time'; if there was 'universal time' what would that mean?

They are saying that time, or rather the perception of time by the observer, depends on where you are located relative to what you are viewing. A really good example of this is the synchronization of GPS satellites' clocks with Earth based clocks.



-FBB

a reply to: ImaFungi

This is where the subject of entropy might be useful.
Viewing Hookes spiral watch spring in two dimensions (Newton/Hooke debate)(Phi with universal expansion theory Newgrange, Ireland).
If the Watch spring remained a fixed spiral (like the Phi in a Conch shell) it could provide no energy.
The potential energy of the watch spring is greater when it is wound up in a tight spiral.
As the spiral unwinds and approaches the 0 limit (Conch shell) it can provide no energy.

Entropy: a thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work.

In this simple example the entropy change in the spiral watch spring is moderated by an escapement mechanism.


OT but IMHO the evil Davinci would hold the patent for Briggs and Stratton pull starters not Newton and certainly not Nietzsche.

Hi.

Last night there was about 4 inches of fairly light snow on my car, no ice at all though.

I'm super lazy so I turned on the vehicle, set the defrost to max, and went back inside for about twenty minutes while the car warmed up.

I now have a huge crack in my windshield.

Is it possible I caused this?

There doesn't appear to be any type of "impact" source, just a really long diagonal crack that starts from where the driver's side heater would have been blowing on the windshield.

The temperature outside was about 25 degrees in Fahrenheit.

Cheers.

a reply to: Steffer


Hate when that happens.
That will teach you not to use a blow torch to melt really thick ice..

originally posted by: Cauliflower
a reply to: Steffer


Hate when that happens.
That will teach you not to use a blow torch to melt really thick ice..

I thought you only weren't supposed to pour hot water directly on your car.

I figured that the slow change in heat, as the vehicle warmed up, wouldn't have caused any damage.

I feel like such an idiot now.

EDIT: Oh, and there was no ice, only snow.

originally posted by: FriedBabelBroccoli

originally posted by: Nochzwei

originally posted by: ImaFungi
a reply to: Nochzwei


'Time' is not 'a thing'; therefore time cannot be compressed.

On the contrary time is a physical entity and definitely a thing.

Define 'time' as you are using it please. Further a definition of physical entity would also be helpful because as it stands I don't really understand how you are using it.

Thanks

-FBB

physical entity is something physical. as time is coupled to dark matter, they together become a physical entity. read the thread in my signature.

originally posted by: greenreflections
Why are you bringing 'galaxy' word to no end? I understand you have a lot on your plate answering all kinds of questions but please, I was referring to the period of cosmic expansion before any galaxy could be formed. You must have taken me for some one else.

Let's look at what you wrote once again:

originally posted by: greenreflections
I think that one cannot say space-time has a form. It expands arbitrary. When needed, on demand. When the demand is too much, black hole forms))

I see no reference to inflation here, so I presumed you were talking about the expansion of the universe, especially through the use of present tense "when the demand is too much..." instead of "was" and "black hole forms" instead of "formed". If you're referring to inflation I suggest to not use present tense and actually mention inflation. There are lots of ideas about what happened in inflation and one idea is that black holes formed during that event however one consequence of that idea is that there would be black holes of various sizes as a result. So far observations have suggested there's a shortage of intermediate sized black holes as this idea would predict:

www.spaceanswers.com...

originally posted by: dragonridr
Space time is just a way of locating something in the universe nothing more. Think of it as street signs letting you know where you are. Those street signs only work when you have two.

How does frame-dragging fit into that view, or does it?

Gravity Probe B has finally confirmed that the Earth drags spacetime around as it rotates like a spoon twisting in a jar of honey,

originally posted by: ImaFungi
a reply to: Arbitrageur

I am sure there can be other explanations for that, like the rotation of materials including our planet, perhaps an effect of dark matter or energy, or a certain interaction with a certain matter moving in a certain way and of certain material properties.

We presume dark matter is involved in that amount of distortion of space-time. I'm not sure how the rotation of our planet could cause such an observation, since if that was the cause why wouldn't other objects be similarly affected? There are some other rings like that but they are relatively rare.

I think if you apply the constraint of what else we know, alternate explanations are going to be limited.

We have other measurements of course like time dilation and frame-dragging, but since our clocks and satellites tend to be on or around the Earth that's where we observe those effects. Aside from observing these space-time effects how would you propose to make a direct observation?

originally posted by: FriedBabelBroccoli
They are saying that time, or rather the perception of time by the observer, depends on where you are located relative to what you are viewing. A really good example of this is the synchronization of GPS satellites' clocks with Earth based clocks.

I corrected your link. Copy the whole link like you did if not embedding, but to embed the video only use the video code at the end, not the youtu.be part. Nochzwei should watch that since he keeps denying my claim there's relativity engineering involved in the GPS system.

By the way another consequence of absolute time is that three events which are simultaneous for one observer would be simultaneous for all observers. Einstein said it seems that way in ordinary circumstances but we can show how John might perceive a sequence of events A then B then C in that order, but Mary in a different frame of reference might see the same events with a different sequence as C then B then A in that order. A third observer might see all three events happening simultaneously. The reason we never noticed such differences before Einstein is that relativistic effects were not commonly observed. Even today we don't have observers traveling at the speeds shown in this illustration, but this is what we think actually happens to a lesser extent say in a spacecraft relative to Earth, which can't happen under absolute time:

Relativity of simultaneity

Events A, B, and C occur in different order depending on the motion of the observer. The white line represents a plane of simultaneity being moved from the past to the future.

a reply to: Steffer
Have you ever used a glass cutter to cut glass? It doesn't cut all the way through the glass, it just puts a tiny scratch in it and that's enough to allow the glass to break easily.

If you had a brand new windshield I'd be surprised if what you did would break it. You may not even be able to find it now after the crack, but maybe a rock hit your windshield at some point in the past and made a small defect in the glass surface not unlike a glass cutter makes. You might not even notice it unless the sun hit it a certain way. Obviously the defroster blowing on the windshield created some thermal stress and if it had a place to focus like where a rock hit the windshield, a crack can form and grow very long.

This is one reason I don't like to follow large trucks, because truck tires have more of an open trajectory in the rear when they kick up rocks, so they can hit your windshield. When most cars encounter rocks they are more likely to hit the car's rear fender instead of flying up in the air and hitting your windshield.

a reply to: Nochzwei

The physical part of time is in the SI unit definition; wikipedia

Based on caesium microwave atomic clock

With the development of the atomic clock in the early 1960s, it was decided to use atomic time as the basis of the definition of the second, rather than the revolution of the Earth around the Sun.

Following several years of work, Louis Essen from the National Physical Laboratory (Teddington, England) and William Markowitz from the United States Naval Observatory (USNO) determined the relationship between the hyperfine transition frequency of the caesium atom and the ephemeris second.[6][19] Using a common-view measurement method based on the received signals from radio station WWV,[20] they determined the orbital motion of the Moon about the Earth, from which the apparent motion of the Sun could be inferred, in terms of time as measured by an atomic clock. They found that the second of ephemeris time (ET) had the duration of 9,192,631,770 ± 20 cycles of the chosen caesium frequency.[19] As a result, in 1967 the Thirteenth General Conference on Weights and Measures defined the SI second of atomic time as:
FOCS 1, a continuous cold caesium fountain atomic clock in Switzerland, started operating in 2004 at an uncertainty of one second in 30 million years.

the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.[6]

This SI second, referred to atomic time, was later verified to be in agreement, within 1 part in 1010, with the second of ephemeris time as determined from lunar observations.[21] (Nevertheless, this SI second was already, when adopted, a little shorter than the then-current value of the second of mean solar time.[22][23])

During the 1970s it was realized that gravitational time dilation caused the second produced by each atomic clock to differ depending on its altitude. A uniform second was produced by correcting the output of each atomic clock to mean sea level (the rotating geoid), lengthening the second by about 1×10−10. This correction was applied at the beginning of 1977 and formalized in 1980. In relativistic terms, the SI second is defined as the proper time on the rotating geoid.[24]

The definition of the second was later refined at the 1997 meeting of the BIPM to include the statement

This definition refers to a caesium atom at rest at a temperature of 0 K.

It is physical in that it is the series of cycles of an atom at a 0 kelvin.

-FBB

wiki or MS has not yet wised up on wt I said about time in my last post. but eventually they will come around to it. it maybe pointed out that I am talking of ambient time and not mans chronometer time. If time was not physical, you cannot achieve anti gravity by negating time.
a reply to: FriedBabelBroccoli

a reply to: ImaFungi

Same for quarks. Is the hypothesis that a quark is something that exists a testable theory?

My grandfather used to try to teach me physics while we rode around together in his Studebaker.
He had a trailer that he towed and always used to make a big thing about crossing his safety chains under the tongue.
One of the routes we traveled ran alongside a deep quarry with rainwater at the bottom.
He told me a story about a man who was sleeping in his travel trailer parked next to the Quarry.
Apparently he died when his wife unhooked the trailer and it rolled over the edge.
Thought maybe he had a Quarrel with grandma or something I was about 8.
You have me wondering now, has there been an update since 1965 or was Murray just a good swimmer?

a reply to: FriedBabelBroccoli

I know. But dragonrider said 'we learned universal time does not exist';

I was attempting to lead him down a series of questions, which would make him potentially notice, that it is not that 'we learned that universal time does not exist', it is that we learned that 'universal time may or may not exist, but either way, it seems as if we cannot know it or use it as a measurement'.

originally posted by: ImaFungi
a reply to: FriedBabelBroccoli

I know. But dragonrider said 'we learned universal time does not exist';

I was attempting to lead him down a series of questions, which would make him potentially notice, that it is not that 'we learned that universal time does not exist', it is that we learned that 'universal time may or may not exist, but either way, it seems as if we cannot know it or use it as a measurement'.

I am working my way through Arbitrage's link concerning time perception so I wont really comment on whether we may or may not be able to measure a universal time. I generally write scipts now for doing these calculations/rendering so it could be a while.

Wish I could be more helpful on that front.

-FBB

a reply to: Cauliflower

i wish I could but I cannot detect the point you were attempting to make.

a reply to: ImaFungi

Einstein once said "I should have been a plumber"
(Think RicHard Trethewey under the sink)

originally posted by: ImaFungi
a reply to: FriedBabelBroccoli

I know. But dragonrider said 'we learned universal time does not exist';

I was attempting to lead him down a series of questions, which would make him potentially notice, that it is not that 'we learned that universal time does not exist', it is that we learned that 'universal time may or may not exist, but either way, it seems as if we cannot know it or use it as a measurement'.

"universal time may or may not exist" depends on how you define universal time. The non-existence of "absolute time" as defined by Newton is a consequence of what we know of the speed of light and the fact observers can be in different reference frames as explained by Einstein.

However one might hypothetically assign a special relativistic reference frame to the universe, where one's velocity with respect to the cosmic microwave background was zero, and use that as a reference frame for the universe. One problem with that is we know our motion with respect to the CMB only approximately, but the bigger problem would be using a reference frame other than our own as that would require inconvenient corrections.

So in a typical misnomer fashion, we have defined a "universal time" (sometimes abbreviated UTC) which is not the aforementioned hypothetical "time of the universe", but it's "universal" in the sense that all time zones on Earth can refer to the same UTC, and you can even find a UTC column in NASA mission plans for astronauts in orbit. A "universal day" in "UTC" universal time is the time it takes for the earth to make a complete rotation which is good enough for civil purposes but not for scientific purposes because the Earth's rotation is slowing down and has irregularities, so for those scientific purposes there's "Terrestrial Time" aka TT which differs from UTC each time leap seconds are used.

TT takes Earth's gravity into account, so if you wanted a real "universal time" not on Earth like TT and UTC, but of the universe, the problem isn't so much how to deal with special relativity, but how to deal with general relativity. The gravitational influence of all bodies has no exact limit, so where do you put the universal clock for universal time if not on Earth's surface? There is nowhere in the universe that we know of where the general relativistic effect on clocks from masses will be zero.

originally posted by: ImaFungi
a reply to: Cauliflower

i wish I could but I cannot detect the point you were attempting to make.

That just means none of us are as clever as Cauliflower because we can't figure out what he's talking about. Or I suppose there could be alternate explanations, but I'm pretty sure most people are in the same boat as you here, including me.

a reply to: Arbitrageur

Yes, all of what you say about universal time echoes my sentiments; you are speaking about the difficulty of humans knowing universal time; there is always a difficulty between humans attempting to know truth, and whether or not truth exists independent of human knowledge or attempt at knowledge. I was saying; just because humans have difficulty knowing universal time, or just because it is impossible for humans to know universal time, does not mean a human can say 'universal time does not exist'.

Universal time is the objective truth of the fact that reality exists continuously, regardless of what consciousnesses exist within it and how they might measure it. Universal time is the true orientation and relative movement of all that is continuously at all times and spaces. Obviously humans cannot utilize this fact, obviously it is incorrect to say universal time does not exist.

originally posted by: ImaFungi
a reply to: Arbitrageur

Yes, all of what you say about universal time echoes my sentiments; you are speaking about the difficulty of humans knowing universal time; there is always a difficulty between humans attempting to know truth, and whether or not truth exists independent of human knowledge or attempt at knowledge. I was saying; just because humans have difficulty knowing universal time, or just because it is impossible for humans to know universal time, does not mean a human can say 'universal time does not exist'.

Universal time is the objective truth of the fact that reality exists continuously, regardless of what consciousnesses exist within it and how they might measure it. Universal time is the true orientation and relative movement of all that is continuously at all times and spaces. Obviously humans cannot utilize this fact, obviously it is incorrect to say universal time does not exist.

Of you want a true universal time it's the speed of light. Everything in the universe moves at the speed of light including you. However do to the relationship of space and time it doesn't seem that way. The closer you get to the velocity of light time for you slows down. Alternately if you could manage to find an area of the universe where you could remain at total rest you would move through time at the speed of light. Without time we would be left with a universe that everything goes speeding off at the speed of light needless to say this wouldn't be good for our existence.

If you want to understand space to me you need to understand mikowski space. Imagine when you were born you are given will say energy to move through space time. You never have more or less then the speed of light. How this energy is used is dependent on where you are and the mass you have in and around you. As you travel through time relative velocity will all ways be less then the speed of light. If you managed to get moving at the speed of light time for you stops as we only have a limited amount of energy for moving through space time.

This isn't a fabric of the universe it is a law or a property of the 4th dimension. If we could separate ourselves from the forth dimension we would see we can plot everything from beginning to end it's all ready there we only get to see small slices of this as we travel through time. Depending on where you are dictates what slice of space time you see. You are taking a property and trying to turn it into something else entirely. If you want to know the fabric of the universe that would be gravity it holds everything together and effects all points in the universe. Without it nothing would exist

originally posted by: dragonridr
Everything in the universe moves at the speed of light including you.

I understand the concept you're trying to convey and it's an interesting concept, but I think the language needs a little work. Here's a man trying to explain the concept in very simple terms:

www.youtube.com...

I agree the speed of light is an ultimate reference, and this obviously has profound implications, including E=mc²

a reply to: Arbitrageur

Why does the value c², multiplied by m, equal energy?

The amount of consistently ticked intervals it takes for light to move an amount of consistently distant intervals;

Why does 'multiplying' that relation of intervals, by 'whatever mass is'; lead to 'whatever energy is'?