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Author | Topic: Expanding time? | |||||||||||||||||||||||||||||||
cavediver Member (Idle past 3960 days) Posts: 4129 From: UK Joined: |
The title of this thread is expanding time as a question More than 100 replies came and went...and maybe I failed to see it. But last I heard... time is a measure of movement. As such, it is a tool... made by man... to serve man. It is not a force, such as gravity. It is only a means by which we cope with our everyday efforts and observations of movement, large or small. To say time and space are relative terms is correct...in math. But physically...space and mass are relative, and their relationship is measured by gravitational effects Time is cognitive construct. An intellectual appliance. thief Welcome to pre-20th century science. Enjoy your stay. Given the dogmatism of your statements, I suspect you may be stuck there a while...
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DevilsAdvocate Member (Idle past 3418 days) Posts: 1548 Joined: |
Thief,
Here is a book for the uninformed layman that will help you out (though it is about a decade old itself) and explain some of the underpinnings of modern cosmology and quantum physics. It is called Hyperspace by theoretical physicist Michio Kaku. The first section goes into the history of todays understanding of multidimensional space including the 4 dimensions of spacetime that we humans can percieve. Like cavediver rebutted, you are 100 years behind the power curve and are talking in terms of the 19th century and prior. Trailblazers such as 19th and early 20th century mathematicians and physicists Carl Gauss, Bernhard Riemann, Theodor Kaluza, Oskar Klein and of course Albert Einstein (this is not an all inclusive list) at the turn of the century helped explore and define the nature of spacetime and layed the foundation for the field of quantum mechanics. Theoretical physicist and leading string theorist, Brian Green's books "The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory" and "The Fabric of the Cosmos: Space, Time, and the Texture of Reality" give us a more up to date picture of today's understanding of quantum mechanics and multidimensional space. Kaku has a new book called "M-Theory: The Mother of All Superstrings" but I have not had a chance to read it yet. As I myself am a layman I defer to Cavediver to correct me if I am wrong in any of this. I am just trying to help out another physics layman. ![]() For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring. Dr. Carl Sagan
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Modulous Member (Idle past 302 days) Posts: 7801 From: Manchester, UK Joined: |
If there were a giant tape measure between two galaxies and I made a reading at one moment. Then I take a vacation and read it again, does it now measure greater than previously? Or does the tape measure expand with space and read the same as before? As far as I am aware it would measure greater than previously. Space has expanded, but physical objects in space maintain the same dimensions (the forces holding them together ensure this).
Also what book might be a good choice to learn about current cosmology for someone with about 5 years of science/engineering background, but no previous coursework in cosmology? I might not be the perfect candidate for book recommendations on this topic. You might find Brian Greene's The Fabric of the Cosmos rather good, I know I did with a similar length of background in electronic engineering and physics.
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Larni Member (Idle past 171 days) Posts: 4000 From: Liverpool Joined: |
Space has expanded, but physical objects in space maintain the same dimensions (the forces holding them together ensure this). Does this expansion have any effect on vacuum energy? Does it get more diffuse as space expands? I'm sure I'm thinking like a layman here, so if it's a non-question I'm cool with that. Edited by Larni, : No reason given.
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Modulous Member (Idle past 302 days) Posts: 7801 From: Manchester, UK Joined: |
Does this expansion have any effect on vacuum energy? Does it get more diffuse as space expands? I think it might have an effect on vacuum energy/vacuum energy density. I don't think anyone has a definitive answer as to what that effect is at this time. I don't think it is simply analogous to the way other diffusion processes works I'm afraid - since I think space and the vacuum energy have an intimate relationship of sorts.
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onifre Member (Idle past 3268 days) Posts: 4854 From: Dark Side of the Moon Joined: |
Hi Larni,
Does this expansion have any effect on vacuum energy? As I understand it, it is because of the vacuum energy density that there IS an expansion. It stays constant because there is no negative pressure(or positive gravitational force).
Does it get more diffuse as space expands? Again, as I understand it, the expansion is at an accelerated pace, indicating that the vacuum energy density is still constant(positive). What I believe does change is the matter energy density. I believe it decreases, im not sure by how much though. "I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth."--Bill Hicks "I never knew there was another option other than to question everything"--Noam Chomsky
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cavediver Member (Idle past 3960 days) Posts: 4129 From: UK Joined: |
Does this expansion have any effect on vacuum energy? Does it get more diffuse as space expands? Good question - it depends ![]() ...on the nature of the vacuum energy. A cosmological constant contrubution does not dilute. Other forms of dark energy will dilute, but still drive an accelerating expansion. And then there is the hypothetical contribution which actually grows with dilution! (ABE this doesn't make sense! I mean its effect grows as the universe expands - the reverse of the diluting) This is what gives rise to the Big Rip ![]() Edited by cavediver, : No reason given.
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Larni Member (Idle past 171 days) Posts: 4000 From: Liverpool Joined: |
So, you can't give me a straight answer?
Congratulation Cavediver, you have just proved that God made the universe ![]() I hope you're happy with yourself ![]()
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thief Junior Member (Idle past 5850 days) Posts: 30 Joined: |
Thief here....
Okay, your perspective is complex and includes the collective knowledge of all the life time efforts of the afore mentioned math experts, scientists, and genius type people...but do you think of time as an energy, a form of mass, or neither?
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DevilsAdvocate Member (Idle past 3418 days) Posts: 1548 Joined: |
Thief writes: Thief here....Okay, your perspective is complex and includes the collective knowledge of all the life time efforts of the afore mentioned math experts, scientists, and genius type people I am glad you realize this. Not many layman do. Many think that without training, education they can comprehend concepts that have taken decade if not centuries to develop. A good quote that sums this up is by Isaac Newton (though he himself did not originate this metaphore but rather it is recycled from the 12th century) in a letter to his rival Robert Hook:
Isaac Newton writes: If I have seen a little further it is by standing on the shoulders of Giants. Thief writes: ...but do you think of time as an energy, a form of mass, or neither? I'll take a crack at this. Though I will defer to our resident physicist Cavediver if I get this wrong. Space-time is a 4 dimensional zero-point energy field in which energy and matter resides. Spacetime, energy and matter are all intricately linked physically in our universe. Spacetime is really a difficult concept for layman (like myself) to even begin to understand. However, to answer your question technically the answer is no, time is not energy or matter but rather part of the framework (I think mathematicians and physicists use the term 'manifold') in which energy-matter resides and interact. Also energy and matter themselves are two different forms of the same 'substance' as defined by Einstein's famous E=MC2 forumula. Edited by DevilsAdvocate, : No reason given. Edited by DevilsAdvocate, : No reason given. For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring. Dr. Carl Sagan
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thief Junior Member (Idle past 5850 days) Posts: 30 Joined: |
Perhaps my question was too simple...which would lend to answers of complexity
I was taught existence is material as is solid, liquid, or gas.... or it is a form of energy. Time is a dimensional quality..not a quantity...though we often speak of time as something we run out of. As a dimensional quality...it is purely of our mindful efforts Divisions of length 'exists' only in our thoughts. A distance traveled is metered for the sake of calculation but the act of measurement does not generate mass nor speed. I am aware that extreme speed or extreme gravity 'warp' our perceptions, and the calculations to understand such things suggest even greater inconceivable effects...but to treat time as mass or energy, is difficult to accept. I see a digression coming. Perhaps a discussion about the singularity could help? thief
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onifre Member (Idle past 3268 days) Posts: 4854 From: Dark Side of the Moon Joined: |
Im skeptical of your intentions but...
Time is a dimensional quality..not a quantity...though we often speak of time as something we run out of. You are confusing physics and the everyday world you live in. Time is a dimensional quality in general relativity, in physics, in cosmology. It is a dimensional quality when describing the space we experience. In this sense time has never been refered to as "running out".
As a dimensional quality...it is purely of our mindful efforts It is purely of the mindful efforts of people much smarter than you and I to have figured out that time was a dimensional quality.
Divisions of length 'exists' only in our thoughts. A distance traveled is metered for the sake of calculation but the act of measurement does not generate mass nor speed. Yes, and the tribes men who live in the rain forest have no use for a calculator. Time IS used for the sake of calculations, by people who are calculating! If you don't want to recognize time as a dimention, then don't. If you aren't calculating anything that requires you to take time into consideration, what do you care? However, if you are going to calculate something that required you to take time into consideration, then you better see it as a 'thing' that is a part of the geometry of the universe or you are going to fuck things up.
I am aware that extreme speed or extreme gravity 'warp' our perceptions, Of what?
and the calculations to understand such things suggest even greater inconceivable effects... What 'such things' are you talking about?
but to treat time as mass or energy, Who is doing this? Who is treating time as mass or energy? 3 spatial dimensions and 1 time dimention describe the geometry of our universe...where's the problem? Oni "I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth."--Bill Hicks "I never knew there was another option other than to question everything"--Noam Chomsky
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Agobot Member (Idle past 5847 days) Posts: 786 Joined: |
Larni writes: Does this expansion have any effect on vacuum energy? Does it get more diffuse as space expands?
I believe you have to get rid of certain assumptions if you want to get the "whole" picture of how everything fits together in the universe from the smallest constituent parts to the largest(that's what most physicists say anyway). I know this might cause more confusion than understanding but unless we drop certain kinds of realism and locality, all the effects seen in experiments in different fields of physics cannot be explained. Take the photon for example. Andromeda is now 2.4 mln. light years away but in the past, theory says, it was closer. Regardless of this, a photon emitted from a star within the galaxy, will not travel any distance towards the Milky Way, from its frame of reference. This is because at c, time dilation becomes infinity so any distance within the universe from the photon's frame of reference is zero, whether there is metric expansion or not. What's even more mind-boggling is that every emitted photon is everywhere in the universe at once, while in transit. The enigma lies in the question - what is "everywhere" for the photon? And what is the "universe"? You cannot grasp this while holding onto to realism and locality. Those 2 notions are characteristic of our experience, not of how the universe is. Space and time are relative concepts, not fixed ones. They utterly depend on the observer's frame of reference. Edited by Agobot, : No reason given. Edited by Agobot, : No reason given. Edited by Agobot, : No reason given.
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thief Junior Member (Idle past 5850 days) Posts: 30 Joined: |
Hi Onifre
So...Geometrical concepts height, width, length,and time are required to understand complex events, and some events calculate to observations that may be difficult to deal with if exposed to them At the speed of light, oncoming light sources would color shift, and no light source following you can be seen You would have to deal with a perceptual warp Some believe that time slows as the speed of light is approached. Would you continue to age? A journey through space, would later bring you home to find all the people you knew, to be dead by several hundred years. Your perception of time would be warped. I can think of one situation where time does not apply. thief
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onifre Member (Idle past 3268 days) Posts: 4854 From: Dark Side of the Moon Joined: |
Hi theif,
Currently your post is going off topic so I won't continue to reply as to not clutter yet another BB and Cosmology thread with nonsense. No offense, - Oni "I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth."--Bill Hicks "I never knew there was another option other than to question everything"--Noam Chomsky
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