Before you go to Darwin, could you please compose a paragraph for the newsletter on your next talk about The Nature of Time.
The nature of time is that the proper time will disappear into the past before you know it, unless you travel to Darwin at the speed of light. Time flies like an arrow!
The nature of time discusses the most important dimension we are able to perceive, the aptly named 4th dimension.
While seemingly simple to those of us stuck in it, it is actually a lot more complex.
Understanding it better is what has led us to the next scientific world , that of quantum mechanics.
This will be a light hearted look into the window of the physics of the future.
As Allan wrote time is an arrow.
It allows us to fit events that happen to us into the past, present and future.
What can we say about time generally?
[audience for insight]. Might find some new ideas here.
Comments. which where when why what how and who. are good questions for any scientist.
1. Time is perception, you cannot separate the two. how
2. Time is a severely local occurrence and current occurrence [when- now]. [where]
3. It is an observable but not repeatable phenomenon [cue Omar Kyam
“The moving hand writes and having written moves on.”] perception
4. Time seems to go only in one direction, from the past to the future.
often called entropy or decay and strangely related to heat or energy.
5. It describes rates of change between objects leading to the concepts of speed and mass.
Indeed this is often how it is measured. rate of change what
6. Events that recur regularly enable us to measure it by the frequency of how often they occur compared to other events.
But this is of course at our scale and with our human perception. [measurable]
5. We can discuss time at a human body level.
How many breathes we normally take in a minute.
How fast our pulse is in a minute.How many steps we can take in a minute.And we do.
These events occur to objects at a human speed and size.
Yet if we move up just a few scales or down a few scales time seems to change dramatically.
Objects at an atomic level move extremely rapidly in time, albeit over minute distances.
A computer can go through a hundred million actions during 1 heart beat. Far faster than the human mind can observe.
A star in the Sky will still be in the same position relative to most of the other visible stars during a human lifetime.
Yet this is all relative to our human sense of proportion.
Once we go either way far enough we find that time is not the same at other scales as it is at ours.
At one end we have the quantum effect. We can no longer predict whee and when an observable event will happen.
At the other end we can see our distant past but have no idea of the current state of objects far away.
2. A digression on local time
Time is measured by local phenomenon and events around us on the earth.
The initial concept was of day and night representing the 24 hour rotation around the earth.
The passage of the sun overhead throwing shadows that increased and decreased led to the sundial and a division into a 12 hour day [and assumed night].
Hour glasses of sand then enabled the hour to be broken into minutes and the minutes into seconds.
Clocks were a late invention 1500s? that enabled even more rapid and accurate measurement until we had the stopwatches of today with hundredths of a second.
Now time can be measured by the breakdown or radioactive caesium atoms, almost a true atomic scale.
At the same time physical properties were slowly being explored. The three dimensions classically are length, width and height.
Typically referred to as space.
If one were to use vectors for direction I would actually think there are 6 such dimensions as everything goes in a mirror direction [the other way] as well.
Time runs with vectors [or vice versa] and again always one way.
Mass and Gravity and electricity also exist but are not part of the four dimensions other than existing in them.
Gravity itself, but not mass, is actually a byproduct of time and space that does not exist as a real force even though we are held to the floor here by it.
The use of dimensions to describe nature is fraught.
We all have a basic understanding of what the first three are in a sense of measurement, and direction.
Time however lacks both measurable length and solidity.
It is all around us and part of us but untouchable.
We can only observe it through its effects on us and other objects.
That is why it is not included in the 3 dimensions.
Yet other things are measurable and palpable but undefinable.The jolt of electricity.
The sudden pull of a magnet and the feeling of mass from soft and squidgy or a breath of air to dense and impenetrable.
This raises the questions of are there other dimensions connected in some way to these other quantities.
* How many dimensions are there? Theoretically infinite
Practically how many of them exist that we may be able to detect in some way.Here is where maths and physics interconnect.
The multidimensional lobby invented string theory where the different dimensions, acting on mathematical principles, interact with each other.
Amazingly there are mathematical predictions and models which suggest it may be real.
Sub atomic particles [in name only] have spins and vectors positive and negative charges, matter and antimatter which follow these rules.
I would like to point out this interesting observation. A 2D creature can never directly see a 3D creature.
We can design cubes in the fourth dimension and yet are unable to represent them in 3D space.
Yet we can see both 3D and 2D in our minds and analyze them.This ability to perceive both space and time by necessity implies
that thought, the mind, is actually working in a 5th Dimension with 4D representation.
There is a simple way for observation to go back in time. Due to the marvels of video cameras we can rewind and replay past sequences.
The egg falling and breaking always breaks the same way.Yet always unscrambles perfectly on rewind.
No two eggs will break in exactly the same way.
This process of action going in one direction only is the definition of time passing.
There is an interesting notion of parallel worlds where every event can spiral off in a new pathway for ever.
Like the Sliding Doors film but on an unimaginable continued eternal program.
This would be a case of different time events as well.Ripples in time.
If it is feasible and if it is happening it would lead to changes that would most likely mean that it was impossible or totally probable.
Let me know if you ever find out so I can adjust the glitch.
Computer worlds or Sims.Another infinite mirrors paradox.
If it is possible then we must be living in a Sim.
Like Neo in the film.And here the concept of time takes on a new meaning A computer program can be paused [stopping time].
Rewound [Going back in time].And even reformatted [Changing the past] so the egg does not drop.
As you can see having proved it is impossible we can also prove that it is real. The definition of a Quantum state.
Now to try to achieve what Professor Hawking could not.
A simple explanation of time and relativity.
The laws of physics are invariant in all frames of reference
Postulate 1: The laws of physics must have the same form in all inertial frames of reference.
Postulate 2: The speed of light through a vacuum is constant, regardless of the motion of the source or observer.
Forget the clocks running at different speeds.
The person going into space at near light speed returning young while everyone else is getting old.
For all practical purposes time and space actually work together.
What effects them is the presence of mass and motion
Mass can only exist if it has dimensions in both time and space.
Time and space can only exist where mass is present.
If a mass moves away from another mass [speed] it develops more mass [extra energy counted as mass] and becomes shortened[like a blue shift.
This is known as
As masses move apart [distance] time speeds up. As they move together it slows down.
If they move at the same speed, in the same vicinity they come closer to having the same time.
This is being close or relative to each other. Hence the theory of relativity.
The bigger a mass is the more it both slows and distorts time space near it.
Time passes faster atop a mountain than at sea level due to the mass of the earth.
Strange but true .
If we look at just the sun and the moon going through space together with no other planets or objects.
Just the two of them. At the same distance apart.
what can we say about them and their movement and forces?
1. The earth is rotating about the sun? ie in orbit
2. the sun is rotating about the earth? ie in orbit
3. The earth is also spinning in its rotation about the sun?
4. The sun is spinning in its rotation about the earth.
5. The two objects will crash into each other due to gravity?
6 The two objects will go in different directions but come back to each other?
7. The two objects will go in different directions and never return?
8. The two objects will come back together at some indeterminate time if they last long enough.
9. the earth has less mass than the sun.
10 . the sun has less mass than the earth.
11 They are both traveling through space in a straight line?
12. They are both traveling through space and time in a straight line?
13. They both are moving?
14. They both are not moving?
15. If they are both not moving do they have any velocity?
According to Newton an object moving through a direction in space will continue to move in a straight line unless acted upon by a force.
Hence both the sun and the moon must be moving in straight lines. [If they are moving.]
So how does the earth go around the sun if it is moving in a straight line?
The answer is that the volume of space and time that the earth is moving in is altered.
Due to both the mass of the earth and the sun on the space time continuum.
As an independent and unrelated observer we see the earth appear to orbit the sun.
To some one on the earth they are traveling in a straight line through their time space volume.
The line however is bent mathematically both in direction and time.
Continually changing with the mass effect.
If I can show a video of the famous trampoline example.
It gives an idea in 3D of what is actually happening in 4D which are minds are unable to visualize.On a flat surface the ball will just roll across and off the trampoline.
With the mass distortion of the bowling ball to the surface the other ball goes into a circular orbit.
Here the forces are friction and resistance from the altered trampoline surface.
In 4D the effect is the same without any force.
Philosophy, Heavy stuff.
Physics and maths describe effects which we perceive.
We can see a ball traveling through the air, estimate its path. Feel its impact on our fingers and hear its impact with out ears.
Yet virtually everything that we use to describe the mechanics can be broken down into a simple binary code of dots and dashes.
We do not need the ball to exist to describe time, length, height, width volume acceleration on a computer printout.
The mind works on or in different levels or dimensions to that of the physical world.
It is in one sense outside of them or inside of them to be able to perceive them which it is able to do for want of a better word by our senses.
We cannot find an analogy to to think of or explain perception other than that we know that we do it.
Time is a part of of our ability of perception.
We can describe it mechanically in terms of changes in other objects that we perceive.
Our perception depends on time passing and going in one direction.
We are able to augment our limited human senses with other devices that the world, just like a Road runner cartoon, supplies when the time is right.
We have a much better understanding of the codes that describe our physical world.
Yet like a mobius band or a blind person reading braille we can only go around in the meaning of the code.
Not understanding how or why it is written.
When discussing time we are discussing its nature and attributes in the physical or real world.
When we get down to the fine print there appear to be inconsistencies.
This is due to the Brownian motion effect. Our inability to be able to see the actual interactions without affecting them in our attempts to do so [microscopically]
or to be able to act at all on the macroscopic level.
We also lack the ability to tie concepts of mass and energy and electricity and magnetism together in a satisfactory way.
Quantum theory describes mathematics in 4th, 5th and higher dimensions.
If such concepts exist mathematically . They do.
Then giving mass and energy motion and dimensions demands that they exist at higher levels and that the parts visible in our dimension
have other qualities in the other dimensions.
Which they do.
Hence the power of the atom and the incredible forces bound up in tiny rotating and moving particles.
‘Time is elastic’: Why time passes faster atop a mountain than at sea level Place one clock at the top of a mountain. Place another on the beach. Eventually, you’ll see that each clock tells a different time. Why? Time moves slower as you get closer to Earth, because, as Einstein posited in his theory of general relativity, the gravity of a large mass, like Earth, warps the space and time around it.
Scientists first observed this “time dilation” effect on the cosmic scale, such as when a star passes near a black hole. Then, in 2010, researchers observed the same effect on a much smaller scale, using two extremely precise atomic clocks, one placed 33 centimeters higher than the other. Again, time moved slower for the clock closer to Earth.
1 and 2 Neither the Sun nor the Earth rotate about the other.
Explanation: ? Both the Sun and the Earth orbit around the centre of mass of the solar system which is known as the solar system barycentre.
Imagine two donut-shaped spaceships meeting in deep space. Further, suppose that when a passenger in ship A looks out the window, they see ship B rotating clockwise. That means that when a passenger in B looks out the window, they see ship A rotating clockwise as well (hold up your two hands and try it!).
From pure kinematics, we can’t say “ship A is really rotating, and ship B is really stationary”, nor the opposite. The two descriptions, one with A rotating and the other with B, are equivalent. (We could also say they are both rotating a partial amount.) All we know, from a pure kinematics point of view, is that the ships have some relative rotation.
However, physics does not agree that the rotation of the ships is purely relative. Passengers on the ships will feel artificial gravity. Perhaps ship A feels lots of artificial gravity and ship B feels none. Then we can say with definity that ship A is the one that’s really rotating. [depends on definition of gravity]
So motion in physics is not all relative. There is a set of reference frames, called inertial frames, that the universe somehow picks out as being special. Ships that have no angular velocity in these inertial frames feel no artificial gravity. These frames are all related to each other via the Poincare group.
For the Earth going around the sun and vice versa, yes, it is possible to describe the kinematics of the situation by saying that the Earth is stationary. However, when you do this, you’re no longer working in an inertial frame. Newton’s laws do not hold in a frame with the Earth stationary.
This was dramatically demonstrated for Earth’s rotation about its own axis by Foucalt’s pendulum, which showed inexplicable acceleration of the pendulum unless we take into account the fictitious forces induced by Earth’s rotation.
Similarly, if we believed the Earth was stationary and the sun orbited it, we’d be at a loss to explain the Sun’s motion, because it is extremely massive, but has no force on it large enough to make it orbit the Earth. At the same time, the Sun ought to be exerting a huge force on Earth, but Earth, being stationary, doesn’t move – another violation of Newton’s laws.
So, the reason we say that the Earth goes around the sun is that when we do that, we can calculate its orbit using only Newton’s laws.
you may describe the motion from any reference frame, including the geocentric one, assuming that you add the appropriate “fictitious” forces (centrifugal, Coriolis, and so on).
But the special property of the reference frame associated with the Sun – more precisely, with the barycenter (center of mass) of the Solar System, which is just a solar radius away from the Sun’s center – is that this system is inertial. It means that there are no centrifugal or other inertial forces. The equations of physics have a particularly simple form in the frame associated with the Sun.
M1d2/dt2x? =GM1M2(r? 1?r? 2)/r3+…
There are just simple inverse-squared-distance gravitational forces entering the equations for the acceleration. For other frames, e.g. the geocentric one, there are many other inertial/centrifugal “artificial” terms on the right hand side that can be eliminated by going to the more natural solar frame. In this sense, the heliocentric frame is more true.
ust one thing! One mustn’t neglect the non-idealities of the barycenter itself, which has a location in the Milky Way that biases it gravitationally at least. On the surface this is splitting hairs, but the greater point is that the idealness of any reference frame is also relative, and no “ultimate” frame exists.
[Wittgenstein] once greeted me with the question: “Why do people say that it was natural to think that the sun went round the earth rather than that the earth turned on its axis?” I replied: “I suppose, because it looked as if the sun went round the earth.” “Well,” he asked, “what would it have looked like if it had looked as if the earth turned on its axis?”
A rotating frame is distinguishable from a nonrotating frame, without reference to anything external. This is true both in Newtonian mechanics and in special and general relativity. There are various ways to tell if you’re in a rotating frame, including a Foucault pendulum, a mechanical gyroscope, or a ring-laser gyro of the type used in commercial jets. The Foucault pendulum as a proof of the earth’s rotation dates back to about 1850. (Long before then, heliocentrism had become accepted among physicists on less definitive grounds, such as the fact that Kepler’s laws have a simple form in a heliocentric frame.) As a relativistic example, the analysis of the famous Hafele-Keating test of general relativity required the introduction of three effects: kinematic time dilation; gravitational time dilation; and the Sagnac effect, which is sensitive to the rotation of the earth.
From the perspective of general relativity, there is something wrong per se with using a geocentric point of view to describe the entire universe. While coordinate systems are global in Newtonian mechanics, they are local in general relativity. Coordinate systems are local charts on Riemannian space-time in general relativity. They do not have universal extent. A mandated geocentric perspective does not make sense in terms of general relativity.
4 In fact, our gaseous sun is divided into different zones and layers, with each of our host star’s regions moving at varying speeds. On average, the sun rotates on its axis once every 27 days. However, its equator spins the fastest and takes about 24 days to rotate, while the poles take more than 30 days. The inner parts of the sun also spin faster than the outer layers, according to NASA.
All told, the Sun loses a total of 4 million tons of mass via Einstein’s E = mc² with each new second that passes. This mass loss, however small it is, adds up over time. With each year that goes by, the loss of this mass due to nuclear fusion causes the Earth’s orbit to outspiral by 1.5 cm (0.6 inches) per year. Over its lifetime so far, the Sun has lost the equivalent of the mass of Saturn due to nuclear fusion.
The straight line is in 4 dimensional space!! Seeing the 4th dimension earth curves a light beam goes much straighter due to velocity.
Your question suggests that you are using the term “spacetime” to mean just “space”. “The Earth is travelling in a staight line in spacetime” is a way of expressing Newton’s First Law of motion in four dimensional spacetime. Actually, they only move in straight lines if spacetime is Euclidian. I.e. If the shortest distance between two points is a straight line. In general, they move on trajectories that represent the shortest distance in four dimensions. This will generally be a curved path because spacetime is curved. Specially near a black hole.