There is only now. You can live in anxiety and fear of what might happen, then something completely different happens when unplanned variables occur. Revisiting past memories in regret and remorse, reliving the pain, keeps people living in the past. Consciousness translates from the metaphysical to the physical, from the psychological to the reality our neurons perceive as reality. People live in the past and future all of the time, and forget about the now. Carpe diem is more than just a trendy saying. Eastern philosophy and scientific studies have profound results in their research and the way they perceive their universe and reality. A unified way of thinking is needed to focus our energy on the now but for the infinite future.

I am partially convinced.

I am convinced that now for different observers is different and they can’t agree on a single now (if they are moving with respect to each other), but there is still a now for every one of them. A bit like a group of observers could see a rainbow, but each would be looking at a slightly different version of that rainbow.

What is it that makes something in my future move into my past. It seems Special Relativity doesn’t address this (yet?).

I’m not convinced.
This method doesn’t allow use to see the future. It only reduces the delay in seeing (do to the speed of light.) The best we can do is to go the speed of light, then there’s no delay (even tho the object maybe light years away. )
A distant observer sees our past do to the speed of light. This method also allows seeing us with a greater delay.

I’m not convinced at all:
There is a past which we can trace back, on a cosmic scale right down to the big bang, and we are fairly sure about the cosmic history or, if you will, the cosmic past – on large scales.
The present is a “floating” point transferring permanently from the past to the future. For us humans, it should be one of the major endeavors to “grab the moment” and live it.
The future is unknown. We can speculate to some extent and on some scales what the future might hold, such as the transformation of our Sun into a red giant and then a white dwarf, or the mergers first with Triangulum and later with Andromeda or, looking out even farther both into space and time, the picture of “our” cosmos being a single, quite massive galaxy – and nothing else within what we know as the cosmic horizon.
Something like a “now slice” ? I consider it absolutely meaningless, and it certainly is different from any idea of simultaneity (which we usually understand to have some meaning in terms of mutual relation, being between events ot in relation to us).

This honestly blew my mind. The fact that a hypothetical sentient being billions of light-years away moving towards or further from Earth in the right way can actually see a “future” now-slice from our perspective raises all kinds of philosophical issues like the existence of free will (i.e., how can that being see our future before we have even made the decisions to create that future?) that I can’t wrap my head around. But from a scientific POV, I have started processing the notion that a higher-dimensional being might see time as just another spatial dimension and can move freely from the past to the future to the present like we move from left to right, up to down. If I think of humans as 3-D beings trapped in a 4-D or 5-D world, these paradoxes make more sense–if we are seeing the implications of a higher-dimensional universe from our 3-D perspective, we are bound to run into paradoxes and weirdness that doesn’t make sense to us.

If we define being “real” to be the ability to establish physical communications, then the answer is no. The reason is simple. There is no possibility of the alien to influence the past or the future of the concerned person. There is no way to establish physical communications. Hence, the supposed “now” is only “virtual” or hypothetical, not real, by definition.

Absolutely believable, Past, Present and Future exists simultaneously. The only problem I have with that fact is , do we therefore really have free will if the future already exists?.

Again we are in the problem of using the words “real” “exist” “past” “present” and ” future” “now”. These terms can be scientifically defined or philosophically, or common sense current daily life defined. But first we must agree on those uses and understanding.
When saying present instant here, in science terms means measured at a given physical time, which implies, ¿what precision in the measurment? 10 to minus ??? ”nanoseconds? true you can say that “now” can be syncronus for two observers in the same reference. If time is as well cosidered as a quantum, yes then we have a minimal measurement of time. Asuming time is as well quantum, physically you can talk about a present instant in a given reference. But in what concern the reality for a human observer there is not a present, any perception of human beings are perceptions of a change, what it is perceived is a change, so there
is not an instant for human beings. Bergson in his discussion with Eistein about time, he introduced the idea that for the humans the primary perception and aprehension of reality it is “duration”, statement which I fully share. For the humans duration plus memory constitue the reality and the time. Kant said that time and space are ideas a priory, those we now know after the science of evolution of living beings, that this ideas a priory in our brains are absolutly neccesary for survival and normal life. When we pass from that reality for humans to think about if the time is or not an object a physical object, a phisycal entity, then we are in a complete different field.
I need to advance more in this course to answer to you if time is a physical entity or as some scientist afirm, it is just the measure of space with a different unit, since finally time is always a comparaison of movements, it means comparaison of measurement of space. If finally space is quantum, then time will be as well quantum.
But in any case what can not be perceived by any observer is a state of the world which have not yet in its own local reference ocurred. The universe evolve but according to entropy law do not go back against the arrow of time. It is not he same to say you or me see things before or later, than to affirm an observer can see the state of the universe,which have not yet ocurred in the arrow of time. True the arrow of time is not the time we have up to this lesson analyzed. A distant observer can see the collapse of a Star which is in the future to myself, but nobody can see the collapse of that star if it have not happened in its reference system. Ok, happened for whom? : for the start itself.
So my conclusion is that nobody can see the future of a given referece system calling future of that system an state of facts of that system which have not ocurred for itself.

I see a lot of doubt and speculation within this thread. And as this course does not include Quantum Mechanics then you all fall within the same rationalising category, emotion. The problem is, is that this is science. So unless you have facts and figures to back up your emotional opinion, what you say, feel or express holds zero substance to the truth being learned here.

The past and future both exist because someone moving relative to you is in YOUR past, which also means you are in THEIR future. Doubters are getting stuck on the concept of spacetime. Every person on Earth holds a unique conception of time, which means objects are both in your past and your future. Which ultimately means that we don’t have free will because we can LITERALLY SEE the future.

You think you’re reading this by your own choice?…. “time is an illusion, however persistent” Albert Einstein.

The physical meaning of “now” is in my opinion very different from our intuitive ideas. In the first place, we cannot directly observe (or ‘see’) the things (events) happening at other places in the “now”, since the information about them cannot instantaneously come to ourselves. The “now” of an observer is a mathematical construct, a bridge between past and future of the observer.
Also the aliens far away will have a “now” that is not as a whole immediately accessible (seeable) to them. In fact, as I understand the result of special relativity, the theater of all events and processes is a manifold where space and time cannot be separated in two disjunct pieces (in contrast: Newton thought about time as being an absolute time which is not dependent on reference frames). The time flow of some person, – with past, now and future -, is a somewhat arbitrary chosen direction of movement on that 4-dimensional manifold, and when comparing the time flows of different persons, the velocity with respect to each other has to be taken into account. The “past” of one person can possibly be the (unknown) “now” of an other being, and that is also true for “the future”. So in the story of the special relativity, there is on the manifold no absolute distinction (compartimentalization) between past, now and future.

Convinced to the point of future. Past and present are somehow understandable, but future is (in my opinion) still open…

This concepts is in direct relation with the concept of ‘Eternalism’. Eternalism is a philosophical approach to the ontological nature of time which says,”Past, present and future all exist, exist simultaneous.” But it’s a debatab;le topic currently in physics. So we can’t agrre upon the concept until and unless we get a robust theoretical or experimental evidence.
What ya say?

I am convinced that past and future exist.

Yes, I am convinced they do.

no

From this what i found is that the past present and future are illusory

What if we have free will but that distant relatively moving observers are merely witnesses playing back events in whatever time direction they so choose, in a universe that has instantly unfolded at its inception. That way we have our cake and eat it too: free will and coherent physics models of reality.

Love this course. I am just commenting playfully here, since the comments seem to have inspired a philosophical discussion.

Ithoughit made sense until the speed of light limitation of 45 degrees came up. Now it’s going to take more thought.

The 45-degree limit makes perfect sense to me Penny. If we look at feet and nanoseconds as x and y axes, then the angle between 1 on the feet axis and 1 on the nanosecond axis is, in fact, 45 degrees.

My question is about what we each see on our respective Now slices assuming the alien and I are stationary with respect each other. A super-nova that I see as happening “now” might seem to be happening “sooner”—if that’s the appropriate word—to the alien if he is closer to the super-nova. When we look at things farther and farther away, we are looking into the past. An alien that is a billion light years away is/was existing/existed a billion years ago, so its Now is quite different from mine. If he/she/it/whatever were able to see me at my Now, he would be looking into the future.

James Hogan had an fascinating take on this in his novel “Thrice Upon a Time,” which postulates time travel of information. I highly recommend it for anyone interested in this sort of speculation.

Strange feeling when you think of space-time as a whole loaf of bread that can be cut from different angles…

partially convinced . how can some one see our future with out the rays from us touches there eye..

I can see my past and future right now. Just look into the alien’s bike’s mirror! They are both happening in my now simultaneity, and which one is which depends solely on which direction the alien is driving into.

Now go get a bigger telescope.

Since we haven’t bothered to try to define what “past” and “future” is then we all using our own (and possibly) different interpretations of those concepts which can bring us to different conclusions/insights. I would propose that the concepts of past and future need to be tied to the concept of causality. Events that have occurred that can affect what I am doing now can be said to be in the past. Events that can be affected by what I am doing now can be considered to be in the future.

no an observer who sees a cosmic event before i do is just closer. we are both seeing the past because the light has to travel a distance before we can observe the event.

KINDA (as I don’t fully understand yet)

In my opinion, Brian is not going sufficiently deep in the explanation. The fact that the human is on a bench and the alien is riding a bicycle, give us the feeling that the human is at rest and the alien is in motion but, as we have learned, we can consider that is the human who is in motion and the alien being at rest. From that point of view the “now-there” of the human would be also in the “past-there” of the alien. At the same time we can say that the “now-here” of the alien is in our “past-here”.

So the now slices are respectively tilted in a way that both can say that his “now in the remote distance” is in the past of the each respective local now

SPACE —->

His now here —- My now there

My now here —- His now there

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For comparing “now slices” and determine whether an event is in the future or in the past of another event, we have to specify the location of these events. This is the reason I am talking of my “now here or there” and his “now here or there”.

When we see a block universe, the components have relativity of spontaneity.

The eternal moment of the now contains all times. Past present and future occur in the now slices of relativity. The causality of identity can have the sequences incorrect, or out of sequence.

Yes, indeed it was a convincing explantation,But why should the angle always be 45 degrees

“Spacey Wacey timey whimey,” as Dr. Who would say, but yes I get it, I’ve had the view of the Universe with me for awhile now that has all space and time existing always, with only our perspective limited by now slices.

a lot of these comments seem to be more philosophical than scientific or mathematical. IMHO

Yes, I am convinced by the relativistic reasonings that the past and future are real and truly exist, just like the present. This perspective aligns with the understanding of time in modern physics, particularly in the framework of relativity theory.
According to relativity, the concept of “now” is not absolute but depends on an observer’s frame of reference and their relative motion. Different observers moving at different velocities will have different perceptions of simultaneity. It implies that what is considered the “present” for one observer may be in the past or future for another observer.
Additionally, the theory of relativity suggests that time is not a fixed and universal quantity but is instead malleable and influenced by factors such as gravity and velocity. This notion is supported by empirical evidence, including experiments with atomic clocks on spacecraft and observations of time dilation around massive objects.
Considering these aspects, it becomes apparent that the past, present, and future are not static, isolated entities but interconnected aspects of a broader space-time framework. Each event or moment in time has its own existence within this framework, and the distinction between past, present, and future is relative to the observer’s reference frame.
Therefore, based on the scientific understanding of relativity theory and the evidence supporting it, I am convinced that the past and future are real and have an existence on par with the present.

yes!

Yes

Based on the principles discussed on this lesson, in some sense they do exist at same time as the time vector in each frame of reference is “consuming” future, processing now and exhausting past. I consider this issue as exchange of messages. A) Both, the unmoving and moving reference frames see the clock in the other one slower. B) The message sent from the moving frame “feels” zero or near zero time passed when received at the unmoving frame, thus “pseudo-syncing” the frames according to the message or photon. Also, this “intra-photon zero time vector” enables the role swapping of moving and unmoving frames. C) The intra-frame transmission is possible only in phase of the time vector. Communications to the past is not possible as c is always positive in all reference frames, and between the frames. D) Thus one can send a message from now to the past, which is actually the local now at the receiving end, provided the communications is inter-frame message exchange. One cannot send a message from local past to now or from local future to local now inside reference frame. Or that’s what I think.