When is Now?

[Nakosis]

Is there an absolute now in the universe?
IOW is there a universal now in which all events occur in throughout the universe.
Our does the universe have different "time zones" such that now in one area of the universe is out of sync with events that happens in other areas of the universe?

So I don't have an answer for this "now" but I'm looking into it.
Feel free to contribute however.

 

[dybmh]

Is there an absolute now in the universe?

Yeah, it was here a moment ago; but you just missed it.

 

[Shadow Wolf]

I'm really not sure. As we understand it, no, not really as much of our present happened already in the past, so our now isn't quite simple.
It's all a strange ball of wibbley-wobley timey-whimey stuff.

 

[Yerda]

I've never got my head around relativity but if I recall correctly two observers have the same 'now' when there is no relative motion between them. So depending on your state of motion what you are calling now is simultaneous with an observer's now on another galaxy millions of light years away. But if you significantly alter your motion your 'now' might be simultaneous with a 'now' millions of years before the other obsever is born in their galaxy or millions of years after they have died.

One of the brainy people will be able to explain, or correct me.

@Meow Mix @Polymath257 @LegionOnomaMoi

 

[Polymath257]

The simple answer is NO.

Two observers is motion with respect to each other will NOT have the same notion of simultaneity. In other words, two events that both seem to be 'now' to one will NOT even be at the same time to another.

 

[The Hammer]

Right there.

 

[Nakosis]

I'm really not sure. As we understand it, no, not really as much of our present happened already in the past, so our now isn't quite simple.
It's all a strange ball of wibbley-wobley timey-whimey stuff.

Yes, our now, what we experience as now, doesn't seem to exist. In fact what we see and what we hear gets processed at different speeds. But our brains processes the information so we experience sight and sound in sync.

However, I'm not asking about what "we" experience as now. Without involving an observer, does the universe have an absolute now?

 

[Nakosis]

I've never got my head around relativity but if I recall correctly two observers have the same 'now' when there is no relative motion between them. So depending on your state of motion what you are calling now is simultaneous with an observer's now on another galaxy millions of light years away. But if you significantly alter your motion your 'now' might be simultaneous with a 'now' millions of years before the other obsever is born in their galaxy or millions of years after they have died.

One of the brainy people will be able to explain, or correct me.

@Meow Mix @Polymath257 @LegionOnomaMoi

The simple answer is NO.

Two observers is motion with respect to each other will NOT have the same notion of simultaneity. In other words, two events that both seem to be 'now' to one will NOT even be at the same time to another.

Ok, but what if we don't involve observers. Lets take it as a given as human observers what we experience as now is an illusion. Light can only travel at the speed of light. Something 4 light years away takes 4 light years to reach us to be observed. Did it actually happen, in the universe 4 years ago?

 

[We Never Know]

Yes, our now, what we experience as now, doesn't seem to exist. In fact what we see and what we hear gets processed at different speeds. But our brains processes the information so we experience sight and sound in sync.

However, I'm not asking about what "we" experience as now. Without involving an observer, does the universe have an absolute now?

Wouldn't black holes change the now in them?

 

[Ben Dhyan]

Is there an absolute now in the universe?
IOW is there a universal now in which all events occur in throughout the universe.
Our does the universe have different "time zones" such that now in one area of the universe is out of sync with events that happens in other areas of the universe?

So I don't have an answer for this "now" but I'm looking into it.
Feel free to contribute however.

Yes, now is all there is, was, or ever will be. The concept of time is merely the awareness of the continuation of now, and by measuring some regular movement or oscillation as a proxy for the continued existence of now.

 

[Shadow Wolf]

However, I'm not asking about what "we" experience as now. Without involving an observer, does the universe have an absolute now?

I'm not sure. Perhaps, but only as we can best percieve it.

 

[We Never Know]

Is there an absolute now in the universe?
IOW is there a universal now in which all events occur in throughout the universe.
Our does the universe have different "time zones" such that now in one area of the universe is out of sync with events that happens in other areas of the universe?

So I don't have an answer for this "now" but I'm looking into it.
Feel free to contribute however.

Planet Day Length

Mercury 1,408 hours
Venus 5,832 hours
Earth 24 hours
Mars 25 hours
Jupiter 10 hours
Saturn 11 hours
Uranus 17 hours
Neptune 16 hours

Years

Mercury: 88 days
Venus: 225 days
Earth: 365 days
Mars: 687 days
Jupiter: 4,333 days
Saturn: 10,759 days
Uranus: 30,687 days
Neptune: 60,190 days

Would their now be the same as our now

 

[Polymath257]

Ok, but what if we don't involve observers. Lets take it as a given as human observers what we experience as now is an illusion. Light can only travel at the speed of light. Something 4 light years away takes 4 light years to reach us to be observed. Did it actually happen, in the universe 4 years ago?

It happened 4 years ago in our reference frame. But it is 4 light years away in our reference frame. In other reference frames, it will be a different distance and will take a different amount of time.

 

[Ben Dhyan]

Ok, but what if we don't involve observers. Lets take it as a given as human observers what we experience as now is an illusion. Light can only travel at the speed of light. Something 4 light years away takes 4 light years to reach us to be observed. Did it actually happen, in the universe 4 years ago?

You say you are talking about absolute now, and then you talk about a relative now, an event happening somewhere and light traveling 4 light years, etc.... Universal or absolute now is independent of events happening anywhere within the universe and observations thereof, it is not a relative, it is absolute.

 

[9-10ths_Penguin]

Ok, but what if we don't involve observers. Lets take it as a given as human observers what we experience as now is an illusion. Light can only travel at the speed of light. Something 4 light years away takes 4 light years to reach us to be observed. Did it actually happen, in the universe 4 years ago?

It's not about the speed of light.

- say you have two flashes set to fire at the same time. They're far apart, but both 4 light years away from you. You're motionless relative to the two flashes.

- someone else, also 4 light years away from both flashes, is in high speed motion.

- when the flashes fire, both flashes will appear to arrive at the same time for you, but at different times for the other person.

 

[Wandering Monk]

Relativity says that moving clocks run slower. But everything in the universe is moving relative to any other thing in the universe. In the scientific sense, there is no such thing as Now. The 3:06 mark on this video directly addresses the question of Now.

 

[Aupmanyav]

You can get tonow only by traveling back in time.

 

[Wandering Monk]

You say you are talking about absolute now, and then you talk about a relative now, an event happening somewhere and light traveling 4 light years, etc.... Universal or absolute now is independent of events happening anywhere within the universe and observations thereof, it is not a relative, it is absolute.

There is no physical tool to measure absolute now. It is a philosophical construct, not a scientific one.

 

[Spirit of Light]

Is there an absolute now in the universe?
IOW is there a universal now in which all events occur in throughout the universe.
Our does the universe have different "time zones" such that now in one area of the universe is out of sync with events that happens in other areas of the universe?

So I don't have an answer for this "now" but I'm looking into it.
Feel free to contribute however.

Since everything is changing all the time (pun not intended) There is nothing called right now, because even if you think "NOW" that moment has already gone into the past.

 

[Nakosis]

It's not about the speed of light.

- say you have two flashes set to fire at the same time. They're far apart, but both 4 light years away from you. You're motionless relative to the two flashes.

- someone else, also 4 light years away from both flashes, is in high speed motion.

- when the flashes fire, both flashes will appear to arrive at the same time for you, but at different times for the other person.

Two things, again you are using observers. Second, you just said these flashes happened at the same time, the same moment in the universe. How could that happen? Your scenario assumes the "now" 8 light years apart is in sync.