eli5 Is it correct to think of events happening on the far side of the universe or in a different galaxy as occurring “at the same time”?
In: Physics
Yeah but the distance between you two is so much that to see each other’s actions will take forever.
You’d both jump at the same time but it’s gonna take 50 billion years to see it lol
If you are seeing it happen (in the sky / through a telescope) it happened in the past relative to you at the time you saw it. If it’s just you thinking about something happening now across the universe then it’s happening now, at the same time.
Yes, you will hear a lot about relativity. But at the end of the day observers don’t alter the situation.
Two events happening at the same time happened at the same time regardless of distance apart. It’s that simple.
Kind of. The speed of light is the speed in which that information travels.
Take our sun for example. It is around 8 light minutes away, meaning that it takes light about 8 minutes to travel from the sun to the Earth. Let’s say that the sun quit shining at exactly 3:00, and at that exact time, you sneezed. The sun going out and you sneezing would have happened at the same time. But it would take 8 minutes for the information that the sun went dark to get to you. So from your perspective, you sneezed at 3:00 and the sun went out at 3:08.
Now, if someone was twice at far from the sun as you and could somehow see you sneeze, from their perspective, you sneezed at 3:08 and the sun went out at 3:16, even though both events happened at the same time at 3:00. That’s why there are theories of Relativity. Because the time in which events are noticed are relative to where the observer is and how fast the observer is moving
On a cosmic scale, time and distances are enormous. So a lot of the stars that you see at night have blown up or burnt out hundreds or thousands of years ago, it’s just that the light of those explosions haven’t reached your eyes yet.
We can’t know in the present what events are happening simultaneously great distances away because the information takes some time to reach us, similarly to how lightning appears near-instantly to our eyes but the information from the sound takes time to reach us. But if we know the distance between galaxies and the speed at which information travels, we can determine what we were doing at the moment the information left its source, and can say those two instances occurred simultaneously.
For example, if you aim a telescope at Mars, you’re seeing Mars 3 to 22 minutes ago (depending on its distance from us). You can’t know what is happening there exactly now because that information is still travelling towards you and hasn’t arrived yet, but you do know what you were doing 22 minutes ago. So whatever happened then occurred “simultaneously” to what you’re seeing through the telescope now.
In terms of extremely far distances, the rate of passage of information (time) is affected by things like relative velocity and gravity. If you take those things into account, you can say that two stars exploding “simultaneously” to your eye through the telescope may be occurring at the same time, or at different times, but definitely not “now”.
It is, in fact happening at the same time, but if you look at it it will take millions of years for you to see it
As you can see, it’s hard to answer this question without bringing up topics such as ‘observer’ and ‘relativity’.
The answer is yes, with the contingency that you could never prove or get outside verification that these events occurred at the same time (within a reasonable time frame)
Clearly things are happening at this moment on the other side of the universe. We can just never know or verify what those things are (until the light reaches us)
Check out The Order of Time, by Carlo Rovelli. He does an amazing job of addressing a lot of this and how we got from Aristotle’s view of “time” all the way through the modern physics definition with respect to relativity and quantum mechanics. (It also debunks some of the flat-out wrong assertions in a lot of the other comments.)
Time is relative. It happened at the time you perceived it so, yes, it happened at the same time as where you are.
If you were closer, you would perceive it differently.
Time is relative. Someone hits a baseball. Light travels very fast so you see it almost instantly at our scale. Sound is slower so you don’t hear the crack until later.
Your mind perceives these things as instantaneous, yet they have time delay. A Cell phone call has time delay. Time is a cruel mistress.
The answer is, events are based on perception.
Time is irrelevant because it has no baseline. Time is dilated due to speed. Nothing matters. You hear yourself talk to yourself in your ear on the phone. You burn your toe but you don’t feel it for a bit. Gravity distorts space time. Speed distorts space time.
Nothing matters. So, yes, what you see is what you get is the easiest way to manage it. God never made a start point or a ticker for time.
Think too much about it and you’ll want to pull the covers up to your neck, tuck in your toes, and try not to think about infinity.
Short answer? No, it doesn’t. “Over there” and “right now” are two concepts that cannot be mixed.
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