It goes to 9 minutes from 8, since every single communication gadget will yell out that the sun has disappeared as reports come in from the other side of the earth.
Kind of. The concept of simultaneity breaks down at distances where the speed of light matters. If we base it on what we currently observe and call "now" on the Sun the eight minute old state we currently observe then what does "now" on earth look like from the point of view of the Sun at that same moment? You can't reconcile a single "now" for observers in both locations.
An alternative take which is also consistent with observable physics is that the speed of light is infinite but it's causality itself that propagates at c.
Thinking in those terms also makes a number of relativistic effects more intuitive. You need infinite energy to reach the speed of light simply because it's infinitely fast. Time dilates when moving because you're encountering approaching causality earlier than you otherwise would have. Time "stops" for anything traveling at the speed of light because at infinite speed it just experiences literally everything in its line of travel at once and the concept of "after" becomes meaningless, encountering all future oncoming causality in a single instant.
This was a bit of a tangent but it's something that has fascinated me for a long time.
I'm trying to understand how that reference frame works when you just just bounce a photon off a mirror and time how long it takes to come back? Like, light must have a non-infinite speed to the stationary observer, or it wouldn't take time to traverse the distance.
It's sort of how if you hold a slinky on one end hanging down, then drop the slinky, bottom will not start falling until the top reaches it. In a sense, bottom will be hanging onto nothing. But of course that nothing is tension from the top of the slinky.
The sun could be gone but its influence would remain. Kinda like getting out of a pool and looking back to see the waves on the surface that you caused.
There is a really great short story by Larry Niven based on a similar premise:
"Inconstant Moon"
There is also an "Outer Limits" episode based on this. I watched that before knowing the short story and it is one of only 2 or three OL episodes that I still have an active memory of...
Assuming its midday, and the moon is on or near the horizon, it would actually still be seen for an additional 1.3 seconds after we see the sun disappear. If its high in the sky however, it would disappear only a few ms after the sun, unless it was in a full or partial eclipse, where it would disappear at the same time to our eyes.
Any visible planet or asteroid would. So some stars would also appear to blink out, but those would take longer to blink out. So the moon would go after 8 minutes, Jupiter would take 43 minutes to stop receiving light, and another 35-52 minutes to disappear for earth depending on orbital locations.
Presumably we would get something on radio/tv/internet from the side facing the sun once they realized it, that of course being only if they hadn't already been eradicated by a horrific shockwave caused by whatever event caused the sun to vanish before they had a chance to report what they saw, because supernovae tend to travel at very close to the speed of light, so there wouldn't be much time for them to react.
And if this is a supernova, you might just have time to grok what happened before the planet was obliterated under your feet from the shockwave.
So I guess... chances are we would just barely understand what happened before we were gone.
It takes 8 minutes for the light to travel from the sun to Earth. Because light in a vacuum travels faster than anything, including information, we would not and could not know it had disappeared for 8 minutes. This means Earth would continue to follow its orbit around a non-existent sun for 8 minutes because the Sun’s gravity would still be acting on the Earth.
If it was nighttime, you wouldn’t notice the sudden lack of sunlight (other than if it was a full moon) but you’d almost certainly notice the change in gravity.
Edit: actually, you wouldn’t feel any difference in gravity or experience any change of acceleration. What you would experience is a very tiny vibration, of 1 million push notifications being sent to your phone from the other side of the planet.
I don't think you'd actually "notice" the gravity.
Earth would still retain it's mass, and we're much closer to it, so it's lesser mass acts much more on us than the sun's greater.
Though, the earth would stop orbiting the sun and travel on a mostly tangential path travel nearly radially away from where the sun was, instead of the elliptical path it currently travels.
This is a very interesting physics question that I may look into further. Specifically what would the theoretical acceleration be, due to the lack of the sun? Is it above a humans level of perception?
It's weird to say that light travels faster than information, because light is information. In other words, top speed for information IS speed of light.
you’d almost certainly notice the change in gravity.
Really? can you actually percieve the sun gravity? Do you mean that we would get like a tsunami beause of the tidal effect? Now I kinda want a documentary about this.
Which two event are you talking about being simultaneous? The Sun going out and Earthers observing it? Those things will not be simultaneous in any reference frame, because they are "light-like" separated. (ie they lie on a 45 degree line in a Minkowski plot.)
I think what he means is when the light from the sun disappearing arrives at earth, that’s effectively when the event of the sun disappearing happened from the earth’s perspective.
In about 8 minutes and 20 seconds, we would lose the Sun’s gravitational force. Namely, gravitational waves travel at the speed of light (186,000 miles per second or 299,000 kilometers per second). This also means that we would be in complete darkness 8 minutes after the Sun disappears
I’m 0% an expert in this, but I think they move at light speed all the time. Light is “affected” by mass only indirectly, since the light travels in a straight line through local space but space itself is curved by the mass.