this post was submitted on 08 Aug 2024
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[–] cmgvd3lw@discuss.tchncs.de 22 points 3 months ago (3 children)

Now I am curious, somebody explain. if it just stopped burning, would we know after 8 mins, if we lived on the opposite side?

[–] hemko@lemmy.dbzer0.com 55 points 3 months ago (5 children)

Moon would "disappear" when it no longer reflected Sun's light.

It would also start getting very cold fast

[–] marcos@lemmy.world 18 points 3 months ago

It would probably take more than a day for the cold to be so intense that you can't possibly explain with some normal local phenomenon.

[–] tate@lemmy.sdf.org 16 points 3 months ago

The moon might be on the daylight side, so we wouldn't necessarily observe that.

[–] Routhinator@startrek.website 14 points 3 months ago (1 children)

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.

[–] Emmie@lemm.ee 4 points 3 months ago* (last edited 3 months ago)

It’s kind of odd that it doesn’t matter for a single human whether they die from sudden car accident or get obliterated by supernova. Both events feel equal

[–] Anticorp@lemmy.world 6 points 3 months ago (4 children)

Does heat travel at the speed of light? I just realized I have no idea how the heat from the sun travels to earth.

[–] ironhydroxide@sh.itjust.works 31 points 3 months ago

The "heat" IS the radiation. So, yes.

[–] 0ops@lemm.ee 13 points 3 months ago (2 children)

Someone correct me if I'm missing some nuance here, but heat doesn't get transferred directly through space because heat is vibrating molecules and space is a vacuum. The sun radiates (speed O' light). A lot of that radiation just reflects off the earth (or we wouldn't be able to see it), but a lot of it gets absorbed. THAT's when it's converted into heat energy. It's also why the greenhouse effect is a global phenomena: light energy comes in across the vacuum relatively easily, turns to heat on Earth instead of being reflected, heat energy cannot escape as easily as light energy.

[–] Anticorp@lemmy.world 4 points 3 months ago

Neat! Thanks for sharing.

[–] GreyEyedGhost@lemmy.ca 4 points 3 months ago

Infrared light is absorbed quite easily, producing heat, and the sun emits a lot of it. Of course, all photons that are absorbed and not reflected will produce thermal energy, and infrared radiation is commonly referred to as radiant heat. The other two heat transfer methods are conduction and convection, which requires a medium to transfer through.

[–] emuspawn@orbiting.observer 6 points 3 months ago (1 children)

When there is a total solar eclipse, the temperature does drop dramatically. But it might not be detectable on the other side right away for sure.

[–] 200ok@lemmy.world 3 points 3 months ago

It does! And if you're in a place where night animals are noisy, they get noisy for the length of "dusk", totality, and "dawn"!

[–] theneverfox@pawb.social 2 points 3 months ago

Yes, we have conduction, convection, and radiative heat transfer. Vacuum insulates the first two, it's the light from the sun that heats us up

[–] Rai@lemmy.dbzer0.com 5 points 3 months ago (1 children)
[–] WolfLink@sh.itjust.works 11 points 3 months ago

It wouldn’t really be faster than normal nighttime cooling. However, that cooling would continue instead of having the sun to start warming stuff up in the morning.

[–] bluemellophone@lemmy.world 21 points 3 months ago* (last edited 3 months ago) (4 children)

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.

[–] cmgvd3lw@discuss.tchncs.de 7 points 3 months ago (3 children)

Interesting, so you are saying light is faster than gravity?

[–] nublug@lemmy.blahaj.zone 10 points 3 months ago

light speed = gravity speed

[–] FundMECFSResearch@lemmy.blahaj.zone 2 points 3 months ago* (last edited 3 months ago)

From an AI, so take with some salt:

Yes, gravity is believed to travel at the speed of light.

According to Einstein's theory of general relativity, the effects of gravity propagate through spacetime at the speed of light. This means that if a massive object were to suddenly change its position, the gravitational effects would not be felt instantaneously by objects around it, but would instead spread outward at the speed of light.

This is in contrast to the classical Newtonian view of gravity, which treated it as an instantaneous force. Einstein's theory showed that gravity, like other forms of electromagnetic radiation, obeys the speed limit set by the speed of light.

Experimental evidence, such as observations of binary pulsars, has confirmed that gravity does indeed propagate at the speed of light, as predicted by general relativity. This is a crucial aspect of our modern understanding of the nature of gravity and its relationship to the fabric of spacetime.​​​​​​​​​​​​​​​​

[–] ironhydroxide@sh.itjust.works 6 points 3 months ago* (last edited 3 months ago) (2 children)

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?

[–] ironhydroxide@sh.itjust.works 4 points 3 months ago

Gravitysimulator.org has an interface you can simulate what happens, though it's timeframe is on the order of days. Not seconds.

[–] Tlaloc_Temporal@lemmy.ca 2 points 3 months ago

Why would it travel radially away? The resulting gravity wave from a disappearing stun much push the Earth a little, but changing its orbit that drastically would mostly destroy Earth anyway.

[–] mattreb@feddit.it 3 points 3 months ago

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.

[–] abfarid@startrek.website 2 points 3 months ago (1 children)

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.

[–] lone_faerie@lemmy.blahaj.zone 2 points 3 months ago

I think that's just the wording. My interpretation of that is any satellite or space probe sending back readings to Earth wouldn't be faster than the sun visually disappearing from the sky. Even with the information being transmitted at the speed of light, there's always going to be some sort of processing delay, along with the limited bandwidth of the transmission.

[–] Nakoichi@hexbear.net 8 points 3 months ago

Yes, because of the medium of communication you are using right now.