this post was submitted on 08 Aug 2024
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Science Memes

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submitted 3 months ago by [email protected] to c/[email protected]
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[–] [email protected] 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.

[–] [email protected] 7 points 3 months ago (3 children)

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

[–] [email protected] 10 points 3 months ago

light speed = gravity speed

[–] [email protected] 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.​​​​​​​​​​​​​​​​

[–] [email protected] 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?

[–] [email protected] 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.

[–] [email protected] 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.

[–] [email protected] 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.

[–] [email protected] 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.

[–] [email protected] 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.