Does light make us heavier and does the Earth's rotation affect our weight?

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Discussion Overview

The discussion revolves around the effects of light on weight and whether the Earth's rotation influences weight. Participants explore the concept of light pressure and its potential impact on mass, as well as the propagation of light through the Earth.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions if light makes us heavier during the day due to its pressure on atoms, suggesting that if light pushes them, it must also push the Earth.
  • Another participant notes that light does exert pressure, but only on certain atoms, primarily those in the skin and clothes, and that this pressure is not easily detectable without sensitive instruments.
  • A participant proposes a hypothetical scenario where light pressure is significant enough to measure, discussing how it would affect objects based on their surface area to mass ratio.
  • There is a mention of the theoretical concept that turning on the sun could create a pressure wave that would travel through the Earth at the speed of sound.

Areas of Agreement / Disagreement

Participants express varying views on the effects of light pressure and its implications for weight, with no consensus reached on the overall impact of light on weight or the specifics of how light interacts with matter.

Contextual Notes

Participants highlight limitations in understanding the penetration of light and its effects on different materials, as well as the conditions required to measure light pressure accurately.

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Hello I am new to physics and I did no knew were else I can ask this question so i am sorry if I am in the wrong place.
My question is : if light makes us heavier by pushing our atoms does it means we are heavier in the day time? and the answer should be yes but then I thought if light pushes me, then it also pushes the Earth, which means that the Earth is pushing me when I am in the opposite site of the sunlight (the other part of the sphere) meaning that I am always weight the same. but should not the of the sunlight travel trough the Earth with the speed of sound?
My English is bad and I am very sorry for it.
But I am weary confused and i hope you can help me.
I Sincerely thank you!
 
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If you had a very sensitive scale then it could indeed measure the radiation pressure from sunlight.
 
if light makes us heavier by pushing our atoms does it means we are heavier in the day time?

Light does push on us. But not on all our atoms. Just on the ones in our skin and clothes. It does not penetrate very far. It does not push very hard. Not enough to be easily detectable. You have to use fairly sensitive instruments in laboratory conditions to detect light pressure.

But pretend for the moment that light pressure was large enough to measure easily...

Because the light does not penetrate very far, that means that it would still only directly affect surfaces facing the sun. Light pressure would correlate well with surface area. It would not correlate well with volume or with mass.

Suppose that you had two bodies. One had a high surface area to mass ratio and one had a low surface area to mass ratio. Which would be accelerated more strongly by light pressure?

but should not the of the sunlight travel trough the Earth with the speed of sound?

If you turned on the sun (like turning on a light switch) then, theoretically, this would create a pressure wave. Yes, this pressure wave would move through the Earth at the speed of sound.
 
jbriggs444 said:
Light does push on us. But not on all our atoms. Just on the ones in our skin and clothes. It does not penetrate very far. It does not push very hard. Not enough to be easily detectable. You have to use fairly sensitive instruments in laboratory conditions to detect light pressure.

But pretend for the moment that light pressure was large enough to measure easily...

Because the light does not penetrate very far, that means that it would still only directly affect surfaces facing the sun. Light pressure would correlate well with surface area. It would not correlate well with volume or with mass.

Suppose that you had two bodies. One had a high surface area to mass ratio and one had a low surface area to mass ratio. Which would be accelerated more strongly by light pressure?



If you turned on the sun (like turning on a light switch) then, theoretically, this would create a pressure wave. Yes, this pressure wave would move through the Earth at the speed of sound.

Thank you!
I am less confused now
 

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