Does sunlight push the Earth ever so slightly?

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    Earth Push Sunlight
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Discussion Overview

The discussion centers around the concept of radiation pressure from sunlight and its potential effects on the Earth's gravitational orbit. Participants explore the relationship between the momentum of photons emitted by the Sun and the gravitational forces acting on the Earth, considering both theoretical implications and practical calculations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the momentum of photons from the Sun could create a noticeable effect on the Earth's orbit, suggesting that radiation pressure should be considered alongside gravitational forces.
  • Others argue that while theoretically possible, the effects of radiation pressure are likely negligible compared to gravitational forces, as both forces are relatively weak.
  • One participant provides a formula for calculating radiation pressure and notes that it is negligible, citing specific intensity values at the Earth's surface.
  • A later reply reiterates the initial idea about the potential effects of radiation pressure and solar wind, suggesting that these forces may push the Earth outward but also lead to energy loss, which could counteract any outward motion.

Areas of Agreement / Disagreement

Participants express differing views on the significance of radiation pressure in relation to gravitational forces. There is no consensus on whether the effects of sunlight on the Earth's orbit are substantial or negligible.

Contextual Notes

Some calculations and assumptions regarding the intensity of radiation pressure and its comparison to gravitational effects remain unresolved, and the discussion does not clarify the extent of these effects on the Earth's orbit.

Chaos' lil bro Order
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Considering that the Sun radiates EM photons at many different wavelengths onto the Earth and that these photons carry a momentum which they impart into the Earth upon contact, wouldn't the aggregate of all these 'pushing' photons create a noticeable effect on the the Earth's graviational orbit around the sun? I wonder about the intensity of this radiation pressure in proportion to the intensity of sun's graviational effect. Since a lot of our estimate as to what the Earth's interior composition is based on inferred knowledge of the Sun's mass and the moon's mass we should take into account the radiation pressure's effect which pushing our orbit further out from the sun than if the sun suddenly went 'lights out!' but its mass remained constant in the dark blackness.
 
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theoretically yes but i doubt itd be noticeable as both the forces inquestion (photon pressure and gravity) are very weak
 
It's relatively easy to calculate the radiation force, and it is negligible.
The pressure =2Icos\theta/c (Gaussian units) for reflected sunlight
(Icos\theta/c if s\absorbed). I=12X10^5 ergs/cm^2-sec at the Earth's surface.
 
Chaos' lil bro Order said:
Considering that the Sun radiates EM photons at many different wavelengths onto the Earth and that these photons carry a momentum which they impart into the Earth upon contact, wouldn't the aggregate of all these 'pushing' photons create a noticeable effect on the the Earth's graviational orbit around the sun? I wonder about the intensity of this radiation pressure in proportion to the intensity of sun's graviational effect. Since a lot of our estimate as to what the Earth's interior composition is based on inferred knowledge of the Sun's mass and the moon's mass we should take into account the radiation pressure's effect which pushing our orbit further out from the sun than if the sun suddenly went 'lights out!' but its mass remained constant in the dark blackness.
The radiation pressure as well as the solar wind tends to push the Earth outward and thereby increase its energy. But the motion of the Earth through the solar wind causes loss of energy and tends to slow the Earth down a bit. I suspect that these very small forces almost cancel each other out.

AM
 
Chaos' lil bro Order said:
Considering that the Sun radiates EM photons at many different wavelengths onto the Earth and that these photons carry a momentum which they impart into the Earth upon contact, wouldn't the aggregate of all these 'pushing' photons create a noticeable effect on the the Earth's graviational orbit around the sun?
http://images.google.ca/imgres?imgu...m=10&hl=en&lr=&rls=SUNA,SUNA:2005-51,SUNA:en"
 
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