Does the Earth get bigger from the sun?

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Discussion Overview

The discussion revolves around the concept of whether the Earth is expanding due to mass added from the sun's energy and other sources, including space dust and meteors. Participants explore various aspects of this idea, including thermal equilibrium, mass accumulation, and the implications of the Earth's core cooling.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • One participant proposes a theory that the Earth is expanding due to added mass from the sun's energy, questioning its validity and the extent of such expansion.
  • Another participant argues against this theory, stating that the Earth is in thermal equilibrium, where energy absorbed from the sun is re-radiated, preventing continuous heating.
  • Some participants note that the Earth does gain mass from absorbing space dust and meteors, estimating this to be about 100 tonnes per day, but express uncertainty about whether this results in expansion or contraction of the planet.
  • It is mentioned that the cooling of the Earth's core may contribute to a shrinking effect, complicating the understanding of the overall mass change.
  • Further contributions clarify that the mass gained from solar wind is negligible compared to the total mass of the Earth.

Areas of Agreement / Disagreement

Participants generally disagree on the implications of mass gain from the sun and other sources, with some asserting that the Earth is gaining mass while others question the significance of this gain in terms of expansion or contraction. The discussion remains unresolved regarding the overall impact of these factors on the Earth's size.

Contextual Notes

Participants express uncertainty about the contributions of solar particles and the significance of mass gain relative to the Earth's total mass. There are also unresolved questions about the relationship between mass gain and the cooling of the Earth's core.

leonstavros
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I ran into a theory that stated that the Earth is actually expanding due to added mass from the sun's energy. Is this true and if true by how much?
 
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No, it is not true. The Earth is in thermal equilibrium. This means that over the course of time, the energy absorbed from the Sun is re-radiated out to space. If this were not the case, the Earth would just keep getting hotter and hotter.

And even if the Earth retained this energy, its mass equivalence over the 4.5 billion year lifetime of the Earth would only amount to about 0.000005% of the Earth's present mass.
 
The Earth does get heavier from absorbing space dust and meteors. I've heard that this is about 100 tones per day This is a faint echo of how the planets formed. While heat (IR) from the sun does get radiated back into space, it sounds plausible that other particles from the sun could become ordinary matter and build up here. (That might be included in the 100 tones figure above, I'm not sure.)

But the core is also cooling and thus shrinking. So the planet is definitely getting heavier, but I don't know if it is contracting or expanding.
 
Algr said:
The Earth does get heavier from absorbing space dust and meteors. I've heard that this is about 100 tones per day This is a faint echo of how the planets formed. While heat (IR) from the sun does get radiated back into space, it sounds plausible that other particles from the sun could become ordinary matter and build up here. (That might be included in the 100 tones figure above, I'm not sure.)

But the core is also cooling and thus shrinking. So the planet is definitely getting heavier, but I don't know if it is contracting or expanding.

100 tonnes per day works out to 0.000003% of the Earth's mass over 4.5 billion years.

The solar wind striking the Earth could only contribute 1/1,000,000 of that.
 
Janus said:
100 tonnes per day works out to 0.000003% of the Earth's mass over 4.5 billion years.

That's why it is a "faint echo". In the early solar system there was far more matter in scattered random orbits, so huge quantities were always hitting Earth. Now it is almost all swept up, so what's left is hardy noticeable.
 
Thank you all for your input, I guess Earth is so huge that daily added masses hardly make a dent.
 

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