Does the Earth get bigger from the sun?

[leonstavros]

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?

 

[Janus]

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.

 

[Algr]

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.

 

[Janus]

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.

 

[Algr]

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.

 

[leonstavros]

Thank you all for your input, I guess Earth is so huge that daily added masses hardly make a dent.