[VadeRetro]

The more I think about Dr. Manuel's theory, the crazier it seems. Even if surface conditions can completely mask the spectroscopic signature of iron, an iron sun is more massive than a hydrogen sun.

We've known the mass of the earth since before 1800, when Cavendish measured the strength of the gravitational force. From the mass of the earth, its orbit around the sun, and Newton's Law of Gravitation, we know the mass of the sun. If you somehow make the sun more massive, then it takes more velocity for the earth to maintain a stable orbit at its current distance.

Which only brings me back to the point that I'd expect someone to have noticed by now if the sun had more iron and more density than we think. Are we going too fast for the current model of the sun's composition but nobody's noticed?

[jpsb]

Your point about the known mass of the sun troubled me too, the only explaination I can think of is that the iron core might not be that massive relative to the densely packed H we think is at the center of the sun.