The sun is in/at the centre of the solar system.

Which is right and why?

  • Either is correct, but " in the centre" is more popular.
    – zondo
    Apr 3, 2016 at 12:26
  • 2
    It might make more sense not to include a preposition at all (The sun is the centre of the solar system), since if the sun wasn't there, by definition there wouldn't be a solar system for anything to be at the centre of, so there wouldn't be a centre. Apr 3, 2016 at 14:03
  • @zondo: Your NGram simply shows the general case. For the specific case of the sun and the solar system, a better understanding of such relationships in the minds of ordinary speakers has led to at becoming the preferred choice in recent decades. Apr 3, 2016 at 14:09
  • @Inazuma: I don't know the physics well enough to say whether the (gravitational) centre of the solar system is actually within whatever we consider to be the "surface" of the sun, but I do know enough to know that the centre of the system won't be exactly the centre of the sun. That's because strictly speaking each planet orbits some gravitational centre between itself and the sun (which in the case of Jupiter will be some distance from the centre of the sun, but I don't know exactly how far out it would be). Apr 3, 2016 at 14:39

1 Answer 1


Since the centre of something is a theoretical point - with no inside as it were - in this case "at" and "in" mean the same thing. I would hesitate myself to extend this to replacing the phrase with "is the centre" unless the object you're referring to also can be conceptualised as being a point, that is, having only one dimension and a location. If the scale was very large one might assert the Sun could be thought of this way, but this approximation becomes less correct the more human a scale one adopts. "At" can be thought of as meaning "proximal to", while "in" would normally mean "inside". Aside from dimensional considerations there are the common associations these terms have with actions. Since they are often used to describe actions, perhaps this is the source of our comfort with using "in"? "The girl poked it at the centre" or, "the dart hit the board at the centre" might be correct but would be comparative oddities for example.

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