• Question: How many molecules would the sun have?

    Asked by LastDinosaurClone to Deborah, Euan, Maheen, Rob, Stu on 13 Jun 2016.
    • Photo: Rob Stanley

      Rob Stanley answered on 13 Jun 2016:

      I’ve just looked this up, and a common guess is that the sun has about 1,200,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 atoms (or 1.2 octodecillion atoms)!

      Molecules are made of one or more atoms. I don’t know enough physics or chemistry to be able to say whether this definition changes the answer, sorry!

    • Photo: Euan Allen

      Euan Allen answered on 13 Jun 2016:

      Hi LastDinosaurClone,

      Great question!

      The composition of the sun is roughly 91% hydrogen and 9% helium (there are smaller amounts of other elements, but we’ll ignore these). Using the mass of the sun and the mass of hydrogen and helium, we can guess that there are roughly 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 hydrogen atoms and about 1000 times less helium atoms. Therefore we can say (like Rob said earlier) that there are just over a octodecillion atoms in the sun.

      The hydrogen molecule is constructed using two hydrogen atoms. So the number of molecules in the sun is half this number.

Comments