Calculate the number of atoms in the universe? The following steps will guide you through this calculation.
a) Planets constitute less than 1% of the total mass of the universe and can, therefore, be neglected. Stars make up most of the visible mass of the universe, so we need to determine how many atoms are in a star. Stars are primarily composed of hydrogen atoms and our sun is an average-sized star. Calculate the number of hydrogen atoms in our Sun given that the radius of the Sun is 7 x 108 m and its density is 1.4 g/cm3. The volume of a sphere is given by
(Hint: Use the volume and density to get the mass of the sun)
b) The average galaxy (like our milky way galaxy) contains 1 x 1011 stars, and the universe contains 1 x 109 galaxies. Calculate the number of atoms in an average galaxy and finally the number of atoms in the entire universe?
c) You can hold 1 x 1023 atoms in your hand (five copper pennies constitute 1.4 x 1023 copper atoms). How does this number compare with the number of atoms in the universe?
