2nd October 2019

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# How many atoms are there in the universe?

At this level, it is estimated that the there are between 1078 to 1082 atoms in the known, observable universe. In layman's terms, that works out to between ten quadrillion vigintillion and one-hundred thousand quadrillion vigintillion atoms.

Likewise, people ask, how many atoms are in a single human cell?

Another way of looking at it is that this is 100,000,000,000,000 or 100 trillion atoms. Interestingly, the number of cells in the human body is estimated to be about the same as the number of atoms in a human cell.

How many atoms are in the world?

Silicon is half the mass of iron, so if the earth were entirely silicon, there'd be twice as many atoms. I bet we can say that the number of atoms in the earth is something like 10^49-10^50.

How many atoms are in a strand of DNA?

The phosphate group contains 4 atoms. Multiply that by 6 billion nucleotides and you get 204 billion atoms. Of course, that's just an estimate since human DNA isn't composed of only 'T' nucleotides, and I think some of them can have more than one phosphate group (not sure).