Now consider, the human world stands about midway between the infinitesimal and the immense . The size of our planet is near the geometric mean of the size of the known universe and the size of the atom. The mass of a human being is the geometric mean of the mass of the earth and the mass of a proton. A person contains about 1028 atoms, more atoms than there are stars in the universe. In our 150 pounds of protoplasm, in our three pounds of brain, there may be more operational organization than there is in the whole of the Andromeda Galaxy. The number of associations possible among our 10 billion neurons, and hence the number of thoughts humans can think, may exceed the number of atoms in the universe.
The sun orbits the galactic core at the speed of about 220 km/s and takes about 230 million years to make one revolution around the center of the Galaxy. If the Sun was to be scaled down to the size of a white blood cell, the Milky Way would be the size of the continental United States. Kilogram for kilogram, the human body generates 8000 times more power than the Sun. You have about 10 trillion cells in your body and the length of one uncoiled strand of human DNA is approximately 2 meters. The moon is only about 400,000 km away, so all your DNA would stretch to the moon and back almost 1500 times (to put that in perspective, all the planets in our Solar System can fit between the Earth and moon). To put in another way, the DNA in all your cells put together would be about twice the diameter of the Solar System.
The size of an atom is governed by the average location of its electrons. Nuclei are around 100,000 times smaller than the atoms they’re housed in. If the nucleus were the size of a peanut, the atom would be about the size of a baseball stadium. If we lost all the dead space inside our atoms, we would each be able to fit into a particle of lead dust, and the entire human race would fit into the volume of a sugar cube.
As you might guess, these spaced-out particles make up only a tiny portion of your mass. The protons and neutrons inside of an atom’s nucleus are each made up of three quarks. The mass of the quarks, which comes from their interaction with the Higgs field, accounts for just a few percent of the mass of a proton or neutron. Gluons, carriers of the strong nuclear force that holds these quarks together, are completely massless.
If your mass doesn’t come from the masses of these particles, where does it come from? Energy. Scientists believe that almost all of your body’s mass comes from the kinetic energy of the quarks and the binding energy of the gluons.