123. Good Scientific Analogies

I love a good analogy. If you know of any please pass them on.

Brian Greene, The Hidden Reality
If an atom were magnified to be as large as the universe, the same magnification would make the Planck length the size of an average tree.

For a star as massive as the sun to be a black hole, it would need to be squeezed into a ball about three kilometers across; a body as massive as the earth would become a black hole only if squeezed to a centimeter across ------

The human retina is a thin slab of 100 million neurons that’s smaller than a dime and about as thick as a few sheets of paper. For computer-based retinal system to be on a par with that of humans it would need to execute about a billion operations each second. The modern desktop computer can operate at a billion operations per second.

Independent estimates based on the number of synapses in the brain and their typical firing rates yield processing speeds of about 10 to the 17th operations per second. If we use this estimate for brain speed, we find that a hundred million laptops approach the processing power of a human brain.

A Briefer History Of Time - Stephen Hawking
'Today we know that stars visible to the naked eye make up only a minute fraction of all the stars. We can see about five thousand stars, only about .0001 percent of all the stars in just our own galaxy, the Milky Way. The Milky Way itself is but one of more than a hundred billion galaxies that can be seen using modern telescopes—and each galaxy contains on average some one hundred bullion stars. If a star were a grain of salt, you could fit all the stars visible to the naked eye on a teaspoon, but all the stars in the universe would fill a ball more than eight miles wide.'

Forgot where these came from.

If the string theory is correct the number of strings in one atom would equal the number of Christmas trees it would take to fill the solar system.

If the nucleus of an atom was the size of a football placed in the center of a football stadium. The electrons would be circling at the outer edge of the stadium.