THE UNIVERSE The universe (Latin: universus) is all of space and timelal and
their contents, 10) including planets, stars, galaxies, and all other
forms of matter and energy. While the spatial size of the entire
universe is unknown, 31 it is possible to measure the size of
the observable universe, which is currently estimated to be 93
billion light-years in diameter. In various multiverse hypotheses, a
universe is one of many causally disconnected il constituent
parts of a larger multiverse, which itself comprises all of space
and time and its contents.
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The physical universe is defined as all
Ilontively referred to as spacetime)
how old is this earth?

Efficiency is an act of doing something

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -