THE SOUTHWORTH PLANETARIUM 207-780-4249   www.usm.maine.edu/planet
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 70.2667° W  Altitude:  10 feet below sea level Founded January 1970 Julian
Date:  2459344.18
2020-2021: CXXVI
                       "Horatio, why aren't we speaking Danish?"
                                               -Hamlet


THE DAILY ASTRONOMER
Monday, May 10, 2021
Amazing Astronomy Facts III

We continue with our "amazing astronomy facts" list which, we're happy to
report, has generated a lovely amount of positive feedback. In fact, the
list will likely extend into tomorrow or even the next day, depending on
how many graphics we use.

*AIRY NOTHING*
We all know that outer space is filled with, well, space: an enormous
amount of it separates even the closest stars.   What is less well known is
that inner space is also mostly empty space.

Regard a scale model of the hydrogen nucleus and it attendant electron:

[image: nucleus.gif]
Yes, the electron- which one should not truly regard as an discrete object
in space, but never mind- would be two miles or so from that nucleus on the
left were it as large as the circle used to depict it.    In three
dimensional space, however, that means that the nucleus is isolated within
33 cubic miles of empty space. The electron loiters (again,not the best
word) along the membrane of this immense sphere.

*Almost everything consists of empty space!*

Squeeze all the empty space out of the moon and one could fit it neatly
inside a soup can.

[image: oakImage-1603985177355-mediumSquareAt3X.jpg]


Squeeze all the empty space out of every single human being who has ever
lived, including those who are alive now
[image: a-large-crowd-of-people.-vector-background-.jpg]

and all the material comprising them would be as large as...

[image: index.jpg]
*A single sugar cube.*

Neutron stars are the only objects in the physical Universe known to be
devoid of inner space. They represent the densest form of material.   A
single sugar cube of material taken from a neutron star would weigh one
billion tons!

The sensation of solidity, which we experience whenever we hold onto an
object or whenever an object makes contact with us, is a consequence of the
electromagnetic force or the exchange of photons between the impacting
bodies.    This force prevents objects from passing wraith-like through
each other.

That space pervades the entire cosmos, both the outer reaches and the inner
depths, is one of astronomy's most amazing notions.

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