THE SOUTHWORTH PLANETARIUM
207-780-4249       www.usm.maine.edu/planet
70 Falmouth Street  Portland, Maine 04103
43.6667° N,                    70.2667° W
Founded January 1970
            "Heavens above!'


*THE DAILY ASTRONOMER*

*Thursday, June 2, 2016*
*Blowing up Space-Time and a Working Sun*



Through Pandora's Jar, the Universe speaks to us.  That statement might
sound grandiose and absurd, but we're convinced that some strange agency
has dominion over that vessel and chooses what questions we withdraw from
it.  For instance, this morning we received a question about space-time. I
dutifully inscribed the query on parchment and placed it in the jar with
the other parchment strips.  Then realizing that we needed to answer two
new Pandora parchments today, I then reached in and extracted them.
Voila...one of the questions was the one that was just inserted.   It
languished in the jar for all of two minutes.   Obviously, the cosmos
demands rapid answer.   What other explanation -besides that the question
was on top and I just grabbed it first- is there?


*"If the Universe is expanding, does that mean that, in addition to space,
time is expanding? And what does that “expansion” mean – are all yardsticks
growing, and are seconds getting longer too? There being no external
reference, maybe this is moot, but I’ve always wondered whether time is
also blowing up…?*"  - N.C.   Wells, Maine

You have pinpointed the problem with the notion of pervasive expansion
throughout the Universe.    We measure objects in all the dimensions
(length, breadth, width and duration) in relation to an established
standard.    For instance,in 1983 the meter was been defined as the length
of space along which a light beam propagating through a vacuum travels in
1/299,792.458 of a second.   This definition is still valid today.     Now,
if, lengths are gradually increasing throughout the Universe, the increase
would be uniform.    If, similarly, time is also "increasing," so that a
given increment now is longer than it was in the past and more brief than
it will be in the future, this change will also be pervasive throughout the
cosmos.   Since we measure time and space according to set standards, we
won't notice this expansion as the standards, themselves, will change
proportionally.

Universal expansion is measurable because almost all the galaxies appear to
be moving away from our own.   This apparent divergence away from the Milky
Way is illusory.   Observers in other galaxies would see the galaxies
expanding away from theirs, as well.    Space expands as a result from the
"Big Bang," a event believed by most cosmologists to have created the
Universe about 13.8 billion years ago.

Measuring a complete space-time expansion on the micro-level isn't
possible.     Such expansions are believed to be so minute as to be
negligible, anyway.  Of course, we wouldn't know, anyway.


*"In a recent DA, you said that the energy from the Sun needs hundreds of
thousands of years to get out into space.     If that is true, how do we
know that the Sun is still working?"         -S.F.,  South Portland*

Yes, the sunlight you see today was likely created in the Sun's core about
100,000 - 300,000 years ago.       We are bathed in ancient starlight every
day.  However, we know that the Sun's core is still producing energy
because of "neutrinos," nearly massless particles produced in nuclear
reactions.    Neutrinos pass through the Sun like cannon balls through fog
banks so they escape from the core immediately.   In fact, in the time it
takes you to read this sentence, trillions of neutrinos from the Sun's core
and other sources have passed through your body, through Earth and into
outer space where they will likely travel for billions of years without
constraint.



*​The detection of electron neutrinos from the Sun's core indicates that*
*our parent star is still producing energy in its core.   (Image: SOHO)*

Even though a neutrino would only have a fifty percent chance of being
absorbed by a light year of lead, some of them will occasionally interact
with certain atoms, such as chlorine.  For instances,  the interaction of a
chlorine atom and a neutrino will produce argon through a radioactive
process that scientists will detect.    The detection of these solar
neutrinos (properly called "electron neutrinos") lend us the assurance that
our Sun is working just fine!


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FROM THE CATACOMBS OF INFINITE KNOWLEDGE
Neutrinos were once thought to have had no mass.  Now, physicists know they
contain some mass, albeit precious little.    A single neutrino's mass is a
minute fraction of that of an electron, which is just a whisper of a thing
(or a non thing, if you're a devotee of the new Zen Quantum religion.)
While a single neutrino is the ultimate lightweight, the neutrinos en mass
might have enough matter to account for much of the dark matter spread
throughout the Universe.
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