Wednesday, August 31, 2011

An end of August poem

Van Gogh's Starry Night

Star Fishing

Today I want to tell you about variable stars.
They intrigue me because they change.
They change in brightness.
Some repeat cycles with almost clocklike precision
others change irregularly.
Some require only hours or days
to return to their starting brightness.
Others require years to change.
Yet, whether they change imperceptibly or violently
all variable stars change.

The most spectacular variable is the Nova.
It can get up to 200,000 times brighter than the Sun.
But, alas, it is temporary.
It periodically blows off a tiny percent of the Sun’s mass
at speeds up to 600 miles a second
until it loses too much mass to continue.
Whereas Supernovas brighten up to 10 billion times
the Sun’s brightness for a few days
and then fade away forever.

One more thing.
Variable stars change their brightness by pulsating
ever expanding and contracting
like a balloon,
They repeat their brightness cycles
from one day to hundreds of days
and are hundreds of times more luminous
than the Sun.

Well, that’s it.
Now go out into your yard
lean back in your recliner
gaze up into that black starry sky
and see if you can find your own variable star
amidst the 8000 stars visible to the naked eye.
See if you can catch its luminosity.
Surely you can.
Surely you can.

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