The universe doesn’t change too much over the millennia. We see
the same planets, stars, and constellations that the ancients wondered
over. They still fill us with awe, and poets and lovers alike continue
to be enchanted by their presence. Yet there is one notable exception
to our universe that is unique in history. We have literally dozens
of near-Earth objects (NEO) that appear overhead nightly; and their
number is growing.
Since October 4, 1957 , we have had an ever-increasing number of artificial
satellites orbiting our planet. Currently, more than 8000 objects
ranging in size from a basketball to the Russian MIR are tracked by our
Space Surveillance Network. When viewing conditions are just right,
almost all of them are visible to the naked eye. As a matter of fact,
on a clear moonless night away from the bright city lights, anyone with
just a little patience will see dozens of satellites within a few hours.
The problem isn’t in seeing them so much as in knowing what it is you are
seeing.
With the exception of our Sun, all the bodies in our solar system "shine"
because of reflected sunlight. What does this mean? In order
to see them, satellites must be fully illuminated and the viewer must be
in darkness. That is why almost all of them are best viewed in the
hour or so after sunset and before sunrise.
I said "almost all" because there is now one exception: the IRIDIUM
series of communication satellites. This constellation of "birds,"
67 in all, provides world-wide coverage for the next generation of cell-phone
and pager communications. And they are bright. Because of their
shape, and the fact that they are spinning in orbit, they reflect sunlight
from one of their three 4’ by 8’ cell panels in a predictable and continuous
series of flashes. These flashes are sometimes of magnitude -8 ,
or about 20 times brighter than the planet Venus, and are bright enough
to be seen during daylight hours!
So next time you’re investigating a "flashy" dawn or dusk UFO sighting,
consider the IRIDIUM. It’s our high tech, not theirs.
*
*
*
