Mid-afternoon. You have been down with
stomach flu since the middle of the night. You slept for most of the morning,
had steamed eggs for lunch and you and Carol watched the DVRed "King and Maxwell". Earlier while
looking at an article Doug sent on Huff-Post Science you found another article
on why UFO's have never landed and never will. Add and post because this shows
the better odds of seeing aliens only in imagination. - Amorella
1544 hours. The article is
excellently written and I have no reason to question it.
** **
David J. Elcher
Editor-in-Chief, Astronomy magazine
Why UFOs Have Never Visited
Earth -- and Probably Never Will
Posted: 08/06/2013 5:15 pm
In this day and age we are awash in a sea
of information overload -- much of it good and much more of it utter nonsense.
It pervades TV, social media, and cellphones. Much of it panders to people's
faint wishes rather than sticking to the facts, and nowhere is this better
illustrated than the garbage pseudoscience programs catering to UFO
enthusiasts.
A significant part of the population in
many countries believes that UFOs have visited Earth. No matter that none has
plopped down in the middle of Central Park and asked to be whisked off to
dinner at Tavern on the Green. These supposed encounters and sightings
typically occur in the middle of nowhere where large numbers of witnesses don't
exist.
It's really a central part of being human,
the longing to not feel alone in the universe. And who could blame us? Our
Milky Way Galaxy contains something like 400 billion stars, of which the Sun is
just one. (We don't know exactly how many stars the galaxy holds because dwarf
stars are very faint and can't be observed over long distances.) And
astronomers know of approximately 125 billion galaxies. By back-of-the-envelope
calculations, that's roughly 50,000 billion billion star systems that could
host life. What are the odds we're the only one with sentient beings --
intelligence -- civilization? Not very high.
But the fact that life, even civilizations,
could be common in the cosmos is very different from asking whether other
beings have traveled to see us. What UFO proponents and sci-fi story writers
too often fail to appreciate is the distance scale of the universe. It is HUGE.
REALLY HUGE.
To begin to understand it, get some sheets
of paper and a ruler with metric measurements (yes, the one everyone else in
the world uses except Americans). Tape together five 8-1/2" by 11"
sheets end to end and draw a long line along the bottom. Now you can start
drawing a picture of the solar system, just the tiny region around our Sun and
planets.
Draw the Sun on one end of the line and, 1
centimeter away from it, mark a dot to represent Earth. On the scale of 1 cm =
1 Astronomical Unit (the distance between Earth and Sun), you can now fill in
some of the other planets. Mercury and Venus lie between the Sun and Earth.
Mars gets plotted at 1.4 cm from the Sun, and Jupiter at about 5 cm. Plot
Saturn at around 9.5 cm, Uranus at about 19 cm, Neptune at 30 cm, and Pluto
(yes, a dwarf planet) a little shy of 40 cm.
The main asteroid belt lies between Mars
and Jupiter, and the Kuiper Belt, the disk of icy comets and asteroids, lies
between 30 and 50 cm from the Sun. The so-called Scattered Disk, a thin
population of comets that have been knocked into strange orbits, extends to
about 120 cm, near the edge of your drawing.
Now consider where we have been in terms of
solar system exploration. Our most ambitious planetary spacecraft have all been
concentrated on Mars, Jupiter, and Saturn, close to Earth on this scale. All of
the space missions that have carried humans have extended to the Moon, a barely
perceptible distance away from the dot representing Earth.
Look at the overall diagram you've put
together. On this scale, the Oort Cloud, the enormous shell of 2 trillion
comets that surrounds the solar system and in some ways marks its edge, extends
to a distance of 1,000 meters -- 10 football fields end to end. The distance to
the nearest star would be more than 2-1/2 times farther away. The scale of the
Milky Way Galaxy on this chart would stretch 1/6th of the way to the Moon.
The point is that the distances between
objects in space are incredibly vast, even in our solar system -- let alone
between stars in our galaxy or in other galaxies. Yes, I know technology is an
ever-improving thing for any given civilization, and that someday we may be
able to travel far faster than we now believe.
Yet physics is physics, regardless of how
technology changes. Light can travel at the fastest known speed because it has
no mass; anything with mass takes an incredible amount of energy to start
moving at any impressive speed. With an ion propulsion engine, the best
technologically feasible idea we now have, we could travel to the nearest star
in something like 75,000 years.
But that's only if the world's politicians
had an unlimited budget to offer up for such a project. And there are serious
logistical problems too. How do you stock a spacecraft with enough munchies for
a 75,000-year trip?
When it really comes down to understanding
the physics of space travel and the vast distances between stars, it's pretty
discouraging for the idea of flitting about throughout the galaxy. And black
holes acting as wormholes don't help, either. (An old sci-fi idea is that you
could travel through a wormhole and end up in a different part of the universe,
in a flash. But if you're first pulled into a string of protons 10 kilometers
long, it doesn't really matter where you come out. It's pretty much going to
ruin your day.)
So the idea of interstellar travel is, at
least for now, awfully, incredibly, naïvely, amazingly, staggeringly
optimistic.
It's far more likely that the universe is
teeming with life -- even intelligent life -- but that dreams of standing
beside beings from other worlds are just that -- dreams.
David J. Eicher is Editor-in-Chief of Astronomy
magazine, author of 16 books on science and history, and president of the
Astronomy Foundation. His book COMETS! Visitors from Deep Space will be
out in October from Cambridge University Press.
From Huffington Post.
(com)/+
** **
This reminds you of other odds you have
taken over your lifetime. - Amorella
Yes. I committed to a
mostly 'imaginary' circumstance because to say the odds were impossible was not
in the cards, at least not for me. I survived both professionally and
personally. Those odds, in my mind, were greater than I expected. To survive
such a situation and to live out my life as I have is many times greater than
my one-time expectations.
An allowance for my help, boy. - Amorella
I paid the piper.
And more you will pay, boy. - Amorella
No problem, Amorella. The
more I will pay. Nothing is ever free, anywhere.
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