Originally posted by nv4711
Druscilla, I wasn't talking about whether or not a solar sail powered craft is suited for manned space travel. I was talking about the idea that the
ominous "aluminum foil" could have been a solar sail from an unmanned space probe, launched by an alien civilization perhaps tens of thousands of
years ago. It crashed on Earth, and the pieces of the solar sail littered the fields of Roswell.
Just imagine what will happen on a distant planet, a few ten thousand years from now, when the Voyager probe crashes there. Maybe its a relatively
young Planet, the people there just mastered nuclear power only 3 years earlier, they are making the first baby steps with radio astronomy, jet air
planes just came into service and space travel is science fiction.
We send out these space probes - it is plausible that other civilizations would do the same. Forget about how long it would take to get anywhere, that
wasn't the point of Voyager either, it is about sending a "message in a bottle".
IF there are/were other intelligent technological species with space faring understanding at least on par and equiv-tech to ours, a chance random
probe finding us could be a probability.
Keep in mind, however, as a matter of perspective:
"Put three grains of sand in a vast cathedral, and the cathedral will be more closely packed with sand than space is with stars"
- Sir James Jeans
The universe is astoundingly dumbfounding stupendously vast.
Take those 3 grains of sand, and then, for our galaxy alone, make that 500-700 billion grains of sand scattered to a density of no more than 1 grain
of sand per 1000 sq/ft, where some areas have a density of one grain of sand per 3000 or 4000 sq/ft where densities vary in proximity to the galactic
consider that those grains of sand are stars, not planets, and then consider the finite size in comparison to those grains of sand any planetary motes
Probability of finding any one planet among those sand grains, much less chancing upon a civilization remarkably equivalent tech enough to understand
solar sails is almost inconceivable.
Finding a crashed alien space probe embedded in the shattered rib cage of a fossilized Brontosaurus would seem more likely considering the Dinosaurs
held the throne of this planet for some 300 Million years while we, humans, have only been consciously around for what? 50,000 years as Homo
The razor thin section of time we've been around, coupled with the density of the galaxy in stars and planets makes the chance that any chance
robotic probe would ever reach this solar system, much less the near invisible speck of our tiny little rock of a planet extremely remote.
Now, if perchance, by some remote chance there is/was some alien civilization in our reasonable locality of, say a 200 light year bubble, and said
proposed civilization targeted every single star in a 200-300 light year bubble for robotic probes as a matter of random chance in shooting off
disposable probes in every which way direction, then, perhaps, maybe, potential goes up, but, we still need to consider Jupiter and Saturn as enormous
gravity wells and system janitors for having a tendency to attract and such up anything chancing upon our system.
Additionally, we've further got our moon as another barrier reef against interstellar flotsam ever making planet fall, and even then, our tiny little
rock is so small, the sun's gravity well itself has a greater chance of pulling any wayward probe in for a sizzle.
For a robotic probe to reach us, and find us, such a probe would necessarily need be more than just a message in a bottle, but have some autonomous
programming that would allow it to seek out life, like us, where then it could then go about the task of avoiding Jupiter, Saturn, our moon, and
finding us for a 'hello'..