Cosmic Threat

Most of us go around in our daily lives living a kind of two dimensional existence, never taking into consideration the vast expanses of space surrounding this planet.  What happens when disaster threatens to shatter our existential bubble of security?  What happens when humanity is faced with the cosmic threat?

When most people think about danger from space one thing comes to mind:  Asteroids.  Our solar system has a large asteroid belt and many stray into earths neighborhood.  In February of 2013, a massive meteorite impacted in Russia, the fireball was captured by tons of cameras, here is a compilation of videos of the event:

http://www.youtube.com/watch?v=ztrU90Ub4Uw

So these videos sparked a huge awareness about space danger, and may even have had a part to play in NASA's recent increase in funding.  But what can NASA or anyone else really do about objects from space, isn't it just a matter of time on the historical scale before another world ending rock comings smashing down?  The first step is to be able to see meteorites coming, an advanced detection system is a prerequisite to preventing planetary collision.

We are currently watching only a very small percentage of the sky, its is unfortunately big, and so much of our observation ends up being amateur observers rather than professional because only a small amount of NASA's budget can go into randomly pointing telescopes up at space in the attempt to catch a glimpse of asteroids before they hit us, at which point we would just have to watch the asteroid hit us.

That's right, so if one of those observers sees an asteroid, there is nothing we can do about it, or at least nothing has ever been done, then again, i couldn't find any mention of humans ever seeing an asteroid impact coming either, so maybe it's a moot point.  But supposing we did point enough telescopes up at the sky, what could we do about an inbound asteroid?

If the asteroid is large enough, it can pose a threat to every life form on the planet, the first thing one usually imagines when trying to stop an impact is simply blow up the asteroid before it reaches earth, but upon examination, this is some what less practical due to the fact that upon reaching earth, the asteroid would be millions of little asteroids instead of just one big one, a scenario that will probably end just as badly for us.  So what about pushing the asteroid?  If we can send a ship or robot to divert the asteroid's course before it reaches earth, we should be able to dodge the rock entirely.  This seems to be a possible solution, so should we invest all of our space resources into telescopes and rock pushing robots?  Well hold your horses, because there are other cosmic threats yet to be discussed.

It turns out that a huge number of things in space could kill us, lets just consider a few for a moment, first, there are comets, like asteroids but made of ice that trails behind them as they melt.  Getting nailed with one of these suckers wouldn't be to much fun either.  It's thought that the Tunguska event in Siberia was a comet  based on the fact that meteorite rock was never found at the site, this is one of the great explosions of the ancient world, it was seen and heard at a great distance.

Besides rocks and chunks of ice, there are now plenty of man made objects floating around, our orbit is full of objects such as nuts and bolts, space suit gloves, metal fragments, old satellites and even rocket components.  This might not seem like a huge deal until you realize that everything in orbit is moving super fast, and getting hit with even a small object at those speeds is sure to ruin your day.

Then there are strange objects observed by astrophysics, black holes, quasars, super novas, ect.  This zoo of strange phenomenon is something far removed from our experience, and poses little existential threat to earth, however, in the future when humanity becomes a space faring civilization, we will undoubtedly begin to encounter these objects more and more often.  The chance of something like a black hole coming by our neighborhood is low, but if it did, it could destroy the entire solar system, a black hole is a collapsed star so dense that almost nothing can escape from its center, known as a singularity.  Occurrences such as this are terrifying to imagine, but a more inevitable type of calamity awaits our own sun...

We will one day billions of years from now be forced to travel out into the cosmos because of the inevitable collapse of our home star, this will occur when enough of its fuel hydrogen has been converted to helium, the star will expand briefly to a red giant as heavier chemicals begin to fuse, engulfing the earth and whole inner solar system, then it will collapse into a tiny white dwarf star, cold and dead.   Our only hope for surviving this calamity is to head for the stars, to set up civilizations on many worlds scattered through space in order to safeguard the continuity of the species.
 
But we may have to go further than that, because as we speak the Andromeda galaxy is headed strait on a collision course for the milky way!  That's right, in billions of years, our galaxy will collide with another galaxy, when galaxies collide, it is mostly gravitational interaction because there is so much space between all of the stars that they will probably never hit each other.  However, the impact upon their organization will be profound, stars will literally be thrown into the vast reaches of intergalactic space to wander alone in the void forever.  Not so nice.

That about wraps is up for space phenomenon of doom, but there is one more cosmic threat i have yet to mention.  This is the threat of extraterrestrial biological entities, either invading earth or posing some physical or pathological threat on our explorations of the galaxy.  We don't know what aliens will be like when we find them, it is likely they will share many similarities with our chemistry, perhaps even DNA itself, when we find alien life, we will learn a great deal about the origins of life and the possibilities of alternative types of chemistry.

When we think about aliens, we are thinking about something, as the name implies, that is unknown.  We are prone to fearing that which is unknown , as well as imbuing it with the negative characteristics of humanity itself, this is part of why EBE's are usually depicted so negatively in the media.  There is of course the possibility of alien invasion, but one must wonder why when every resource possible to imagine is in abundance on uninhabited worlds in space, and if they are capable of crossing the great void of interstellar space, an astounding accomplishment, why would they come all this way to kill us or steal material they could just as easily have found on any other planet?

So its unlikely that a society advanced enough to traverse between the stars would have interest in conquest, at least in the conventional sense, it is true that any contact between an advanced society from outer space and our society on earth would probably have incredible, unforeseeable and quite possibly negative consequences.  This is the basic principal behind the concept of the prime directive in star trek, which is to never interfere in the development of a pre-warp civilization.

But what about encountering aliens out in space?  When our explorations take us to other solar systems, we may find alien biospheres, what kind of danger lurk there?  Well, the answer is probably similar to the kinds of challenges people face when traveling to regions foreign to them.  You have to worry about being infected with micro organisms and parasites, so fore knowledge and precautionary measure are important, being infected with an alien organism is probably as lethal as being infected by any organism that your body has never seen before, unless the chemistry of the aliens is radically different, we can probably use similar measures to defend ourselves from them as we do on earth against bacteria and viruses.

Well, that covers most of the basics,  lets hope that humanity gets those space telescopes working and we can build lots of asteroid pushing robots and maybe even a planetary energy shield.  Whatever the solution, it is important that everyone keep in mind the reality of space danger, going into the future it will become of primary importance to the basic safety of our existence.