General Question
To Ensure Human Survival, Should we Colonize Space?
If we wish to survive in the long term, it would seem to me that we must begin the development process for space colonization ASAP. Looking back through Earth’s geologic history, we see from the fossil record that there have been a number of events that proved so catastrophic that large portions of all life on earth went extinct due to them. Truly mass extinctions happen on average once every 50 to 100 million years.
The last one, 65 million years ago, ended the 150 million year Age of the Dinosaurs, yet many small mammals survived, making way for the advent of larger, more complex mammals and eventually man. Our best evidence suggests that an asteroid or comet about the size of Mount Everest hit Earth on the Yucatan Peninsula and the resulting shock wave plus the nuclear winter generated by the global dust cloud did in the dinosaurs. Yet along with small mammals; crocodiles, turtles and snakes survived; so there is a substantial chance man, with his ability to hunker down in well-stocked bunkers, could survive such an event as well.
But the past is littered with mass extinctions. Yellowstone park is one of the largest volcanic calderas on Earth, with a diameter of about 50 Km. Over the past 2 million years, it has erupted about every 600,000 years; and it last erupted 600,000 years ago. When it goes again, it may wipe out much of the life in North America and pose a severe threat to global populations; but it is not likely to be a end-of-humanity event.
Much larger volcanic events called giant fissure eruptions can occur along subduction zones where one tectonic plate bumps up against, and slides under another. Iceland has small fissure eruptions routinely, but there has not been a giant, life-ending one on Earth since complex life emerged. Should such an event happen again, it would likely spell the end of human and most other life on Earth.
Other threats include impacts with very large asteroids, comets, planetoids or even wandering planets or black holes. The supernova of a nearby massive star could impact all life on Earth. Likewise, more remote massive stars can generate gamma ray bursts, the highest energy events in the universe short of the Big Bang. If Earth had the misfortune of being aligned with the energy beam of a gamma ray burst, even from a star as far as 1,000 light years from Earth, that would likely spell our doom. The radiation coupled with the warming produced in our atmosphere by collisions with the charged particles, and the destruction of our protective ozone layer would deliver a deadly punch.
The Earth’s Magnetic field is also known to go through fluctuations. It occasionally reverses poles. If it were to collapse for any significant amount of time, it would allow solar radiation to strip away Earth’s protective ozone layer and rob of us of our protection from cosmic radiation.
Finally, the Sun itself will begin growing hotter. In about 1 billion to 2.3 billion years, it will heat Earth to the point life on it will be threatened. At that time, our Sun will vaporize all water on Earth and heat the planet to temperatures at least as severe as those on Mercury, where it is hot enough to melt lead. In about 7.25 billion years, the Sun will become a red giant. Cosmologists are not yet certain whether the Sun’s outer atmosphere will actually engulf Earth during its red giant phase, but the best guess is it will. This, of course, would end the existence of our planet, melting us and swallowing us up in the Sun’s core.
So it’s a sure bet something is going to wipe us out if we hang around here and wait long enough. The scary part is nobody currently knows which of the possible threats will do the job, or when it will occur. Given all that, it makes a great deal of sense to start the process of figuring out how to colonize space NOW.
From the time President Kennedy gave the order to put man on the moon, it took science 10 years to figure out how. Finding an Earth-like exoplanet and landing a colonizing force on it will be many thousands of times more complex than the moon shots were. But I have no doubt it can be done, and probably for less in real terms than it cost mankind to fight WWII. Why don’t world leaders gather, begin the public education process it would take to build global support for space colonization, and get the ball rolling on actually doing it? Who knows, with the money and cooperation required, maybe it would stave off WWIII, which with the current nuclear arsenal could be one more possible human extinction event.
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