Updated: Apr 1, 2020
The idea of humans becoming an interstellar species-- being able to live across the stars-- has enthralled our culture for nearly our entire existence, from the Greeks to the latest science fiction. We may forever only gaze up at the stars from Earth, never to reach another star. Climate change is altering our planet, and some have wondered if we may have to leave Earth to another distant planet. We will never escape climate change, and unfortunately, we will never leave the Solar System, and Earth may be our home forever.
The Alpha Centauri system is the closest system to us. This system is only 4.3 light-years away or 25 Trillion Miles, this system also has a planet in the habitable zone of its star (Alpha Centauri B), which has the capability to hold human life. Why don’t we leave now? It was determined that with current technology, even with our fastest method of transportation, it would take around 19,000 years and 600 to 2700 generations of humans. To bring this into perspective, 19,000 years ago humans were still hunters and gatherers, while Neanderthals and Mammoths still walked the Earth.
One possible solution would be to develop a habitable colony ship where humans could live for thousands of years, or at least until they reach Alpha Centauri. Unfortunately, this is highly unlikely. Living for generations in space would require you to have space children: although a human has never been pregnant in space, NASA has experimented with pregnant rats to see how weightlessness affects a life form during its development in the womb. This study found that babies born in space have major defects such as an increase in cardiac deceleration which is a slowing of the heart periodically, delayed body righting responses (which involves balance and normal standing positions), and decreased branching of gravistatic afferent axons, which makes it more difficult to send messages to different parts of the brain. There are many other problems that challenge the survival of humans in space.
In space, the human body also has major negative afflictions. For example, without gravity, there are major issues. One problem that affects astronauts is the weakening of bones in space. On average, bones lose 1-2% of their mineral density every month. This causes bones to become extremely weak in space over the course of a few months, but over a few years, it’s unknown how weak human bones may become. Space radiation is also a major concern for would-be space explorers. Our atmosphere protects us from most outer space radiation. In a spaceship, astronauts beyond low earth orbit experience extreme amounts of cosmic radiation. Astronauts are only allowed to stay on the ISS for 6-9 months for this reason, but even in this amount of time astronauts have increased chances of radiation sickness, cancer, and risk of degenerative diseases. Space can also have detrimental effects on the central nervous system. These issues have challenged manned missions to outer space since the inception of space exploration.
Some may say these issues can be overcome with time, and we may develop medicine and ways to counteract them, but imagine being trapped in a big metal vault, never being able to set foot on the ground ever again. With even your children’s children never being able to see another planet, how could you possibly stay sane in this environment? Think of how many fights have broken out between humans in the past 100 years in their natural habitat. Now think of how many fights would break out over the course of several thousand years. One fight or disagreement could result in destruction, or even a slight navigation error could cause a different outcome in the ship’s destination.
Even if we do make it past these many hurdles, Proxima Centauri B might not be as habitable as it seems. Many studies have been conducted to see if Proxima Centauri could actually be inhabited, and results are unclear. All we know is that the planet is in the habitable zone of its star, which means liquid water can exist. This does mean it has the potential to host life, but we won’t know until we go there ourselves. Can you imagine traveling for thousands of years just to see a barren world? Not to mention that even if we went Alpha Centauri, the gravity is twice as much as Earth’s, which could have dire effects on our space weakened human bodies. This planet would never be as perfect for human life as Earth is, and no matter how far we travel or where we look it, is nearly impossible we will find a gem like Earth.
It seems that many humans think the damage we are doing to our home planet can be reversed or avoided, but it is very likely that much of this damage will be the end of life as we know it. It is predicted that it will take 65,000 years for carbon dioxide levels to return to pre-industrial revolution levels, and that’s only if we stop all CO2 emissions now. Technically, it is possible for humans to become an interstellar species, but it may take hundreds if not thousands of years to achieve this. There are ways humans could reach the stars, but we need time to develop this technology, and it isn’t possible; we simply don’t have the time. Climate change is a real threat. If we don’t work to stop it now, the one oasis of life we have come to know will reach its sad and desolate conclusion, which seems more and more likely as we destroy the beloved land we call home.