Whenever NASA announces that one or more Earth-like planets have been found in the habitable zone of its star, at some light years away, the discussion about life outside the Earth is resumed, and especially if we would be able to reach one of the so-called “life-sustaining planets”.

But, finding a planet that can support life as we know it, what would be the costs of leaving Earth to a new home?

Well, there are a number of challenges to overcome in order to reach this new planet. The humanity has not yet been able to develop a technology that allows a travelling at the speed of light, which is necessary to reach distant planets in an acceptable time. Whereas to get to a planet, far from us at one light-year, the travel would require one year (at the speed of light). With the technology we currently have, where the maximum speed a man-made machine has reached was 252,792 km/h (the space probe Helios), traveling one light-year, which has 9,461,000,000,000 kilometers, would take 4,272 years!

Okay, we’ve got technology to travel at the same speed, or faster than light. Could we live the necessary time in space? This is another difficult part. Our body needs gravity: without this force pulling us down, we stop exercising, which we do every day by simply standing up. Thus, in space our body loses muscle mass and bone density, in addition to other bizarre things. But a great challenge is the long exposure to space radiation. The human body is not accustomed to, since we have the natural protection of the terrestrial atmosphere. Without even mentioning the work that would carry, in addition to the crew, the basic survival items like food and water.

But imagine: somehow we have overcome all the adversities of the journey to the “promised land.” How does it like? Orbiting the habitable zone of its star, it’s expected that there is liquid water on its surface, but is that water drinkable? Like Earth, most of our water is in the oceans, which have other elements like salt, making it impractical. If the process of desalination is expensive here, imagine on another planet where water can be mixed with other elements like methane, for example. And the atmosphere? Does it have oxygen or is it formed almost entirely by carbon dioxide (poisonous gas) as on Mars?

Finding a planet capable of sustaining life, being able to reach this planet, finding water and planting food… can breathe.

These are just a few things we should think about before trying to leave our little blue planet. The human being still needs to evolve very technologically and, above that, we need to think about looking after our current home while we can’t move.