Why human will not be able to move to the Earth’s twin planet, even if it exists

Almost every star you see in the night sky serves as the center of the planetary system, and there are about 100 billion stars in our galaxy. But are there worlds like Earth?

Just a couple of days after launching in May 2009, it took the Kepler space telescope to discover its first potentially inhabited planet in the sun-like star Kepler-22. Another 2.5 years were spent confirming the status of the found exoplanet. Finally, on December 5, 2011, the first exoplanet was officially announced, the orbit of which is in the habitable zone of the parent star. Unfortunately, despite all the similarities, Kepler-22 b turned out to be an ocean planet rather than a rocky world like Earth.

The Kepler telescope is able to determine planets only by the transit method, when the planet passes through the star’s disk, slightly changing its brightness for observers. Therefore, the vast majority of exoplanets discovered with its help revolve in orbits around small stars – red dwarfs. Their habitat zones are much closer, and the period of revolution of the planets around them does not exceed several days, which greatly simplifies the search.

According to scientists, for every planet whose transit through the disk of the parent star we can observe, from 10 to 100 of them are located at a different angle. And we are only talking about red dwarf planets. Although in the Milky Way, most of the stars are red dwarfs.

Despite the fact that our solar system can be called rare for the Milky Way, we must understand that we are talking about tens of billions of similar systems. It is difficult to imagine that only one turned out to be a habitable planet.

In August 2019, the Astronomical Journal published the results of a study that gives the most accurate estimate of the presence in our galaxy of Earth-like planets in the orbits of sun-like stars. As part of this study, an interesting method has been developed to estimate the number of such planets. The results are simply amazing: 

Planets similar in size to the Earth, with a period of revolution around their star from 237 to 500 days, should occur in about every fourth system formed by a star like the Sun.

Thus, we get at least two billion planets in the Milky Way, which should be similar to the Earth in most respects. Does this mean that we have two billion potentially inhabited worlds?

If we talk not so much about intelligent life as about biological life as a whole, we know that it is enough to originate, and it can adapt to almost any conditions. An excellent confirmation of this is extremophiles, various organisms that can survive in various extreme conditions, from unbearable heat and cold to exposure to chemicals poisonous to people and even outer space (for example, tardigrades).

But can we find a double planet of the Earth, which will be able to move if necessary? This is where the chances begin to tend to zero. Today we can confidently say that life was emerging on Earth at a time when it was literally like hell, and we would definitely not be able to exist in those conditions.

Life itself has made the Earth what it is now. And that is why, if we find a planet as similar to ours as possible, it will mean that it has formed over billions of years under the influence of biological life on it, and since we are not part of this biosphere, we will have to adapt to it.

This may not be any easier than, for example, colonizing Mars, because the history of the formation of another biosphere will be extremely different from ours. Even if the biochemistry of the creatures on this planet is as similar to ours as possible, it will be different.

The “native” virus drove us home for two months – can you imagine what the virus will do to us from another planet?

It is just right to recall the “War of the Worlds” by Herbert Wells.

Even if we discover the existence of billions of inhabited worlds, this does not mean that you can pack your bags, setting off in search of a new beginning on another planet. We will remain chained to the Earth and will continue to be a part of it. Earth is us. So our main task should be to preserve it for our own sake.