There are countless problems with moving from Earth to another habitable exoplanet. The human body evolved under the pressure of Earth's atmosphere, and is influenced by the exact pulling power of the Earth's gravity. If there is too little pressure, the body would explode, too much, and it will implode. If the gravity is too strong or too weak, the individual would not be able to move, or have their muscles slowly waste away. Humans have to maintain a body temperature of about thirty seven degrees Celsius to stay healthy. If one gets too hot or too cold, they will either die of hyperthermia or hypothermia. The body also needs oxygen, but too little or too much can result in hypoxia or oxygen toxicity. There are many restrictions for living on other planets, so many people are questioning whether it is worth trying to find another Earth.
Over the past 2 decades, scientists have found over 1,800 exoplanets, and studies suggest the universe holds about at least 100 billion more. Most of the planets found over the past years are so called "super Earths," planets larger than Earth by up to 10 Earth masses. These planets have proved to be extremely common around other stars, but they are not in range of their star's habitable zone, so there is no possibility that humans could live on them. Space exploration has its limits "even the closest exoplanet would take hundreds of years to get to, so unless we develop a much faster spacecraft, we're stranded for the time being." If the human race was truly desperate, a settlement may be able to be built on Mars, but even this is nearly impossible. It takes nine months just to get to Mars, and with only two people on board, four tons of food is needed for a five month visit on Mars, which would already be too much weight for the shuttle to launch, even without the materials to build a small town on the red planet.
Mars has been the focus of attention for a very long time, although there is no evidence to support that life exists there.