What are the planets suitable for human habitation?

The planets suitable for human habitation are Kepler -22b and Mars.

1, Kepler -22b: Kepler 22b is a planet in Cygnus, about 600 light years away from the sun, and its size is 2.4 times that of the earth. It has a greenhouse effect similar to that of the earth, and its surface temperature is about 22 degrees Celsius. Kepler -22b may be one of the planets suitable for life, because there may be water in its atmosphere, and it has a suitable climate and a warm climate.

2. Mars: Mars is about 228 million kilometers away from the Earth, and its average orbit is about 228 million kilometers away from the Earth. There is a great possibility of life on Mars, and there is liquid water. Although there is no evidence of life on Mars at present, the climate and environmental conditions on Mars are similar to those on Earth, which makes it possible for human beings to establish colonies and live on Mars.

The formation of stars

Planets may be formed by the collapse of nebulae. Nebulae are huge gas clouds, dust and other tiny substances floating in the universe. When a part of the nebula begins to collapse under the action of gravity, the density of matter will increase sharply, leading to the accumulation of matter in this area. These blocks of matter eventually formed the planet as we know it.

When the nebula collapses, the matter gathers into a cluster, and the temperature and pressure will gradually increase. When the temperature rises to a high enough level, the accumulated matter will start nuclear fusion. Nuclear fusion is a reaction that can transform hydrogen atoms into heavier helium atoms and release huge energy. This energy will produce intense light and heat, forming the stars we see.

The above contents refer to Baidu Encyclopedia-Kepler -22b Baidu Encyclopedia-Mars.