Do you know which planets are suitable for human habitation?

At present, the only planet suitable for human habitation is the earth, and the planets that may be suitable for human habitation are zhiKepler-438b, Kepler-62e, Gliese 832 c, Kepler- 1544b and Gliese 180 c.

：

1, Kepler -438b: This dao planet in Lyra was discovered by scientists at the Smithsonian Center for Astrophysics of Harvard University, which is about 470 light years away from the Earth. It revolves around a white dwarf star, which meets the living conditions of human beings: solid surface and potential running water.

2. Kepler -62e: This planet is 1200 light-years away from the Earth, and it is a potential water source planet. The climate above it is wet and cloudy all the year round. Its rotation period is about 122 years, and its size is about 1.6 times that of the earth. There may be life on this planet, so it is not easy for human civilization to immigrate to the past.

3.Gliese 832 c: This planet is located in the constellation Crane, which may be close to the earth's temperature and has obvious seasonal variation. It may be pregnant with life, but it may also be as hot as Venus. In any case, human beings need to make great efforts to survive on it.

4. Kepler-1544b: This is a newly discovered planet, which was first reported in 20 16. Kepler-1544b is about 1 138 light years away from the earth. The period of its revolution around the star is 168.8 days. It also conforms to the living conditions of human beings.

Gliese180 c: this planet is only 38 light years away from the solar system. Of course, it also meets the living conditions. It is considered as a super earth, and its size is about 6.4 times that of our earth.

Come on, tell you the distance of light years!

Let's talk about the word light year first, because it has the word "year", so it is often mistaken for a unit of time, so that it is sometimes misused. For example, it may be misused in some popular songs to describe a long time, such as "a blink of an eye, a light year." This is a misunderstanding.

Light-year is a unit of length, which is generally used to measure the distance between celestial bodies. Literally, the distance that light travels straight in a cosmic vacuum for one year is 9460' 7304' 7258' 0800 meters, and the speed of light [m/s] × 1 year [y] = light years.

Example:

It takes about eight minutes for light to reach the earth from the sun (that is, the distance from the earth to the sun is eight minutes).

The nearest known star in the solar system is proxima centauri Centauri, which is about 4.22 light years away.

Our galaxy is about 654.38 million light-years in diameter. Suppose there is a spacecraft approaching the speed of light from one end of the galaxy to the other, which takes more than 65438+ million years. But this is only for static observers (relative to the Milky Way), and people on board feel that the journey is actually only a few minutes. This is due to the time expansion phenomenon of the moving clock in special relativity.

The astronomical observation range is extended to a vast space (called the total galaxy) over 1000 billion light years.