Extraterrestrial

The so-called gravitational equilibrium surface refers to the surface formed by the same point of gravity. On Earth, we call the gravitational equilibrium surface that coincides with the stationary ocean surface the "geodetic level", which is actually equivalent to what we often call sea level.

Harrison Schmitt is the world's twelfth human to set foot on the lunar surface and the only scientist to have landed on the moon. On the 50th anniversary of the first human landing on the moon in June 2019, he warns that many people may be allergic to the dust on the lunar surface

The milky way is a huge galaxy with hundreds of billions of stars, and the sun is just one of the less prominent stars that, along with many other stars in the galaxy, orbits the centre of the galaxy.

The moon is the closest planet to the earth and the brightest and most easily observed object in the earth's night sky. Because the moon is always facing the same way towards the earth, for us humans living on earth, we can only ever observe one fixed side of the moon.

So far, we have not found any trace of life on Mars. No one knows whether there is life on Mars. However, when we are exploring Mars, sometimes we will see some interesting scenes, even some garbage. It is strange that there is no one on Mars. Why is there garbage? Where does this rubbish come from?

Nowadays, Mars is obviously unsuitable for direct human habitation, because the environment of Mars is very different from that of Earth, such as Mars is unusually arid, desolate and without a trace of life. Despite this, scientists are still keen to explore Mars

Between the Earth and the Moon there exists a much more empty space than imagined, so what can be put down in this space?

Compared to radio messages sent by humans, this method seems to be more suitable for intelligent civilizations to announce their presence in the universe, because this method belongs to the "broadcast" in space, and intelligent civilizations in all directions can be observed

In our solar system, there are 2 planets in the habitable zone of the solar system, one of which is our home planet Earth, and the other is Mars

After the sun evolves into a red giant, the hydrogen in its core is almost completely fused into helium, so the nuclear fusion inside the sun stops, after which the sun loses its internal radiation pressure and continues to collapse, leading to a constant increase in temperature and pressure in its core, while the helium in the central region of the sun is gradually compressed into the condensed state.