Just finished admiring the beauty of the super red moon, come and see other "abilities" of the moon

Source: Science and Technology Daily

Astronomy around

◎ Li Jian

On the night of May 26, the supermoon coincided with a total lunar eclipse, and a red full moon lit up the starry sky on summer nights.

"Poor moon, where is it going, going to leisurely?" Is it someone else's world, only to be seen over there, the east end of the light and shadow? "In the eyes of the ancients, the moon has always been the most poetic celestial body. Putting wine on the moon, it brings people countless questions. Where does the moon come from? Why is the night sky hanging high? Without the moon, what changes would the Earth face?

The tides weaken and the magnetic field dies

Without the Moon, the most direct effect on the Earth would be the weakening of tidal phenomena. The Moon is the main "driving force" that produces ocean tides. Without the moon, the daily rising and falling tides would cease to emerge, replaced by gentle fluctuations of the waves, which would change direction and cause dramatic changes in the climate. Sea level will also be affected, losing the pull of the moon's gravity, the sea water will be almost evenly distributed across the surface, and the sea level at the poles will rise sharply.

The moon and tides have more than that, they are also the "guardians" of the Earth's magnetic field. The Earth has a solid core surrounded by a liquid outer nucleus, and the main material in the inner and outer nuclei is iron. The temperature of the outer core increased from more than 4,000 degrees Celsius near the mantle to more than 6,000 degrees Celsius near the core, almost as hot as the sun's surface. The molten iron becomes a plasma state here, and they act as convective movements in the outer core, like a "generator", forming a powerful inductive magnetic field.

It is this magnetic field that protects us from the sun's high-energy charged particles, and also prevents the solar wind from eroding the Earth's atmosphere. The latest research shows that the moon's moisture pulling force is the main factor driving the convective movement of the outer core, and the energy it produces in the outer core is measured in trillions of joules per second, keeping the "earth's dynamo" alive, thus maintaining the earth's magnetic field.

Without the moon, the Earth's magnetic field would be greatly weakened or even disappeared, the solar wind would "blow away" the Earth's atmosphere, high-energy radiation would hit the surface, and life would face extinction.

The earth's axis swayed and the climate went crazy

The Moon also has a key role in keeping the Earth's axis of rotation stable for a long time. We know that the equatorial plane of the Earth does not coincide with its orbital plane (ecliptic plane) and has an inclination of about 23.5 degrees, which makes the Earth have four seasons of spring, summer, autumn and winter.

Since the Earth is rotating, the rotational speed on the equator is the largest, which makes its shape not a positive sphere, but an approximate ellipsoid with slightly flattened poles and slightly bulging equator. Both the Moon and the Sun are moving near the ecliptic plane, and their gravitational pulling force has a tendency to drag the equatorial part of the Earth's uplift toward the ecliptic plane, thereby reducing the inclination. But because the Earth is rotating rapidly, their efforts have not "succeeded", and the final result is "mutual compromise" - the inclination angle is still basically stable at 23.5 degrees, but the direction of the Earth's axis of rotation is slowly changing direction in space.

Without the moon, the Earth's axis of rotation would swing sharply, even more than 90 degrees. Changes in inclination will lead to dramatic changes in the Earth's climate: when the axis of rotation is perpendicular to the surface of the orbit, the heat of the sun received in every corner of the earth is essentially constant throughout the year; when the axis of rotation becomes parallel to the plane of the orbit, people will spend half a year exposed to the hot sun, while the other half will be shivering in the dark and cold. Every year, there are only two extreme seasons of extreme heat and cold.

Other effects are difficult to measure

As we have studied it, we have found that the moon may be incredibly important to us, and there are many other effects that are difficult to accurately estimate.

Without the moon, life on Earth might be difficult to form, or delayed by hundreds of millions of years. About 4 billion years ago, the Moon was much closer to Earth than it is today, and the tides on Earth may have been a thousand times larger than they are today. At that time, the Earth's rotation cycle was only about 6 hours, and it experienced a high tide every 3 hours. Puddles formed after the tide recedes evaporate due to sun exposure, leaving behind salts, minerals and organic compounds. Frequent tides "concentrate" these chemicals, which chemically react under solar radiation to form more complex organic compounds, such as fatty acids and proteins, which ultimately lead to the formation of life.

Without the moon, we would probably have to struggle with the lack of heavy metals such as gold and platinum. The Moon was born in a super-big collision about 4.5 billion years ago — a Mars-sized object, Theia, colliding with Earth. The Earth lost most of its primordial crust, the shell of Theia and part of the mantle were shattered, and the splash of material eventually condensed into the moon. The heavy metal-rich core of Theia remains on Earth. The vast majority of the metal mines we mine today come from it. The heavy metals of the earth itself are basically deposited in the core, and it is only possible to "see the light of day" when the volcano erupts.

Without the moon, the Earth would have suffered more asteroid impacts, and would have become a hurricane paradise due to its faster rotation, making it difficult to build our homes...

Without the moon, the biological clocks of countless creatures would have changed radically. The night sky is so dark that you can't see your fingers, owls will have more difficulty foraging, insects will not find their mates, and fish that synchronize with the tides will have disorders in foraging and breeding...

Thanks to the moon, it helps the formation of life and watches over the growth of life. And I believe that in the near future, it will also become the first stop for human beings to step out of the earth, and become our space base for exploring other celestial bodies! (The author is an associate researcher at Beijing Planetarium)