The young moon rises above national reserve Wildlife Seedskadee in Wyoming, September 16, 2016. Credit & Copyright: USFWS.
Compared to other space objects, the Moon is very close to us, but I would like it to be even closer. Close enough that I can see the smallest details on its surface without a telescope or binoculars.
Of course, such closeness would entail terrible problems. For example, intense tides, the complete absence of good dark nights for stargazing, and something else ... oh yes, the complete destruction of life on Earth. I guess I've changed my mind, Luna better stay where she is.
The average distance to our satellite is 384,467 kilometers. I say "average" because the moon is actually moving along elliptical orbit. At the nearest point, the distance is only 363,104 kilometers, and at the farthest point, it is 405,696 kilometers.
Thus, light traveling at 300,000 km/s would take just over a second to reach our satellite. The moon is very far away.
But what happens if the Moon is much closer? How close can it be and still be our satellite?
Again, I must remind you that these are purely theoretical considerations. The moon is not approaching us, but on the contrary - it is slowly moving away from us by almost 4 centimeters per year.
Let's go back in time, billions of years ago, when the young Earth collided with an object the size of Mars. This catastrophic collision threw great amount material into the orbit of our planet. Over time, under the influence of gravity, this material formed the Moon that we see today.
Shortly after its formation, the Moon was much closer and the Earth was spinning faster. At that time, the length of a day on Earth did not exceed 6 hours, and the Moon made one revolution around the Earth in just 17 days.
At a distance that corresponds to the Roche limit, tidal forces and self-gravitational forces are equalized. Thus, any instability will lead to the destruction of the satellite. Credit & Copyright: Theresa Knott. The Earth's gravity stopped the Moon's rotation, and the Moon's gravity gradually slowed the Earth's rotation. Thus, in order to preserve the overall angular momentum system, the moon must constantly move away from us.
But if you consider another scenario in which the moon is spinning faster than the planet, then the moon should be getting closer to us. And it won't lead to anything good.
For any gravitational interactions there is a critical point, which is called the Roche limit. The Roche limit is the point at which an object held by gravity comes so close to another celestial body that it begins to collapse.
The Roche limit is determined by the masses, sizes, and densities of the two objects. For example, the Roche limit for the Earth and the Moon is about 9,500 kilometers, assuming the Moon is a solid ball. In other words, if the distance to the Moon is 9,500 kilometers or so, then the gravity of the Earth will tear our satellite apart.
All that remains of the moon is a ring of small objects orbiting our planet. Over time, all these small objects will fall to the Earth and these will be very bad days for all life on Earth.
But don't worry, this will never happen to Earth, but you might be surprised to know that it will happen to Mars. Its largest moon, Phobos, rotates faster than the planet, which means that in a few million years, it will cross the Roche limit and be torn to pieces by its planet.
Researchers believe that Mars' moon Phobos may someday turn into a ring around the Red Planet. Credit & Copyright: Celestia. And one moment. After reading this article, you may have the following question: because I am also a separate object, and I am closer than the Roche limit, so why haven't I been torn apart yet?
In fact, the force of gravity that holds you to the surface is very small compared to the chemical bonds that keep the molecules that make you up stable. That is why physicists consider the force of gravity to be a rather weak force compared to all other forces in the universe. Only gravitational forces black hole can violate your chemical bonds and tear you apart.
So, the minimum distance at which the Moon remains the Moon is approximately 9,500 kilometers, otherwise our only satellite will collapse and destroy all life on Earth.
You can set a reminder about them in your messenger and we will remind you in advance about the supermoon and tell you the time of sunrise and sunset and other information about it. Since this event is rare, it is easy to miss and therefore we recommend setting this reminder.
What Happens During Supermoons
First, the moon in the sky becomes as large and bright as possible. On the night of the supermoon, you can observe the largest moon. In this case, it should be remembered that at the moment of moonrise above the horizon, an optical illusion arises and the moon is seen as very large. It has nothing to do with the supermoon.
Secondly, the maximum approach of the moon affects the tides, they are the largest on this day.
Also, according to statistical studies, the full moon affects the psychological and physical state of a person, and therefore, on the days of the super moon, this influence should be maximum. However, this is only a theory that still needs to be proven and researched.
What does a supermoon look like
Bigger and brighter
In a supermoon, the moon is visually larger by about 7% and 16% brighter than an average full moon.
biggest in winter
In winter, the earth comes closer to the sun, and during the supermoon, the sun pulls the moon more towards the earth with its gravitational force. Therefore, winter supermoons are visually larger than summer ones.
Biggest at moonrise
During moonrise, it appears above the horizon and seems huge and very beautiful. This is because visually it is located against the background of landscape elements and we can compare its size with familiar elements - trees, buildings, mountains, etc.
This effect is called moon illusion.
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The closer the Moon is to the Earth, the stronger its influence. Thus, it turns out that during supermoons, the impact of the moon on our planet is maximum.
Russian amateur astronomers have started uploading videos of a noticeably enlarged moon today. There are videos on the Internet with Far East and from Siberia. weather conditions in last night allowed for observation.
The term "supermoon" is used to refer to the period of the full moon, when the moon gets as close as possible to the earth in its orbit. Astronomers call this point perigee. The distance from our planet to the satellite at this moment will be about 356,500 km. The full moon will come tonight at 16:52 Moscow time, and the super moon can be observed throughout the night from November 14 to 15.
The Moon hasn't come this close to Earth since January 1948. True, then the distance between our planet and its satellite was another 50 km less. But the repetition of such a close rendezvous will have to wait 18 years. The next comparable supermoon is not expected until November 2034.
According to NASA, in a supermoon, the satellite will appear from Earth 14 percent larger and 30 percent brighter than full moon at the apogee. This effect will be especially noticeable when observing the Moon rising above the horizon. You can see the supermoon both in the city and in nature, the main condition is a cloudless sky.
On the synoptic map of the upcoming night, a huge anticyclone that captured the Urals and Siberia is clearly visible. This hearth high pressure contributes to the dispersal of cloudy fields over a vast territory from the Kama region to Yakutia, keeping severe frosts everywhere. Cloud fields are concentrated along its borders - over the Arctic regions, for the most part European Russia, the extreme south of Siberia and the Far East. This is where you won't be able to see the supermoon.
But the Urals, the inhabitants Western Siberia, Krasnoyarsk Territory and Yakutia, if desired, will be able to enjoy the spectacle of a large and bright moon. The main thing is not to freeze at low temperatures.
Experts have been arguing about the connection between supermoons and all sorts of cataclysms for many years. Some of them note that on the days when these phenomena are observed, destructive earthquakes and volcanic eruptions often occur. They also remember the 2004 earthquake in Southeast Asia, and the tremors in Japan in 2011. Now the earthquake in New Zealand is also associated with the supermoon.
Experts admit that approaches to the Moon do not pass without a trace for our planet. Earthquakes ripen in the bowels, and the Moon, due to its gravitational influence, can theoretically push events a little bit. But meanwhile the entire tidal effect of the Moon is small. It's as if we went up or down 30 centimeters in 6 hours. So it is still impossible to say that it is the supermoons that are responsible for earthquakes.
In every this moment time, the Moon is no closer than 361,000 and no further than 403,000 kilometers from the Earth. The distance from the Moon to the Earth changes because the Moon revolves around the Earth not in a circle, but in an ellipse. In addition, the Moon is little by little moving away from the Earth by an average of 5 centimeters per year. People have been observing the gradually decreasing moon for many centuries. There may come a day when the moon will break away from the Earth and fly away into space, becoming independent celestial body. But this may not happen. Balance gravitational forces holds the moon firmly in Earth orbit.
Interesting fact: The moon moves away from the earth by about 5 centimeters every year.
Why is the moon moving away from the earth?
Any moving body wants by inertia to continue its path in a straight line. A body moving in a circle tends to break away from the circle and fly tangentially to it. This tendency to break away from the axis of rotation is called centrifugal force. You feel the centrifugal force at the playground, on the high-speed swings, or when the car swerves sharply and pushes you against the door.
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The word "centrifugal" means "running away from the center". The moon also strives to follow this force, but it is kept in orbit by the force of the earth's gravity. The moon stays in orbit because the centrifugal force is balanced by the earth's gravity. The closer to the planet its satellite is, the faster it revolves around it.
What is the reason? Any moving object has a moment of momentum. The moment of a rotating body depends on the mass, speed and distance from the axis of rotation. The moment can be calculated by multiplying these three quantities together. Scientists have found that the moment of rotation of a given body does not change. Therefore, when an object approaches the axis of rotation, due to the law of conservation of moment, it will rotate faster, since the mass in this equation cannot be changed arbitrarily.
The moon used to be much closer to the earth
This law is called the law of conservation of torque. The moon makes one revolution around the earth in about 27 days. But 2.8 billion years ago, the Moon, closer to us, revolved around the Earth in 17 days. According to Clark Chapman, an astronomer at the Planetary Science Institute in Tucson, Arizona, the Moon was once even closer. At the time of the formation of the Lunar Earth 4.6 billion years ago, the period of the Moon's revolution was only 7 days. If then anyone could see the moon, he would be amazed by the huge size of the rising blood-red moon.
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