On Earth, you can see at night and see the moon shining brightly from hundreds of thousands of miles away. But if you went to Venus, that wouldn’t be the case. Not every planet has a moon – Why do some planets have many moons and others none?
I am a physics instructor A follower of current theories explaining why some planets have moons and others don’t.
Originally, the Moon was called a natural satellite. Astronomers note Satellites as objects in space Circulates larger bodies. Since the Moon is not man-made, it is a natural satellite.
Currently, there are two main theories as to why some planets have moons. If the moons are inside what is called a planet they are held by gravity Hill spherical radiusOr they form together with the solar system.
Hill spherical radius
Objects a Gravitational force on other objects nearby. The larger the object, the greater the force of attraction.
This is because of gravity We are all on earth Instead of floating.
The solar system is dominated by the Sun’s massive gravitational pull, which holds all the planets in orbit. The Sun is the most massive object in our solar system, meaning it has the greatest gravitational influence on objects such as the planets.
For a satellite to orbit a planet, it must be close enough to the planet to exert enough force to keep it in orbit. is called the minimum distance to keep the satellite in orbit Hill spherical radius.
The Hill sphere radius is based on the mass of both the large object and the small object. The Moon orbiting the Earth is a good example of how the spherical radius works. The Earth revolves around the Sun, but the Moon is closer to the Earth and the Earth’s gravitational pull captures it. The Moon orbits the Earth faster than the Sun because it is at Earth’s heliocentric radius.
Small planets such as Mercury and Venus have a small spherical radius because they cannot exert a large gravitational force. Any potential moons will be pulled by the Sun instead.
Many scientists are still looking into whether these planets may have had small moons in the past. When the solar system was formed again, they There may have been moons It was blown away by collisions with other space objects.
Mars has two moons, Phobos and Deimos. Scientists are still debating whether these came from asteroids that passed close to the radius of the Martian globule and were captured by the planet, or whether they formed at the same time as the Solar System. Further evidence supports the first theoryBecause Mars is near the asteroid belt.
Jupiter, Saturn, Uranus, and Neptune have large spherical radii because they are much larger than Earth, Mars, Mercury, and Venus, and they are farther from the Sun. Their gravitational forces can Attract natural satellites like moons In orbit. For example, Jupiter has 95 moonswhen Saturn has 146.
Moons forming with the solar system
Another theory suggests that some moons formed at the same time as their solar system counterparts.
Solar systems begin with large disks of gas orbiting the Sun. As the gas orbits the Sun, it condenses on the planets and moons that revolve around them. The planets and moons all rotate in the same direction.
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But only a few moons in our solar system may have formed this way. Scientists have predicted that of Jupiter and Saturn The inner moons formed during the formation of our solar system Because they are very old. The remaining moons in our solar system, including the outer moons of Jupiter and Saturn, may have been gravitationally captured by their planets.
Earth’s moon is special because it can form in a different way. Scientists believe that a long time ago, a large, Mars-sized object collided with Earth. During that conflict, a large piece It took off from Earth and went into its orbit And became the moon.
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Scientists speculate that the moon was formed this way because they found a type of rock called basalt in the soil on the moon’s surface. Basalt of the Moon Looks like the same Similar to basalt found inside the earth.
Ultimately, the question of why some planets have moons is still widely debated, but factors such as a planet’s size, gravity, mountain spheroid radius, and how its solar system formed may play a role.
(Author: Nicole Granucci, Instructor of Physics, Quinnipiac University)
(Disclosure Statement: Nicole Granucci has not received shares in, consulted for, owns, or received funding from any company or entity that may benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.)
This article has been republished Conversation Under Creative Commons License. Read on Original article.
(Other than the headline, this story was not edited by NDTV staff and was published from a syndicated feed.)
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