Why Is There No Planet Between Jupiter And Mars, Even After Having Ample Space?
The universe is full of awe and miracles. It has become a source of wonder for many. However, some get excited about it, while others get petrified. There are also people who cherish the vastness of this universe. With our steps on the moon and our eyes on Mars, we always look for symmetry in the universe. But the beauty lies in the imperfection, in its un-symmetry. According to one of the renowned scientists, Dr. Frank Drake, the probability of life on the Earth is 1 in 60 billion, which can be demonstrated with the help of the Drake equation. Such is the imperfection of our universe. One such imperfection is observed in the universe around our neighbor planet, i.e., Mars.
What Is Asteroid Belt?
An Asteroid Belt is a cluster of space rocks between Mars and Jupiter’s orbits. These are often called as planetoids because of their incapability of becoming the planet. These belt lies are scattered in an area that is more than two-and-a-half times the space between the Earth and the Sun. Furthermore, these rocks are considerably small, from the size of a small plateau to a few thousand meters in diameter.
Why Are Asteroid Belts There Instead Of The Planet?
In the early years of our solar system, the rock and dust circling around the Sun were pulled by a force defined as gravity. These planets have motion decided by gravity and are defined under the principles of Kepler’s law of planetary motion. However, not all the ingredients are ample enough to create a new world. Thus, it became a region for the asteroid belt.
There are four major factors that decide the formation of a planet. These factors are:
1. Landmass
2. Planet Diameter
3. Gravity between its neighbor planets
4. Space Between the Two Neighbors
1. Landmass:
As per NASA, a planet in our solar system needs to have at least 1/200 of the moon’s mass, which is about 4 * 10²⁰ kg. For a planet to exist between Mars and Jupiter, it has to have a mass more than Mars but less than Jupiter. Thus, for a planet to exist between Mars and Jupiter, it needs to have a mass between 6.39 × 10²³ kg and 1.898 × 10²⁷ kg. The whole mass of the Asteroid belt is 2.39×10²¹ kg which is more than the minimal requirements of a planet but less than the mass that needs to be combined together as a planet to sustain the gravity between Mars and Jupiter.
2. Planet Diameter
The minimum diameter required to exist in our universe is around 800 kilometers. Else, it will fall into the planetoid. Further, if a planet has a natural satellite more than its own size, that planet is considered a dwarf planet. Such is the case with Pluto. The average diameter of all the asteroids combined is around 1420 Km. Talking about aspects of forming a planet, 1420 Km is again ample enough to form a planet. However, the smallest planet in our solar system, Mercury, has a humongous diameter of 4,879.4 km. However, the diameter of Mars is 6,779 km, while the diameter of Jupiter is a staggering 139,820 km. For a planet to exist, it needs to have the size of Mercury, let alone forget the size of Mars and Jupiter. Thus, the formation of all the asteroids to form a planet is seemingly impossible by considering diameter as the factor.
3. Gravity between its neighbor planets
Gravity is considered as the force by which a body attracts another body through its center. When it comes to celestial bodies, gravity is calculated between the Sun and the planet. Furthermore, as per our calculation, we have found the gravitational force of Mars is 3.71 m/s², and the gravitational force of Jupiter is 24.79 m/s². For a planet to sustain the gravitational pull of Mars and Jupiter, it must be very far from them, or the planet’s gravitational pull must be between 3.71 and 24.79 for longevity. However, we have calculated the probable gravity of the planet that could have been at the place of the Asteroid is a nominal 0.0325 m/s². This gravity is simply not enough to sustain between giant planets like Mars and Jupiter, but this can be ample enough to form a planet somewhere in low-gravity space in the universe.
4. Space Between the Two Neighbors
By space between the two neighbors, we mean the orbital area in which the planet occurs. It is the area in which a planet clings to orbit around the Sun or its parent star. The current distance between Earth and Venus is 242.26 million Km, while the current distance between Mars and Earth is 93.336 million Km. However, the current distance between Mars and Jupiter is 588 million Km. Taking the mean distance between Mars and Jupiter to place a planet of the size of Earth at the place of an Asteroid belt will make the current distance between the respective planet and Jupiter will be around 250 million Km. The given 250 million Km is sufficient space for the planet to exist. We can say that the Asteroid belt is the correct place for a planet to exist. However, things do not seem to work out due to other gradients that may act upon every celestial body.
Final Thoughts
All the aforementioned points prove that sufficient elements are present to form a planet. But, these elements were simply insufficient to make a planet between Jupiter and Mars. Further, those asteroids still cling to hover around because of being shepherded by the humongous gravity of Jupiter. This motion is called mean motion resonances. Thus, Jupiter’s gravitational pull tugs on the Asteroid to add up and reinforce each other. However, the planet tugs can quickly reboot the Asteroid out of the solar system. Thus, looking at the formation of the asteroid belt is a great way to depict the imperfection of the universe.
These resonances probably stripped the ancient asteroid belt of most of its mass. So the asteroids we see today are the few survivors that somehow escaped Jupiter’s grasp. — Marc J. Kuchner, NASA’s Goddard Space Flight Center
Footnotes: The Drake Equation
The Kepler’s Law Of Planetary Motion
