Planet Essay Sample

Have you ever wondered what makes a planet a planet? Well, there are three criteria that they need to meet to be considered/certified as a large planet. To begin with they must orbit a star. Planets often circle stars because they have a very strong gravitational pull. Our moon orbits the earth, and we can look at a solar system in the same way. Can a planet not orbit a star? Well, Astronomers discover dozens of “rogue planets' roaming the galaxy without a star. It's not the first time astronomers have discovered so-called "rogue planets'' — free-floating planets that wander aimlessly through space without a host star to orbit. But they thought it was a somewhat rare phenomenon, until now. In addition, it must also be big enough to have enough gravity to force it into a spherical shape. How big does a planet have to be before it has enough gravity to crush it into a sphere? For bodies made mainly of rock, the minimum size to become a self-gravitating sphere is about 600 km diameter; but, for bodies mainly made of ice, the minimum size is about 400 km diameter. Gravity is what holds the planets in orbit around the sun and what keeps the moon in orbit around Earth. The gravitational pull of the moon pulls the seas towards it, causing the ocean tides. Gravity creates stars and planets by pulling together the material from which they are made. Furthermore, It must be big enough that its gravity cleared the neighborhood of similar size near its orbit around the Sun. What is the meaning of clearing the neighborhood? Clearing the neighborhood around a celestial Body's orbit describes the body becoming gravitationally dominant such that there are no other bodies of comparable size other than its natural satellites or those otherwise under its gravitational influence. How does a planet clear its Neighborhood? The phrase refers to an orbiting body (a planet or protoplanet) “sweeping out” its orbital region over time, by gravitationally interacting with smaller bodies nearby. In conclusion, the three criteria are important and required for a planet to meet to be considered/certified as a planet.