When an object is launched upward, it rises up to a speed limit, stops momentarily, and then begins the downward movement. However, there is a certain speed value at which the object no longer returns to Earth and simply leaves towards outer space. This minimum speed to exit a celestial body is called escape velocity.
The escape velocity is related to the mass (M) of the planet or star you want to escape from, with the radius (R) of that planet and with the universal gravitation constant (G), which has a value of 6.67 x 10 -11 Nm2/kg2. The equation below determines the escape velocity:
Note that this equation does not depend on the mass of the body being thrown out of the planet or star. So, for a very or a little massive body, the escape velocity will be the same. The table below indicates the escape velocity for some celestial bodies:
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The escape velocity also doesn't depend on the direction in which the body will be launched, but there are situations where launching objects into space can be done more easily. Near the equator, the Earth's rotation speed is as high as possible, which causes the object to be launched to gain extra energy. In addition, the launch should preferably be done in the east direction, following the Earth's rotation movement.
You black holes are extremely massive elements that have an escape velocity greater than the speed of light. For this reason, not even the light itself, entering a black hole, can escape from it.
By Joab Silas
Graduated in Physics
Would you like to reference this text in a school or academic work? Look:
JUNIOR, Joab Silas da Silva. "What is escape velocity?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/fisica/o-que-e-velocidade-escape.htm. Accessed on June 28, 2021.
