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An alternative expression for the escape velocity v e particularly useful at the surface on the body is: = where r is the distance between the center of the body and the point at which escape velocity is being calculated and g is the gravitational acceleration at that distance (i.e., the surface gravity). [11]
In astrodynamics, the characteristic energy is a measure of the excess specific energy over that required to just barely escape from a massive body. The units are length 2 time −2, i.e. velocity squared, or energy per mass.
"The first 1000-year-old is probably only ~10 years younger than the first 150-year-old."–Aubrey de Grey, 2005 [1]. In the life extension movement, longevity escape velocity (LEV), actuarial escape velocity [2] or biological escape velocity [3] is a hypothetical situation in which one's remaining life expectancy (not life expectancy at birth) is extended longer than the time that is passing.
One of the best-known examples of an event horizon derives from general relativity's description of a black hole, a celestial object so dense that no nearby matter or radiation can escape its gravitational field. Often, this is described as the boundary within which the black hole's escape velocity is greater than the speed of light.
One classical thermal escape mechanism is Jeans escape, [1] named after British astronomer Sir James Jeans, who first described this process of atmospheric loss. [2] In a quantity of gas, the average velocity of any one molecule is measured by the gas's temperature, but the velocities of individual molecules change as they collide with one another, gaining and losing kinetic energy.
It is related to the hyperbolic excess velocity (the orbital velocity at infinity) by = =. It is relevant for interplanetary missions. Thus, if orbital position vector ( r {\displaystyle \mathbf {r} } ) and orbital velocity vector ( v {\displaystyle \mathbf {v} } ) are known at one position, and μ {\displaystyle \mu } is known, then the energy ...
If there is a strong thermally driven atmospheric escape of light atoms, heavier atoms can achieve the escape velocity through viscous drag by those escaping lighter atoms. [2] This is another way of thermal escape, called hydrodynamic escape. The heaviest species of atom that can be removed in this manner is called the cross-over mass. [3]
Mean orbital velocity of the Moon around Earth. 1,400 5,040 ... Escape speed from Earth by NASA New Horizons spacecraft—Fastest escape velocity. 17,000: 61,000: