and the wholecosmos. On Earth all bodies have aweight, or downward force of gravity, proportional to their mass, which Earth’s mass exerts on them. Gravity is measured by the acceleration that it gives to freely falling objects. AtEarth’s surface the acceleration of gravity is about 9.8 ...
always coincide, however. For example, theMoon’scentre of mass is very close to its geometric centre (it is not exact because the Moon is not a perfect uniform sphere), but its centre of gravity is slightly displaced towardEarthbecause of the stronger gravitationalforceon theMoon’snear side...
aScientists have found facts to explain life and nature and thereby reshape ideas. Examples are plenty-- discoveries such as the earth going around the sun by Galileo, the principles of gravity by Newton, the evolution of species by Darwin, to name only a few. As a result, society has wi...
Here are some facts about sleep.Sleep at advised timesIn 2021, the Ministry of Education(MOE)advised that junior and senior high school students should go to bedbefore 10 pm and 11 pm respectively(分别的).How do astronauts sleep?Just like on Earth, a person in space goe...
It is large enough for its owngravityto mould it into a spherical shape, and its orbit doesn’t have other small objects around it. Can you see Neptune by looking into the sky? No, you can’t actually see Neptune with the naked eye because it is so far from earth. But as we said...
causing it to accelerate in the general direction of the centre of the planet. Departures from the spherical shape and the effect of Earth’s rotation cause gravity to vary with latitude over the terrestrial surface. The average gravitational acceleration atsea levelis about 980 cm/sec2(32.2 fee...
John P. Rafferty writes about Earth processes and the environment. He serves currently as the editor of Earth and life sciences, covering climatology, geology, zoology, and other topics that relate to... John P. Rafferty Fact-checked by ...
Earthquake, any sudden shaking of the ground caused by the passage of seismic waves through Earth’s rocks. Earthquakes occur most often along geologic faults, narrow zones where rock masses move in relation to one another.
As far as is known, life exists only on Earth. Most life-forms reside in a thin sphere that extends about 23 km (14 miles) from 3 km (2 miles) beneath the bottom of the ocean to the top of the troposphere (lower atmosphere); the relative thickness is comparable to a coat of ...
Mercury also presents difficulties to study by space probe. Because the planet is located deep in the Sun’s gravity field, a great deal of energy is needed to shape the trajectory of a spacecraft to get it from Earth’s orbit to Mercury’s in such a way that it can go into orbit ...