Sir
Isaac Newton said that the gravitational force of the earth acts not only on
the bodies that are close to the earth, such as an apple but also on those
bodies that are very far away, such as the moon.
But
how does a celestial body, like the Sun, which is almost 9.3 million miles away
from the Earth, control the Earth in its orbit?
An
early idea was that it was a force acting at a distance, for example, the sun
pulls all bodies, such as the earth, towards itself without any connection.
In
the middle of the 19th century, the physicist Michael Faraday (1791-1867)
reported that a magnet creates a magnetic field around itself and another
magnet interacts with it at the location of the field. Based on the idea of the
field, we can say that the Earth also creates a gravitational force field. The
force on the apple and the moon is not caused directly by the Earth, but by the
gravitational field at the location of the apple and the moon. If the sun
suddenly disappears, what will be the effect on the earth? How long will it
take for Earth to know that the Sun's gravitational field has ended? It can't
happen quickly, because according to Einstein's special theory of relativity,
no information can travel faster than the speed of light, so it would take
about 8 minutes for the Earth to feel the gravitational field and the lack of
sunlight.
