What would happen to Earth if there were no light?
Presuming the question is about what happens if the sun, our
principal source of light, suddenly disappeared, what follows is a
scientifically credible answer:
Without sunlight, plants die, then animals die.
Without sunlight earth's atmosphere cools.
Note that the Earth does not immediately freeze. The Earth's
interior contains many radioactive elements and as they decay the
heat released will keep the interior warm for a long time to come.
The surface, however, will rapidly radiate heat into space, and
fall to the temperature of the solar system's outer planets.
Earth's oceans contain considerable latent heat, these would
require months or years to freeze solid. The ocean surfaces would
begin freezing from the poles towards the equator within a matter
Grass and trees would begin dying within days. Pine trees would
last among the longest as these can remain buried beneath ice for
months at a time. Water would precipitate out of the atmosphere,
making the air very dry and cold.
If the sun went missing altogether, which is the source of
gravity holding the solar system together, the planets, including
Earth would fly off in straight lines until ultimately interacting
with some other massive body millions of years hence.