What is dark matter ?? Please explain

Dear student,
In astronomy dark matter is a type of matter which is believed to account for a major part of the total mass in the universe.
It does not emit or absorb light or any other electromagnetic radiation.
It cannot be seen with the help of a telescope.
The existence of dark matter and its properties are inferred from its gravitational effects on visible matter, radiation, and the large-scale structure of the universe.
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