Dark Matter
According to Newtonian physics and Kepler’s law the planet
close to the star orbits faster and that far from the star orbits slower.
For example in our solar systems mercury orbits the sun
faster than the Neptune.
Ok that all said and we know that’s because of gravity.so,
what relates it to a dark matter.
but when observing the orbital speed of the stars in the
galaxies astronomers found below result.
(below are three graph with various presentation skills but all are same,i included this for better understanding)
as per the keplerian prediction the stars far from the center of galaxy should have less rotational speed then that of close to the galaxy center but astronomers got surprising result the stars far from the center rotating at almost the same speed as that closer to the center.so,there must be mass spread out beyond the center of the galaxy and this mass bound the stars in the galaxies and that's why can't escape.
calculations showed that galaxies must contain about ten
times as much “dark” mass as can be accounted for by the visible stars. In
short, at least ninety percent of the mass in galaxies, and therefore in the
observable universe, is invisible and unidentified and that they called "DARK MATTER".
21% of universe is made of DARK MATTER and only 4.9% is made up of ORDINARY MATTER which we can see (you,me ,stars,planets,gases,galaxies etc) while 74% is made up of DARK ENERGY.
we are just a tiny fraction of the universe !!!
21% of universe is made of DARK MATTER and only 4.9% is made up of ORDINARY MATTER which we can see (you,me ,stars,planets,gases,galaxies etc) while 74% is made up of DARK ENERGY.
we are just a tiny fraction of the universe !!!
