Well, there are eight planets in the solar system starting with Mercury, then Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Pluto. As per the International Astronomical Union Pluto was reduced to dwarf planet status. Pluto is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune. It was the first and the largest Kuiper belt object to be discovered. After Pluto was discovered in 1930, it was declared to be the ninth planet from the Sun.
Currently, there are six dwarf planets officially designated by the IAU: Pluto, Ceres, Eris, Makemake, Haumea, and 2015 RR245.
Mercury, Venus, Earth and Mars are the rocky planets nearer to the Sun, and Saturn, Jupiter, Neptune, and Uranus are the gas giants.
Dark matter is composed of particles that do not absorb, reflect, or emit light, so they cannot be detected by observing electromagnetic radiation. Dark matter is material that cannot be seen directly.
It turns out that roughly 68% of the universe is dark energy. Dark matter makes up about 27%. The rest – everything on Earth, everything ever observed with all of our instruments, all normal matter – adds up to less than 5% of the universe.
Since at least the 1920s, astronomers have hypothesized that the universe contains more matter than seen by the naked eye. Support for dark matter has grown since then, and although no solid direct evidence of dark matter has been detected, there have been strong possibilities in recent years.
“Motions of the stars tell you how much matter there is,” Pieter van Dokkum, a researcher at Yale University, said in a statement. “They don’t care what form the matter is, they just tell you that it’s there.” Van Dokkum led a team that identified the galaxy Dragonfly 44, which is composed almost entirely of dark matter.
Albert Einstein showed that massive objects in the universe bend and distort light, allowing them to be used as lenses. By studying how light is distorted by galaxy clusters, astronomers have been able to create a map of dark matter in the universe.