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.
The JWST is a space telescope developed by NASA, ESA, and CSA. The telescope is named after James E Webb, who was the administrator of NASA from 1961-68 and played an integral role in the Apollo space program. JWST was launched on 25 December 2021 from the Guiana Space Centre in French Guiana.
It is designed to provide improved infrared resolution and sensitivity over Hubble and will enable a broad range of investigations across the fields of astronomy and cosmology including observations of some of the most distant events and objects in the Universe such as the formation of the first galaxies, and allowing detailed atmospheric characterization of potentially habitable exoplanets.
JWST’s primary mirror is a 6.5 m (21 ft)-diameter gold-coated beryllium reflector with a collecting area of 25.4 m2 (273 sq ft). If it were built as a single large mirror, this would have been too large for existing launch vehicles. The mirror is therefore composed of 18 hexagonal segments which will unfold after the telescope is launched.
JWST will orbit the Sun near the second Lagrange point (L2) of the Earth-Sun system, which is 1,500,000 km (930,000 mi) further from the Sun than the Earth’s orbit, and about four times further than the moon’s orbit. Normally an object circling the Sun farther out than Earth would take longer than one year to complete its orbit. But near the L2 point, the combined gravitational pull of the Earth and the Sun allows a spacecraft to orbit the Sun in the same time that it takes the Earth. Staying close to Earth allows data rates to be much faster for a given size of the antenna.
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