Sun -Planets -Comets – Important Points/Facts
1-Temperature = 6000 C on surface and 16 million C in core
2-Density = 1.41 times that of water
3-Age = 4.6 billion years
4-Diameter = 13,91,785 km (~1.3 million km)
5-Period of rotation = 25 days 9 hrs
6-Speed of rotation = 7179.73 km/hr (Earth’s rotational velocity = 1675 Km/ hr)
7-Equivalent to 3,32,900 Earth masses.
8-The Sun is rather large and bright,compared to the majority of stars in the Milky Way.
9-The Sun is composed of roughly 98% hydrogen and helium. Jupiter and Saturn, which comprise nearly all the remaining matter, possess atmospheres composed of roughly 99% of these elements.
10-A dark patch on the surface of the Sun is known as sunspot
11-Sunspots appear as dark areas because they are about 1500° cooler than the surrounding chromospheres.
12-Each spot has a black center or umbra, and a lighter region or penumbra, surrounding it.
13-Venus, the nearest and most similar planet to Earth in the Solar System, has an atmosphere 100 times denser than our own, with little or no geo-magnetic field. This is an exception.
14-A corona is a distinctive atmosphere of plasma that surrounds the Sun and other celestial bodies.
15-The two largest, Jupiter and Saturn, are composed mainly of hydrogen and helium
16-The two outermost planets, Uranus and Neptune, are composed largely of substances with relatively high melting points compared with hydrogen and helium , called ices, such as water, ammonia and methane.
17-A comet is an icy small Solar System body that, when passing close to the Sun, heats up and begins to outgas, displaying a visible atmosphere or coma, and sometimes also a tail.
18-Comets, composed of ice and dust, originated outside our solar system. Their elliptical orbit brings them close to the Sun and into the inner Solar System.
19-One of the larger comets is the Halley’s Comet. The orbit of Halley’s Comet brings it close to the Earth every 76 years. It last visited in 1986.
20-Comets are among the most spectacular and unpredictable bodies in the solar system.