Earth, Sun and Moon Notes

SUN

•         The Sun is a star.

•         Our Sun is just like the other stars, we see in the night sky.

•         It is also the only star that we see during the daytime.

•         It is the closest star to the Earth, about 1.5 million kilometres away.

•         It is a huge ball of hot, burning gases.

•         The temperature at the centre of the sun is about 15 billion degree Centigrade (°C), and on the surface, it is about 6000 °C.

•         The sun has a thin layer of atmosphere called the corona.

PLANETS

What is a Panet?

•         The celestial object that revolves around the sun is called a planet.

•         The planets were formed during the process of solar system formation, when clumps began to form in the disk of gas and dust.

Mercury:

•         Mercury is the planet closest to the Sun.

•         Less than half of the size of Earth, it is the second smallest planet in the solar system.

•         Mercury has a very little atmosphere, and similar to the Moon, has a dusty surface covered with craters.

DWARF PLANET

•         In 2006 the International Astronomical Union (IAU) approved a new classification scheme for planets and smaller objects in our Solar System.

Their scheme includes three classes of objects:

(1)      "small solar system bodies" (including most asteroids and comets)

(2)      “much larger planets” (including Earth, Jupiter, and so on)

(3)      “in-between sized dwarf planets".

Figure 15: Pluto

•         Pluto, formerly the smallest of the nine "traditional" planets is now considered as a dwarf planet.