Write notes on:
i. Mercury
ii. Venus
iii. Mars
iv. Saturn
v. Pluto
vi. Shooting Stars
vii. Night-sky
viii. Milky-Way galaxy
i. It is the first and the smallest planet of our solar system. Its mass is approximately 1/18th mass of the earth. Its outer surface is rocky and contains mainly nickel (Ni) and iron (Fe) at the center. Due to the weak gravitational field and a short distance from the sun, it has a very thin atmosphere that contains potassium and sodium. Also, the difference between day and night temperature is very large. The side facing toward the sun is 4720C and opposite side -1730C. It has no moon.
ii. It is the second planet to our solar system and is the neighbour to the earth. It is the brightest planet. Its outer atmosphere consists of white clouds of carbon dioxide. It is the only planet that is spinning from east to west, which is in the opposite direction to other planets. Due to this sun rise in the west and set in the east. It has no moon.
iii. It is also called red planet due to reddish colour. It has a negligible atmosphere. And this atmosphere made up of mainly carbon dioxide also contain nitrogen and argon in small amounts. Its pole is covered with dry ice (solid CO2). Phobos and Demos are two moons of mar. Here is the image of solid ice found at one of the poles of Mars -
iv. Saturn is the sixth planet from the Sun and the second largest planet.It is also called “The Ringed Planet” that is composed mostly of ice particles, with a smaller amount of rocky debris and dust. Is size is 850 times earth. Saturn is one of five planets able to be seen with the naked eye. It has three luminous rings that adds its beauty. Its surface temperature is very low. Its largest moon is Titan. Here we can see the comparison between earth and Saturn in term of its size -
v. Pluto is known as a dwarf planet. Its orbit is elliptical. It is very cold, dark and yellowish planet. The surface density is similar to that of the earth. It core contain silicate rock surrounded by water, methane and carbon monoxide in the solid form. Pluto has its moon Sheron form a binary system means they both revolve around their common center of mass.
vi. Various substances of different sizes keep on coming to the earth regularly. When they enter the earth surface they burn due to the presence of friction caused by the earth gravity and a long thin line of light can be seen, this is called a Shooting star. The falling substance are called meteors.
Sometime it is also called falling star. These are not a star (don’t confuse with the word star).
vii. All are knowing that earth takes 24 hrs to complete one rotation but this is not true actually earth takes 23 hrs and 56 minutes to complete one rotation. That’s called the sidereal day and represents the time taken for Earth to rotate relative to the fixed stars, not to the sun (because we’re orbiting our sun, so it’s not a totally stationary point relative to Earth). So in these 4 min, left star undergoes angular displacement of 10. In a month of 30 days total angular displacement becomes 300 and within 6-month angular displacement will be 1800 that means after 6 months the same star will not appear. This shows that night-sky keep on changing.
viii. The Milky Way is the galaxy that contains our Solar System. A big cluster of stars is known as a galaxy. Here cluster means a large collection of stars. During the night and in the clear sky we can see the belt of milky belt stretching from north to south. It is of spiral shape with diameter is about 1 lac light year and the thickness of the middle part is about 15 to 20 thousand light years. Most of the star in this galaxy are bluish and young.