Stars and our solar system. 

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Some science we should always know. Much of science cannot be forgotten at all.  We will see such science that will be useful for everyone from young to old. 

🎷 WHO - World Health Organisation

Solar system:- 

1. Our solar system was formed 4.6 billion years ago.
2. The Sun has eight planets, moons of planets, and numerous asteroids, meteoroids,  dwarf planets, Kuiper belt and comets all together form the solar system.
3. In order from the Sun, there are four terrestrial planets (Mercury, Venus, Earth and Mars); two gas giants (Jupiter and Saturn); and two ice giants (Uranus and Neptune).

🌞 Sun:-

• The sun is a medium size star. The sun is in the center of our solar system. Its surface temperature is above 6000° C.
• Sun is big enough to hold 13 lakh Earths within it. 
• Due to the Sun's gravitational force of attraction, the planets, comets, and other celestial objects revolve around the sun. 

Planets:- Mercury, Venus Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are the eight planets revolving around the sun. 
Period of revolution:- The time taken by a planet to go once around the Sun is called the period of revolution of the planet. 

Revolution:- The motion of a planet around the Sun is called the revolution of the planet
Period of rotation:- The time taken by a planet to complete one rotation about its axis is called its period of rotation. 

Moons:- A small heavenly body revolving around a planet is called its satellite or moon.
The Earth's natural satellite, 

The moon, is about 384400 km from the Earth. 
Planets and their moons
Mercury - 0
Venus - 0
Earth - 1
Mars - 2
Jupiter - 95
Saturn - 146
Uranus - 27
Neptune - 16

Asteroids

• Small remnants of heavenly bodies revolving around the sun between the orbits of Mars and Jupiter are called asteroids. 
• They are also called minor planets. 
• Asteroids are much smaller than planets.

☄️ Comets

1. Many comets revolve around the sun in highly elliptical orbits.
2. Halley's Comet completed one revolution around the sun in about 76 years. 
3. Halley's Comet is expected to appear in 2062. 

Meteors

1. Small pieces of matter, called meteoroids, move at random in the solar system. 
2. If any meteor approaches the earth's atmosphere a large amount of heat is generated due to friction with air. Hence its temperature rises so much that it starts burning. It is called a meteor. A burning meteor looks like a shooting star. 
3. Most of the meteors were born completely before reaching the Earth. 
4. The meteors which reach the earth are called meteorites.

Artificial satellites
India, as well as some other Nations, have launched many satellites into orbits around the earth. They are called artificial satellites.

1. Some artificial satellites launched by India are 
2. Aryabhatta, 
3. INSAT, 
4. IRS, 
5. Kalpana-1, 
6. Edusat, and 
7. Bhaskar. 

Uses of artificial satellite

1. Making contact with objects in space
2. Earth observation
3. Communication
4. Weather forecasting 
5. Navigation: Satellites can be used for the Global Positioning System(GPS).
6. telecommunication
7. Broadcasting radio and TV programs
8. Scientific research
9. Making accurate maps
10. Space research
11. Implementing educational programs.

📡 Radio telescope
The Tata Institute of Fundamental Research has set up a radio telescope close to the Pune Nashik Highway at Khodad near Narayangaon. 
GMRT: Giant Meterwave Radio Telescope.
 The moon the natural satellite of the Earth is the heavenly body nearest to the Earth.
If the moon rises at 7:00 p.m. on a certain day, it will rise at 7:50 p.m. the next day. 

Constellations:- 

1. An area on the celestial sphere in which a group of visible stars forms a perceived pattern, typically representing an animal, mythological subject, or inanimate object.
2. The International Astronomical Committee has so far recognized 88 constellations. 37 constellations belong to the northern hemisphere sky and 51 belong to the southern hemisphere sky.
3. Ancient Indian astronomers had imagined 27 Nakshatras. 

• Ashwini
• Bharani
• Krittika
• Rohini
• Mrighasira
• Ardra
• Punarvasu
• Pushya
• Ashlesha
• Magha
• Purva Phalguni 
• Uttara Phalguni
• Hasta
• Chitra
• Swati
• Vishaka
• Anuradha
• Jyestha
• Moola
• Purvashada
• Uttarashada
• Sharavan
• Dhanishta
• Shatabisha
• Purvabhadra
• Uttarabhadra and
• Revati.

What is the importance of the polar star ⭐?
Ans: 

• The polar star is nearest to the north celestial pole of the sky and appears practically stationary from the Earth. 
• Polar Star lies almost along the axis of rotation of the earth. 
• A polar star can be used to find the direction while navigating 🧭. 

Pluto 

• The revolution of Pluto around the sun does not satisfy the criteria used by the International Astronomical Society to define a planet's orbit. Hence Pluto is no longer considered a planet. 
• Now Pluto is classified as a dwarf planet. 
• Examples of the dwarf planet 

• Ceres
• Pluto
• Haumea
• Makemake
• Eris.

 

 🎻 period of revolution

• Planets have different periods of revolution. 
• The period of revolution of a planet depends on the distance between the planet and the sun. 
• The period of revolution for the Earth is 365.24 days or one year.

• 🚀 Jupiter takes about 12 Earth years, or 4,333 Earth days, to orbit the Sun.
• Neptune takes 165 Earth years, or 60,190 Earth days, to complete one revolution around the sun. 
• Jupiter has the shortest day in the solar system, taking only 10 hours to rotate once.
• Neptune:- One day on Neptune takes about 16 hours.

🌹 Mercury

1. Mercury is the planet nearest to the sun. 
2. Due to bright sunlight, it is difficult to see Mercury.
3. Mercury can be seen at sunrise or sunset on the horizon. 
4. Mercury is the smallest planet in the solar system. 
5. Mercury speeds around the Sun every 88 days, traveling through space at nearly 29 miles (47 kilometers) per second, faster than any other planet. 
6. Mercury spins slowly on its axis and completes one rotation every 59 Earth days. 

🎷 Venus 

1. All planets rotate about their axis from the west to the east, while Venus and Uranus rotate about their axes from the east to the west.
2. Venus has phases like the phases of the moon. 
3. Venus is called the morning star or evening star as it is seen very bright just before sunrise or just after sunset. 
4. The Venus revolution period of about 225 days.
5. Venus takes 243 Earth days to rotate one time.  

👏 Superior planet:- A planet whose orbit lies outside the Earth's orbit is called a superior planet. Mars and Jupiter are the first to superior planets. 

🎈 Inferior planet
A planet whose orbit lies inside the earth's orbit is called an inferior planet.
Mercury and Venus are inferior planets. 

🦢 Mars

1. Mars appears red because its soil is rich in iron. Hence it is called the red planet. 
2. Mars completes one rotation every 24.6 hours.
3. Mars makes a complete orbit around the Sun in 687 Earth days.

🦅 Jupiter

1. Jupiter is the largest planet in the solar system.
2. Jupiter rotates very fast completing one rotation only in 10 hours. 
3. Jupiter's period of revolution around the Sun is 4,330.6 Earth days.

 

🥁 Saturn

1. Saturn has rings around it.
2. The density of Saturn is less than that of water.
3. Saturn is a massive ball made mostly of hydrogen and helium. So we can't stand on Saturn.
4. Saturn has more moons than any other planet in our Solar System.
5. Saturn has a moon bigger than Mercury.

🎇 Uranus 

1. The planet Uranus rotates about its Axis from the east to the west like Venus.
2. The planet is made of water, ammonia, and methane.
3. The lowest minimum temperature measured on Uranus is −224 °C.

🔱 Neptune 

• A day on Neptune is 16 hours.
• A year on Neptune is about 165 Earth years.
• Neptune is about four times wider than Earth. 
• Neptune has 16 moons.

*एक क्षण रडवून जाईल 

तर दुसरा क्षण हसवून जाईल

 या जीवनरूपी प्रवासात 

येणारा प्रत्येक क्षण 

जीवन जगण्याची कला

 शिकवून जाईल.......*

*आपलं शिस्तप्रिय बोलणं 

आणि वागणं 

आयुष्यात खुप महत्वाचं ठरतं. 

कारण आपलं सुंदर दिसण 

हे फक्त समोरील व्यक्तिला 

आकर्षित करू शकतं,

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आणि वागणं 

हेच त्यांच्या ह्रुदयात 

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