Q) Which organization did declare that Pluto is just a dwarf planet ?
Q) What is the process called by which planets complete one orbit around the Sun ?
Q) What is the diameter of the sun?
Q) Who put forward the model of current solar system?
Q) Which planet does not have a moon?
Q) What are asteroids?
Q) What are meteors?
Q) Explain about moon?
Q) What is a solar system?
Q) Write a short note on the Heliocentrictheory?
Q) Explain briefly about the stars?
Q) Explain briefly about the constellations?
Q) Explain briefly about the planets?
Q) Explain briefly about the sun?
Q) Explain briefly about the earth?
The bodies we see in the sky from the Earth are called
- The twinkling spots of light that we see in the sky at night are called
- The star that is closest to the Earth is the Sun.
- A Star is a gigantic, glowing ball of plasma.
- Stars are first formed as clouds of dust and gas.
- Stars are
self-luminousand give a tremendous amount of energy in the form of light and heat.
- Most stars are between 1 billion and 10 billion years old.
- Stars that have really strong gravity grow smaller over time and eventually turn into black holes.
- The hottest stars give off a bluish light while the cooler stars give off reddish light.
- Stars seem to twinkle because their light travels through the earth's atmosphere and the turbulence in the atmosphere affects the way stars are seen.
- All the stars that make up the Milky Way Galaxy revolve around the centre of the galaxy once every 200 million years or so.
- A constellation is a group of visible stars that form a pattern when viewed from Earth.
- The pattern they form may take the shape of an animal, a mythological creature, a man, a woman, or an inanimate object such as a microscope, a compass, or a crown.
- The sky was divided up into 88 different constellations in 1922. This included 48 ancient constellations listed by the Greek astronomer as well as 40 new constellations.
- Two of the more easily recognisable constellations are Ursa Major and Orion. Others include Canis Major, Leo and Taurus.
Ursa Major is also known as the Great Bear. It is known as the Big Dipper because it takes the shape of a large ladle.
- The Pole Stars is always found directly over the northern horizon.
- During ancient times sailors and other travellers used the pole stars to find directions at night.
- Orion is one of the most visible constellations. Because of its location, it can be seen throughout the world.
Orion is named after a hunter from Greek mythology. Its brightest stars are Betelgeuse and Rigel.
- Orion is shaped like a hunter with a raised club.
- Solar means
'of the Sun'.The Sun occupies central position in the Solar System and other celestial bodies in the system revolve around it.
- In addition to planets, the Solar System also consists of moons,comets,asteroids,minor planets, and dust and gas.
Nicolaus Copernicus first put forward the model of current solar system. This model says that all planets and moon revolving around the Sun. This is also known as Heliocentric theory.
- The Sun is almost 5 billion years old. The gravitational field of the Sun holds the entire Solar System together.
- The sun is made up of hot gasses, mainly helium and hydrogen.
- The surface temperature of the Sun is 5700 °C.
- The Sun's diameter is 1,392,000 kms, it is 109 times bigger than the Earth.
- The distance of the Moon from the Earth is less than half the diameter of the Sun.
- The Sun is the primary source of heat and light for living beings on Earth.
- Life on Earth is possible because of its optimum distance from the Sun. Earth is neither too far from the Sun nor too close to it.
- Sunlight reaches the Earth in about 8 minutes.
- A planet is a celestial body that orbits a star. All the planets are spherical in shape.
- They are non-luminous, i.e., they do not produce light of their own. Instead, they reflect the light of the Sun that falls on them.
- Every planet spins on its own axis. This is called rotation.
- Planets also move around the Sun along a fixed elliptical path of their own called an orbit.
- One complete orbit around the Sun is called a revolution.
The Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune are the eight major planets in the Solar System.
- When the Sun was formed, the colder outer parts of the disc broke up to form the four giant planets - Jupiter, Saturn, Uranus and Neptune. They are mainly made of gas. They are very cold and they are called outer planets.
- Inner part of the disc, rock and metal lumps came together to form the inner planets.
- There is a very easy way to remember the planets in the order of their distance from the Sun. the first letters of the words give you the order of the planets - My Very Elegant Mother Just Served Us Noodles.
- The International Astronomical Union declared that Pluto was just a dwarf planet like Ceres, Eris, Sedna and UB313.
- The Earth is a unique planet, as it is only here that life has been found.
- It is third planet from the sun and the largest among the inner planets.
- The Earth is not a perfect sphere. It is flattened at the poles and therefore its shape is referred to as a spheroid.
The Earth is known as the Blue Planet as two-third of the Earth is covered by water.
- The Earth is surrounded by a blanket of air called the atmosphere.
- The Earth rotates on its axis, and revolves around the sun.
- The rotation of the Earth causes day and night and the revolution of the Earth causes the seasons.
The favourable conditions that facilitate life on the Earth are:
- Optimum distance from the Sun.
- An average surface temperature of 14°C
- Suitable seasons and weather conditions
- Adequate availability of liquid water
- The presence of an atmosphere that protects living things from harmful ultra-violet radiations from the Sun.
- Earth is like a Sphere.
- Explorers who set out on voyages around the world came back to the place they started from. This could happen only if the world was round.
- The shadow cast by the Earth on the Moon during a lunar eclipse is circular.
- The images of Earth taken from space show that it is spherical.
- When you see a ship coming to a port, you can see the top of the ship, and then gradually the base of the ship. If the Earth were flat, you would see the whole ship at once.
The celestial objects that revolve around the planets are called their natural satellites. They are also called the moons of the planets.
- Except Mercury and Venus, all the other planets have moons.
- The Moon that we see in the sky is the only satellite of the Earth. It shines because it reflects the light of the sun.
- It is about 384, 400 km away from the Earth. The Moon takes 27 days and 8 hours to complete one revolution around the Earth.
- There is no air on the Moon. It gets hot (100°C) in the day and cold (- 150 °C) in the night. It has an uneven, rough and rocky surface with huge craters.
- The shape and the position of the Moon as seen from the Earth, however, varies each day.
- We have a full moon night (purnima) about once a month. The full moon gets smaller till a fortnight from the full moon night; it cannot be seen from the Earth. This is called the New moon night (amavasya).
- On 29 July 1969, Neil Armstrong became the first human to land on the Moon.
- Celestial bodies that revolve around the Sun between the orbits of Mars and Jupiter are called asteroids.
- Scientists believe that these are parts of planets which exploded millions of years ago.
- They could also be matter that was left over after the planets were formed. They are known as planetoids.
- Meteoroids are pieces of rock moving at tremendous speed around the Sun. when the rock masses come near the Earth, they are pulled in by the Earth's gravity.
- As the meteoroids enter the Earth's atmosphere they begin to glow as a result of heating due to friction.
- The streaks of light the burning meteoroids produce as they fall to the Earth are called meteors.
- The partly burnt fragments of rock materials sometimes fall on the surface of the Earth causing huge dents or craters. These fragments are called meteorites.