Q 1. Who was the first person to declare that Earth revolves around the Sun and not vice-versa. He also formulated a heliocentric model of the universe which placed the Sun, rather than the Earth, at the center.
De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) was his publication which was released just before his death in 1543, is considered a major event in the history of science.
Q 2. Who is called the father of Geography?
Q 3. Who created the first map of the world?
Image Courtsey: theatlantic.com
Q 4. The Universe comprises of millions of Galaxies. The galaxies are made up of millions of stars held together by the force of gravity. Earth is a part of Milky Way Galaxy or Akash Ganga which contains 300 billion, Sun is one of them (image below). Which is the nearest spiral galaxy to Milky-way galaxy? Also known as Messier 31, M31, or NGC 224, it’s more famous name is on a mythological princess.
Q 5. Many theories were given over the period of time to explain the origin and evolution of the Universe e.g. Big Bang Theory,The Steady State Theory(by Bondi, Gold and Hoyle) etc. One of them is ‘The Pulsating Theory’. What does the theory state?
Q 6. There are multiple theories and explanations on the formation of the planets and our Solar System. ‘Nebular Hypothesis’ is one of the most widely accepted explanation, what does the theory state?
Q 7. Which of the following statements about the Sun is NOT TRUE?
a.) Sun accounts for more than 99% of the mass of the Solar System. b.) The source of Sun’s energy is Nuclear fusion reaction. c.) It has surface temperature of about 6000 degree C. d.) Hydrogen and Helium are the main gases present in the Sun. e.) None of the above
Q 8. Superimposed on Sun’s white light are hundreds of dark lines called ____________________ lines after the famous scientist who discovered them. Each line indicates some element present in the solar system. Very interestingly, the study of these lines helps in understanding the composition of the Sun’s atmosphere and the temperatures in it’s various layers.
Q 9. What is the time taken by Sunlight to reach Earth?
Q 10. The outermost layer of the Sun is called ____________. It is visible only during Solar eclipse.
Ans 1. Nicolaus Copernicus (He has also in 1517 set down a quantity theory of money, a principal concept in economics to the present day, and formulated a version of Gresham’s law in 1519, before Gresham.
In 140 A.D. Ptolemy propounded that Earth is the center of the Universe and the Sun and the other heavenly bodies revolve around it. In 1543, Copernicus said that Sun is the center of the Universe not Earth. Kepler supported Copernicus but said that Sun is the center of the Solar System not the Universe.
Ans 2. Hecataeus
Ans 3. Anaximander. In 6th century BC, he drew a map of the then known world, assuming that the earth was cylindrical.(Pythagoras was his student)
The first Greek to draw a world map using the assumption of a spherical earth was Eratosthenes. Ptolomey first drew maps of the world using latitudes and longitudes and conic projection. In 150 AD he produced a six-volume atlas called Geographia containing several maps of the world known during his time.
Ans 4. The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years from Earth in the Andromeda constellation. The Andromeda Galaxy is the nearest spiral galaxy to our Milky Way galaxy, but not the nearest galaxy overall. It gets its name from the area of the sky in which it appears, the constellation of Andromeda, which was named after the mythological princess Andromeda. (In 1924, Hubble first demonstrated the existence of Galaxies beyond Milky Way)
There are basically 3 types of galaxies as shown below.
Ans 5. According to this theory, the universe is supposed to be expanding and contracting alternately i.e. Pulsating. At present the universe is expanding.
Ans 6. The nebular hypothesis is the idea first put forward in general terms by Immanuel Kant in 1775, and then more specifically by LaPlace in 1796, that the solar system formed through the progressive condensation of a gassy nebula which once encircled the Sun. It was suggested that as this nebula rotated and contracted, rings of gas were cast off at various stages from which the planets subsequently condensed. Accordingly, the outer planets would have formed first, followed by Mars, the Earth, Venus, and Mercury.
Ans 7. (e) – None of the above
Ans 8. Fraunhofer Lines
Why do they occur?
They occur because cooler gas, which is higher in the Sun’s atmosphere, absorbs some colors of the light emitted by hotter gas lower in the Sun’s atmosphere. Sir Isaac Newton (1642-1727) discovered that if white light is passed through a prism, it separates into a rainbow, which is called a spectrum. While studying the spectrum that sunlight made, Joseph Fraunhofer (1787-1826) discovered some dark lines scattered among the colors. These dark lines were segments of colors missing from the complete spectrum. Fraunhofer counted 574 of these lines, which we now call Fraunhofer lines.
Ans 9. 8 minutes 20 seconds (or 500 seconds)
Ans 10. Corona
The Sun comprises of three layers,the glowing surface of the Sun that we see is called Photosphere. Above the Photosphere is the red coloured Chromosphere and beyond it is the magnificent Corona which is visible only during Solar Eclipse.