Science Through Postcards

SCIENCE THROUGH POSTCARDS

Dr Jayant Narlikar

	Preface
	About the Book
	Contents answers to the following questions .....
Q.1	Why does the sky look blue?
Q.2	Why does the Sun look red when it sets?
Q.3	What is meant by the statement "the ozone hole is growing?" Why is it dangerous? What precautions must be taken to control it?
Q.4	If a tunnel is dug into the Earth to go all the way to the other side of the surface, and if a ball is thrown into it, what will be the motion of the ball?
Q.5	Why is the weight of an object less on the equator than on the polar region?
Q.6	Why do we see shooting stars, i.e., stars falling on the Earth?
Q.7	When we study or photograph a distant star, is it really there?
Q.8	How can we prove that the Earth revolves around the Sun?
Q.9	How are the orbits of the planets determined? Why are they elliptical?
Q.10	How is the distance between the Earth and the Sun measured?
Q.11	What effects will be observed if the mass of the Earth is suddenly increased?
Q.12	Who was the first to find the radius of the Earth and how did he measure it?
Q.13	Has the 10^th planet been found?
Q.14	Why does the Sun shine?
Q.15	How was the Sun formed? How are the planets formed around the Sun?
Q.16	What is meant by the statement "the Sun will eventually become a giant star?"
Q.17	Why do stars twinkle? Why don't the planets twinkle?
Q.18	Can the man made satellites remain stationary in the sky?
Q.19	Like the eclipses of the Moon and the Sun, is the Earth also eclipsed and can we observe it from the Moon?
Q.20	What do we mean by moonlight? Can we see the Earth rise and set from the Moon?
Q.21	Did the Moon originate out of Earth? Why is there no atmosphere and life on the Moon?
Q.22	How are comets formed?
Q.23	What is a meteor shower?
Q.24	Will the comet Swift-Tuttle hit the Earth? It so, what will happen on the Earth? Can this danger be averted? Is there similar danger from other comets or small meteoroids?
Q.25	What are white dwarfs and Neutron stars? What is the contribution of the Indian scientist S. Chandrashekhar in this field?
Q.26	What are black holes? Are black holes found in the universe? Can the Sun turn into a black hole?
Q.27	What is a quasar?
Q.28	What are binary stars?
Q.29	What happens to objects collapsing in a black hole?
Q.30	What is a white hole? How can it be observed in space?
Q.31	What are the special features of space telescopes?
Q.32	How are the stars in our Galaxy counted?
Q.33	Is the universe finite or infinite? How can this be ascertained?
Q.34	What is meant by the expansion of the universe? What is it expanding into?
Q.35	Is there life beyond the Earth? Are there any life forms on other planets in the solar system? How can other, possibly more advanced life forms be detected?
Q.36	What are UFO’s or flying saucers? Have they come from other planets? Do extraterrestrial beings come to the Earth through such spaceships? Where do UFO’s come from?
Q.37	Sometimes there are reports of flying saucers in newspapers. Are they not true?
Q.38	Many airplanes crash, boats sink and clocks stop in the Bermuda Triangle - what could be the power behind such mysterious events? Could there be some supernatural or extraterrestrial power active there?
Q.39	In ancient times, was there a highly advanced civilization on the Earth?
Q.40	How are radio waves formed?
Q.41	What is meant by radioactivity?
Q.42	The water does not turn into vapor until it is heated to 100⁰ C or to the boiling point. How does the water vapor rise from the sea at temperatures around 30⁰ C?
Q.43	A block of iron sinks in water whereas a ship made of iron floats on the water. Why?
Q.44	Who measured the speed of light first and how?

	About the author