Enjoyable questions and problems

Photo credit: NASA and JPL. Image from Wikimedia Commons.  This image is licensed under the  Creative Commons   Attribution-Share Alike 3.0 Unported  license.  Some of the readers of this blog have been telling me that it is difficult to see Mercury. In Bengaluru, the Sun will rise at about 6:40 AM tomorrow. I have set the alarm to wake me up to see mercury at 6 AM. But it is not always easy for me to get up that early! I have found a good solution to the problem. Tomorrow, the Sun will set in the West, at about 6:30 PM, in Bengaluru. After seven PM, I will be able to see two bright planets in the west. I saw them today. The brighter one is Venus, and it will be lower in the sky than the other. The other one will be Jupiter. I am excited about these planets. More than four hundred years ago, in the year 1610, the Astronomer Galileo started observing these two planets with a home-made telescope. He saw that all of Venus was not uniformly lit. It has phases, like the moon, showing

  Image Credit: http://solarsystem.nasa.gov/planets/index.cfm . This is a montage of planetary images taken by spacecraft managed by the Jet Propulsion Laboratory in Pasadena, CA. Included are (from top to bottom) images of Mercury, Venus, Earth (and Moon), Mars, Jupiter, Saturn, Uranus and Neptune. Ask people you meet if they have seen the planet Mercury.  Most will say they have not seen it.  If they say they have seen it, ask them when they saw it and where.  Why is it so difficult to see? It is a planet close to the Sun. During part of the year, you see it rise on the eastern horizon. On some of these days you can see it about 45 minutes before sunrise. During another part of the year, it can be seen within 45 minutes of Sunset on Western horizon. You cannot see Mercury when the Sun is shining. The sunlight is much more powerful than the light from Mercury. It is dangerous to look at the Sun directly, because its rays can damage your eyes. Today, when I write this, it is be

  Cropped by Ramani. This file is licensed under the  Creative Commons   Attribution 3.0 Unported  license. Attribution:  Adeeb Atwan A fast motorbike went down our street one morning, making a big noise. Ten minutes later, my mom dropped her coffee mug. Can you say that the cause of mom dropping the coffee cup was the motorbike’s noise? Or was it a case of mere coincidence? This type of question was known long ago. An old Indian proverb talks about a crow and a palm tree. The crow came and sat on a palm tree and soon the tree fell down. Can we say that the crow’s sitting was the cause of the tree falling?    Or was it a case of mere coincidence? Srinivasan Ramani