The most recent SOHO spacecraft picture of the Sun
Image Credit: SOHO/ ESA/ NASA
As I mentioned in my last post, today is the first day of the International Year of Astronomy. The IYA is starting with an effort called "Dawn of the International Year of Astronomy." The point is for as many people as possible to look safely at the sun at noon today. At some places, astronomers will have special telescopes or other projectors to give all passers-by a safe view of the sun. (Simply looking with your eyes is dangerous and will permanently damage your eyes!) If it is cloudy where you live, or if you missed it, or if it was cloudy, you can look here at pictures taken by NASA's STEREO spacecraft, which are looking at the sun from two different angles.
The sun is the ultimate source of the energy most life on Earth needs to survive. Even when you are using coal or oil or gasoline to survive, the chemicals you are burning were made with the help of energy from sunlight by plants millions of years ago. Storms on the sun affect our life on Earth, causing electrical blackouts, communications failures, airplane route diversions, and the aurorae. (For more, see "space weather" websites such as SpaceWeather.com)
Though you may think of astronomy as a science that happens just at night, when we can see the stars, the sun is a crucial part of astronomy. The sun is the closest star to the Earth, and we can study and probe the sun in ways that we cannot probe other stars. We also think that our best chance of finding life in the Universe is by looking around sun-like stars, because we know that life can exist around such stars!
All astronomy therefore really starts with the sun. So it is only appropriate that the Year of Astronomy start with the sun.