Author(s): Lucie Green

Science

110 times wider than Earth; 15 million degrees at its core; an atmosphere so huge that Earth is actually within it: come and meet the star of our solar system Light takes eight minutes to reach Earth from the surface of the Sun. But its journey within the Sun takes hundreds of thousands of years. What is going on in there? What are light and heat? How does the Sun produce them and how on earth did scientists discover this? In this astonishing and enlightening adventure, you'll travel millions of miles from inside the Sun to its surface and to Earth, where the light at the end of its journey is allowing you to read right now. You'll discover how the Sun works (including what it sounds like), the latest research in solar physics and how a solar storm could threaten everything we know. And you'll meet the groundbreaking scientists, including the author, who pieced this extraordinary story together.

When we think of celestial objects, we think of Mars, Saturn, the stars and distant galaxies. What we don't think of is the celestial object that is the largest object close to us, and the one that affects us the most. This is, of course, the Sun. In this interesting book Lucie Green gives us a complete run down on what the sun is and why it is so interesting to the scientists that study it. Early observers thought that the Sun was on fire, maybe made of coal. But in the late 18th century after a transit of Venus they were able to calculate the mass of the Sun and come to the conclusion that, if it were made of coal, then it could only burn for 6,300 years. Even then they knew that the Earth was older than that. So what could be powering it?
It wasn't until the twentieth century, and the advent of nuclear physics, that it was postulated that the Sun was powered by nuclear fusion of Hydrogen into Helium at its core. However the Sun would be quite a boring thing if that were all it was. Observations of the Sun showed that it was marked by Sun Spots and closer observations showed huge storms and solar flares on its surface. These events are driven by the Sun's magnetic field, which unlike Earth's fairly benign one, has a complex pattern, twisting around itself and creating complex solar weather. The predictions of how these processes work has become important in our increasingly electronic world, where solar storms can even affect events of Earth. I enjoyed this book and I now find myself sneaking an occasional admiring glance at this object which so dominates our lives and the daytime sky. Peter