There are lots of ways to learn astronomy. You can join an astronomy club and learn from the members, or you could enroll in a course at a local school, or community college, or university. Or you could simply take the time to read up on it on the Internet or in your local library. These are all good methods, but your choice will depend partly on what’s most easily available, whether you’re prepared to spend a lot of money, … Continue reading →
Stars are hard to study because, apart from the Sun, they are so far away that they appear as nothing more than geometric points of light. All that we can measure about this light (without getting complicated and breaking out the spectrometer) is its brightness and its colour, but fortunately this is enough for us to work out quite a lot about the star. Its colour, for example, tell us how hot the star is at its surface. If you’ve … Continue reading →
Ah, but you can if you wait till night time! You can’ t see any stars in photographs taken from the Apollo missions because they were all taken in broad daylight. As any photographer will tell you, a camera can only cope with a narrow range of brightnesses, so that the aperture setting and shutter speed are very important if a photograph is not to be over- or under-exposed for given lighting conditions. In this age of automatic point-and-click digital … Continue reading →
The surface of the Sun is usually around 5800 degrees centigrade, but is a blistering 13.6 million degrees at the core. The core is where the nuclear reactions happen, with hydrogen atoms fusing together to make helium, and this is what powers the Sun and creates all the heat. The outer atmosphere of the Sun, called the chromosphere and which is only visible during a Solar Eclipse, has a temperature of about a million degrees, with occasional heat-waves all the … Continue reading →
Is this a trick question? Because, strictly speaking, the Sun is a star. The Sun is roughly 150 million kilometers away. But the normal English usage of ‘star’ refers to things that only come out at night. In that case, the nearest star is Proxima Centauri, a red dwarf positioned 4.2 light years away in the southern constellation of The Centaur. It is a member of a bright triple star system, but is not visible to the naked eye itself. … Continue reading →
