In front of us, lie vast clusters of stars, satellite groups that orbit the heart of our galaxy. These are globular clusters, over 150 have been discovered.

 

 

 

Here astronomers have found the answer to one of the greatest questions in astronomy, how long has our galaxy existed?

 

 

 

Globular clusters are really fascinating groups of stars. They contain about a million stars each. And the thing that is really cool about them is the stars are really tightened pack. 

 

 

 

If you could visit a globular cluster, the night sky would be spectacular, many of the stars would be as bright as the full moon.  And the night time sky in all directions would be filled with bright nearby stars, a bit like fireworks all the time. Apart from their sheer number, there are something intriguing about the stars found in these clusters. 

 

 

 

One of the very interesting aspects of globular clusters is that there is no sign of young stars.

 

 

 

 

 

Stars are a bit like people. Look at them, and you can guess their age, and the life they have lived. With people that might be gray hairs, or wrinkles, with stars, it is their color and their size. 

 

 

 

So the biggest stars, the most massive stars, the ones with the most gas, live life of fascinating.They live very short amounts of time, but they burn very brightly, and they are very, very hot，and so they tend to be blue. 

 

 

 

On the other hand, you have the red stars which use their energy very conservatively, last for a long time, don’t blow too brightly, and those stars last for a very long time.