We think of space as a vacuum, but there are regions of different density. There are winds blowing from stars and other objects that clear out vast bubbles in space, and look absolutely fantastic in pictures. And might have been critical for Earth to even exist in the first place.
Astronomers have found that sometimes the Universe changes. Things move, things explode, things get brighter or dimmer. In fact, knowing this has helped astronomers discover some very important aspects of the Universe. Today we begin a two part series on Transients and their role in astronomy.
When you think about the best pictures in astronomy, almost every one is a nebula; the pillars of creation in the Eagle Nebula, or the complex Helix Nebula – or my personal favourite, the Ring Nebula. They’re beautiful, wispy clouds of gas and dust that signify both the birth and death of stars. Today we give tribute to nebulae.
After the big bang, all we had was hydrogen, a little bit of helium, and a few other trace elements. Today, we’ve a whole periodic table of elements to enjoy, from oxygen we breathe to the aluminium cans we drink from to the uranium that powers some people’s homes. How did we get from plain old hydrogen to our current diversity? It came from stars, in fact successive generations of stars.