The closest star to the Earth, aside from the Sun, is Proxima Centauri, a small red dwarf star that is part of the Alpha Centauri system, roughly 4 light years away. If you don’t know light years, the distance is a staggering 37,800,000,000,000 Km. Beyond that our stellar neighbourhood fills in as you move 20 light years in any direction, and by 100 light years, there are dozens of stars around us. This gives a stellar density of about 0.14 stars per cubic parsec (a parsec is about 3.26 light years), pretty normal in terms of the number of stars in a given...
This story popped up yesterday, and I can imagine it will go far, since it talks about life in the universe. I get it, it’s what people are interested in, and at least this story is focused on the science of why this is the best place to look for intelligent civilizations, instead of “Oh hey there’s a strange ring of material around a star, must be an alien superstructure.” But I digress. So where is the best place to look for life in the universe? The answer is in a Globular Cluster. A globular cluster is one of the...
Nebula. Collapse. Protostar. Main Sequence. Red Giant. Planetary Nebula. White Dwarf. This is the cycle of life for a star like our Sun. By observing stars across the galaxy, we see snapshots of different points in a star’s life cycle. It’s the same with people; If you went for a walk in a city and observed people for a day, you would see every single stage of a person’s life: Infant, child, adolescent, youth, adult, middle aged, senior. How would you put them in order if you knew nothing about them? With people you might go up and ask them, but with stars we can...
Honestly this could be the name of a new TV show, similar to ‘when buildings collapse,’ or ‘here’s what Kim Kardashian did today.’ I’ll take the colliding galaxies, simply because they can hold my attention longer. Galaxy collisions are some of the most massive and long term events in the universe. The result is the formation of billions of stars, the change in orbit of Billions more, and the complete restructuring of a galaxy. Since we see a snapshot of the Universe whenever we look at a single galaxy, we tend to see collisions happening at all stages of the...
It sounds like something out of a science fiction novel. The incredible and rare dark star cluster, hiding the evil super villain’s headquarters. A dark star cluster is something I would imagine as a spooky, eerie type of place where everything you see changes when you enter its space. Science fiction aside, a dark star cluster is real, and it’s a new type of cluster that is similar to the mighty dense globular clusters that orbit most galaxies. Globular clusters orbit in a halo of space around the centres of galaxies, and though our Milky Way harbours 150 of them,...
Globular Clusters are tightly packed collections of hundreds of thousands of very old stars, spherically distributed around the Milky Way Galaxy. They undergo little change, have nearly no gas, and have a stellar density way higher than the rest of the Galaxy. The first one discovered, in 1665, is messier 22, one of the most well studied, easily visible, and interesting globular clusters. Based on observations, this globular cluster contains at least two black holes. It is also one of only three globular clusters ever found to host a planetary nebula, a gaseous shell emitted by a dying star with...
More than two-thirds of stars are not solitary like our Sun. They are binary systems, meaning they contain two stars that orbit each other about their common centre of gravity. Stars like our Sun are much more rare, and we are not sure what the difference in formation is between binary and solitary systems. Binary systems are much more useful from a scientific perspective, as we can study their orbital period and separation to infer a wide range of properties such as masses and distances. A special class of stars, called RR Lyrae variable stars, have puzzled astronomers for years...
When I do Planetarium shows, one of the things I like to talk about during the Milky Way – Andromeda collision that will happen in 70 Mlllion years, is the fact that very few stars will actually hit each other. Yet we still call it a ‘Galaxy collision.’ One of the questions I always get is “Will the Earth survive this?” I usually ask the audience. The response is usually a unanimous ‘No way!” And then I tell them how big Galaxies are and they can’t believe how unlikely it is that the solar system will be affected. Consider the...
I’ve talked about black holes previously, and only in our own Galaxy, and only the big one in the middle, Sag A*. When I speak with the public and with kids about Black Holes, most people never really understand that there aren’t just one or two kicking around, but potentially there are as many as a Billion Black Holes in our own Galaxy! The problem is, we are not very good at finding them. It makes sense, they give off no light, and we can only find them through indirectly measuring their effects on the surrounding environment. We can sometimes see...
