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...
Have you ever heard of an object called ‘Hanny’s Voorwerp?’ It’s a thin wispy ghost-like blob at the edge of a Galaxy. It was discovered by Dutch schoolteacher Hanny van Arkel in 2007 as she was classifying galaxies as part of the Galaxy Zoo project. Since then, astronomers have been studying its origin, as it was the first of a brand new phenomenon in astronomy. This past week, a new data set of wispy trails at the edge of Galaxies have been released as part of a Hubble study by Bill Keel of the University of Alabama, Tuscaloosa. The new Hubble...
On the York Universe radio show this past Monday evening on astronomy.fm, I was having a discussion with another host about how so many things in Astronomy can take Millions or even Billions of years, yet there are still all kinds of phenomena that happen in seconds, hours, weeks, years, or on the scale of human lifetimes. Stars live for hundreds of Millions of years at the low end, yet the intense brightening from the Supernova death of a massive star lasts for only a few days or weeks. It’s as if the Universe is piquing our interest with short...
There are multiple types of Supernovae that have been observed throughout the Universe. Classifying them is difficult because the conditions of each one are not always similar. There are now seven different classifications of these stellar explosions, that are divided (and subdivided) by their spectral characteristics. By studying the light from supernovae, we can determine what type it is, and identify what kind of stellar environment led to its destruction. The supernova remnant 3C 397, shown above in the constellation Aquilla at a distance of 33,000 light years, has thought to have been expanding for 1-2 millennia. Originally thought to have...
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...
It’s been a good couple of years for lunar eclipses, we are in the midst of what we call a tetrad, which is a series of four lunar eclipses spread out evenly over a period of time, usually 2 years, in this case April and October. For observers watching the April 4th morning eclipse, in my boat here in Toronto, you won’t be able to see it because the Moon will set and the Sun will rise just as it gets good. Plus you would have to wake up at 5:30am to go look at it. Pretty much everyone East...
The deeper we peer through the cosmos, the more we are looking into the distant past. Light from other galaxies takes millions of years to reach us, and so when that light has finally arrived at Earth, it is millions of years old, a snapshot in time of the distant galaxy. The furthest we can see is so far back in the history of the universe, that galaxies haven’t even formed yet. As we look at the large-scale structure of the Universe, we see it filled with a cosmic web of galaxy clusters, containing tens of thousands of galaxies each....
