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....
Mercury, the smallest planet in the solar system, and closest to the Sun, is only a little bit bigger than Earth’s Moon. But the Moon is comparatively reflective object. Mercury is thought to be made of the same rock as the Moon, so what is the difference? Why do objects in our Solar system have different brightnesses? The key is in a property called albedo. It’s basically how much light an object reflects, measured as a fraction. For example, the Moon reflects 12% of the light the Sun shines on it, so it has an albedo of 0.12. The albedo...
When Canadian Astronaut Chris Hadfield was in space, on the International Space Station (ISS), he stayed there for six months, the standard length of stay for an astronaut. On the ISS, three of the six-person crew are replaced every three months. After returning to Earth, Hadfield could barely walk. He had lost bone density and muscle mass, his immune system weakened, cardiovascular functions slowed, and he produced less red blood cells. The lack of gravity is bad for humans, The longest a human being has ever been in space was Russian cosmonaut Valeri Polyakov, who was in space for a staggering...
We call it dark matter because it doesn’t give off light, right? Well there is a lot of matter than doesn’t radiate, but the difference is that whatever the stuff is that we call dark matter doesn’t interact with anything through the small-scale fundamental forces. The only way we have been able to detect it’s presence is through large-scale gravitational interaction. Dark matter is ‘dark’ because it doesn’t interact with anything in a way that lets us figure out what it’s made of. Well now that we’ve got that out of the way, we can look at the new...
A few months ago I talked about Astronomers seeing the gas cloud known as G2 passing the central black hole of the Milky Way, called Sagittarius A*, and how we had hoped to watch the black hole destroy it in order to learn about the behaviour of supermassive black holes. As we all sat and watched the passage of the cloud over the course of a few months, we were surprised to find that the cloud remained intact and passed straight by Sag A*. When we last checked in, the leading theory was that the ‘cloud’ actually was a dense...
