Have you ever seen the North star, Polaris? It’s decently bright and very close to the North celestial pole. Lining up with the rotation axis of the Earth, the North celestial pole is the point in the sky that never moves, day or night. If you know how to find Polaris, it becomes easy to find the cardinal directions and navigate by the stars. And finding it simply requires finding the big dipper, a bright and easily recognizable object. The same rules apply in the southern hemisphere. But even though there is no southern star, there is another fantastic object in the South that can guide you to the...
Titan is the most interesting body in the solar system from a weather standpoint. It has a thick and robust atmosphere, a liquid cycle of methane and other hydrocarbons, and it has seasonal variations in these patterns. It’s essentially a cold and oxygen-deficient version of Earth. Because the seasons on Titan take 7.5 years to pass, we have few opportunities to study them up close with the Cassini spacecraft. So as long as Cassini is operating, we are using our time wisely to see how Titan is changing. The first major change is a giant ice cloud that has formed...
Every time a comet slowly approaches the inner solar system, astronomers get excited. We are hopeless romantics, wishing the new comet will brighten enough to be labeled the next ‘comet of the century.’ Yet we have had our hearts broken before, more often than not. The most recent fizzled comet was nearly two years ago with the burn up of comet ISON as it passed close to the Sun. It made for a spectacular view for SOHO and SDO looking at the Sun, but for the rest of us it was just another heartbreak. But once again we have hope; A...
I was out on a sunny day a few weeks ago waiting for a bus, and as per usual I have my head up in space (I would say up in the clouds but that is too low for me). I noticed the Moon up in the sky, just past first quarter, and I was thinking about the angle of the illuminated side and how it related to some of the positions of the Earth and Sun in space. I wondered what information we could gather from the way it looked. It led me to this ‘illuminating’ post. I realized...
As the inevitable launch of humans to Mars slowly approaches over the coming decades, we are using our best technology to study our neighbour in detail. With multiple orbiting satellites and ground surveyors, we are slowly learning more about the geology, climate, environment, and history of Mars. It feels as if every new discovery is a surprise, and we never expected Mars to be such a dynamic and complex world. With science and technology improving every year, humanity is focussing efforts on the red planet. The latest incredible discovery comes from radar data from the Mars Reconnaissance Orbiter (MRO). The...
Time to celebrate! It’s the shortest day of the year in the northern hemisphere, and the longest in the southern. The first day of Winter here, and the first of Summer down south. Although as a Canadian, Winter usually starts a lot earlier. Why do we have seasons? A common misconception is that the Earth is closer to the Sun in Summer, and further in Winter. Well I can tell you the Earth reaches perihelion (its closest point to the Sun) on January 3rd, and it certainly isn’t a warm day in Canada, historically speaking. So the reason for the...
If you guessed that I was referring to the Pleiades, you are correct. The small open star cluster, Messier 45, is about 440 Light Years from Earth, relatively close for a star cluster. We are able to see it with the naked eye in Autumn and Winter here in the Northern Hemisphere. The stars in the Pleiades are young and bright blue, meaning they are very massive and hot. By young, I mean somewhere around a hundred Million Years, about 40 times younger than the Sun. The smears of blue in the above photo show that the cluster is still...
