It’s always funny explaining astronomical time to a non-scientist. I often get the craziest looks when I mention a million years as being a ‘blip on the radar.’ Perhaps there is some immortal alien race out there who would understand how nothing much happens on the scale of the universe in a million years. To humanity and our ever-accelerating advancement, a million years is thrice the age of our entire species. But I guess Einstein was right when he said that ‘it’s all relative.’ This brings us to Saturn, a planet as ancient as the solar system. Moderately old in...
The Milky Way is a decently big Galaxy. At 100,000 light years across, it is a full size barred spiral galaxy and distinctly different from what we would call ‘dwarf galaxies.’ But there are much larger galaxies in the universe. Most reside near the centre of a massive galaxy cluster and are the result of Billions of years of mergers and collisions. But some appear large because of their incredibly powerful release of energy. A new Galaxy discovered in the early universe by a team of astronomers from the National Centre for Radio Astrophysics is an incredible 4 million light years...
Whenever I give a planetarium show to an audience, I always like to let time pass quickly. The stars appear to move, but I quickly point out that it is in fact the planet Earth turning that gives the stars their apparent motion through the night sky. I then reassure them that stars do move, it just takes a very long time for them to move a noticeable amount. Why is this? The above animation of Barnard’s Star is a clue. Photographed once per year, Rick Johnson created this animation showing the movement of the small red dwarf. Barnard’s star...
Stars are far apart, especially compared to the everyday distances in human experience. The fastest a human being has ever travelled is just shy of 40 Km/s, and even at that incredible speed it would take 30,000 years to reach the closest star. That is an incredible distance no matter how you slice it. Taking it a step further, most stars in the sky are 20-200 times further away, and that’s just the population of stars we can see. So if we go beyond and talk about galaxies and the distances between them, we are literally talking astronomical quantities. Yet even with...
The thing about black holes is that they are very dense. If we took the entire 2,000,000,000,000,000,000,000,000,000,000 Kg of the Sun (This is the real mass of the Sun) and turned it into a black hole, it would be about 6 Km in diameter. It is theorized that there are around 100 Million Black holes in the Milky Way Galaxy alone. But if they aren’t near a large reservoir of gas and dust, with their small size they are pretty harmless and invisible. The only way we could find them would be through their gravitational influence, which is hard to...
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...
Quasars are Galaxies with incredibly massive Black Holes at their centre. These Black Holes are fuelled by a swirling disc of material that can be ejected in a long jet along their axis of rotation, all due to the conservation of angular momentum. This accretion disc can be so hot that it causes the central region of the Galaxy to shine more brightly than the entire Galaxy of stars surrounding it. A Belgian team using the Very Large Telescope (VLT) studied a population of 93 Quasars spread over Billions of Light-Years, and noticed that the rotation axes of the Quasars...
