1,200 Km / s. That’s fast. Fast enough to race around the entire Earth in 30 seconds. Except that it’s not a bullet, it’s a star, larger and more massive than the Earth. And a multinational team of astronomers has discovered it, and more importantly, where it came from and why it’s moving so fast. Hypervelocity stars (HVS’) are an uncommon phenomenon, since the conditions necessary to accelerate them to incredible speeds are rare. There are only about 20 HVS known, and the first was found only ten years ago. So where do they come from? There are only a...
It’s not often that we find new star clusters within our own Galaxy. Technology has been good enough to see the stars in the Milky Way for decades, and the grunt work in identifying and cataloguing local clusters is more or less finished, but occasionally we get lucky. A tiny and extremely distant globular star cluster has been found in the outskirts of the far side of our home galaxy. Currently named Kim 2, it pales in comparison to the other 150 Milky Way globular clusters, containing 10-20 times fewer stars and having less than half the stellar density. The...
There is a loose hierarchy of the cosmos that repeats. Stars form clusters, and then galaxies. Galaxies form clusters, and then these form clusters of their own, called superclusters. Gravity dominates the structure of such collections, yet all we feel and see from Earth is a relatively homogeneous distribution of stars. How do we see this hierarchy? If we zoom in, looking at a patch of sky so tiny that we can’t see any stars, what do we see? This patch of sky is about the size of a grain of sand held at arm’s length, and if we point the...
The Milky Way Galaxy has about 26 associated satellite galaxies, which is strange to imagine, since we think of a galaxy as a massive collection of Billions of stars. The dwarf galaxies are not easily visible since they are small, so they tend to blend in with the background of Milky Way stars that are much closer. You might also notice from the above image that the dwarf galaxies are distant, lying beyond the 100,000 light year scope of our large spiral home. Most of them likely originated in the turmoil of protogalaxy collisions that occurred billions of years...
I thought Hurricanes had powerful winds. The strongest wind ever recorded was a gust up to 400 Kph near a tropical cyclone in Australia. But Earthbound wind has nothing on Galactic wind. Around the time when our ancestors were just learning to walk upright, the core of the Milky Way Galaxy unleashed a blast of gasses and material at 2 Million Kph. Millions of years later, we see the aftermath of this eruption as two massive bubbles of material blown out above and below the galactic centre, at least 30,000 Light Years tall! The lobes were discovered by the...
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 sometimes forget just how big things can be in the Universe. And I often forget just how small and insignificant we are in the grand scheme of things. Then I see a Galaxy like IC 1101 side by side with our own and I very quickly remember. About 350 Million light years from Earth IC 1101 is the largest galaxy in the known Universe in terms of actual size. If you didn’t notice the image above, it shows our own Milky Way Galaxy as a little tiny dot in the bottom left corner, and then Andromeda our closest neighbour,...
Launched in December of 2013, the European Space Agency (ESA)’s GAIA Mission will be the next great mission to find exoplanets, planets orbiting stars other than our own Sun. However, GAIA’s main mission is not to search for planets, but to look at the motion, physical characteristics, and distance of up to one Billion stars with incredible precision. It’s a given that the satellite will invariably find planets by seeing the ‘wobble’ of a star due to the gravity of a planetary system. One of the strengths that GAIA posesses over other exoplanet studies is that it will search a...
I’ve seen a lot of lovely images from the Spitzer Space Telescope. It takes infrared images and can see the fine structure of galaxies, where stars are forming and where they are not forming. The photos paint a picture of the history and evolution of a galaxy. The latest image released last week shows some amazing features. The Cyan light in the image is a combination of blue and green coloured light representing infrared wavelengths of light at 3.4 and 4.5 microns. This wavelength shows the stellar population in the galaxy. The red light is representing dust features that glow...
