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 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...
Every single massive galaxy has a black hole at its center, and bigger galaxies have bigger black holes. It almost seems like a natural progression, with a bigger galaxy meaning more stars and material to feed a bigger black hole. However, most of that material doesn’t make it to the central black hole. So how does a massive galaxy with hundreds of billions of stars spread out over hundreds of thousands of light years contribute to a black hole that at most is solar system sized? The answer might lie in another elusive and enigmatic gem of the universe: Dark...
Image submitted to an image processing competition called ‘Hubble’s Hidden Treasures’ are expected to be amazing, but this is the only one I’ve seen that will make you happier. This cosmic ‘smile’ is in the constellation Ursa Major, and is made up of the light from four galaxies, each with Billions of their own stars. This is the biggest happy face ever found! The two eyes are very distant galaxies known as SDSSCGB 8842.3 and SDSSCGB 8842.4. So why do we see this ring structure? You might think that the Galaxy is stretched by gravity, but its something much more...
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...
Today I found a few nice images that I wanted to talk about, and each one revealed something different about the object that was being imaged. I thought it would be a good chance to show everyone how astronomy is really the study of patterns of light, speaking from a minimalist perspective. We learn literally everything about the Universe beyond the solar system from the photons we see. From photons we can deduce the mass, distance, density, composition, behaviour, formation, and evolution of the cosmos. Pretty stellar! (pun intended) Here are some recent images and what we learn from them....
Last year we received some incredible news about Cosmology and the Big Bang. An experiment devised to find the signature of the inflationary model of the Universe told the world they had done it! The world cheers, as did many scientists; but of course there are always reasons to be sceptical, especially with claims that have such an impact for humanity let alone the science world. And now it seems the scepticism was correct, as the conclusive result has now been deemed inconclusive. This doesn’t mean its false, not by a long shot, but it does mean the research team...
This Galaxy, NGC 7714, has an odd shape. In fact we call it a ‘Peculiar Galaxy.’ Why doesn’t it have the characteristic spiral arms if it is indeed a spiral? Why doesn’t it look more diffuse and football shaped like an elliptical galaxy? The reason is that like millions of other galaxies in the Universe, it has recently collided with a nearby companion galaxy. Now using the term ‘collided’ is not really accurate. In reality the two galaxies are interacting via gravity. During a ‘collision,’ stars in the interacting galaxies don’t physically hit each other. The galaxies are incredibly large,...
