On the outskirts of the Milky Way galaxy, its two major satellites can be seen, the large and small clouds of Magellan. Both considered irregular galaxies, they are more like swarms of stars, similar to gnats here on Earth. But even though they lack structure, they are still alive. The large magellanic cloud contains the single largest active star forming region in the entire local group of galaxies. This is the Tarantula Nebula. In the core of the tarantula, huge supernova shockwaves blast gas and dust, triggering star formation while forming dense filaments away from the center. Along the entire...
Big stars tend to stick together. They all require incredibly dense regions in which to form, but once they do, they do a great job of blowing away and ionizing any other gas and dust in the vicinity. This is why nebulas in distant galaxies are great tracers of massive star formation. The bigger and hotter the star, the more UV light it produces, the more it ionized a gas cloud, the more we see gorgeous nebula. So it’s no surprise that when I look at the nebula below, I can guess that the central stars are huge, outweighing our...
Welcome to a new series of posts that will characterize 1000 amazing facts about the Universe. There is so much out there that we have yet to learn, and every day, astronomers across the globe are using their research to reveal the deepest secrets of the cosmos. This series will look at the strangest, coolest, most exciting facts that we have discovered in hundreds of years of modern science. Fact #4: Most of the stars in the universe are red dwarfs smaller than our Sun. There is a leap of understanding that happens when a child learns that our Sun...
They may look like they are standing still, but galaxies are all spinning. Spiral galaxies have the lovely regular spin of a disk, while elliptical galaxies are all over the place, a buzzing hive of stars. We don’t see this rotation in real time because it takes millions of years for it to be noticeable. The Milky Way takes 250 Million years to spin just once around it’s axis. Looking at this rotation rate vs. distance from the galactic center was what originally led to the discovery of dark matter. Some galaxies do in fact spin slower than others, but how does...
Did you know that more than two-thirds of stars are part of multiple systems, where two or more stars orbit a common center of Gravity? This means that the Sun is one of the minority, being on its own. Most of the multiple systems out there are in fact double star systems, but some of them are triples and a few are quadruples. One such quadruple star system, known as DI Cha (in the chameleon constellation), was recently imaged by Hubble. The system lies in the southern constellation of Chameleon, about 520 light years away. The quadruple system is a...
Is this a giant hole in space? I show a picture similar to this as I ask this question to students and audiences that I host in my planetarium. Most people answer that it is a black hole, or dark matter, or dark energy, or something strange like that. But the amazing thing is that it is actually a thick cloud of dust that is opaque, letting no visible light from the distant stars pass through. The funny thing is that the cloud is transparent in infrared light, but in the visible spectrum it highlights something interesting about the universe:...
Why should a galaxy have bluish spiral arms dotted with red patches and dark lanes. Why should it have a central region that is yellow and spherical rather than flat? Why are they flat to begin with? Because Galaxies are so huge, and made from hundreds of Billions of stars that change over the course of their lives, a galaxy shows the entire life cycle of a star in its own structure. Stars are born along spiral arms, where most of the thick dust and gas clouds are concentrated. The dark dust lanes of spiral arms condense to form stars,...
Looking at the universe in different parts of the electromagnetic spectrum can reveal features and structures that are invisible to human eyes. The vast black emptiness of space explodes into a sea of colour when we use cameras to expand our vision. Looking at a galaxy through human eyes can be a simple and seemingly uninteresting view, but in infrared, microwave, or ultraviolet wavelengths we see the deeper layers of the vast array of stars. The closest large spiral galaxy and a cousin of our own Milky Way, the Andromeda galaxy, is revealed in ultraviolet. The Galaxy Evolution Explorer (GALEX)...
When Charles Messier catalogued 100 different objects in the night sky, he couldn’t have imagined the richness and detail of each one of his individual discoveries, or that we would ever see them in such incredible detail as to understand what they truly are and how they evolve. But every time I see a new image of a well-known object, I not only see the new and amazing details revealed, I see the next level of technology that enables us to see it in a new light. This image of Messier number 64 gives me that view. Messier 64 is...
Ever heard the term ‘champagne flow?’ I’m not talking about a celebration, it’s actually a term in astronomy. When a cluster of massive stars form and ionize the surrounding hydrogen cloud, the hot gas propels itself through the layers of cooler gas at the cluster outskirts. When the hot gas finally bursts through to the vacuum of space, it flows rapidly like a newly opened bottle of champagne. This is exactly what’s happening in the cluster RCW 34, a young, gaseous cluster in the southern constellation Vela. The interesting thing about this cluster is that its nearly invisible in optical...
