When the first stars and galaxies started to form, it was like a spark of a massive chain reaction where the vast amounts of gas and dust that had clumped together were quickly converted into dense, luminous star clusters. This was the beginning of the formation of the heavier elements that would eventually make up all that we see on the planet Earth. But when did this massive tirade of star formation end? When we look at galaxies in the present epoch, most don’t form stars very rapidly at all, and giant elliptical galaxies are all but devoid of gas,...
We call it dark matter because it doesn’t give off light, right? Well there is a lot of matter than doesn’t radiate, but the difference is that whatever the stuff is that we call dark matter doesn’t interact with anything through the small-scale fundamental forces. The only way we have been able to detect it’s presence is through large-scale gravitational interaction. Dark matter is ‘dark’ because it doesn’t interact with anything in a way that lets us figure out what it’s made of. Well now that we’ve got that out of the way, we can look at the new...
Yesterday I posted some of my own photos of the Moon and Mars in conjunction from the night before. Last night I went out again knowing that there was another planetary conjunction in the works. The Moon was now with Venus. People on the internet and in person were asking me “Mars? I thought the Moon was near Venus,” and “Venus? I thought the Moon was near Mars.” It really speaks to the fact that most people don’t realize how quickly the sky changes from the point of view of an Earthbound observer. So what happened between the Mars-Moon and...
The observations of our galaxy throughout history have told us that our Milky Way is roughly 100,000 light years across. A number confirmed time and time again by scientists with better and better instruments. But recently a team from the Rensselaer Polytechnic Institute in New York, USA, published a paper challenged that idea, saying the galaxy is much bigger, up to 150,000 light years in diameter. They used the Sloan Digital Sky Survey’s (SDSS) data to look at the distribution of stars outward from the centre of the galaxy, in reference the the galactic plane. They discovered that the stellar distributions oscillated...
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...
First of all, in case you didn’t know, according to a few sources, today is not just Valentine’s day, but also: Impotence Day, Condom day, Singles Awareness Day, Ferris Wheel Day, Congenital Heart Disease Day, and Pet Theft Awareness Day. And on to the Astronomy! A classic favourite would be the Heart Nebula. Located 7,500 light years away in the constellation Cassiopeia, this heart-shaped HII emission nebula is located along the plane of the Milky Way galaxy. HII regions like this one are used to probe the massive star formation in a galaxy. This is because massive O and B...
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,...
You might think simulating the entire Universe is difficult, and it is, but not for the reasons you would think. The Physics is actually somewhat straightforward. We know the math behind star formation, Gravity, and fluid dynamics, and throwing in a few other effects is not too bad. The hard part is finding a computer powerful enough to do the calculations in a reasonable amount of time. Think about it. Imagine having a universe of 100 Billion ‘particles’ used for a simulation. Each particle has a starting point, and that it pretty easy to do. But then for every...
You need to see this animation. It’s an amazing picture showing the Hubble Ultra Deep Field and the small patch of sky Astronomers had to aim at in order to photograph it. The moon is there for comparison. The patch of sky is about the size of a grain of sand held at arm’s length. Courtesy of gfycat.com, it really puts things in perspective. The crazy part is that if you look in any direction in the universe, in patches of sky as small as this one, you see the exact same thing. There are more galaxies in the Universe than we...
