How do we determine the size of the Universe? How do we know how far away the planets and stars are? How can we measure it without ever being there? The answer, as it always is in Astronomy, is light! More Photons = More Science! Here’s my video explaining the concepts of Parallax, spectroscopic parallax, and type 1a supernovae! Space is big, and although we can figure out how big it is, its another challenge all together to understand and comprehend its sheer size.
A supernova is the only event in existence that happens on both astronomical and human scales (If you think of others – tell me). It involves a massive stellar explosion and release of energy that can match the output of an entire galaxy, yet this release happens in the blink of a cosmic eye, about two weeks. For all that could live in the incredibly vast amounts of empty space between galaxies, a supernova is a great indicator that stars do in fact inhabit this space. Recently, the Hubble Space Telescope confirmed that two such supernovae have been discovered. In...
After yesterday’s post about some data that has caused us to rethink a theory, I wanted to follow it up today with an even bigger bit of data that could substantially change an even bigger theory. Dark energy was discovered as a large-scale repulsive force in the universe that is responsible for the acceleration of its expansion. It was discovered by looking at type 1a supernovae in distant galaxies. since the supernovae all explode with the same mass limit, they appear to all have the same intrinsic luminosity. If we know how bright they actually are, we can compare them...
There are multiple types of Supernovae that have been observed throughout the Universe. Classifying them is difficult because the conditions of each one are not always similar. There are now seven different classifications of these stellar explosions, that are divided (and subdivided) by their spectral characteristics. By studying the light from supernovae, we can determine what type it is, and identify what kind of stellar environment led to its destruction. The supernova remnant 3C 397, shown above in the constellation Aquilla at a distance of 33,000 light years, has thought to have been expanding for 1-2 millennia. Originally thought to have...
Even I was blown away when I saw this image a friend sent me. Gravitational lensing is a rare occurrence, and a supernova is a rare occurrence, so to see a supernova in a gravitationally lensed galaxy deep within the universe is exceptional. So exceptional that it was spotted for the first time ever in a Hubble image of the distant universe. That dot in the image is a single supernova in a very distant galaxy, split into four images by the gravitational lensing of the galaxy cluster in front of it. But there is also a secondary lensing effect from...
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...
Cassiopeia A is the expanding remainder of a massive star that exploded 340 years ago in he constellation of Cassiopeia (hence we call it Cas A for short). As the star erupted, hot radioactive material was shot out in all directions, churning up the surrounding outer debris, before the star finally tore itself apart. Simulations of supernova explosions have found it difficult to model the extreme conditions during this process, even when using the world’s best supercomputers. So what are astronomers missing? By studying recent supernovae like Cas A, astronomers can study the processes that formed these massive expanding shock waves, leading...
The best ever image of a Cometary Globule has been released by the European Southern Observatory (ESO) from the Very Large Telescope (VLT) in the Atacama desert in Chile. It looks a lot like a nebula right? In actuality a cometary globule is a very specific type of nebula. It’s very faint, and it’s formation is a matter of debate among the astronomical community. A cometary globule is small, containing the mass of a few suns worth of material. Compare this to a typical nebula, which has enough material to form thousands or even hundreds of thousands of stars. The...
I always like to bring up the crazy ways in which two areas of science that seem completely disconnected can relate to each other, occasionally giving incredible insights. By looking at the ocean floor, a world human beings can’t reach without special pressurized equipment, we are learning about space, a world human beings can’t reach without special pressurized equipment. So how is the ocean teaching us about space? Physicists at the Australian National University have been studying seafloor dust that has been raining down on Earth as micrometeorites over the past 25 Million years. The dust is thought to originate...
About 170 years ago, a star nearly exploded in the Southern constellation Carina. I say nearly for a few reasons. On Earth, observers saw a dim, seemingly-average star become the second brightest star in the night sky. It stayed that way for 20 years before slowly fading. When we looked at it with telescopes, we found that whatever happened to Eta Carinae, it ejected more than 30 times the mass of our Sun in that short twenty year period, creating what we now call the homunculus nebula. Eta Carinae is a multiple star system 7500 light years away from Earth, so rest assured any...
