The Sun, stars, nebulae, galaxies, planets; We can see them all from our lonely cosmic address, but not all is revealed in the light our eyes see. We need to look at the entire electromagnetic spectrum to understand the range of objects we see in the universe. Our closest star shows us how different it can look when you change the observed wavelength. In high energy ultraviolet and X-ray light we can see the most powerful sunspots emitting their bursts of radiation and the swirls of solar plasma releasing ultraviolet energy in all directions. We still have a few years...
Lurking in the depths of a galaxy, hidden from human eyes, lie millions of monsters. They could swallow you up in an instant, sealing you off from the outside world and devouring you atom by atom. This sounds like your typical Hollywood monster movie, but with millions of black holes hidden throughout the galaxy, its more real than you might think. Supermassive black holes, the largest ones that reside at the centers of galaxies, are much easier to see. They are devouring gas and dust rapidly, resulting in bright emission across the electromagnetic spectrum, especially in x-rays. For many galaxies,...
One of the largest and brightest star clusters in the Milky Way galaxy is the Arches cluster, and its easy to see why. Lying only 100 light years away from the supermassive black hole that lies in the heart of our galaxy, it formed in an incredibly dense environment. It lies 25,000 light years from Earth in the constellation Sagittarius, and contains thousands of massive stars, including 160 that are hot, young, and exceptionally more massive than the Sun. Only 1 in 10 Million stars in the galaxy are as bright as these massive central 160 stars. Though it is...
Of the approximately 100 Million galaxies in the visible universe, we see incredible variation. We always try to classify them based on their shape, size, and peak radiation, but even then we still find others that stray from the usual patterns. In recent years, a new class of galaxies named Extremely Luminous Infrared Galaxies (ELIRGs) has been found with data from the Wide Field Infrared Survey (WISE). Now the king of the ELIRGs has been found, the most luminous galaxy in the universe. The galaxy, designated WISE J224607.57-052635.0, has a luminosity equal to 300 Trillion suns, and may owe its brightness...
In Canis Major, nearly 12,000 light years from Earth, lies an emission nebula that always makes me think of a particular comic book character. NGC 2359 is 30 light years across, and is colloquially known as Thor’s Helmet. The complex structure of Thor’s helmet consists of bubbles and filaments, and is due to a series of bursts from the massive star HD 56925. This star is a rare Wolf-Rayet star, which consistently expels its outer layers of gas at high velocities, and is characterized by its very high temperature. The blue bubble in the above image is a result of...
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...
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...
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...
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....
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...
