When you start to think about the most massive and extreme ‘stuff’ in the universe, you inevitably go to Dark Matter and Dark Energy. They exist as opposites, one with incredible gravity holding the universe together, and the other a mysterious vacuum energy tearing it apart. Studying this cosmic tug of war gives astronomers a chance to determine the past and future of the entire universe. To study the immense scale of these two quantities, the Baryon Oscillation Spectroscopic Survey (BOSS) program of the Sloan Digital Sky Survey-III (SDSS) constructed a 3D map of the sky, amounting to a volume...
Neutron stars are the most extreme objects in the universe that have been proven to exist. Black holes are very likely, but we’re still not 100% sure about them. A black hole is like a giant squid in the ocean. We’re pretty sure they exist, but nobody has caught one. The neutron star on the other hand is like a blue whale, everybody knows they exist, and they are massive, rare, and beautiful. Of course, once we know something exists, the next logical step is to figure out how it behaves, to characterize and generalize it, and to identify where it’s...
Black holes form when a massive star runs out of fuel. Gravity causes the core to collapse down to an object so dense that light itself can not escape. In the Milky Way galaxy, there are expected to be over 100 Million black holes, though of course we can’t see them. The one we can see is the supermassive black hole Sag A*, lying deep within the core of the galaxy. But how did Sag A* form? Was it from the merger of many smaller black holes? Or is there some other process forming the most enigmatic objects in the...
Data is fascinating. And what’s even more fascinating is that the laws of nature produce predictable patterns in data. For example, if you toss a coin 100 times and measure how many times heads comes up, you’ll get a number between zero and 100. If you repeat that experiment again and again and again, you’ll get different values each time, but usually the number will be around 50, and 50 will come up more than any other value if you repeat the experiment enough times. If you plot this data, with the # of heads in 100 coin tosses on...
As I’ve said before, the most powerful, most energetic, most intense processes happen in the center. The gravitational center of the Earth, the Sun, and the galaxy are all places where temperature, pressure, and interactions of matter and energy are pushed to their limits. When you look up to the sky it’s easy to see the Milky Way (unless you live in an urban center). Do you ever wonder where the middle of it is? Where that supermassive black hole lies? Astronomers know where it is, but you need infrared cameras to see it past the thick dust that blocks...
Baryonic matter, which is everything we are made of and everything we can see in the universe, is not a lot of stuff. I mean to a tiny Earthling, it’s a heck of a lot, but if you put it all together it only makes up about 5% of the total Mass-Energy in the Universe. If you’ve ever seen the Millennium simulation, it highlights the fact that both baryonic and dark matter are organized into filaments of mass, with the baryonic matter at the densest points, ie the galaxies. What lies between these dense nodes and filaments are vast empty...
The merger of black holes proven by LIGO yesterday looks amazing in this simulated view in today’s APOD. What would normally take a third of a second has been stretched out to show the entanglement. And remember, these things are far more massive than the Sun, so to be moving this quickly and merging is an extremely high-energy interaction. And kablammo, matter converted to energy, gravitational waves aplenty, and an even bigger black hole. Happy Long Weekend!
The elements that make up our world and our selves, where do they come from? Sure there is plenty of Oxygen in the air, Silicon and Carbon are just lying around, and a bunch of other stuff can be found across our planet. but where did they come from originally? We know that most of the elements are synthesized within stars, but which ones aren’t? Which ones are made in a lab? The Big Bang gave rise to the first elements Hydrogen and Helium, which eventually clumped together to form the first stars and star producing the heavier stuff. Lithium,...
We know that galaxies like our Milky Way are far more massive than we can see. The dark matter in the Milky Way makes up 90% of it’s total mass. Another way of saying this is the Mass to Light ratio, comparing the total mass inferred by the rotation speed of the galaxy to the total mass of stars in the galaxy. This ratio, M/L, for the Milky Way, is about 10. But for a galaxy cluster, the M/L ratio is more like 100. Galaxy clusters are not just dense collections of stars and massive galaxies, they are also immense...
In the early universe, there was a huge amount of swirling matter and light that didn’t really have much structure. Compared to today’s much more regular dotting of galaxy clusters and superclusters, the early universe was all over the place. But as will all things, there had to be a first. a first star, a first galaxy, and even a first galaxy cluster. The massive cluster of galaxies known as IDCS J1426.5+3508 is the most distant massive galaxy cluster ever discovered, and it has some interesting properties that point to how it formed and evolved so quickly. One such property is...
