I saw an article last night about gravitational waves, that a black hole merger was detected by not just the Laser Interferometer Gravitational Wave Observatory (LIGO), but by another project altogether, the Virgo collaboration. This is the first gravitational wave detection confirmed by two separate groups, and it marks the beginning of a new era of experimental science, the first in astronomy in over two decades. Around 1.8 Billion years ago, to black holes merged in a faroff galaxy. They had masses of 31 and 25 times that of the Sun, though with their incredible density they would each be...
How did supermassive black holes form in the early epochs of the universe? More importantly, how did they have enough time to grow as large as they did? The answer requires a very different universe. And back then, conditions were much different than they are now. There was a lot of gas, little dust, no stars, and a plethora of dark matter. Astronomers have spent decades observing early quasars, massive active galaxies powered by huge black holes feeding on surrounding gas. But these galaxies are seen so early in the universe’s history, one starts to wonder how a black hole finds sufficient...
In the early Universe, things were quite different. The first stars were much more massive than stars today, and contained mostly Hydrogen. Astronomers have good ideas about how they formed, but other objects from around this time, namely black holes, are much tougher to account for. Early black holes were huge, with no explanation for how they grew so large. “Early” means “first Billion years after the Big Bang,” but even in that time, it’s hard to determine how observed black holes could grow as large as 100,000 solar masses. I say 100,000 solar masses, because that is the mass of two ‘seed’ black holes, discovered...
Where do the heavy elements on the periodic table come from? The general answer is from what’s called the r-process of stellar nucleosynthesis. This translates to ‘rapid neutron capture’ being the method by which most of the elements heavier than Iron are formed on the periodic table. This process requires immense energy and was originally thought to only occur within core-collapse supernova explosions. “Understanding how heavy, r-process elements are formed is one of hardest problems in nuclear physics,” said Anna Frebel, assistant professor in the Department of Physics at the Massachusetts Institute of Technology (MIT) and also a member of...
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...
There was a report about a month ago that a Fast Radio Burst (FRB) produced a repeating signal. This is big news because we really don’t know what causes FRBs, and once they have ended it can be difficult to trace their source. But a repeating signal means we can pinpoint their origin and potentially figure out their root cause. It’s no wonder the astronomical community was excited…and skeptical. Most of the FRBs that have been discovered were in archival data – data from past surveys that were given a closer look. Only a few have been seen in real-time, so when...
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...
The gravitational center of most objects and clusters in the universe are the place where the most massive and high energy interactions take place. For the solar system, the Sun’s core is hot and energetic. For star clusters, central regions host the most massive and brightest stars. For galaxy clusters, the most massive galaxies in the universe are seen in the center. And for individual galaxies, the Milky Way included, the core is where the fun happens. In the core of our galaxy, there are many massive and powerful objects, not limited to a supermassive star cluster, pulsars, supernova remnants,...
Looking at the universe in radio waves is a fascinating sight. For one, the radio sky is very weak; If you placed your cellphone on the Moon facing back at Earth, it would be brighter than all other radio sources in the entire sky by a factor of a million. But as with every other part of the electromagnetic spectrum, it has scientific value in studying the sky. Over the past decade, astronomers have been identifying several Fast Radio Bursts (FRB), short bursts of radio waves from different places in the universe that last for a few short seconds. These are...
