Measuring Dark Energy Like a BOSS

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...

A Direct Black Hole

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...

Seeding The Supermassive

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...

Black Holes ARE Dark Matter?

Dark matter could be almost anything.  With little data other than how much total dark matter mass exists, we can’t decode much about what individual chunks of dark matter might be made of.  I’ve talked before about Massive Compact Halo Objects (MACHOs) and Weakly Interacting Massive Particles (WIMPs), but these are just two possibilities.  Other theorists have talked about Modified Newtonian Gravity (MNG), where gravity may work differently on the grand scale than it does on our small Earth scales.  Or perhaps it’s something I haven’t seen before.  Maybe what we call dark matter is just a large population of ancient black holes....

Heavy Metal

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...

A Lonely Universe?

Life in the universe is a fascinating topic.  The simplest question: Are we alone? It breeds so many deeper and more profound scientific questions, like “How many habitable planets are there?” “How likely is life to develop on any given planet?” and “How long can a civilization survive?” We can’t answer them definitively, but we can narrow it down. The Drake equation, shown above, was first developed by Frank Drake, the head of the Search for Extraterrestrial Intelligence (SETI), in 1961.  He took the question of are we alone and made it quantifiable, in a probabilistic way.  It lets us...

Blast From The Past

A supernova is the death blast of a giant star, far larger than our Sun.  Massive stars go out with a bang, outshining entire galaxies, allowing us to see them across the universe.  A supernova observed in 2013 occurred in a distant galaxy and took over 30 Million years to reach Earth, where the timing was perfect for us to observe and study it.  And now that it’s been studied, the explosion was truly the death of a giant. The supernova, named 2013 ej, was discovered in June 2013 in the galaxy M74 in the constellation Pisces.  It was the closest supernova...

Dark Matter is Complicated

The fact that we have found gravitational waves tells us that we have come a long way in terms of science and technology.  We detected a perturbation in the fabric of space-time that was one one-thousandth the diameter of a proton.  It’s insane to think about that level of precision.  And yet we still can’t find Dark Matter, the stuff that is literally everywhere in the universe.  Is it our problem? Or is dark matter just on a whole different level? By now, we know that dark matter isn’t some clump of stuff sitting out there in space.  But that...

The Nearby Supernova Revealed

Remember last week when I was talking about the evidence for some ancient-but-astronomically-recent supernovae? It turns out there is other evidence! Evidence that has helped scientists narrow down the potential source locations. Data from the Cosmic Ray Isotope Spectrometer (CRIS), an instrument aboard NASA’s Advanced Composition Explorer (ACE) spacecraft, has helped us figure out where the recent supernovae might have come from.  CRIS measures what we call cosmic rays, atomic nuclei that have been accelerated across the galaxy at close to the speed of light.  CRIS has been around for a while, and through 17 years of cosmic ray observations,...

A Ring of Fire

A direct consequence of Einstein’s theory of general relativity, and an observational way to prove it, is gravitational lensing.  It requires a powerful gravitational source to work, such as a galaxy or cluster of galaxies.  It works in a similar way to a lens of glass, where rays of light are bent toward a single source, increasing the brightness.  In this case, instead of glass, the bending of the rays is due to the curvature of space. Light rays coming from the source would otherwise miss Earth, but instead are bent toward us when there is a massive object in front of it.  It’s...