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...

The Largest Neutron Star in Existence

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...

The Problem With Baryons

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...