Spectroscopy is one of the most useful tools of modern astronomy. With it we can identify the atomic and molecular composition of celestial objects, we can measure the relative motions of stars, and we can observe the expansion of the cosmos. Modern telescopic spectroscopes generally use a device known as a diffraction grating.
Numbers Game
There’s a popular video from Numberphile that shows how the sum of all the integers, adding them up forever is -1/12. If that ties your brain in a knot, it should. How is it possible for 1 + 2 + 3 + … to be a negative number? The answer is that it’s not…quite. It’s not that the video is …
Easing Tension With Neutrinos
a new paper published in Physical Review Letters gives a measure of neutrino mass, and it does so by alleviating the tension between cosmological parameters.
Why Hawking is Wrong About Black Holes
The recent controversy over black holes has put Stephen Hawking in the spotlight. It turns out what he proposes isn’t that controversial, and isn’t necessary to resolve the dreaded firewall paradox.
On the Edge
A black hole is normally defined in terms of its event horizon, but there are actually different kinds of horizons a black hole can have. This becomes particularly important when dealing with dynamic black holes.
One Singular Sensation
A new paper shows that we can simulate magnetic monopoles in condensed matter. This research may give us a better understanding of hypothetical magnetic monopole particles that could solve one of the great mysteries of astrophysics.
Give and Take
How do we determine the mass of a star? One way is to look at the motion of binary stars. Their motion due to their mutual attraction allows us to calculate their masses by their orbits.
And Yet It Moves
We all know the Earth moves, but how can we tell? It certainly doesn’t feel like we’re spinning around the Earth. But there is a simple experiment that can show the motion of the Earth, known as a Foucault pendulum. It’s an experiment you can do at home with a baseball, a hook screw and some string.
Taking the Quantum Leap
The common view of the atom is that of a compact nucleus with electrons swirling around it like little planets. But this “mini solar system” idea leads to a serious problem.