I happened to miss last month’s newsletter, but now that March has arrived it’s that time again.
The big news this month is that a book I’ve been working on is finally out. Radio Skies: 40 Years of the Very Large Array covers the history of the VLA, the discoveries it has made, and where it is heading in the next decades. It’s filled with beautiful pictures and fascinating infographics and was written by yours truly. You can order it online at the VLA Online Shop.
We all know what stars are, but there are still details about stellar evolution we don’t fully understand. Take, for example, the demise of Wolf-Rayet stars. These are massive stars at the end of their life that are casting off their outer layers as large nebulae. It has been thought that the cores of these stars quietly collapse into black holes, but a new study shows they can explode as a new kind of supernova.
Of course, when a star like our Sun dies, it expands into a red giant before its core collapses into a white dwarf. One question we’ve had is how this might affect any planets it might have. This month astronomers found evidence of planetary fragments falling into a white dwarf, which supports the idea that planets are not simply cast off as a star becomes a red giant.
The remnant cores of larger stars typically become neutron stars, also known as pulsars or magnetars depending on the strength of their magnetic fields. Its generally be thought that highly magnetic pulsars rotate very quickly, but astronomers have discovered an object that seems to be an ultra-long period magnetar. We have no idea how they can slow their rotation so much while retaining a strong magnetic field.
The most massive stars generally die as black holes, and since stars rotate we assume most black holes rotate as well. It’s difficult to measure black hole rotation, though. A new study tries to solve this problem, showing how the rotations of merging black holes might be studied through their gravitational waves.
Love the Planets
We continue to learn more about exoplanets. By observing the transit of one particular exoplanet, astronomers were able to measure its Love number. This number tells you the shape of a planet. In this case, the exoplanet is shaped roughly like a rugby ball.
Closer to home, a study looked at why Neptune and Uranus are different colors, despite having very similar compositions. It turns out it has to do with layers of smog. Another study looked at comets and discovered why the heads of comets are often green, but the tails of comets never are. It all comes down to a bit of astro chemistry.
Galaxies are known to collide from time to time, and ours is no exception. A study using recent Gaia observations has even shown that sometimes our galaxy even eats other galaxies. Even the Milky Way enjoys a good sausage breakfast.
Of course, when galaxies merge, so does their dark matter. If only we knew what dark matter is. One popular candidate has been hypothetical particles known as axions, but a new study has found that to be unlikely. So, the mystery remains dark for astronomers.
A Better Love Story Than Twilight
Finally, as Starlink brings the internet to remote regions of the world and even war-torn Ukraine, it also has a downside. As a new study shows, the increasing number of Starlink satellites are interfering with the search for asteroids that might collide with Earth, thus increasing our risk of an unanticipated strike. As with most technology, Starlink gives with one hand and takes with the other, and we should keep that in mind.
That about wraps it up for this month. For most of us, it has been a long winter of discontent, not yet made glorious summer. But soon, ’tis spring, and roots are shallow rooted. As we hope for peace and a full emergence from quarantine, remember there’s just one rule babies, you got to be kind.
Until next time, I wish you and yours health and comfort.