Category Archives: Astronomy

Astrophysics at Ludicrous Speed: But Why? on stellar collapse

It should be no surprise that aging scientists from all fields gravitate (ha!) to astronomy as we get more interested in the grand fates of things. Fortunately there are many sites and channels to scratch that itch, giving us a perhaps too comfortable view of complex material. The life and death of stars is an example where the high level explanations of gravity versus fusion do work but where the many omitted details cause midnight befuddlement.  Where does the energy come from?  Where does it go?  Wait… how fast – Relativistic speeds?

Anonymous Youtuber “But Why?” breaks the barrier with this beautiful video on the collapse of very big stars – the kind that leave neutron stars or black holes in their wake. It isn’t all symmetric implosions and classical rebounds and the thought of a giant object collapsing 5000-km in a tenth of a second boggles the mind.  The depth of detail is breathtaking, the amount of research inspiring, and taught me much new physics that I incorrectly thought I already knew.

Youtube Channel: But Why?


He who keeps cool will collect (photons): Christian Ready on the JWST instrument package

Sports Illustrated quoted this Japanese proverb back in 1975 in conjunction with Cal’s championship men’s gymnastic team of that era.  The adage abides with the James Webb Space Telescope now in its halo orbit around the Sun-Earth L2 point, its optics and instruments slowly cooling to their ultimate cryogenic temperatures, the better to collect the faint signs of heat from the early universe.  Little has been said to the public about the instruments nestled in the big box behind the 6.5-m primary mirror.  This is perhaps not surprising.  There are no secrets here, just that the real science goals and the optical engineering to meet them are fiendishly complex.  Friendly Neighborhood Astronomer Christian Ready tackles the challenge, explaining where the precious photons will go and what will happen to them once they arrive.  The comment section clamors for more detail on the MIRI cryocooler which will take the mid-Infrared Instrument’s focal plane array below 7K.  Here’s to hoping for a full video on this beast, built across the hall from me, and on which I spent a couple of weeks when the team was shorthanded.

Youtube Channel: Launchpad Astronomy


Bird Up: JWST completes major deployments

As the man said after the Eagle landed: “You got a bunch of guys about to turn blue. We’re breathing again. Thanks a lot.”

The James Webb Space Telescope, largely designed, built, and tested at Space Park in Redondo Beach, has launched, raised itself from the spacecraft, deployed its 5 layer sunshield, and put its primary and secondary mirrors into place.  It will take another few months for the telescope to cool in the shade and then to commission the instruments before science measurements can begin.

It has been a long and contentious wait but the magnitude of this accomplishment is worth celebrating.

Youtube Channel: Northrop Grumman

An Impey Trifecta: Dark matter, strange correlations, and observing time

The online astronomy office hours from the UofA continue apace.  Every week  Prof. Chris Impey answers  ex tempore a mix of questions from planetary science to the fate of the universe from a thirsty audience across the globe.  A large Indian contingent stays up until the wee small hours of their morning to join in.   Part of the fun is pausing the video and trying to figure out the answer  from basic considerations before resuming.  It is fun to be right but more  instructive to be wrong.  I’ve been moved to send in three questions over the past couple of sessions and all have been answered.

  1. When in relation to the Big Bang did dark matter originate?
  2. There is a surprising correlation between supermassive galactic black hole size and the population of old stars in a galaxy. Can telescopes now resolve individual stars in distant galaxies well enough to distinguish old from new to establish this connection?
  3. Observational results come from the successful.  How do astronomers get precious telescope time?

Youtube Channel: Astronomy State of the Art


Backyard history: Southern California’s impact on astronomy

Silicon Valley has reshaped the earth, Hollywood has driven our perceptions of it, and not always for the better.  Less well known is the outsized role California has played in understanding our universe.   Mt. Wilson, Mt. Palomar, and their astronomers have had a Copernican impact on where we stand in the grand scheme of things.  The word ‘vision’ gets bandied about a lot these days but George Ellery Hale had it in spades.  Here’s how the two observatories that housed Hubble, Humason, ShapleyZwicky, Baade, Rubin, and Schmidt came to be.

The third video from Corning’s Museum of Glass shows that the path to science is not always smooth and that learning from mistakes is the norm.  The original 200 inch pyrex disk for the Palomar primary did not go according to plan and had to be recast.  The second attempt succeeded and even so, it took ten years of painstaking grinding and polishing at Caltech before it was ready for use.

Youtube Channel: Palomar Observatory

Youtube Channel: Irish Astronomy

Youtube Channel: Corning Museum of Glass


The time is out of joint: Chris Impey on the tick-tick-tock of the stately clock

Steven Weinberg wrote a famous book, “The First Three Minutes” on the early stages of the universe.  The same universe became transparent to light some 370,000 years later.  There are other landmarks in post-Big Bang time going down to bewildering fractions of a second.

But the early universe was very hot, very dense, and gravitationally very different from the comfortable-to-us 1 g we experience today on the surface of the earth.  Einstein has convincingly shown that spacetime is accordingly divorced from that human experience.   Clocks, for example, are affected by gravity and satnav constellations have to take this into account.  Did the first three minutes flow the same way three minutes flow in the here and now?  I sent that question to Chris Impey’s online office hour and he kindly answered.  It is a tantalizing response and one that will require substantial further study to fully appreciate – perhaps finally diving into the guts of GR.   It makes me wonder even more intensely why we anthropomorphize those intervals the way we do.

Youtube Channel: Astronomy State of the Art

Composer Toru Takemitsu has set the general idea to music.

Youtube Channel: Orquesta Sinfónica de Xalapa


Low-key Relativity: skydivephil on gravitational waves, the Universe, and everything

The mere detection of gravitational waves two years ago was cause for celebration and, for those of us skeptical of LIGO, eating of crow.  Now gravitational wave detections regularly cue electromagnetic observatories on the ground and in space with tighter integration to come.

Youtuber skydivephil puts the camera on several researchers active in developing the next generation GW systems and the ever more ambitious cosmological probing that these observatories will enable.

Youtube channel: skydivephil

Skydivephil and the unnamed narrator are self-effacing providing few details about themselves, not even their names in the nonexistent credits.   They also have enviable access to many leading physicists and institutes, largely on the theoretical side.   The style is simple: Let the speaker speak.  It is a refreshing antidote to the modern space documentary which highlights the doom-and-gloom with an explosion and visual effect every fifteen seconds.   Whatever one may think about string theory, loop quantum gravity, or their alternatives, it is refreshing to hear about them from the purveyors.  Here’s the “Before the Big Bang” playlist with an assortment of views on modern cosmology (note that the episodes are in reverse chronological order.)


Theme and Variations: Nahre Sol adapts and explains ‘Happy Birthday’

Pianist Nahre Sol delightfully explains sixteen levels of pianistic complexity in about ten minutes.  That doesn’t mean there are only sixteen but, damn, what a lower bound for the recreational pianist to aspire to!

Youtube Channel: Wired
and the separate Nahre Sol Youtube Channel

Sol is in good company.  Here are Mozart’s Variations on “Ah, vous dirai-je, Maman” which we know as something else.

Youtube Channel: Canacana Family


Misnomers: Dr. Srinivasan on Mostly Neutron Stars

It took me a year and an email to understand how merging neutron stars could generate heavy elements.  For this you need protons and from where do these protons come.  The year was for intermittent research and the email due to failing in that research.  As it happens, neutron stars are chock full of particulate goodness, far more than their name implies.   On the one hand it is good to know how it works, on the other hand it shows that my research skills could use some improvement.

Dr. G. Srinivasan, Researcher Emeritus from the Raman Research Institute explains the beaks and gizzards of these dense objects in great detail.   His 12 part lecture series “A Random Walk in Astrophysics” is also available.

Youtube Channel: International Centre for Theoretical Sciences

Horizon Event: The big EHT reveal

The Event Horizon Telescope team announces its major discovery following two intense and quiet years of data analysis on top of a longer period of development.   A nice testament to aperture synthesis and international collaboration as the rest of the world spirals into madness.  Damn!!!

Youtube Channel: National Science Foundation

Context for the interested public:
Youtube Channel: Sixty Symbols