Greetings from Palmia Observatory
Well this week we listened to some interesting discussion on on E(8) symmetry and Theories of Everything and Starship SN9 finally makes a test hop, but first this Resident Astronomer got in line for his first COVID-19 vaccine injection.
After waiting a couple of weeks for an appointment, my time was finally up. This mass injection site at Soka University was a convenient location and after winding the car through all the pylons and standing in lines and checking in and getting through the paperwork, I received by first "jab", as BBC reporters refer to the injection. All in all, once I was in the line of automobiles for parking and then foot paths of people lined up, the final time to injection and 15 minute observation time, the whole process only took about an hour. I didn't have any reactions then, but the next day, I did have a bit of sore arm. Anyway, the whole operation at Soka was very well organized.
|Waiting in line for COVID-19 vaccine at Soka University (Source: Palmia Observatory)|
Next up, I've been following the "Into the Impossible" podcast with Dr. Brian Keating, UCSD, who always has long form, 2-3 hour podcast discussions, with leading physicists and thinkers. You may recall previous blog posts with some of his comments and reports from the Simons Observatory, where he is the current Director.
This time he continued the discussion on Theories of Everything with two alternative views of how to construct a theory of everything (TOE). We should remember that the purpose of some TOE is just to reconcile General Relativity with Quantum Mechanics. The standard mainstream approach, say with string theory for example, is to look for ways to quantize gravity so that it matches up better with quantum mechanics, which is understood as the more fundamental theory.
This time Dr. Keating had two guests, Eric Weinstein and Garrett Lisi, who each have been developing alternative TOE where the approach is to go the other way around. Their separate approaches are to start with geometry, which is primary in general relativity, and then try to represent quantum mechanics as a theory of geometry. So, this is different, and we have been trying to follow and understand how this might work.
|Interesting podcast with Keating, Weinstein & Lisi on TOE (B. Keating, "Into the Impossible")|
If you want to sit through the whole 2-3 hour podcast, you can check it out at: https://www.youtube.com/watch?v=QCKCQNFsJUw&feature=youtu.be
So, how do you even begin to geometrisize quantum mechanics and quantum field theory and the Standard Model of particle physics? I can't say I understand much of it, but one thing comes through and that is the use of higher dimensional Lie Groups, like the Euclidian group, E(8), instead of the more common Standard Model, SU(3) x SU(2) x U(1).
This toy model of E(8) and the Standard Model, as shown in a recent blog post, "It Starts with a Bang" by Ethan Siegel. You can see that E(8) has a lot more degrees of freedom available with which to begin including gravity. How all of this would work is not clear and it is not clear even if the inventors have completed all of the work to show how this might work.
On particular point I heard and liked was the how effectively the early pioneers of QFT used ideas of beauty and symmetry as guides to find good theories of particle physics and forces. But for the last 50+ years, the use of beauty and symmetry has not made much progress. Now Weinstein uses something called Geometric Unity, while Lisi relies on E(8) symmetry. They point out that even though super-symmetry has failed to find any of the predicted particles supposedly a result of supersymmetry, it need not be that the idea of supersymmetry is wrong, only that that particular instantiation of it which results in those particles might be wrong. So, beauty and symmetry might still be guiding principles to select a theory for further testing, even though supersymmetry has yet find any of its predicted particles. It might be that relying more on a geometrical interpretation of these principles might indeed be the breakthrough needed. I can't tell, but wait for new news and better understanding of the theory of E(8) and geometric unity. So, we will have to wait and see.
|Comparison of E(8) and SU(3)xSU(2)xU(1) of Standard Model (Ethan Siegel, "It starts with a bang")|
For me, what this whole topic did, was remind me and really all physicist wannabes, of going back and reviewing all of our Lie Groups and Lie Algebras. I am still struggling to understand how E(8) is defined, but here is a Wikipedia description of part of the definition.
|Euclidian Lie Group E(8) has enough degrees of freedom for TOE? (Source: Wikipedia)|
Understanding E(8) is going to take some time, so for now the other big news is the test hop of Starship SN9 from the SpaceX facility in Boca Chica, TX. The test hope had been delayed for various reasons, but getting FAA approval was often mentioned in Twitter feeds. So, we looked up what is required to get FAA approval to launch a rocket. It turns out, with so many more opportunities for commercial suppliers of rockets and launches that the FAA has reviewed and updated and streamlined the approval process to adjust for the rapid prototyping and learning that is being accomplished now. The revised approval requirements for safety, launch, and re-entry and recovery of spacecraft is now covered in FAA Part 450, which comes in at just 785 pages.
|If you want to review the licensing requirements for rocket flights (Source: FAA Part 450)|
Ok, with all the launch bugs worked out and approval in hand, Starship SN9 test hop on February 2. In this screenshot from LabPadre's video, we can see SN9 nose above the clouds of smoke, as Starship SN10 stands quietly nearby.
|Starship SN9 ignition, while SN10 stands nearby (Source: LabPadre)|
The test hop up to the assigned altitude seemed to go perfectly. Here you can see the Starship in flight and a camera on SN9 show the engine exhaust and the ground below after 40 seconds of flight.
|Starship SN9 performs flawlessly at 40 seconds into flight (Source: SpaceX)|
SN9 travelled higher on all engines until planned shutdown at about 10 km altitude. Then SN9 successfully transitions to the "belly flop" mode of horizontal flight to bleed off all of the kinetic energy in preparation of landing. The aerodynamic fins do a great job of maintaining the deceleration profile and control the tracking back to the landing pad.
|Starship SN9 in horizonal deceleration mode for landing (Source: SpaceX)|
As the Starship falls to the ground, the engines are supposed to restart and the rocket returns to upright vertical position for landing. But it seems that only one engine relit and some debris was noticed to fall of the rocket as if some other part, perhaps a failed turbopump from the other engine malfunctioned.
|Starship SN9 readies for landing, but only one engine? (Source: SpaceX)|
Yeah, sadly, the vertical velocity was just too high and the SN9 could not maintain its vertical approach to the ground. This "leaning" position reminded all of the online pundits of the earlier manufacturing history of SN9 led to some support structure failures and the SN9 "leaned" over and hit the high bay manufacturing building. Pundits christened SN9, "Eileen" to commemorate the event. I think Felix was still responding to what looked like it might be a successful landing, until it wasn't!
|SN9 leans into ground crash landing (Source: @Felixschlang and @LabPadre)|
Here you can see the fireball upon the hard landing back at the landing site. Note how close the landing site is to the Starship SN10 is on its launch pad. Yes, the aerodynamic control of the Starship as it returns to Earth seems to demonstrate excellent performance to guide the ship down to the exact spot.
|Starship SN9 explodes on landing in Rapid Unplanned Disassembly (RUD) (Source: SpaceX)|
The next day, after the RUD landing, you can see in this aerial view by RGV Aerial Photography, a lot of SN9 debris, but apparently SN10 and other ground facilities were intact and didn't suffer any damage. So the next step is finish up testing of Starship SN10 and fix any identified failures and lessons learned from SN9. SpaceX learns quickly and fabricates fixes and improvements very quickly so it won't be too much longer until SN9 performs its test hop and flight.
|Starship SN10 on launch pad with SN9 landing pad and debris (Source: SpaceX)|
Until next time, here from our burrow, stay safe, as we recover more of our freedom,