Greetings from Palmia Observatory
Well the night sky is still a bit cloudy and rain and even some hale have struck here in Orange County. But the clouds can be good thing in bringing beautiful sunsets.
|Clouds and sunset can go together in iPhone image (Source: Palmia Observatory)|
In addition to beautiful sunsets, we see some reduction in the infection rate of COVID-19 and restaurants are again free from state control and can serve customers outside and even inside with some restrictions. Here we see Resident Astronomer Peggy holding up our Bloody Mary's as we go out and support our friendly restauranteurs at Kenos. Hmm, we didn't believe that we were taking that much additional risk, and I guess part of the reason is that the news about reopening hasn't caused a great surge in attendance so far.
|Supporting our friendly Keno's and relaxed crowd restrictions (Source: Palmia Observatory)|
In other space news, SpaceX is assembling Starship prototypes faster than they can be launched. Here we see SN9 and SN10 on the launch pad. It is a beautiful thing to see two Starships on the launch pad at the same time.. Twitter is abuzz with talk about some conflict with securing FAA approval to conduct the launch and until that is resolved the manufacturing process is occurring faster than the prototype Starships can be launched. Good luck, Elon!
|Two Starships, SN9 and SN10, ready on launch pads (Source: Nasaspaceflight.com)|
In other physics colloquia news, we were able to sit in on the virtual UCI physics colloquium given by Professor Samantha Sellum on "Planet Formation." One of the things that I had not realized or remembered was that planet formation from the stellar disk around a prototype sun takes places within 10 million years.
|Somethings we know about planet formation (Source: Stephanie Sallum, UCI)|
Another interesting technique for imaging exoplanets around their sun is actually made easier by blocking off part of the light that enters the telescope. This sounds counterintuitive but the main obstacle faced with detecting and monitoring exoplanets is that their sun is so bright and the planet often so close to the sun that it is hard to see the exoplanet in all of the glare from the sun.
But this interesting technique called Aperture Masking is a way of getting higher resolution and cancelling out the glare from the star. In this screenshot from Stephanie's presentation you can see some examples of aperture masking and how the image of the star is cleared up so that any present exoplanet can be more easily identified. Pretty neat; who know you can get better resolution by blocking off some of the light coming into the telescope!
|Using aperture masking to get higher resolution of exoplanets (Source: Stephanie Sallum, UCI)|
It turns out that there is an upcoming conference on habitability of exoplanets. If you want to follow up with all the rest of the exciting exoplanet news be sure to sign up for the upcoming American Astronomical Society (AAS) Meeting on Habitable Worlds, which will be held online from Feb. 22 - Feb. 26. The meeting fee is $75. See you all there!
|Be sure to sign up for the AAS Habitable Worlds Meeting (Source: www.aas.org)|
In other local meeting news, the Cosmos meetup group alerted us to a virtual tour of the ALMA site in Chile. Now readers will remember that when we toured the Atacama desert as part of our 2019 total solar eclipse adventure, we had hoped to visit the ALMA Observatory while we were there, but our tour bus had to just keep driving right passed the turnoff to ALMA. For the rest of that story about our driving past the observatory check out the blog post of July 5, 2019 at: http://www.palmiaobservatory.com/2019/07/can-you-see-big-dipper-in-southern.html
|On our visit to the Atacama desert, we drove right passed ALMA (Source: Palmia Observatory)|
So we looked forward to the virtual tour of ALMA. We would have liked to see the night skies over the array of radio antennas, such as shown below, but we had to settle for just looking at our computer screens.
|Dark skies with ALMA array in foreground (Source: ALMA Collaboration)|
The virtual tour, operated by NRAO, was conducted mostly by observatory scientists, who are still located in the US and spoke from their own homes because of the pandemic. So, we missed out on having a tour guide walking around the observatory, but the virtual guides pointed out how if you wanted to get a more close up view of the observatory site to go online to the ALMA Observer. You can check that out for lots of videos at: https://public.nrao.edu/explore/alma-explorer/
|Lots of virtual video tours of ALMA (Source: NRAO)|
The ALMA Observatory is pretty much next door to the Simons Observatory, so next time when we get back to Chile, we can check out both observatories, When we visited Chile in 2019, we flew from Serena, where we watched the eclipse, up north to Calama airport and then on to San Pedro de Atacama, which was our home base for touring the Atacama desert.
|ALMA and Simons Observatory are pretty close together (Source: Google Maps)|
The Simons Observatory has several telescopes under construction as can be seen in the photo below. The big Atacama Cosmology Telescope (ACT), with its huge radiation shield, can be seen to the left hand side
|Aerial view of Simons Observatory (Source: Simons Observatory)|
The Simons Observatory got construction funding primarily by the Simons Foundation. Who is the Simons Foundation? Well, it is a philanthropic organization started by billionaire Jim Simons. An interesting history of Jim Simons, as told by himself, can be found in this TED talk, "The billionaire who cracked Wall Street." He started off as a mathematician, who then went on to start a hedge fund on Wall Street and turned himself into a billionaire. Along the way he teamed up with mathematician Shiing-Shen Chern, and together they developed the theory of characteristic forms and geometric invariants in 1974. This original invention now has many applications in fundamental physics and cosmological theories and measurements.
|Jim Simons, mathematician, billionaire philanthropist (Source: TED Talks)|
So, with that background, we now can see how everything comes together in this interesting presentation by Brian Keating, UC San Diego, who also is the Director of the Simons Observatory. His presentation was on potential measurement of birefringence in the CMB. This birefringence, which as you know, essentially just means that the refractive index depends on the polarization of the incoming radiation.
|Looking for polarizations in the CMB (Source: Brian Keating, Simons Foundation)|
The Simons Array is being configured to collect polarization data with sufficient accuracy and resolution to identify any real birefringence.
|Getting Simons Array online for CMB polarization measurements (Source: Brian Keating, Simons Foundation)|
Standard models of cosmology are based on measurements of the CMB and if significant amounts of birefringence are detected then some of the basic and fundamental assumptions of the standard model will be questioned. One assumption that is the most fundamental is the requirement that laws of physics are written in Lorentz invariant form. So far, all measurements confirm that the universe and laws are Lorentz invariant, but there are hints of measurements that indicate that invariance might not strictly hold on very large galactic scales. So, we can see in this screenshot from Brian's presentation how Lorentz Invariance is a key pillar holding up all of modern physics.
|Lorentz invariance is major pillar of modern physics (Source: Brian Keating, Simons Foundation)|
But there are hints found in reanalysis of the Planck CMB data to evaluate the extent that the polarization measurements indicate a high level of birefringence.
Cosmic birefringence accumulates over distance so that CMB signal that reaches us know from its released about 380,000 years after the big bang will have travelled a great distance. One way of increasing the amount of birefringence is by a material that pervades all of the space travelled by the CMB. The issue is that the material has to be such that it has a different value of its refractive index depending on the polarization of the incoming radiation. One type of material is the theoretical axion particle, which has not yet been detected but many searches are ongoing. But axion theory suggests that the particle could affect the propagation of EM waves just in that way to cause birefringence.
Now the interesting thing, which takes us right back to the earlier discussion of Chern-Simons theory, is that when the Chern-Simons term is added to the Lagrangian for the EM field, the polarization of the EM field changes.
|Predictions polarization and Lorentz invariance violation (Source: Brian Keating, Simons Foundation)|
So, all of this stuff about Chern-Simons is all new to me, but even the simplest, introduction to Chern-Simons videos are way over my head. I did like this one YouTube video that explain that Chern-Simons theory is a way to combine QFT with Topology
|Using a drone as polarization calibration for Simons Array (Source: Brian Keating, Simons Foundation)|
Until next time, here from our burrow, stay safe, as we recover more of our freedom,