Well the clouds and a bit of rain are back with us this week, so no additional observing with the new Sky-Watcher mount, and the weather forecast soured an prospect of our proposed second attempted search for aurora in Fairbanks, Alaska . But there was an interesting physics colloquium to report on as well as some random recollections following the APS April meeting in Denver.
At this week's physics colloquium, Professor Feng, UCI, provided an illuminating presentation on dark matter and a new search for dark matter. Now, I have sat through many presentations on dark matter and unsuccessful searches for same, but this was the first time that I had an eureka moment about the nature of dark matter. Professor Feng explained how it might be that during the big bang event, dark matter was the predominant matter particle. These dark matter particles would annihilate and produce what we now find as standard model particles. As the universe expanded, the dark matter particle density became low enough that those particles just could not bump into each other very often and the amount of dark matter sort of became frozen out and is mostly still with us today after 13 billion years.
My other takeaway from this part of the presentation was that since it is assumed that the dark matter particles can decay or annihilate to product standard model particles, if the dark matter is very light, then it is not necessary to collide matter at such high energy at LHC and it might be possible to search for lighter weight dark matter particles using lower energy colliders. Since no one knows for sure what form the dark matter will be found in, this opens up more search strategies.
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| Professor Feng, UCI, talks about FASER new dark matter search at LHC (Source: Palmia Observatory) |
Professor Feng then went on to describe the new experiment that his team has proposed and is installing at the LHC at CERN in Geneva. Forward Search Experiment at CERN, or FASER, is faster, smaller, cheaper approach to search for dark matter. Dark matter could exist at various mass scales, and as long as the number and mass density are such as to be in agreement with the cosmological measurement of dark matter, the particles, if they exist, could have any one of these mass scales. The LHC is tuned to search for very heavy dark matter, such as WIMPS, and FASER is designed to search for the lighter version of dark matter. It is faster and cheaper because FASER just relies on the LHC as the source of high energy collisions and it does not need to build a large detector because many particles that are produced, and not used at all at the LHC, are emitted in a tightly collimated beam from the ATLAS detector.
In the diagram below you can see the ATLAS detector located directly in line with the large collider ring, identified as the blue "LHC" line. The particles that ATLAS detects are only those that exit perpendicular to the beam. The high energy beam emitted tangentially to the circular ring, is not noticed or used and escapes the ATLAS detector without any effect. This beam then travels through the ground, through rock and concrete, 480 meters to an unused utility tunnel where FASER will be installed. FASER can have very small detector because the beam of particles is highly collimated, and is thought to be less than a meter in diameter after travelling 480 meters.
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| FASER installation tangent to LHC particle beam near ATLAS Detector (Source: FASER Collaboration) |
That was a really neat presentation after which I met up with Math Whiz, Dave, at the reception following the colloquium presentation. I asked Professor Feng if he had to pay any of the electrical bill to operate the LHC and he said, no, the LHC just makes their runs, independently, and the only thing that happens is they will tell him when they are operating. He then just has to collect data at FASER, with no interaction with LHC. Thanks for that great presentation, Professor Feng!
So, since the weather forecast in Fairbanks was for cloudy weather, we are stuck with some reminiscing about recent adventure at the APS meeting in Denver. Yep, I hoped to be in Fairbanks, Monday through Thursday, in another attempt to catch some photos of the northern lights, but our old constant companions, the clouds, say, no not this time! This was going to be our second attempt in Fairbanks, with the previous attempt described in the blog posts of March 17, 18 and 23, 2019. It's a good thing I didn't buy airline tickets!
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| Scope Nights app forecast shows poor observing in Fairbanks, Alaska (Source: Palmia Observatory) |
So, on to the random recollections from the APS meeting, at the end of which, I checked out of the hotel and took the train to the Denver Airport. The train makes maybe a half dozen stops on the way and the gentle motion of the train makes one wonder which train is actually moving as trains and stations pass by. This was a very relaxing way of imagining the theory of relativity, especially since I hardly ever travel by train, and wonder who or whichever train was actually the one in motion. We know of course that the laws of physics have to be the same for all observers in inertial reference frames just moving in smooth motion passed one another. Hmm, that was fun and I didn't even need to go to the bar car, if there even wasn't one!
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| Riding the train reminds me of Einstein thinking about relative motion between trains (Source: Palmia Observatory) |
It turns out that taking the train from downtown to Denver Airport is really inexpensive. Check out the photo below, as I wait to show the ticket to the conductor, and the ticket only cost $5.25, rather than the $70 taxi ride. In addition, you really get to lean back and relax and consider the special theory of relativity and the thoughts that must of been going through Einstein's thinking as he rode the train in Bern.
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| Inexpensive train from downtown to Denver Airport allows your mind to wander (Source: Palmia Observatory) |
When we got back to the observatory, a book that I had seen and ordered at the Oxford booksellers stall at the APS meeting, rather than packing in my suitcase, had arrived. This little book is an easy read and fills in some of the issues around the big bang with words and discussion rather than equations. I'm really enjoying it and you might too!
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| Easy, 150 page read on the big bang (Source: Helmut Satz, "Before Time Began") |
Back at the observatory, one of the back issues of New scientist, had an article about an app for your smartphone, which would alert you if the LIGO team detected a gravitational signal indicating a merger of two compact objects, somewhere in the detectable universe. Now, for this I don't mind hearing some beep or chirp in this case and it certainly is not annoying as is the robo calls that are always showing up on the phone. But, if you don't mind getting a "chirp" from LIGO, download he app now and wait for the next merger. Who knows, it might be close enough that you can run outside and point your scope in that direction and see some electromagnetic component associated with the merger!
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| Don't be left behind, get quick notification of LIGO merger detection with this app |
Ok, enough APS meeting recollections, it is now time to begin thinking about our upcoming trip to Chile, in search of the total eclipse of the sun on July 2. You can see the path of the eclipse in the drawing below. We will be in La Serena, Chile, for the eclipse, but as you can see some of you might have elected to observe the eclipse from Pitcairn Island, from "Mutiny on the Bounty" fame.
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| Path of total solar eclipse passes through La Serena, Chile (Source: http://eclipsophile.com/total-solar-eclipse-july-2-2019/) |
The Sky Safari Pro app shows the following predicted observation details for the 2019 eclipse. It is scheduled for late afternoon and will be only 13 degrees above the horizon to the south.
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| Sky Safari Pro map showing 2019 total solar eclipse from La Serena, Chile (Source: Palmia Observatory) |
Now we have been above the Artic Circle and I have been below the equator, maybe 40 years ago, but this trip to Chile will be our first time to see the Large and Small Magellanic Clouds, if they are going to be visible at night in July? Well, with a little more help from Sky Safari Pro, we can see that, yes, the LMC and SMC will be up at night. Hooray, so as long as the clouds are nice and stay away we should have plenty of opportunities. This means we need to take a telephoto lens for observing the solar eclipse and corona, as well as the SMC and LMC, and a wide angle lens to capture some of the southern view of the Milky Way. Ok, all of that will still fit in our travel bags.
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In addition, Resident Astronomer Peggy now sees that taking her binoculars should prove useful during our many opportunities to observe the night sky from the seaside and high up in the Atacama desert. Now, I have already verified that the GoSkyWatch iPhone app should work in Chile (or at least, you can enter that as a location), to give us a heads up view of the night sky, but to help with binocular viewing our friends at Amazon say they will deliver this book for our use. So, now we are just back to counting down the days until July 2!
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| What's up in the southern skies? (Source: Pearls of the Southern Sky) |
Finally, I don't know why, but when Resident Astronomer was out and about, perhaps at the hairdressers or somewhere, she happened to snap this image on the TV screen and sent it to me. Hmm, what is she trying to say about this topic? Hmm, maybe Astronomer Assistant Ruby and Astronomer Assistant Danny are healthier than I had thought they were, or maybe its just me?
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| Do dogs actually carry fewer germs than men's beards or Is this real or fake news? (Source: The Ingraham Angle) |
Also, as long as we are talking about dogs, take a look at the following slide from the APS April meeting comparing the use of Artificial Intelligence to search through the gigantic astronomical databases to identify galactic patterns with the test case of identifying the difference between images of fried chicken and labradoodles. This case reminds us of the need to be especially careful in looking through enormous astronomical databases, which is now often done with AI, not to bias the search by our impression of what we hope to find.
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| Using AI in astronomy is like identifying difference between labradoodles and fried chicken (Shep Doeleman, EHT Collaboration, APS April Meeting) |
Until next time,
Resident Astronomer George
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