Well we are back from our Hawaii adventure at the 235h AAS meeting where I demonstrated that I was still capable of playing hooky from school! Anyway, now back in OC we attended a couple of lectures one on using cubesats to train students and do science and another on radio astronomy and can comment on them.
First up though is another attempt to photograph the 3rd constellation of Starlink satellites. The available prediction identified that they would be visible just after sunset, but with predicted magnitude in the 3-4 range. Hmm, well we are not going to see them (we have a hard time just seeing Polaris, magnitude 2, in city lights), but maybe we can just point the camera in the right direction and capture some of the satellites anyway. So, that is just what I tried to do and used 8 second exposure settings in hopes of finding something. The photo below shows an example of just blinding pointing the camera in the approximate position towards the satellites. Hmm, there are some bright dots, not much visible tracking, but everything there might just be stars.
|Blind camera pointing attempt to capture Starlink satellites, 8 second exposure (Source: Palmia Observatory)|
True, there seems to a line of dots, probably stars, but maybe some satellites, to be found in the image. But are they the satellites. I thought maybe the satellites would show up with visible streaking but I couldn't see much of that. So, the image was submitted to Astrometry.net to see if the long line of dots was stars or satellites. Darn! It looks like the dots are really stars, part of the constellation Cygnus.
|Nope; Astrometry shows the dots in a line are stars, not satellites (Source: Palmia Observatory)|
Next up of interest this week was some interesting discussion about radio astronomy at the monthly OCA Astrophysics SIG. We have been listening to the Teaching Company lecture series by Felix Jay Lockman. I met Dr. Lockman at the 232nd AAS meeting in Denver as described in the June 6, 2018 post and told him how I appreciated the lecture series and that I hoped to eventually get back to tour Green Bank Radio Observatory. This is a great lecture series (and you get a virtual tour of the observatory, plus a lot more); just wait for them to go on sale!
|Great DVD lecture series on radio astronomy (Source: The Teaching Company)|
This current lecture was particularly interesting because of the discussion about how radio astronomy tracks the abundances of elements in stars and molecular gas clouds. The quantum mechanical transition frequencies are often in the radio frequency range and this means that the types and amounts of elements can be tracked across the sky location. For instance, in general the cosmic abundances of the most abundant elements are shown in the screenshot below. So you can see for every carbon atom, there are about 3,450 hydrogen atoms and maybe about 0.06 carbon atoms. So hydrogen is the most abundant element in the universe.
|Observed cosmic abundances of elements in the universe (Source: The Teaching Company)|
When the radio telescopes are turned to the large molecular clouds it is found that molecules of carbon are very much present. I was glad to see that ethyl alcohol was very present in the universe!
Dr. Lockman then explained that the reaction rates with which these various carbon compounds can be calculated and the amounts of each of the various compounds can be estimated. Then if these theoretical predictions are compared with the actual measurement of the range of observed molecules, this can be used as sort of a chemical clock. In this screenshot, you can see by comparing the relative amounts of just two of the compounds, you can differentiate the age of the molecular cloud. Then if more measurements are made, using other molecules, you can start to get a much better age of the cloud. Pretty neat!
|Given the rates of molecular transformations, the age of dark clouds can be estimated (Source: The Teaching Company)|
So these carbon molecules, almost the precursors of amino acids, are present in the disks of materials around young protostars and might form the basis for seeding young planets with organic materials. Is this the reason that all Earth based life, and maybe all life anyway, is based on carbon? It is not known, but radio astronomers are investigating one additional factor about organic molecules that can be observed and that is their chiral structure, or their left or right handedness. Since most chiral molecules found in living organisms have a clear preference for one handedness, it will be interesting to see if the same handedness bias is to be found in molecular clouds too! Check out the example of two identical molecules, except for their chiral structure, in the screenshot below.
It turns out that radio astronomers have now detected the first instance of a chiral molecule in space. Propylene oxide can be produced in two forms, one left handed and one right handed. Remember that some people say that chemists want to confuse us so instead of saying the molecule is left or right handed, they introduce "R" for Latin rectus for right and "S" for Latin sinister for left. Now the search for any differing amounts of R or S chiral molecules is ongoing.
Lastly, I attended the local Sigma XI chapter meeting and dinner, where we heard an interesting presentation by Brent Freeze, working with the company Astronics, on how small cubesats are being designed by local Irvine high school students. The cubesats, each a cube, of about 10 cm x 10 cm x 10cm, The student project is funded as part of the Irvine Cubsat STEM Program (ICSP).
Brent is a volunteer who helps in overseeing how the students find tutors and other experts so the students can learn a lot of about the design and fabrication of the satellites. He also helps find the available rocket launches that are assigned to carry the satellites into orbit. This group of high schools has currently launched two satellites so far and is in the process of building two more. This is a great learning opportunity for the students.
One of the new planned satellites will carry an x-ray spectrometer and will scan the skies to find x-ray sources, such as from pulsars. This project follows up on some larger research projects by major corporations to develop and verify the use of a catalog of x-ray pulsars for navigation. If you are "lost" in space, the plan is to look for several x-ray sources, identified by their unique rotary period, and from the measurements of where they are in the sky, you can then calculate you position. So for us Earthbound observers, we can use GPS satellites, but if you are on a spacecraft bound for some distant planet, this new form of X-ray navigation looks very promising.
|Brent Freeze, Astronics, explains how high school students learn with cubesat launches (Source: Palmia Observatory)|
The other satellite being considered by the Irvine students is one that performs measurements in space that touch on the relationship between gravity and quantum mechanics. Most scientific theories are written and applicable in inertial reference frames. The effect of rotation of quantum measurements of interference between photons in interferometers is well understood and verified in laboratory measurements. What is being added to the test now is the effect of rotation on entangled particles that are sent through an interferometer. The interference patter changes during rotation and if sufficient precision can be obtained, any differences between theory and observation might indicate some unobserved effect of gravity or rotation or some such thing. The setup injects two beams of photons in opposite direction into the interferometer and then the rotation of the interferometer causes one beam to lag behind the other and this changes the interference pattern. This effect is understood and is used in rate gyros to measure rotation very accurately. But, how does this tie back to the nature of quantum mechanics? Apparently if the counter rotating beams are of entangled particles, there is additional effects that come up. I don't understand this very well and will have to do some more homework and maybe report back on that topic later.
This project involves testing in orbit, what has already been performed in Earthbound laboratories. By making these types of measurements in space, which are in a different gravitational field and can also be rotating, the exploration of the foundations of quantum mechanics can be further examined. To carry out the actual measurements as required to test the effects of rotating frames of reference and gravity, a system of three satellites is proposed. This system is probably beyond the capability of the students, but it is interesting that they can come close to duplicating an exciting and new opportunity to make progress in further understanding of quantum mechanics. Anyway thanks for a very interesting presentation, Brent, and thanks to Sigma XI for being able to sit in as a guest attendee!
Until next time,
Resident Astronomer George
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