Where armchair and observational cosmologists have fun and do real science and share lessons learned.
Sharing weekly blogs for over three years. Click on archive or search box to find specific topic or any of more than three years of individual posts to show and read more of the post and pictures
Observing with Street Lights
Dark sky sites not always necessary to see the Milky Way (This image was taken ouside of a B&B in Julian, CA)
Saturday, June 11, 2016
Get your copy of Quanta magazine, looking at Mars and Jupiter, June gloom, nuclear R-process, Iggy Azalea will teach you physics and explanation by Jimmy Kimmel
Greeting from Palmia Observatory
Let's get to the mail before we look at some photos of Mars and Jupiter. Retired Big Oil Chemist, Dr Arnold, forwarded a web reference for a great, online, free science type magazine called Quanta Magazine. I've enjoyed it and signed up. Thanks Arnold. If you're interested in timely science type tidbits check it out at:
Now back to Mars and Jupiter. Well, the clouds have been busy blocking most of my attempts, but I did manage to get a couple of shots. I've become quote lazy and don't like taking the time and effort to set up the big scope, with focal length up to 2000-3000 mm, which allows for higher resolution photos of the planets, but I just can't get up the energy to set it up. So, I used the 600 mm lens and wanted to see what image resolution would be possible and I was a little disappointed. See attached. The Jupiter image is quite blurry as the seeing was not very good. The photo was disappointing especially because while tracking Jupiter on the camera live view, I could quite often see much more detail, even the banded structure of Jupiter. Too bad the images I snapped don't show much of that structure. Also, 600 mm lens can't resolve much structure and a longer focal length telescope is needed for that.
Similarly for the image of Mars. See attached. Certainly no canals. Can't see Mark Watney racing around either. Ok, ok, that was just a movie, but it was kind of exciting to think that we actually might in the near future see a real astronaut on Mars.
Well, what to do now with all this gloomy June weather? It's not just the weather either, having just finished up the primary presidential elections in California. Seeing the three major contenders get as high numbers as they got is sort of gloomy too. Ok, ok, back to astronomy.
Anyway, let's check out a couple of physics topics I've been reading about this week. There was an article in Nature a couple of month ago titled, "R-process enrichment from an ancient event in a dwarf Galaxy". Now doesn't that title just really excite you? No? Well, it didn't really grab my attention either and I just passed right over it. Then this issue of Sky and Telescope magazine presented a review of that article and wow, now I see its significance. The article reviews what is known about the source of the elements heavier than iron. My previous understanding was that all elements heavier than iron were formed during supernovae events, which meant that all of us are made of star stuff born in a supernova explosion. Now the exciting discovering in the study is that the merger of two neutron stars produces something like 25,000 times the amount elements heavier than iron than would a supernova. So even though neutron stars are formed as a result of a supernova, it is the merger of two neutron stars where more of the heavy elements are formed. Pretty neat! This also means that when LIGO has enough sensitivity to detect meeting neutron stars that other telescope systems can then study the results of the merger to better understand the whole process. By the way, the "r" in r-process is short and for "rapid neutron absorption, which is the process by which supernova a and now merging neutron stars makes all of the elements heavier than iron.
The other neat astrophysics topic is called the Hanbury-Brown Twiss experiment. Now these two astronomers, referred to as HBT, used an interferometric technique in the 1920's to measure the diameter of stars. Now amateurs are used to describing the diameter of galaxies and planets in terms of the angular size, for example the moon has an angular size of about 1/2 degree, which is the angle extended by the object as seen by the observer. So, once you know the angular size of an object and the distance to that object, you calculate the actual diameter of the object. But when you try to do this trick with stars it is found to be very difficult because the stars are so far away that they appear as point sources, not extended objects like the moon. You would need a telescope hundreds of meters in diameter to be able to resolve the size of the star. So what did HBT do in the 1920's? They used interferometric techniques to create a telescope with effective diaper of a couple of hundred meters and they were able to calculate the diameter of many stars. In fact, they were able to identify the new class of stars now called red Giants. That is pretty neat, but the story continues. In the 1950's the HBT technique came under more severe scrutiny and physicists realized that the standard classical theory of electromagnetic waves was incompatible with the results found in the experiment. So what was going now? Then it was recognized that the more full and complete, and more difficult, full quantum theory of light was necessary to explain the results. HBT then were recognized as the first to identify a way in which the true and real quantum nature of light could be established. Now I had always thought that Einstein did that already with the explanation for the photoelectric effect, but what the experts now say is that the effect just showed was that the atoms in the metal could have been responsible for the quantum effects and it didn't complexly identify the quantum nature of light. So, again we have an example where the study of large objects like stars, leads to greater understanding of the very small. The quantum nature of light was only completely proved when the accuracy and resolution capability of techniques improved enough to show that the quantum description of light was needed to provide a better fit to the data than was possible with the classical electromagnetic wave theory of light, which works perfectly in all the other domains in which it is tested.
Ok, ok, hopefully the June gloom will fade away and we amateurs can get out and look up. If not we can do more physics, right? Hey it's not my fault if the weather doesn't cooperate. By the way, I discovered another ally in encouraging us to study and learn more physics. I saw on The Good a Morning America show, the Aussie pop rap singer, Iggy Azalea, sing her lyrics to the new release "Fancy". Well, a lot of the words were muted for the TV audience, but one part goes something like "I want to hold you down and teach you physics". Hey, she wouldn't have to hold me down, I want to learn more physics, but if you folks are resistant to learning more physics, well, we will just have to send Iggy over to your house. Now, I know a lot of you readers and amateurs are old folks, well at least as old as me, so I found a video from Jimmy Kimmel show where he translates Iggy's lyrics for the old folks in the audience. Yes, it seems she has a goal of eventfully being a teacher after she finishes her music career. So, in conclusion, check out the funny Jimmy Kimmel repartee at: