Well its mostly cloudy with a bit of rain here at the observatory and so no observing for these few days. Actually, there could have been a little bit of observing lightning flashed early in the morning if you are into that kind of thing. It was pretty exciting since we normally don't get
a lot of lightning. Anyway, we are planning to get some real dark sky observing when we attend the Nightfall 2016 party in Borrego Springs. If you want to get in some dark sky desert observing this weekend, October 28-30, check out the details for this mostly free event at: http://nightfallstarparty.com/
So, get yourself and scope to Borrego Springs. We like being able to walk from our reclining chair setup for binocular viewing and our scope tripod setup to the hotel room without having to drive dozens of miles in the dark. We can walk to the restaurant for food and drink (well, actually we have to drive about a mile to downtown Borrego Springs for a really good martini). So get yourself to Borrego Springs in your RV or just setup your tent in the RV park or nearby campgrounds and have some good dark skies.
Ok, ok, if you are not up for that because you are overwhelmed by this political election season, you might want to check out this TED talk, actually just a TED read, on how to talk about politics constructively.
Ok, ok if you not that into politics and just want to drive to an apparently very good lecture series then check out this set of five public free lectures at UC Riverside starting in December. The lecture series entitled "Are we Alone?" and are presented by the UCR Alternative Earths and Astrobiology Center. Thanks to Science Squad Gravity Guy, Ken, for this reference. Now, I don't mind driving a little bit for physics colloquia at UCI and CSULB, but getting to Riverside for an hour lecture might take a little more than an hour, but fortunately the UCR lectures will be videotaped and available (eventually) online. Thanks for the tip, Ken! I'm not sure if I can make it through the freeway construction in Corona, but if you go be sure to check out the graphic description of the construction zone in the September 16 post so you will know what you are in for.
For more information, please visit the UC Riverside Science Lecture Series website at: http://cnas.ucr.edu/sciencelectures/
Now we should cover at least a little astrophysics since we don't have any astrophotos to share this time. At the recent AAS meeting, I picked up a great reference book on asteroids. See below.
|Great reference book (almost 5 lbs and 900 pages) about latest details on asteroids (University of Arizona Press)
Now for me, I just sort of understood asteroids as some chunks of rocks orbiting somewhere between Mars and Jupiter and were probably a failed planet that was disrupted by the gravitational effects of Jupiter. Now, I've actually started to take images (well just a few pixels) of asteroids and in reading up about them find them to be really interesting. Especially now given that we saw in the October 21 post that the paths and orbits of asteroids are subject to non-gravitational Yarkovsky and YORP forces that change their orbits and even spin them up rotationally such that they actually fly apart and self destruct. This makes it possible for asteroids to move along paths that intersect the Earth's orbit. Fortunately, the orbits of asteroids can be tracked by telescopes, including the Arecibo radio telescope. Now, the asteroids have been investigated with robotic spacecraft and their geology and makeup identified. Now planetary scientists are using asteroids as a probe into better understanding of the formation of our entire solar system.
Check out the chart taken from just page 20 of that book. This chart is just sort of the introduction to some of the other discussion to be found in the rest of the book, but to me, that one chart summarizes a lot about how the two main theories of solar system development, the Grand Tack model and the Nice Model, describe first of all how the large gas planets, and to some smaller extent the large ice planets also, are conjectured to have formed at some distance from the sun, and then moved closer in toward the sun, almost to the orbit of the Earth, and then moved on this so called "grand tack" back out to where they are found today.
All of this motion, caused by gravitational and other interaction, resulted in the accretion disk being disrupted and many objects and mass were thrown about, some constituting the late heavy bombardment inward and ejection of more mass outwards, apparently to form the Kuiper belt and beyond. I certainly don't understand yet how the interaction of gravitational forces and conservation of angular momentum interact to cause some planets to move inward for some time and then move back out again, all the while throwing some other objects inward and some other objects far out in the solar system. It also involves somehow the gobbling up of gas and material and clearing out the accretion disk and the interaction of remaining objects with each other in complex resonances in their orbital elements.
Here is where the history and evolution of the asteroids plays a key role in that the Grand Tack model is constrained by the size of the min asteroid belt in the early history of the solar system and later solar system development as described by the Nice model, is similarly constrained by the size of the main asteroid belt. Apparently there is some conflict in getting just one size of the main asteroid belt to fit both of these theories. I assume that a big portion of the book goes into the new findings about the asteroid belt
|Asteroids provide constraints on solar system formation models (Courtesy Asteroids IV, University of Arizona Press)
Finally, considering all of those unread pages gives me pause and a headache and since we had clouds out and about, Resident Astronomer Peggy and I decided we needed a night off and took in a Halloween party at our community clubhouse. It was a lot of fun and a perfect ending to the week that included travel to the AAS and dealing with the water repipe work and having to miss the OCA Black Star party.
|Palmia Observatory Resident Astronomers take the night off for fun!
See you all in Borrego Springs. Hope the desert weather is cloud free!
Until next time