It was bound to happen at some point, that episode that’s just a hodgepodge of short, random bits of crä-crä that I put together as a clip show. This one features five bits of silliness — or maybe six, I lost count. Big-name stars you may remember from other episodes are Brooks Agnew and Gregg Braden, but making their first time appearance we also hear from Christopher Knight and Alan Butler, Ken Parsons, and Jeffrey Grupp. Coast to Coast AM clips feature heavily, so if you don’t like ’em, you may want to skip this episode.
Other segments were Announcements and a Puzzler. You’ll need to go to about 24 minutes into the episode for the puzzler, it’s not in the usual place.
Exposing PseudoAstronomy 
I’ve just downloaded the podcast and skimmed the shownotes. It’s interesting to again note the interface between pseudoscience and science fiction. The claims by Knight & Butler remind me of a Larry Niven short story “Wrong Way Street” in which an astronaut discovers a time machine on the Moon and in experimenting with it accidentally destroys the Moon preventing the evolution of life on Earth.
As for clip shows, this is yet another case of the Americans taking a good(?) idea from another country and running with it. The late Gerry Anderson had a clip episode in all of his puppet series, though he had the wit to vary the circumstances each time he used the concept. The best was probably the final episode of Captain Scarlet, in which a character is confronted by security operatives who claim he is an imposter and must prove his identity by descibing things only he would know about, the clips then follow.
Comment by Graham — February 2, 2013 @ 1:05 am |
A reference to Gerry Anderson and Captain Scarlet in a comment on a Exposing Pseudo Astronomy episode. I think that completes my day. I’m happily going back to bed, my geekout quota filled for the day.
Comment by Johan™ Strandberg — February 2, 2013 @ 9:17 am |
The density of stupid is amazing in the clips on this episode. I just don’t understand how you can stand the Bogon flow at Coast to Coast AM. You must have some special powers Stuart.
Comment by Johan™ Strandberg — February 2, 2013 @ 9:20 am |
Another neat example of technology enabling is the Hawk-Eye and Shot-Spot computerized video systems for line judgement in sports, particularly tennis. Until 2006 no such system was considered reliable enough to use for definitive line calls. The technology improved to the point that the instantaneous position of a tennis ball could be determined with error < 2mm, and the system has been a feature of major tournaments ever since.
btw I'm a tennis fan and IMO the new rule allowing players to challenge line calls (within limits) has greatly enhanced the entertainment of the game.
Comment by Expat — February 2, 2013 @ 10:52 am |
I just came across a nice NASA Goddard video http://youtu.be/UIKmSQqp8wY on crater formation on the moon. Did you have a hand in this? I’m not exactly sure how the LRO contributed to the science behind the video. You have discussed lunar formation theories and the various bombardments (early, middle, late, big, small, inconsequential, ziggurat, etc.) in earlier shows, so maybe all this is covered, but if there is new science here, I would be nice to have it explained.
There isn’t really a good link to the specifics on the Goddard page for the video http://svs.gsfc.nasa.gov/vis/a010000/a010900/a010930/ other than a hint that the animation used the elevation maps from the LRO, so maybe this is just eye candy. Also, the ejecta from the impacts doesn’t look quite right. I thought that when these very large impacts occurred, they resulted in large fallout of debris at the antipode of the impact, or is that only on bodies with atmosphere like Earth? In the video, the ejecta looks hand animated (pretty, but about the same size regardless of impact size) as opposed to simulated. Assuming there is an antipodal fallout effect even without an atmosphere, is there evidence of ejecta depositing on the oposite side of large impacts on the moon?
I’m probably just showing the true depth of my ignorance here, but wouldn’t the LRO elevation data be a great way for showing such deposits by statistical means, even if they are not showing up as a visual feature? I.e., is there on average an increased altitude at the antipode of impacts?
–j
Comment by Johan™ Strandberg — February 3, 2013 @ 2:08 am |
I reviewed the movie on another blog a few months ago. I think one thing to answer several points you made is that this was done in animation software, it’s not a full physics-based simulation. It’s what you’d use to make a movie like Toy Story or Cars. So, no, the ejecta was probably modeled as a particle cloud constrained within a spherical shell.
That said, ejecta does not primarily get deposited on the planetary antipode. The vast majority gets deposited within 1 crater radius of the crater rim (the “continuous ejecta blanket”). Beyond that, ejecta deposits are pretty thin. You may be thinking of the idea that when you have very large impacts (forming >1000 km craters), you may get some seismic activity at the planetary antipode that could make chaotic terrain.
Comment by Stuart Robbins — February 3, 2013 @ 3:10 pm |
Thanks for the pointer to your review. It answered a bunch of questions including some I didn’t even ask above, like, “What made the Ray Craters so special.”
The reason I thought eject from VERY large impacts collected at the antipode is descriptions of the Chicxulub impact crater. I have heard it mentioned several times in recent years, but the reference I can pull up right away is a talk by Dr. H. Jay Melosh where he mentions a full orbital simulation of the ejecta (starts roughly at 26:00 in this video http://youtu.be/d8AAdjMwjVs?t=26m )
I have no idea how controversial his theories are, so in this case I’m only quoting him on the orbital mechanics of the ejecta, not the greater question of atmospheric heating from the re-entry of the ejecta.
Obviously this mechanism would only be relevant for large (energetic) impacts, but the Moon is a far smaller body than the Earth, and some of the early impacts (like the SPA and some of the impacts during the Heavy Bombardment) are really massive. (And thus atypical.)
Looking around, I found “Antipodal effects of lunar basin-forming impacts: Initial 3D simulations
and comparisons with observations” http://goo.gl/UedUJ that also mentions “[…] coincides with a period when impacting ejecta also converge near the antipode.” So obviously there is some antipodal effect once the ejecta gets lifted high enough.
I also found a paper “Tycho crater ejecta” http://goo.gl/A4uoT where the authors are modeling ejecta from Tycho and are specifically mentioning that the LRO had located a region antipodal to Tycho that _might_ contain possible deposits of material from that impact.
Since I am not at all familiar with the field, this is for all practical purposes this is just a random walk by googling — A.K.A. Google assisted ignorance amplification.
I’m interested in your comments.
Comment by Johan™ Strandberg — February 3, 2013 @ 5:31 pm