Sunday, February 15, 2015

"Deadliest Planets" from NatGeo, not quite up-to-date on the science


Space Vacationers put up the National Geographic documentary “Deadliest Planets”.  While It’s a little oversimplified, it offers some new material on to what you can see in planetarium movies (as on the Movies blog, Dec. 17 and Jan. 22). The link is here.
  
I had always though Mercury kept the same face to the Sun, tidally locked.  That’s not quite true, but a day is 56 earth days, and any one point has a temperature range of -350 F to 800 F. There is a very thin atmosphere even with oxygen.
  
The idea that Venus might have had water at one time is presented, but a catastrophe happened a couple billion years ago – global warming, abetted by volcanoes.  It’s possible that extremophiles could live in the atmosphere with sulfuric acid.
  
On Mars, the deadliest hazards are radiation, from the lack of a magnetic field, which could be overcome in shelter design, and the fine iron talcum powder from dust storms.
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The documentary actually looks at the atmospheres of Jupiter and Saturn, and shows what the metallic hydrogen in the core of Jupiter could look like.  But it doesn’t mention the possibility of a solid core. It does explain the Red Spot, which is actually an anti-cyclone, that doesn’t die out because there is no solid surface to provide friction.\
  
It also shows Io, where the surface heaves all the time with the nausea of volcanic vomiting, which sends dust clouds of lava particles toward Jupiter.
  
It dismisses Uranus (see notes on a short film after review of “Jupiter Ascending” Jan. 30)  but moves on to Neptune.  But newer information suggests that both Uranus and Neptune have water-ammonia mantles, that is, are waterworlds (see books, Dec. 19).
   
There is a good question, as to how to measure the diameter of a planet.  Earth measurements don’t include the atmosphere, but gas giants do, because we don’t know how deep the atmospheres are.   
There is also very interesting video of what Triton, with its explosive geysers (and resulting dust trails) looks like.  Unfortunately, the film doesn’t mention either Europa or Titan. 

See also "Alien Planet" May 4, 2012 here. 
  
Wikipedia picture of Triton, NASA p.d. photo (from Voyager 2).

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