Space Marvels - galaxies, space-power, "my" asteroid... and comets...

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One of the best things I have ever watched: Invest four minutes for the video clip Wanderers! This -- rather than anger and cynicism -- is what being human must be about...or else, why bother?

Oh, also note: almost all of the places depicted here are real. Many of them extrapolated from photos taken already by our robot emissaries. “We” have already been to these wondrous spots. We are already titans!  On our way to unimaginable greatness.

(Though I will keep trying to imagine.)

== As we move ahead... ==

Could life exist in the Kracken Mare Sea on Titan?  I am working on stories… but right now I am simply jazzed by this image… sunlight glinting off one of Titan’s “seas” of liquid… methane? Ethane? Gasoline?  Take a look at the video: NASA's Cassini captures sunlight glinting off Titan's seas.

You are a member of a civilization that does stuff like this!  Stop letting cynics and fear-mongers undermine your confidence in us.

NASA's New Horizons spacecraft comes out of hibernation on December 6 -- in preparation for an encounter with the dwarf planet Pluto. Closest approach will take place in July. 

NASA/JPL have just released a gorgeous new high-resolution image of Europa -- its icy surface crisscrossed by cracks and ridges. Beneath its icy surface, Europa may have more liquid water than Earth. In NASA's video: Europa: Ocean World, astrobiologist Kevin Hand discusses the possibility of life on Europa. Phil Plait’s “Bad astronomy” site offers a cool riff about a possible mission to Europa. 

It is estimated that Europe’s new Gaia probe will have discovered some 20,000 Jupiter mass exoplanets by the time it completes its survey in 2019. Unlike the transit-eclipse system used by the Kepler mission to discover most of the 2000 or so confirmed exoplanets, Gaia will use the astrometric measurement technique, where planets around another star show up as a tiny wobbling motion of the star as the planet orbits around it. Somewhat less likely to discover Earthlike smaller worlds, Gaia will be far less dependent on just happening to find systems whose ecliptics are lined up toward us.  It will also be far better at detecting planets that orbit farther from their star.

Here’s a fascinating astronomy blog that takes on some big topics. This particular posting tells of Antarctic lichens that seem to have adapted well to  Mars-like conditions.... amazing in its tentative implications.

== New Insights into Galaxies ==

Scientists believe a mysteriously bright object in a galaxy 90 million light-years away could be a rogue black hole evicted during the merger of two galaxies.

A really thought provoking paper suggests that of the estimated 100 billion galaxies in the observable universe, only one in 10 can support complex life like that on Earth. The reason, most other galaxies are either smaller or lower in “metalicity” and therefore have many more Gamma Ray Burst events that can destroy the ozone layers of life-worlds for thousands of parsecs in all directions, conceivably knocking down all but the most primitive, ocean dwelling organisms, making galaxies resemble the image Isaac Asimov portrayed in his novels, one with scads of biospheres, owned only by single cell life forms.

Short gamma ray bursts last less than a second or two; they most likely occur when

 two neutron stars or black holes spiral into each other. Long gamma ray bursts come from supernovae.

Tsvi Piran, a theoretical astrophysicist at the Hebrew University of Jerusalem, and 

Raul Jimenez, a theoretical astrophysicist at the University of Barcelona in Spain, 

explore that apocalyptic scenario in a paper in press at Physical Review Letters.

Compared with the Milky Way, most galaxies are small and low in metallicity. As a

 result, 90% of them should have too many long gamma ray bursts to sustain life, 

they argue. What’s more, for about 5 billion years after the big bang, all galaxies were

 like that, so long gamma ray bursts would have made life impossible anywhere. And inward of 10,000 light years from the center, our galaxy is still dangerous.

Researchers sending up NASA’s Cosmic Infrared Background Experiment on short duration rockets  have discovered something remarkable in the universe's diffuse background light: As many as half of the stars in the universe may have been stripped from their home galaxies and flung into space. Studying the extragalactic background light, Caltech astronomers  say there's just as much background starlight coming from these dim rogue stars as is coming from all of those giant galaxies.

== Reaching toward the sun ==

 A probe will be sent to visit the Sun.  I am interested - of course - in any human effort to … er… sun-dive.  Only there is an interesting design twist here.  Solar Orbiter will have a titanium foil heat shield on the outside painted black, with a hint of charred animal bone.

A very interesting exploration by Keith Henson of the economics and practical aspects of   lifting to GEO a solar power satellite system whose first use would be to laser heat the exhaust of Skylon lifters taking yet more solar power systems to GEO.  A bootstrap method that could (in theory) soon result in vast amounts of clean energy coming to us from the sun... via our collectors in space.

Some portions of this method have received preliminary seed grants from us at NASA NIAC. But many other sources will have to solve many puzzles along the way. It's good to have folks pushing this... while others push to make it unnecessary by vastly improving solar here on Earth.

== Comets and Asteroids ==

Given the results that have come in from the Rosetta Mission's rendezvous with a comet, I thought I'd offer you all a glimpse at my 1981 doctoral dissertation! It dealt with what happens when an icy mix of volatiles and grains gets heated from above. Naturally, some volatiles (e.g. water) sublimate and leave at high molecular velocities -- that get higher as the comet approaches the sun. Large dust grains may stay put but smaller ones get entrained into the escaping stream and become part of the Dust Tail. (Comets have two tails.)  

This means a mantle or coating layer of larger grains starts to build.  This will eventually be thick enough to shield the virgin material, slowing down the rate of sublimation.  Like a thermos coating. But the comet is heading sunward so the grains get hotter and a wave of heat penetrates inward, causing a delayed but large pulse of sublimation which will, here and there across the surface, cause an explosive blow off of the covering mantle, resulting in a surge of heavier grains in the dust tail and venting off pressure from an area.  Some of the heavier grains then rain down elsewhere on the comet surface, causing some areas to build such big layers that they choke off, semi permanently.  When this happens everywhere, the comet goes dormant and begins to resemble an asteroid.

Note that the one visited by Rosetta -- 67P/Churyumov–Gerasimenko -- is not a virgin but has gone through a number of perihelion brushes with the sun, so it's been baked a fair bit. Oh, if only the harpoon anchors had worked to dig the Philae lander onto a good vantage point! I fear that the little lander may not get enough sunlight to do much more science.  And even if it does, those gases shooting out of the mantle layer will likely blow the poor thing into space, before any of the real action starts.  At which point we'll still have the main Rosetta Orbiter...

... for which I am grateful! It's always nice to see your graduate work confirmed, At least superficially, it looks like I shoulda stayed in comet studies.  I was on a roll! Could have evaded the sci fi rat race....

== More personal news from outer space! ==

My own asteroid had its closest approach to Earth on November 18. Asteroid 5748 Davebrin passed within 1.256 AU for a summer that's actually pretty balmy and close.  So close that humanity might someday include it in efforts to access the fantastic riches out there.  May it be disassembled and turned into wonderful things! I just have two wishes. 

First, to share in the action! Hey, I got a claim.

Second? To go out there in person and kiss my...

...oh, never mind. ;-) May you ALL get your own space rocks.  

And each live for fifty more of its orbits.