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While these articles are not space news, I will include them here, because railguns play a big part in my Star Hero campaign. Besides, I have posted railgun-related links here before. I have cross-posted these links in the "In Other News" thread on the NGD.

 

US Navy's railgun project hasn't made a lot of progress

 

On the other hand,

 

China's railgun project may be ahead of schedule

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On 2/6/2019 at 1:54 PM, DShomshak said:

The Feb. 2, 2019 issue of The Economist has three space-related articles:

* A proposal that x-rays might be better than radio for interstellar communications. They spread out  more slowly, don't scatter as much, and there's a whole lot less natural x-ray sources to mask messages.

* A bit of rock brought back from the Moon by Apollo astronauts may originally have been a bit of the Earth. The two-gram grain from the Fra Mauro highlands is a bit of the slashed debris from the Late Heavy Bombardment impact that created the Mare Crisium. The zircon and quartz grains in the rock, however, are of a sort unlikely to have formed in Lunar conditions; they more plausibly formed on Earth. (The brief article doesn't say what features lead to this conclusion.) So, one LHB impact could have splashed the rock from Earth to the Moon (which at the time was only a third its current distance); then another impact put it on the Fra Mauro highlands; and now it's back to its planet of origin. This interests geologists, because the Earth has very little rock that is relatively unchanged from that long ago. (You can judge the rarity by geologists considering being through two massive impacts still "relatively unchanged.")

* And an article on Pentagon proposals for laser-armed satellites to shoot down missiles, in the latest iteration of "Star Wars" missile defense.  The article notes the vast expense of existing missile defense, the likelihood that it would fail against relatively small numbers of missiles, and a "detailed and scathing" analysis of boost-phase interception that the National Research Council produced in 2012. I simply remember a Scientific American article from the 1980s that concluded the laws of physics make any space-based missile defense system, well, considerably harder than advocates make it sound.

 

First item: interesting, but one difficulty is that both broadcast and reception must take place from orbit or the surface of an airless moon or asteroid, since X-rays don't make it through any appreciable atmosphere.  Not an insurmountable detail, but it is an extra step that isn't there for either radio-frequency or visible-light signals.  If you're sending interstellar signals, it's not clear to me how the economics would work pushing you either toward or away from X-rays.

 

Second item: Saw this, and if it works out correct that's a very interesting source of ancient Earth rocks.  I have the impression they have a lot more work needed to establish the terrestrial origin securely, though.

 

Third item:  This again?  Anyone who was paying attention back during the Reagan Administration remembers that building an effective, genuine ABM defense system is exceedingly difficult, whether you use responding missiles or directed-energy antimissile systems.  It's a nice big yummy contract to build a prototype, though, and the people pushing for such systems have the contract as their goal, not a real defense. 

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The only real way to win a nuclear war is to not start one.

 

On the railguns, it seems like they would take up an enormous amount of energy using modern technology. Can a, say, destroyer-class naval vessel produce enough to fire more than once? Would you need to fire more than once?

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At lot earlier in the thread was a suggestion that our dominance over other terrestrial lifeforms comes from our brain size.

Well there is an extensive review of our position on the Neanderthal going on in the academic community. Their tools may have actually been better so we can't claim we were smarter. They were stronger, so how come we are still here and they are gone? 

https://www.bbc.co.uk/news/science-environment-46988399

Might be luck.

 

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Ultima Thule: think coins, not spheres

 

The two bodies in the contact binary that New Horizons flew past back near New Year's ... seem not to be even approximately spherical.  Flat, relatively thin tablets seem to match the images taken once the spacecraft was past the object.

 

EDIT: There's a Whiskey Tango Foxtrot for you.

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