michael_w_busch

michael_w_busch, 1 month ago

@jdnicoll @nyrath My liking Hal Clement's "Still River", about a bunch of planetary science graduate students who make in-retrospect-obvious mistakes, may have something to do with my having once been a planetary science graduate student who made a few in-retrospect-obvious mistakes.

michael_w_busch, 1 month ago

@jdnicoll @nyrath I once spent six months working on a project that turned out to be impossible because the Earth has an atmosphere.

So one of Clement's alien graduate students forgetting to account for wind actually seemed pretty realistic.

michael_w_busch, 1 month ago

@jovikowi @nyrath There continues to be no "Space Force". There is only the USAF Space Command - the same units doing the same things.

And they and their counterparts among other nations' militaries are unconcerned with anything beyond about twice geosynchronous distance.

michael_w_busch, 1 month ago

@sudnadja @jovikowi @nyrath That somewhat demonstrates the point that more distant things are only picked up by military sensors by accident.

Similarly; military surveillance for atmospheric explosions is not intended to and does not provide reliable trajectory information for incoming meteoroids. Despite one person at Harvard who pretends otherwise.

michael_w_busch, 1 month ago

@sudnadja @jovikowi @nyrath The CNEOS fireball list includes information from a variety of DoD spacecraft sensors from the late 1980s onwards. I understand that those include sensors designed to detect atmospheric nuclear detonations (distinguished from impacts by the distinctive double flash).

I am not authorized to know exactly which sensors detected which events.

michael_w_busch, 1 month ago

@foone @cstross It is not advertised; but launches from the United States are all supervised by Range Safety Officers either from NASA or from the DoD.

Said officers have the control for the redundant flight termination systems and will blow them up if the rocket goes off even slightly off course.

(Example: line charges running up the side of the booster, which will rip it to pieces when they are set off.)

michael_w_busch, 1 month ago

@nyrath Me, an asteroid scientist:

Lutetia does not look like that - https://en.wikipedia.org/wiki/21_Lutetia

But the concept art shows that this is not a hard scifi show, so that is not really a complaint as much as a contrast with "The Expanse" - where I enjoyed seeing the actual asteroid shapes on screen.

michael_w_busch, 1 month ago

@nyrath Eros is the most notable example where "The Expanse" included the actual shape of the asteroid. They used data from NEAR Shoemaker as a base and superimposed the station with it.

As an aside:

Andy Cheng, who later developed the #DARTMission to demonstrate asteroid deflection, was the project scientist for NEAR.

So Eros changed everything.

michael_w_busch, 1 month ago

@sudnadja @nyrath There is a shape model available from the DART images of Didymos, but the approach sequence necessarily only covers a bit less than half of the surface (Daly et al. 2024 - https://iopscience.iop.org/article/10.3847/PSJ/ad0b07 ).

For a full model (of the post-impact shape) and direct gravity field, you must wait for Hera.

Similarly; I do not begrudge the animators for "The Expanse" swapping in the shape of the near-Earth asteroid Bennu for that of an unspecified small main belt asteroid.

michael_w_busch, 1 month ago

@nyrath The Psyche spacecraft is on its way. In the meantime; Mike Shepard & Katherine de Kleer have the best shape model we can get - https://iopscience.iop.org/article/10.3847/PSJ/abfdba/pdf .

For Deimos; Carolyn Ernst has provided the best model from current spacecraft data - https://earth-planets-space.springeropen.com/articles/10.1186/s40623-023-01814-7 .

Further updates must await MMX.

michael_w_busch, 1 month ago

@jni @vicgrinberg @muellerwhh The dark forest idea in the second book of the series does not work.

If the assumed hostile aliens existed; they would already know we were here.

And, per the problems with depictions of physicists:

I, a radio and radar astronomer, saw the mutually assured destruction final plot twist in "Dark Forest" coming within 5 minutes. There was no need for any character in the book to tolerate or enable Luo Ji to figure that out.

#3BodyProblem

michael_w_busch, 1 month ago

@muellerwhh @jni @vicgrinberg Among the problems with "Three Body" and "Dark Forest"; Liu Cixin did not inform himself that well about how people do radar astronomy and radio astronomy or about how people have imagined SETI over the past 60 years now.

In the scenario he set up; any of a long list of current radio telescopes (military as well as civilian) could be set to track the galactic plane at any time and run hot, ready to transmit within seconds - and some of them would be.

#3BodyProblem

michael_w_busch, 1 month ago

@vicgrinberg I wrote up some comments on "Three Body" when I first read it in 2015: https://clementsgame.wordpress.com/2015/08/08/science-fiction-round-48-three-body-problems/ .

And refer also to @rr4idic 's comments on "Dark Forest" when it came out later that year: https://clementsgame.wordpress.com/2015/09/20/science-fiction-round-49-the-dark-forest/#more-3429

michael_w_busch, 1 month ago

@nyrath One peculiar thing about that particular article from Sierra Space is that it is not even something that military organizations have much use for.

The company seems to just be following how so many resources go to militaries rather than to other things.

So. Yeah.

michael_w_busch, 1 month ago

@SFRuminations @nyrath I had thought that the future James White envisioned on Earth in "The Dream Millennium" owed more to his writing it in Belfast at the height of The Troubles.

But it is an effective counterpoint to Heinlein.

michael_w_busch, 1 month ago

@SFRuminations That is the one of White's novels that I never managed to find a copy of.