JoeSchmuckatelli

Gotta love a vehicle where the driver is in the back and can't see where he's going.

How much actual rotation of a galaxy's stars can Hubble resolve? (*Edit: star's travel around it's galactic center, not stellar rotation itself) FWIW - googling gets me a bunch of old images, simulated images and pictures with graphs. I'd actually like to see date stamped images so I can see if I can see what the articles describe - - or learn if the distance is so great that we can't tell the motion optically and must infer it from other data. Edit 2: this is cool Spacecraft Flies Through Dusty Tail of Exploded Comet in Unique Chance Encounter (msn.com) Oddly they got magnetic readings from the remnants

We basically got a nicely done ground-cam that watched the thing take off and was pretty much able to resolve the entire flight (glowing blur at altitude). Cam switched to a chase which then introduced a delay on watching the landing. Apparently they wanted to control the story if things went bad. No Branson-esque "Whee - look at us in spaaaace!' footage, and only a very brief SX-style 'look at the planet past our rocket's butt shot.'

Glad to see that I'm not alone in being disappointed by no on-board flight images (except for one very brief look at Earth from the ship at altitude. Still - a great thing to watch!

Grin - this is the general science part of the forums, so it's good to check. As noted, far more educated members than I have the answer!

That looks like Pete's Dragon https://www.pinterest.com/pin/402650022914013090/

Not a chemist, but I suspect it is determined by the chemistry of the LF and how it oxidizes Got a particular LF in mind?

Are they required to use SLS to get funding?

"Freak out the neighbors" Roger that. Space planes can still do that one critical role.

About two decades ago I tried to do this with some reaaaaally old (but new at the time) software that plotted stars and gave a 3D representation of where they were. Was a truly cool program, for the time. I appreciate the answer: tells me that things have not gotten 'simple' after all this time!

Can you do jumps like this to 18 Sco?

..... New Question..... With China and the US (RU too?) currently flying reusable, autonomous VTHL craft - what is the cost effectiveness of the spaceplane these days? SX is presumably cost effective reusing boosters - but every criticism of Shuttle begins with cost and the slow turn around. Have these new designs solved those problems? Is the reusable spaceplane more cost effective as a terminal delivery platform than what SX (and others) are doing now?

What is the dirt crater?

I read an article about this a decade or so ago - presumably quite a bit of efficiency was anticipated. The problem I heard with Osprey and other TR designs was that everything was fine until it catastrophically wasn't. (Note: this is different from the normal kind of plane or Helo problem where people can survive the failure - Osprey wanted to take people with it when it died) IIRC it took a bit of luck and inspiration to get around the problem. - Osprey initially also used a fraught drive shaft design that both contributed to the problem and hid other problems that had to be solved before it became capable. In other words, they fixed Osprey and it kept killing people. Now apparently, it does not - but it remains maintenance intensive. Despite all of this - I remember being pretty excited about the potential at the time. It finally entered service just after I left the Infantry - and I remember being disappointed that I never got to ride one The MC consoled me with a tank, however, so it all worked out!

Elegant answer - thanks. My 'Makes me wonder' posit was more about general planetary cooling - yes, an aside from what we've been discussing - meaning, if internal radiation is the cause of our heat, and lunar tides are so negligible, what does Earth's 'cooling to a hard rock' timeline look like compared to the time it will take for the Sun to reach Red Giant stage? I.E. whether Earth's core will remain hot and relatively liquid / active (meaning it could conceivably retain an atmosphere, and life) for the next 5.4 billion years, or if it will have cooled to a rock before the Sun morphs into a Red Giant

Huh. I pick through articles like this (mind you, grasping only generally the detail they try to explain) and I see that there is some speculation that lunar tides can affect already pressurized volcanic systems: Effects of tidal stresses on volcanic activity at Mount Etna, Italy - Sottili - 2007 - Geophysical Research Letters - Wiley Online Library This comports with some of what I've read about the mantle convection* (e.g. ms3.dvi (yale.edu)) - but its interesting to me that they simply do not even mention tidal effects. I would think that with an essentially fluid body (at scale) with a semi-rigid crust, that significant tidal pressure from the moon might at least contribute to 'stirring the pot'. This article, OTOH talks about how Earth tides keep the Moon's core warmed up: Still hot inside the Moon: Tidal heating in the deepest part of the lunar mantle | NAOJ: National Astronomical Observatory of Japan - English ...and while it does not mention the Earth being warmed by the Moon (aside from some weak implication for further research at the end) - it does make me wonder whether the Moon's influence does contribute to keeping our core hotter than it would be without such a large moon. The thing I find interesting is the absence, at least from my reading, of papers saying - 'nope, the Moon does not heat the Earth's core' or - 'Earth mantle convection moderated by Lunar tides' ...makes me wonder whether the big convection papers are even considering the possibility, even if it were only to discount it. *Makes me also wonder if the Earth's heat is almost solely due to radioactive decay and internal convection, whether the planet will survive 'alive' long enough for the sun to reach its Red Giant stage - or if it will be an inert rock ball like Mars well before then.

Any new word on the Environmental Review? I know SX wants to say ' don't look at that tower over there' but I'm not sure the Fed is willing to ignore it.

You know - you bring up another something I've wondered about... but that our planetary scientists seemingly cannot resolve. However, first to your point about the liquid ocean tides - they do indeed lag a bit behind the position of the moon... the explanation I've received is that (effectively) friction causes the slight lag between the height of the bulge (tide) and position of the moon. Moon pulls everything up towards it, and it takes time for it to spill towards the pull, plus I'm guessing the passing of those inconvenient land masses / continents contributes somewhat to the delay in the oceanic tides. But as far as terrestrial tides: we have planetary scientists saying that tides affecting Enceladus and other moons are driving internal convection which in turn contributes to cryo-vulcanism & etc. I've yet to see anything definitive that describes the relationship between Lunar gravity and terrestrial vulcanism or continental drift / earthquakes. Logically, if the Moon is massive enough to deform the planet, it has to have some effect on those continents and volcanoes... but I don't think anyone has yet figured out what that effect is. Complicating matters is that Venus has no moon, and yet experiences vulcanism... which makes me wonder - how? Grin - Science is fun. Lots left to learn!

China's maritime innovation looks at times like watching SpaceX. They're trying lots of things. Some will inevitably succeed, as they're also doing what SX does: throw money at the problem. The USMC, on the other hand got a lot of things right a long time ago... but innovation in the US Amphibious capability spectrum basically died because of too many cooks. USMC wanted a capable ship-to-shore fighting vehicle that could replace the Vietnam-era stuff we (currently) use that had modernized comms, weapons platform and was capable of keeping up with Abrams tanks. Navy said they only wanted to drop us off over the horizon. Enter the AAAV - which did none of that well. (It had potential to be a good, amphibious, combat capable troop carrier... but trying to also make it hydroplane from OTH? Nope.) Recent experience in our 20+ year adventure introduced the concept that RU Anti-Armor weapons (and presumably CN) exported to everyone meant that Armor was on a down-tick in the perpetual arms race. No one seems to be spending money in the US (yet) to figure this out - but the USMC, having dumped a LOT of weight in the last year (Armor, Arty, MPs, etc) looks to be trying to figure out what the future of American Amphibious Warfare might look like - however we have yet to see what tools / doctrine will emerge.

Tilt rotor aircraft are very difficult, from what I understand.* Prior to fleeting them, they enjoyed a well deserved bad reputation for killing crews and in a not predictable manner. People designated 'crew' and their extended families did not appreciate this and expressed themselves until the 'engineering difficulties were solved'... and now they are all over the place (in the USMC - the Navy gets theirs soon). However "The MV-22 Osprey has a dismal mission capable rate hovering near 60 percent, according to data from the Marine Corps. Corps officials say that mission capable rate is an increase from the low 50 percent levels maintained throughout fiscal year 2018" https://www.marinecorpstimes.com/news/your-marine-corps/2019/06/24/despite-massive-show-of-air-power-nearly-40-percent-of-marine-corps-mv-22-ospreys-are-not-mission-capable/ So as you can see - there is nothing to worry about and more nations should invest in the clearly capable technology! *This 'understanding based on client-side observations rather than manufacturing knowledge. Given that client side users rarely donate to Senate campaigns quite as aggressively as Defense Manufacturers, Client - Side concerns are of no importance when deciding whether to fleet a given miltech

I had not thought about driving tides of the same magnitude via having the smaller moon inward of the larger - or tweaking mass like that. I'm guessing what @tomf described is exactly what I was thinking: a larger inner moon and a smaller outer. Without knowing - is it a fair guess/prediction that such an arrangement might have lower overall amplitudes but sharper delineations?

I've really enjoyed perusing the graph you presented! Interesting to see that there are periodical, off-beat pulses here and there: i.e. the tides at and around the lows at 500 and 1120 (x) are quite distinct from one another. I can only imagine that such a planet would experience some very interesting coastal weathering and have periods of quite variable pelagic navigation (sometimes open water - other times vicious shallows). 3890 shows a single big pulse in the high (above 1.5) where most other parts of the graph get a double high that barely reaches 1.5). With the lowest lows looking to be ~ 0.3, the highest highs (globally) are over 5 times that of the lowest lows - and that's before you take into account shorelines or sea floor. Probably be an interesting place to visit: heck of a place for a surfing competition! There's also a 10 month cycle between the highest Spring tides - which would probably have some form of cultural significance to any intelligent life that evolved there (or lived there long enough). Thanks very much for the time you (and others) took to answer this for me!

Or it was that guy from the 70s Show and his wife talked him down

Huh... I figured that the larger moon would have to be at 90 and the smaller at something like 45 to the sun for the smallest tides. (both at 90 keeps the smaller aligned with the sun) This is one of those things that's easy to forget - until you look into the Big Wave competitions in Portugal, as well as some of the larger river tides (can't think of the names off the top, but there's a well known one in Canada, an impressive tide in China and IIRC something really interesting in Scotland. One of the things I was trying to picture was whether something like a 3:2 resonance would work... and then if so, how often you'd actually get all three tide-ing (??) bodies aligned. If the larger moon were on a similar 1-month (ish) orbit, how do I figure out how often in a year one could expect all three to be aligned to tell prospective surfers and fishermen when to expect Spring tides? (oh - and thanks for the response!)

Okay - except SpaceX.... so it will look like this: