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Comment Re:Unlikely (Score 1) 235

Nope, never been to San Diego. And while America is producing things like Trump and thinking them "normal", I don't think I'll be going.

We have huge canyons, valleys, and hills

Canyons : sites of erosion at tihs time, destroying (after exposing) the rocks and any fossils they contain. Hills similarly are sites of erosion. Valleys : sometime erosion, sometimes deposition as they transport sediment down-valley to temporary or less-temporary storage on their way to the sea. but definitely the valleys are the best chances for finding sites of deposition.

I guarantee with more ground penetrating radar or other scanning techniques there are other samples waiting to be found.

GPR - I've only used GPR down to about 40ft below sediment surface, and we couldn't get a good enough reading to be sure which structures were inclined bedding or void. not the easiest of things to interpret, as you'll know from your own work.

"Other scanning techniques?" Such as?

Still, being able to detect structure down to 40ft below surface doesn't give you permission to dig there, or the funding for the dig. Or the personnel. All the joys of trying to do science in a word of constrained funding and a population who, on average, don't give a flying fuck.

Comment Re:One very quick thought ... (Score 1) 235

Gobekli Tepe (thank you, Slashdot's non-Latin incompetence) is truly fascinating, but would only push the origin of "civilisation" back by 3 or 4 thousand years from early Egyptian and Mesopotamian cities (and since it's late at night, I can't remember the oldest of the Chinese or (Latin)American cities). A step back, but not exactly a surprising one.

But Gobekli Tepe does raise a real question. Where the fsck did the workforce who built it live while building it, and what did they eat? We may have an answer for Stonehenge (NB: "may") ; for Stonehenge's predecessors like Brodgar, we just don't know. People are looking, but ... there is no guarantee that the evidence hasn't been ploughed up in the Dark Ages. And in the Roman era. And in the mid-Iron Age.

Comment Re:One very quick thought ... (Score 1) 235

Useful points (sorry!) on knapping etc.

I was just trying to find some usabel bathymetry data for the San Diego area, and while I'm not exactly sure, at about the time of this site (accepting the dating ; I don't see any major holes in it), it was 10 to 20km in from the coast. More strictly, from the 100m isobath, as an estimate of the sealevel at 130kyr. (No, I haven't even looked for an isostatic curve for the area. Though posing the question does suggest where to start looking.)

Comment Re:AI killing industry (Score 1) 121

A combination of art and science will eventually be able to produce completely convincing audio forgeries

"completely convincing" against what level of sceptical and detailed investigation?

(I'll admit that in contravention of my normal habits, I haven't RTFA, or even tried to find the origina source. But since I've got two hearing aids in as I type, and have never in my life understood why people waste thier time with music, I doubt there'd be any point in listening to any sounds in the report. I often can hardly recognise what I'm saying, let alone anyone else.)

The world of tricking politicians and press offices with Photoshopped images has been going on for ... about 3 days fewer than Photoshop has existed. And the same practises happened in decades and centuries before then - not excluding my crude darkroom efforts for the rag mag (you remember - dark room full of trays of chemicals. NOT the software!) or Holbein and the infamous Mare of Flanders. And just as long, more skilled operatives have been detecting the fakes and exposing them. Having had to do some photo-interpretation for mapping, I've had to pay a bit closer attention to photographs than most people, and I know I'm not particularly skilled or experienced at it. I sometimes wonder how thick some of the people who get fooled by the worse forgeries can be.

So, these first - well, most-recent - efforts at voice synthesis are not particularly convincing. But they'll improve. And the people detecting the fakes will improve. It's what's called an "arms race".

Comment Re:Speaking of delays... (Score 1) 106

ULA's track record with the Atlas V: 100%

Yes, let's take one vehicle in its fifth generation (not counting subrevisions), and ignore its track record with all of its earlier versions that led up to this point and all of their failures, and all of Lockheed and Boeings' other launch vehicles over time, with all of their failures. Lets also ignore that they're going to have to switch engines soon, to an engine with zero track record.

Payloads typically launch on schedule or within a few weeks. .... Some payloads have been waiting literally years due to delays.

Let's totally ignore that Atlas V launches once per two months, while SpaceX launches once per month, and that almost all of the wait time was due to investigation backlog. When it comes to hitting launch windows, SpaceX has a higher average success rate than average than Atlas V

And lets entirely fail to mention the point that ULA charges nearly double what SpaceX does per kilogram. Or that SpaceX is doing everything while rapidly evolving its rocket, to the point that they've basically even switched propellants partway through (denisification radically changes their properties). And while at the same time running an aggressive recovery and refurbishment programme and developing a heavy lift vehicle, with a small fraction as much capital.

Comment Re:What governmen brought to the table (Score 1) 106

As if liquid boosters can't fail catastrophically? Check out SpaceX's last failure. Liquids are hardly immune to catastrophic failure.

And actually more to the point, you've got it backwards. The SRB failure on Challenger was slow, more like a blowtorch. The explosion was when it compromised the external tank (which, obviously, stored liquids).

Solid propellants aren't like explosives. More to the point, you have to keep them under pressure to get the sort of burn rate that is desired for a rocket.

Comment Re:Speaking of delays... (Score 2) 106

Could you remind me how many people SpaceX has killed? Boeing and Lockheed have certainly killed people in the past.

If you're referring to the AMOS 6 ground failure, ignoring that part of the whole point of flying a stack unmanned as much as you can before you fly it manned is to shake out any problems, is that a manned mission would have almost certainly survived that. Unless the launch escape system failed, despite the drama, that was an eminently survivable. How do we know this? Because AMOS-6's hypergolic propellant tanks didn't ignite until the satellite hit the ground. AMOS-6 had the fairing as some extra protection, but on the other hand, the satellite itself isn't nearly as durable as a crew dragon.

The launch escape system ignites within milliseconds of a failure being detected and almost immediately reaches full thrust, accelerating away at 10gs. Here's a graphic of Dragon's abort test superimposed over the AMOS-6 failure. Things like this are the very reason that launch escape systems exist. NASA's last manned space vehicle lacked such a system entirely. And while their design for the Shuttle ultimately wasn't chosen, you know what? Lockheed's proposal didn't have one either. And it had a strong impact on influencing the final Shuttle design outcome.

Comment Re:What governmen brought to the table (Score 1) 106

SpaceX and Blue Origin would not use solids, not because there's something wrong with solids per se, but because they're not "fuel and go", which makes them expensive to reuse - and SpaceX and Blue Origin are all about reuse.

A lack of experience with hydrolox surely factors into the picture for SpaceX and Blue Origin; they'd get significantly higher payload fractions by using a hydrolox upper stage. But they're willing to accept lower payloads in order to simplify their manufacture and ground infrastructure, and in particular because the need their propellants to be storable, and storing LH for long periods is a PITA. Storing methalox is quite difficult, but nothing compared to hydrolox.

Comment Re:What governmen brought to the table (Score 2) 106

Solids really aren't that bad when reusability isn't a concern. They're very high thrust, which is exactly what you want out of a booster, and they're structurally very simple. Their low impulse and high structural mass are not particularly important aspects for boosters. Reuse of solids however gains you very little, because there's so much work in refurbishing them.

Comment Re:What governmen brought to the table (Score 3, Informative) 106

That's not the reason you don't use it for a first stage. The disadvantages of hydrolox (which are numerous) are offset by its incredible specific impulse. But for a first stage, specific impulse doesn't matter that much, while thrust matters a lot. Thrust is in large part proportional to fuel density, as a turbopump sweeps out a fixed volume per rotation, so the denser the fuel, the more mass (and generally all else being equal, energy) it pumps per rotation.

Another aspect is that first stages are big, meaning that cost is more important than specific impulse. By contrast, when dealing with an upper stage, a small increase in mass has a huge increase in first stage size, and since first stages are so large and expensive, that's a big cost. So you generally want a higher ISP upper stage. With the caveat that "storability" requirements for engines that need to restart can shift the balance; because hydrogen is so deeply cryogenic it's difficult to store for protracted lengths of time. Also, the longer you plan to have a stage in usage without maintenance, the more you tend to favour simple propellants over high performing ones, particularly when you're dealing with small, light engines. So for example if you have an interplanetary probe you'll tend to favour a self-pressurizing hypergolic system so that you only have to rely on a couple valves working, even though self-pressurizing propellant tanks are heavier and hypergolics tend to be lower specific impulse. Engines that are smaller still are often monoprops for an even greater degree of simplicity.

Comment Re:Unlikely (Score 1) 235

Part of the criticism of the paper is that the excavation was time-pressured,

Which part of "salvage archaeology" do you misunderstand? Literally, the bulldozers are hovering over the site, wanting to get on with paying work.

impossible to reconstruct

Which part of "salvage archaeology" do you misunderstand? Literally, the bulldozers are hovering over the site, wanting to get on with paying work.

and also had to leave out a few things that would have helped answer some questions.

Which part of "salvage archaeology" do you misunderstand? Literally, the bulldozers are hovering over the site, wanting to get on with paying work.

You have a choice in salvage work. Either get the best results you can now, with the personnel and techniques you have, now, and keep the best records you can, now. Or you get nothing. Big. Fat.Zero.

(You might be able to extend "now" by court action, but while the landsharks are in the shark pool, you need to be nose-down bum-up in the trench because the suit could go either way.

Your other questions are covered in the paper. I don't need to answer them a second time. Get a copy and read it - neither is difficult, and Slashdot does like to claim an intellectually capable readership.

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