Wikipedia:Reference desk/Archives/Science/2023 December 3

= December 3 =

Locating pre-clovis sites
How are pre-clovis sites located? For many of them traditional archaeological site locating techniques don't seemed to be used, and they are often in bizarre or random locations like the Topper site or Cactus Hill. The articles or other sources never seem to mention how they are located either. — THORNFIELD HALL (Talk) 01:09, 3 December 2023 (UTC)
 * The article on the Topper site says it was a chert quarry. Such sites are easy to spot because people would "rough out" stone tools and cores to make the usable chert lighter and easier to pack out. There are typically tens of thousands of flakes and rejects lying all over the area. Abductive  (reasoning) 09:13, 3 December 2023 (UTC)
 * The verb to locate has several meanings. It can mean "to place in a particular spot or position", but it can also mean "to find out where something is located". I assume you mean the latter. I am not sure what is bizarre about the locations of the sites you mention. The archaeological excavations for both sites initially identified them solely as Clovis sites. I do not know how the finder of the Topper site, David Topper, identified the site as a site for archaeological finds, but it was unrelated to any later pre-Clovis theories. The Cactus Hill site was being commercially mined for sand; an archaeological research group testing the site from time to time found Clovis artifacts, which led to an archaeological excavation. The hypothesis of a pre-Clovis layer only arose as a result of such excavations. --Lambiam 09:24, 3 December 2023 (UTC)
 * Reportedly, David Topper was a local forester who spotted stone tools on the ground there and alerted archaeologist Albert Goodyear. --Lambiam 10:19, 3 December 2023 (UTC)
 * I actually read that book, I must have forgotten that part. That's interesting he found them on the surface. There must have been a lot of erosion and they were younger (and above) the pre-clovis artifacts. — THORNFIELD HALL (Talk) 10:23, 3 December 2023 (UTC)


 * Long story short: no-one says "Today I'm going to look for a new pre-Clovis site, where might one be?" Instead they say "Hey, this site I'm excavating seems to have a pre-Clovis layer!" or "Hey, the test results have come in for the site I excavated last year, and some of it dates to pre-Clovis!" {The poster formerly knoiwn as 87.81.230.195} 51.194.245.32 (talk) 09:38, 3 December 2023 (UTC)
 * Or, as happens so often with archaeological or paleontological finds, "someone was doing something ordinary and not at all related to scientific research and found something interesting". --User:Khajidha (talk) (contributions) 22:40, 3 December 2023 (UTC)
 * Long story short: no-one says "Today I'm going to look for a new pre-Clovis site, where might one be?" Is that actually true? In palaeontology it is reasonable to say "Based on our understanding of evolution, palaeoecology, deposition, preservation, geology, etc, we would expect to find such-and-such a fossil in such-and-such an area, so we will look for it there".  That's how Tiktaalik was discovered, for example.  Do similar principles not apply in archaeology?  Iapetus (talk) 11:58, 5 December 2023 (UTC)
 * Much moe modern sites can be found by satellite but early sites like that just don't have any big man made structures. Possibly you could train an AI to recognize sites worth investigating - sites near a river that can be defended and have some resource like flints for example. Maybe where there used to be a river but it has wandered so it isn't overlain by too many later sites. So it may be possible to find them mre systematically in the fture. NadVolum (talk) 23:43, 3 December 2023 (UTC)

Huygens probe
Why was the Huygens (spacecraft) or something like it never repeated? To this day, it is the only landing in the outer solar system. Despite only working for minutes, it provided valuable data about a body that we know very little about. Meanwhile we send countless rovers to Mars? Even though there's still things left to do on Mars (like a sample return mission) tackling Titan again or Europa has steeper engineering challenges, but nonetheless would be a very rewarding feat. — THORNFIELD HALL (Talk) 10:57, 3 December 2023 (UTC)


 * Several reasons, mostly coming down to "sending something to the outer solar system is hard."
 * Mars missions mostly rely on solar power. Some rovers use RTGs, but even those use a solar-powered communications relay. Near Saturn, an RTG is the only option and those RTGs are hard to get, as the supply of Pu-238 is limited. The Mars Curiosity rover has 4.8 kg of plutonium dioxide, Cassini used 28.3 kg because of its higher power requirements.
 * Mars rovers can make use of the existing fleet of orbiters as a communication relay. Every NASA or ESA orbiter send to Mars since around 2000 has that capability, including for each other's landers. Communicating directly from the surface to Earth is hard, as the antenna+transmitter would be either too heavy or power-hungry or too low bandwidth for science data (it can sometimes be used for engineering data, to troubleshoot the high bandwidth comms link). No orbiters exist near Saturn, so a Titan lander must go with its own comms relay, adding cost and mass.
 * Sending something to Saturn requires a bigger launcher or a smaller, less capable payload than sending something to Mars.
 * The low temperature and the communication difficulties make a Titan mission far riskier than a Mars mission. Managers, politicians and taxpayers don't want to see a complete failure, so risks are often avoided.
 * The return on investment happens far slower. For a Mars mission, you've several years of preparation, a few months flight time and a few years of science. For Saturn, add several years of flight time.
 * PiusImpavidus (talk) 12:08, 3 December 2023 (UTC)


 * Add to those the fact that you need the appropriate planetary alignments to be able to use gravity assists (Cassini–Huygens used four). Such multiple alignments arise at rare-ish intervals, you can't launch whenever you like, so the entire mission has to be designed, built and launched to an immovable deadline. For missions involving multi-national co-operation (and funding) this is not easy to achieve. {The poster formerly known as 87.81.230.195} 51.194.245.32 (talk) — Preceding undated comment added 16:58, 3 December 2023 (UTC)
 * Good point. Specifically, when heading for Saturn, you really want that gravity slingshot at Jupiter. There's a few-year window once every 20 years. PiusImpavidus (talk) 20:22, 3 December 2023 (UTC)


 * You haven't even discussed the actual landing yet. Going out there is difficult and expensive but it has been done several times and is sort of routine by now. Going down for a controlled soft landing is another step or two up from that. In the case of Huygens, the thick atmosphere of Titan helped getting the probe down for a soft landing so that it could be expected to survive for a few minutes. However, there was no telling where it would come down, and I'm not sure it is well known even now where it did come down. It should be noted that the main purpose of Huygens was to study the atmosphere during the descent phase, and the landing was a bit of an add-on. To make good scientific use of a lander good knowledge of the landing site is a prerequisite. Europa has only a thin atmosphere, making a soft landing harder than on Titan. Having said that, there is a proposal for a Europa Lander; not sure what the current status of that is. --Wrongfilter (talk) 21:04, 3 December 2023 (UTC)
 * While covering neither, but also involving a moon of Saturn there's also the Enceladus Orbilander proposal. The details in our article cover one of the issues mentioned by others above "" Nil Einne (talk) 11:56, 4 December 2023 (UTC)