Wikipedia:Reference desk/Archives/Science/2021 March 5

= March 5 =

Seabird IDs
In this video, what are the cliff-nesting birds first seen at 23 seconds, and the tern-like birds at 3:30? --24.43.123.79 (talk) 00:19, 5 March 2021 (UTC)
 * The birds at 23 seconds are probably Bermuda petrels, a deduction based on the fact that the list of CornellLab's bird cams shows they have a couple of cams covering this species. PaleCloudedWhite (talk) 07:46, 5 March 2021 (UTC)
 * My best guess for the tern-like birds - based not on personal knowledge, but on perusing lots of google searches - is red-billed tropicbird. The images at our article seem to have very red bills - maybe too red for the birds in the video - though the images of the same species at this google image search seem to fit better. PaleCloudedWhite (talk) 09:10, 5 March 2021 (UTC)

Why Space X didn't reveal the reason behind SN 10 failure?
Why Space X still didn't reveal the reason behind SN 10 failure? Rizosome (talk) 02:49, 5 March 2021 (UTC)
 * Is that the one that blew up within the last day or so? ←Baseball Bugs What's up, Doc? carrots→ 03:26, 5 March 2021 (UTC)
 * Maybe because they aren't yet completely sure what the reason was? Our article already says "due to a suspected methane leak." In any case, as a privately owned company conducting tests on prototypes, they are under no obligation to reveal their findings immediately, and will doubtless only do so when and if it becomes advantageous for them. {The poster formerly known as 87.81.230.195} 2.125.75.168 (talk) 06:20, 5 March 2021 (UTC)


 * It's been a day and a half, what did you expect? It could be easily observed that at least some of the landing legs didn't lock into place, so that might have something to do with it. However, SpaceX (Elon Musk's twitter probably) will let us know when they worked it out, they always have in the past (cf the Starlink 19 landing failure already having been explained). Fgf10 (talk) 09:34, 5 March 2021 (UTC)
 * (ec) Usually they provide a full explanation for such failures, but the investigation needed for a full explanation takes time. If there was a methane leak, then the question is, how come? A leak can perhaps explain the explosion, but there should have been no leak in the first place. Did something rupture? If so what, how, and why? There is also some chatter about the landing legs not properly deploying, which may have been a factor in a chain of mishaps. It is wonderful how the Space X people (that is, people of Space X, not X-Men from space) describe the incident in a self-congratulory text on their website:
 * Fortunately there was no one on board, or they too would have experienced a rapid unscheduled disassembly. --Lambiam 09:45, 5 March 2021 (UTC)
 * Reports yesterday said initially it's suspected there was a leak. Hence the kaboom. That term "unscheduled disassembly" reminds me of when Challenger exploded in mid-air, and the NASA announcer describing things while they were happening called it "a major malfunction". ←Baseball Bugs What's up, Doc? carrots→ 13:57, 5 March 2021 (UTC)
 * First, the announcer who said that didn't have access to live video of the flight. Second, there was no explosion; quoting from memory, what people misperceived as an explosion was only "a fast, almost explosive fire".  Third, if by the Challenger you mean the orbiter, it not only didn't explode, it came away from that event intact, only to be destroyed on impact with the sea surface. --142.112.149.107 (talk) 21:54, 5 March 2021 (UTC)
 * How do you know he didn't have the live video feed? ←Baseball Bugs What's up, Doc? carrots→ 23:11, 5 March 2021 (UTC)
 * He "was reading routine values off gauges at his console". 39 seconds later he reported that the flight dynamics officer had reported an explosion. --142.112.149.107 (talk) 23:44, 6 March 2021 (UTC)
 * He "was reading routine values off gauges at his console". 39 seconds later he reported that the flight dynamics officer had reported an explosion. --142.112.149.107 (talk) 23:44, 6 March 2021 (UTC)


 * It can take months of investigation to understand the causes of such disasters. The Challenger disaster investigation took a long time; the Rogers Commission Report was released in June of 1986, the Challenger disaster happened in January of that year.  The Columbia disaster investigation took a similar amount of time, the Columbia Accident Investigation Board released a report in August, 2003 when the accident happened in February.  The VSS Enterprise crash investigation took even longer; the final findings were released in July 2015, nine months after the October 2014 crash.  I wouldn't expect anything for some time.  -- Jayron 32 12:58, 5 March 2021 (UTC)
 * SpaceX doesn't operate like that in most cases. If the cause is obvious either they or Elon Musk tends to release it within days. That's what has happened with previous Starship tests and Falcon 9 landing failures. The exceptions being the two failures on launches for external customers . Fgf10 (talk) 19:24, 5 March 2021 (UTC)
 * But what if they don't know? The OPs question of "Why hasn't SpaceX said why the rocket failed?" has an obvious answer. "They don't know yet".  -- Jayron 32 20:39, 5 March 2021 (UTC)
 * These are tests that are conducted with the express goal of finding out what failures may happen so that the design can be improved. Everything is heavily instrumented and recorded to make it possible to quickly get at the bottom. --Lambiam 20:46, 5 March 2021 (UTC)


 * Elon Musk:
 * Thrust was low despite being commanded high for reasons unknown at present, hence hard touchdown. We’ve never seen this before.
 * Next time, min two engines all the way to the ground & restart engine 3 if engine 1 or 2 have issues.
 * Tweeted 2010-02-06 01:51 UTC.
 * Remember that the SpaceX Raptor engine is still being developed, tested, and refined. -- ToE 02:18, 6 March 2021 (UTC)


 * Another Musk Tweet:
 * SN10 engine was low on thrust due (probably) to partial helium ingestion from fuel header tank. Impact of 10m/s crushed legs & part of skirt. Multiple fixes in work for SN11.
 * Q from NASASpaceFlight's Chris Bergin:
 * This is a tricky one given that I believe said helium pressurization was added to the CH4 header tank to mitigate what happened with SN8. That's why it's a test program, of course.
 * Musk:
 * Fair point. If autogenous pressurization had been used, CH4 bubbles would most likely have reverted to liquid.
 * Helium in header was used to prevent ullage collapse from slosh, which happened in prior flight. My fault for approving. Sounded good at the time.
 * -- ToE 21:00, 9 March 2021 (UTC)

Role of anaerobic metabolism in the global carbon cycle
Has anyone ever tried to estimate the role of anaerobic metabolism in the global carbon cycle? Jo-Jo Eumerus (talk) 11:17, 5 March 2021 (UTC)
 * The citation quoted in anaerobic metabolism that's most likely to have a good estimate is (on Pubmed) which has a "simliar articles" section that could also point to useful items. Ironically, at first sight one might think that organisms which take carbon dioxide out of the atmosphere, as some anaerobes do, would be good to mitigate global warming. Unfortunately, they turn it into methane, which is an even worse greenhouse gas! Mike Turnbull (talk) 14:10, 5 March 2021 (UTC)
 * Unfortunately, that source is focused on man-made emissions, but I need information on all anaerobic throughput. Jo-Jo Eumerus (talk) 10:51, 6 March 2021 (UTC)
 * : I know of one book that covers the GCC pretty comprehensively, and does mention anaerobes. The book is, with e-book at ISBN=1402039581. Looking at my copy, on page 53 it has a carbon budget in units of 109 tC yr-1 that talks about a "missing sink" — maybe that could be where anaerobes have a role? The book refers to the IPCC's "Climate Change 2001. The Scientific Basis", which has its preface/foreword . Later reports may be even more relevant. Mike Turnbull (talk) 13:14, 6 March 2021 (UTC)