Wikipedia:Reference desk/Archives/Science/2021 June 24

= June 24 =

70s sports car with two engines
Several years a go i read in an auto magzaine about a protype sports car which contained one V6(?) up front and one in the back. I have been completley unable to find any trace of it online, and we don't have a category for Cars Wtih 2 Engines. I beleive the fellow resposible for it was connected with Ford Motor company in some manner: he may have once worked at Ford, or was using Ford engines, or the body of an existing Ford product. The man (and car which was named after him) had a distinctive name, but all that comes to mind is Mondeo (which is incorrect) or that it had a Z. If anyone knows what i am talking about I'd greatly appreciate any information it. Thanks,L3X1 ◊distænt write◊  02:56, 24 June 2021 (UTC)
 * Perhaps the Mosler TwinStar? Not 70s, and not Ford, but a name that could be misremembered as something like Mondeo or having a Z. DuncanHill (talk) 03:04, 24 June 2021 (UTC)
 * I've read of a Mini with two engines, obviously not Ford. Greglocock (talk) 12:51, 24 June 2021 (UTC)


 * Sounds like a DeTomaso Zonda, but I can't find evidence for any with 2 engines; however, a second different Ford engine was developed for a prototype (not a second engine in the same car; see link). Also, the company name was previously deTomaso Modena. 2603:6081:1C00:1187:D850:7CD2:B521:2587 (talk) 18:32, 24 June 2021 (UTC)
 * I think this must be it, the Road and Track article fits the 2016-18 timeline which i think i read about it. Interesting how my brain remembered certain structural bits of the name, but not the name itself. Thanks fot the assistance everyone. Thanks,L3X1 ◊distænt write◊  21:57, 24 June 2021 (UTC)

Telescope to read Voyager Golden Record
Assuming the Voyager Golden Record is facing Earth and uncovered (is it?), due to the diffraction limit, would anyone be able to estimate what size telescope and exposure time are needed to read its track to play back its contents at the current distance? Being a 3D structure, would it be necessary to use parallax or two telescopes to resolve the depth? Thanks, cm&#610;&#671;ee&#9094;&#964;a&#671;&#954; 09:20, 24 June 2021 (UTC)
 * A rough estimate -- you will need a telescope with the mirror of more than 10 million km in diameter. Ruslik_ Zero 09:31, 24 June 2021 (UTC)
 * It might be cheaper just to send a faster vehicle out to catch up to it. Or, presumably, to play whatever duplicate has been retained on earth. P.S. The golden record is contained within a cover, so the best you could do is read the cover. ←Baseball Bugs What's up, Doc? carrots→ 11:40, 24 June 2021 (UTC)
 * , how did you arrive at that number? My calculation results in a mirror much smaller than that. The record is about 30 cm in diameter, and is about 20 billion km away. (There are two Voyagers, each with a Golden Record, but they are about the same distance away, to a first approximation.) So the record subtends an angle of $$\arcsin(30 cm / 20,000,000,000 km) = 8.5 \times 10^{-13}$$ deg, or $$3 \times 10^{-9}$$ arcsec. Extrapolating the log-log plot for visible light in our Diffraction-limited system article, this corresponds to an aperture size of about 30,000 km. EDIT: Correction, that would just suffice to barely resolve the whole record. To actually read the bits on the record would require, I guess, several thousand times higher resolution, so your number may be about right. CodeTalker (talk) 01:45, 25 June 2021 (UTC)
 * I've found no definite value for the length of the recording, but adding the specified or guesstimated lengths of its components I get to about 160 minutes, to be played at 16$2/3$ rpm, meaning there are some 2,500 grooves spanning a width of 3 inches. (Yeah, I know, there is only one groove. ROFL.) So the ratio of groove separation to record width is about 1 : (12/3)×2,500 = 1 : 10,000. This is in the same ballpark as the ratio between Ruslik0's 10,000,000 km and CodeTalker's 3,000 km. --Lambiam 09:15, 25 June 2021 (UTC) ❉❉❉ Correction: CodeTalker's estimate was 30,000 km, giving a ratio between the estimated apertures of only 1 : 333. Also, a resolution that allows an observer to count the grooves is not enough to reconstruct the signal recorded in its modulation. For that, another factor of at least 10 is needed, and much more for high fidelity.  --Lambiam 09:06, 26 June 2021 (UTC)
 * Thanks a lot, Ruslik0, Baseball Bugs, CodeTalker and Lambiam. Good to have a ballpark figure. cm&#610;&#671;ee&#9094;&#964;a&#671;&#954; 10:38, 25 June 2021 (UTC)