Comments on: Bennu’s cobbled equatorial ridge https://behindtheblack.com/behind-the-black/points-of-information/bennus-cobbled-equatorial-ridge/ Mon, 08 Apr 2019 17:18:14 +0000 hourly 1 https://wordpress.org/?v=6.9.4 By: Andi https://behindtheblack.com/behind-the-black/points-of-information/bennus-cobbled-equatorial-ridge/#comment-1066184 Mon, 08 Apr 2019 17:18:14 +0000 https://behindtheblack.com/?p=57564#comment-1066184 Especially since Uranus has a 98-degree tilt to its axis. That would imply that “north” is in a southerly direction compared with Earth.

]]> By: mpthompson https://behindtheblack.com/behind-the-black/points-of-information/bennus-cobbled-equatorial-ridge/#comment-1066179 Mon, 08 Apr 2019 06:41:14 +0000 https://behindtheblack.com/?p=57564#comment-1066179 Robert, if the asteroid had a retrograde rotation, would that place the north pole in the same direction as Earth’s south pole? Looking this up, I see Venus and Uranus have retrograde rotation but it’s unclear which side is designated north. This question is explored at the following URL, but with no clear answer:

https://forum.cosmoquest.org/showthread.php?138723-Which-way-is-North-on-Venus

Or, even a more in-depth discussion here on the same topic:

http://esr.ibiblio.org/?p=5324

Seems Darwin’s question is indeed a very good one.

]]> By: Robert Zimmerman https://behindtheblack.com/behind-the-black/points-of-information/bennus-cobbled-equatorial-ridge/#comment-1066166 Sun, 07 Apr 2019 16:08:42 +0000 https://behindtheblack.com/?p=57564#comment-1066166 In reply to Darwin Teague.

Darwin Teague: That is not a stupid question, it is brilliant. I myself had never asked, which means I don’t really know.

I think, based on past reading of both these asteroid missions as well as others, that they use the asteroid’s rotation to determine the locations of the poles and equator, and then pick north based on its relative location compared to the Earth. In other words, they match the asteroid’s rotation with the solar system, and have north point away in the same direction as the Earth.

This is an educated guess however.

]]> By: Darwin Teague https://behindtheblack.com/behind-the-black/points-of-information/bennus-cobbled-equatorial-ridge/#comment-1066165 Sun, 07 Apr 2019 16:04:47 +0000 https://behindtheblack.com/?p=57564#comment-1066165 Stupid question. How do scientists determine north and south on objects like this?

]]>