Posted on 10/01/2014 1:08:51 PM PDT by Citizen Zed
“When we first saw it in the Grail data, we were struck by how big it was, how clear it was, but also by how unexpected it was,” said Andrews-Hanna
“No-one ever thought you’d see a square or a rectangle on this scale on any planet,” he continued.
Similar to Earth? Not quite.
The scientist and his compatriots point out that the region is comprised of numerous native radioactive elements including uranium, potassium, and thorium which in the past would have heated the lunar crust and contracted upon cooling. That contraction tore into the moon’s surface and formed massively deep valleys.
A smaller scale example here on Earth is the Giant’s Causeway in Northern Ireland, where cooling and contraction produced hexagons with 120 degree angles.
“What we’re seeing is a clever trick of spherical geometry. For structures on this scale, a polygon with 120-degree angles at the corners actually has four sides instead of six,” explained Andrews-Hanna when explaining the lunar feature compared to similar valley’s here on our planet.
Scientists are unsure when this occurred but thanks to the Apollo missions they are estimating that the rifts were made around 3.5 billion years ago.
(Excerpt) Read more at valuewalk.com ...
Put a point on a sphere and make 3 lines from it 120 degrees apart. extend 2 of the lines from that point form part of a great circle. now there will be 2 other points you can put on those lines that will have similar great arcs that intersect at the 4th point.
Ah!
it’s over by that crater
Draw a triangle on a sphere with one corner on one of the poles, and the other two corners on the Equator, and you have a triangle with three 90 degree corners. The surface of a sphere can be covered by eight of those.
Split the surface of the sphere into four equal triangles and you have four triangles with 120 degree corners. These are consequences of spherical geometry.
Oops, and thanks Rodamala.
Thanks colorado tanker. Extra to APoD.
BTW, I’m looking for someone to take over the APoD list, must be more reliable than the current listmeister (me) who spends far too little time online.
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