APOD: Western Moon, Eastern Sea (2022 Jan 28)

[APOD Robot]

Western Moon, Eastern Sea

Explanation: The Mare Orientale, Latin for Eastern Sea, is one of the most striking large scale lunar features. The youngest of the large lunar impact basins it's very difficult to see from an earthbound perspective. Still, taken during a period of favorable tilt, or libration of the lunar nearside, the Eastern Sea can be found near top center in this sharp telescopic view, extremely foreshortened along the Moon's western edge. Formed by the impact of an asteroid over 3 billion years ago and nearly 1000 kilometers across, the impact basin's concentric circular features, ripples in the lunar crust, are a little easier to spot in spacecraft images of the Moon, though. So why is the Eastern Sea at the Moon's western edge? The Mare Orientale lunar feature was named before 1961. That's when the convention labeling east and west on lunar maps was reversed.

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[jks]

Hi,

Today's nice APOD has the wrong date at the top and the Discuss link directs to yesterday's discussion.

jks

[gmPhil]

Interesting point in passing about what's East and what's West on the moon. After a bit of searching, I found this article with some background info:
https://the-moon.us/wiki/IAU_directions

[orin stepanek]

What caused the Square corners?

[Chris Peterson]

Mare_Orientale_Nov_27_2021_TGlenn_1024.jpg
What caused the Square corners?

What square corners?

[bls0326]

"Interesting point in passing about what's East and what's West on the moon. After a bit of searching, I found this article with some background info:
https://the-moon.us/wiki/IAU_directions


Thanks for the link. What a mapping mess - historical perspective, telescopic perspectives, exploration perspective, geocentric perspective!

[neufer]

What caused the Square corners?

What square corners?

Lacus Autumni refers to the dark "lakes" in this high-Sun view. The bright-walled 18-km diameter crater in the lower left is Lallemand, while the 37-km crater straddling the upper margin is Schlüter A.

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The "Triple Goddess" symbol of the waxing, full & waning moon.

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<<Lacus Autumni (Latin autumnī, "Lake of Autumn") is a region of lunar mare that lies near the western limb of the Moon. Along this side of the lunar surface is a huge impact basin centered on the Mare Orientale.

Two concentric mountain rings surround the Orientale mare, the inner ring being named Montes Rook and an outer ring called the Montes Cordillera. Lacus Autumni lies in the northeastern quadrant of the gap between these two mountain rings. This section of the lunar surface is difficult to observe directly from the Earth.

The selenographic coordinates of the center of the mare are 9.9° S, 83.9° W. It is approximately 195 kilometres long and trends from the southeast to the northwest, reaching a maximum width of 90–100 kilometres. The irregular appearance results from the lunar basalt emerging from the surface to fill in low areas between hummocky hills.>>
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<<The Triple Goddess is a deity or deity archetype revered in many Neopagan religious and spiritual traditions. In common Neopagan usage, the Triple Goddess is viewed as a triunity of three distinct aspects or figures united in one being. These three figures are often described as the Maiden, the Mother, and the Crone, each of which symbolizes both a separate stage in the female life cycle and a phase of the Moon, and often rules one of the realms of heavens, earth, and underworld.>>

[orin stepanek]

Mare_Orientale_Nov_27_2021_TGlenn_1024.jpg
What caused the Square corners?

What square corners?

[Chris Peterson]

Mare_Orientale_Nov_27_2021_TGlenn_1024.jpg

Mare_Orientale_Nov_27_2021_TGlenn_1024.jpg
What caused the Square corners?

What square corners?

I don't see anything I'd characterize that way. Those look like basalt filled trenches, or crater ring sections - hard to tell when viewed so obliquely.

[Tom Glenn]

In case anyone is interested, when I first published this data back in early December I created a Lambert equal area cylindrical projection of the image featured in today's APOD. Shown below is a cropped portion of this projection, showing the regions referenced in the posts above. The main mare basalt of Mare Orientale is at left, and the narrow basalt "trenches" are Lacus Veris and Lacus Autumni.

[neufer]

In case anyone is interested, when I first published this data back in early December I created a Lambert equal area cylindrical projection of the image featured in today's APOD. Shown below is a cropped portion of this projection, showing the regions referenced in the posts above. The main mare basalt of Mare Orientale is at left, and the narrow basalt "trenches" are Lacus Veris and Lacus Autumni.

Clementine image: Lacus Veris

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<<Lacus Veris (Latin vēris, "Lake of Spring") is a small lunar mare on the Moon. In selenographic coordinates, the mare centered at 16.5° S, 86.1° W and is approximately 396 km long. The mare extends along an irregular 90° arc from east to north that is centered on the Mare Orientale, covering an area of about 12,000 km². Author Eric Burgess proposed this mare as the location of a future manned lunar base, citing a 1989 study performed at the NASA Johnson Space Center.

This small, roughly crescent-shaped mare region lies between the ring-shaped Inner and Outer Rook mountains that form part of the Orientale impact basin. It lies in a topographic lowland about 1 km below the surrounding peaks. Based on data collected during the Lunar Orbiter missions and from Earth-based telescopes, the mare includes some material from the surrounding highlands. The density of crater impacts indicates that this mare is an estimated 3.5 billion years old, and it finished forming roughly 340 million years after the impact that created the Oriental basin.

The mare contains eleven sinuous rilles formed from lava tubes and channels, with lengths ranging from 4 to 51 km. Many of these rilles begin in the Rook mountains and flow to the base of the mountainous scarp. There are also several shield volcano formations, each with a diameter of less than 10 km. The geological formations and the lack of collapse depressions suggest that the mare was formed by thin lava flow through tubes, rather than through basalt flooding by fissure eruptions.>>