Spectacular mountains on the moon will come into view for sky watchers on Sunday, September 4.
These mountains mark the edge of the Imbrium, also known as the Great Imbrium Basin, a vast lava plain on the lunar surface that was formed by a massive impact from space nearly 4 billion years ago.
Imbrium is the largest basin on the near side of the moon, measuring about 721 miles (1160 kilometers) in diameter. Although only half the size of the South Pole Aitken Basin on the far side of the Moon, Imbrium is still one of the largest craters in the solar system.
related: Moon Viewing Guide: What to Look for on the Moon’s Surface
The northernmost mountain arc is the Lunar Alps — or the Alps — which are made up of hundreds of peaks and stretch 173 miles (280 kilometers). The highest of them, Mont Blanc, rises 2.2 miles (3.6 kilometers) above the lunar surface.
There is a rupture in the lunar Alps, called the Alpine Valley — or Alpine Valley — that forms when the lunar crust descends between parallel faults. On September 4, this area should be visible with binoculars or a telescope.
Below the Lunar Alps and to the southeast of the moon is the Caucasus Mountains – Montes Caucasus – a mountain range below the lava floodplain connecting the Imbrium and Serenitatis, also known as the “Sea of Tranquility” in the southeast.
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The Apennine Mountains – Montes Apenninus – border the southeastern edge of the Imbrium. Named after Italy’s Apennine Mountains, this rugged mountain range rises from the famous nearby lunar crater Eratosthenes and arcs from east to northwest to meet Imbrium at Cape Fresnel. Then, it itself is located in Imbrium and Mare Serenitatis.
Surrounding the southern side of the Copernicus Crater are the Montes Capatus Mountains. Opposite this side of the Imbrium, to the northwest of the crater, is a plain of basaltic lava known as the Iridium Sinus, or Rainbow Bay.
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Imbrium, part of the lunar violent past
Considered the second youngest lunar basin, lunar scientists believe Imbrium formed 3.85 billion years ago when a protoplanet collided with the moon.
This impact corresponds to a period in lunar history known as the Late Heavy Bombardment (LHB), also known as the Lunar Cataclysm.
LHB occurred in the solar system between about 410 and 3.8 billion years ago, when the Earth system (including the Moon) and other inner planets experienced a massive increase in space rock impactors.
While there is no definitive explanation for this increased bombardment, some planetary scientists believe it may be due to the solar system’s giant planets changing their orbits by interacting with loose matter such as gas, dust and even small space rocks.
This may have disrupted the asteroid belt between Mars and Jupiter and the Kuiper Belt comets on the outer edge of the solar system, putting them in eccentric orbits that make contact with the inner planets — Mars, Earth, Venus and Mercury — and the moon.
After the impact that formed the Imbrium Basin, further space rock impacts left smaller, younger craters in it. Then over the next few hundred million years, volcanic events flooded the area with lava, leaving lava-filled craters known as Mare Plaques.
Thus, the Imbrium region with its mountains, ridges, channels, plains and craters marks a fascinating insight into the Moon’s geological history. Sky watchers have an exciting opportunity to see it in person on Sunday.
Editor’s Note: If you took a photo of Mare Imbrium and want to share it with Space.com readers, please send your photo, comments, and your name and location to email@example.com.
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