If you’re looking for a great little place to point a small telescope the next few nights, let me suggest Mare Imbrium, the largest of the lunar “seas”. That’s Latin for Sea of Showers or Sea or Rains. Lovely name. The last time it rained there was never.
All the Moon’s seas are enormous basins excavated by asteroid impacts between 3.1 and 4.2 billion years ago. Cracks and fissures in the Moon’s crust from the collisions served as conduits for deeper lava to rise and fill the basins with molten rock. These great pools cooled and solidified, forming the large grey spots that make up the face of the Man in the Moon that even a child notices today.
Many of the seas are ringed by mountain ranges formed by faulting of the lunar crust during the impacts aided by slumping of material off the fresh slopes.
Earth’s mountains in contrast are lifted up when tectonic plates collide or pile up during volcanic eruptions.
Three ranges shape the outer boundary of the Sea of Rains – the Carpathians, the majestic Apennines and Caucasus. The Alps form part of a second inner ring of peaks. Each is named for its sibling range in Europe. Over the next few nights we’ll see all four cast awesome shadows as the Sun rises over their craggy peaks.
Tonight features the Alps, Apennines and Caucasus and the spectacular craters Plato and Copernicus. Tomorrow night, the Carpathians, north of Copernicus, come into view. The reason these features look most dramatic now rather than closer to full Moon is because the terminator cuts across the region. Along the terminator, the boundary separating lunar day from night, the Sun is just rising and every little peak casts a shadow.
While binoculars will reveal Plato, Copernicus and the mountain rings, a small telescope will show the scene best. I wish you a clear and not-too-cold night!