Certainly looks like somebody welded together two hollow hemispheres.
Naturally, our moon is hollow. Otherwise the tail (moon) will be wagging the dog (earth). Our moon is way too big.
[Brandenburg - Past Events that may have Devastated the Planet - 25th Annual Mars Society Convention - YouTube]
Mars was destroyed in a nuclear war.
Dr Brandenburg says the destruction happened millions of years ago, but I heard that some Mars inhabitants were rescued and transported to Earth before the catastrophe.
Obviously there’s atmosphere both on the moon and Mars. You recall the footage of Americans planting the Old Glory and it fluttered. It goes to show there’s air.
And we hear about dust storms on Mars. Dust storms? Yep, there’s air on the red planet as well. And NASA and other agencies “discovered” water on Mars many times. (Like the Chinese Three Miles Gorge Dam collapsed at least five times. LOL) Where there’s water, there is atmosphere.