On this date in 1877, astronomer Asaph Hall discovered a moon for Mars: Phobos, the larger of 2 moons. He discovered the other moon, Deimos, later that year.
Laser surveys have revealed hundreds of earthworks in the Amazon. Researchers estimate the ancient Amazon civilization could have supported 3 million people.
A globular cluster is a spherical collection of stars orbiting in the halo of spiral galaxies. Our own Milky Way galaxy has over 150 globular clusters.
A conjunction is when 2 objects share the same right ascension. The Jupiter-Mercury conjunction on August 15 is the next one. Look for them before sunrise.