Back to Glossary

The Moon

The Moon is Earth’s only natural satellite—a rocky, cratered body about one‑quarter the diameter of Earth, orbiting at an average distance of approximately 384,400 km. It influences tides, stabilizes Earth’s axial tilt, and was formed about 4.5 billion years ago following a collision between Earth and a Mars-sized object.

Source: science.nasa.gov

APODs including "The Moon"

Highlights of the Summer Sky

05/06/2017

Highlights of the Summer Sky
Image Credit: Universe2go.com / NASA APOD

What's up in the sky this summer? The featured graphic gives a few highlights for Earth's northern hemisphere. Viewed as a clock face centered at the bottom, early summer sky events fan out toward the left, while late summer events are projected toward the right. Objects relatively close to Earth are illustrated, in general, as nearer to the cartoon figure with the telescope at the bottom center -- although almost everything pictured can be seen without a telescope. Highlights of this summer's sky include that Jupiter will be visible after sunset during June, while Saturn will be visible after sunset during August. A close grouping of the Moon, Venus and the bright star Aldebaran will occur during mid-July. In early August, the Perseids meteor shower peaks. Surely the most famous pending astronomical event occurring this summer, though, will be a total eclipse of the Sun visible over a thin cloud-free swath across the USA on 21 August. Follow APOD on: Facebook, Google Plus, Instagram, or Twitter