2. Describe: Months are another unit of time based on an astronomical event. Click Reset, and move the Sim. speed slider to the right a quarter of the way. Click Play, and observe the movements of Earth and the Moon for one month. (Note: You can use the calendar in the upper right corner of the 2D VIEW tab to determine when a month has passed.) A. Describe the movements of Earth and the Moon over the course of a month. B. What astronomical event corresponds to the passage of one month? It takes approximately 28 days for the Moon to revolve around Earth. Revolution is the elliptical motion of a body traveling around another body in space.

As you observe the Earth and the Moon over the month, you'll notice that the Moon travels in an elliptical orbit around the Earth, completing one full cycle roughly every 28 days. This means that you can witness the different phases of the Moon over this period, from the new moon where it's barely visible to the full moon shining brightly, as it transitions through waxing and waning phases. Meanwhile, the Earth rotates on its axis, making a full spin approximately every 24 hours, giving us the familiar cycle of day and night. The passage of one month correlates with the Moon's complete revolution around the Earth, which is intrinsically tied to the lunar cycle. This astronomical event is driven by the gravitational interactions between the Earth and the Moon, influencing not just the visibility of the Moon but also impacting ocean tides on Earth as the Moon's position relative to the Earth changes. This cycle is even the basis for the name of the month itself in many cultures, reflecting its fundamental connection to timekeeping!