The pull of gravity keeps the Moon in orbit around Earth. The distance between the Earth and Moon is about 380,000 kilometers. A crew of astronauts leaves Earth on a Monday and lands on the Moon on a Thursday. They land on the side of the Moon facing away from the Earth. On what day would the astronauts be able to see Earth from the Moon? Explain.

The same side of the moon always faces the Earth.

To determine the day the astronauts would be able to see Earth from the Moon, we need to understand the relative positions of the Earth, Moon, and the direction in which the Moon rotates.

Since the astronauts landed on the side of the Moon facing away from the Earth, they would not be able to see Earth right away. The Moon rotates on its axis once every 27.3 days, which means it takes the same amount of time for a complete rotation as it does to orbit the Earth. This is why we always see the same face of the Moon from Earth.

Given that the astronauts traveled from Earth to the Moon in three days, and taking into account the Moon's rotation, we can determine the day they would be able to see Earth.

First, let's establish a reference point: the day they land on the Moon, Thursday. Now, we know it takes approximately 27.3 days for the Moon to rotate, so one full rotation would take 27.3 days / 360 degrees = 0.0758 days per degree.

The astronauts landed on the side of the Moon facing away from Earth, so they would have to wait for the Moon to rotate 180 degrees before they can see Earth.

Therefore, the time it takes for the Moon to rotate 180 degrees is 0.0758 days per degree * 180 degrees = 13.644 days.

Adding the 3 days it took for the astronauts to reach the Moon, the total number of days would be 3 days + 13.644 days = 16.644 days.

Now, we need to determine which day this corresponds to, starting from the Monday they left Earth.

Since the total number of days is 16.644 days, and starting from Monday, we can round up to the nearest day to find out when they would be able to see Earth. Rounding up gives us 17 days.

Therefore, the day the astronauts would be able to see Earth from the Moon is 17 days after the Monday they left Earth.