The Moon is Earth’s only natural satellite and plays an important role in our lives. Scientists believe the Moon formed about 4.5 billion years ago, shortly after Earth. The most widely accepted theory is the Giant Impact Hypothesis. According to this theory, a Mars-sized object crashed into the young Earth. The collision blasted a large amount of debris into space, which eventually came together to form the Moon.
The Moon revolves around the Earth in an oval-shaped orbit that takes about 27.3 days to complete. At the same time, it also rotates on its axis once every 27.3 days. Because the Moon’s rotation and revolution take the same amount of time, we always see the same side of the Moon from Earth. This is called tidal locking.
The Moon appears to change shape throughout the month. These changes are called the phases of the Moon, and they are caused by how much of the Moon’s sunlit side is visible from Earth. The main phases are new moon, first quarter, full moon, and last quarter. Between these phases are crescent and gibbous phases. The cycle from one new moon to the next takes about 29.5 days.
Sometimes the Earth, Moon, and Sun line up just right to create an eclipse. A lunar eclipse happens when the Earth is directly between the Sun and the Moon, and the Earth’s shadow falls on the Moon. This can cause the Moon to appear red, which is why it’s sometimes called a “blood moon.” A solar eclipse occurs when the Moon passes between the Earth and the Sun, casting a shadow on Earth. These events are rare and only visible from certain parts of the world.
The Moon has always fascinated people, and in 1969, humans went there for the first time. Neil Armstrong and Buzz Aldrin became the first people to walk on the Moon during NASA’s Apollo 11 mission. Armstrong’s famous words were, “That’s one small step for man, one giant leap for mankind.” A total of 12 astronauts walked on the Moon between 1969 and 1972. Their journeys taught us a lot about the Moon’s surface, structure, and history.
Today, scientists continue to study the Moon using telescopes, satellites, and space missions. Many countries, including the United States and others, are planning to send people back to the Moon and even build permanent bases there in the future. The Moon remains a key to understanding our planet, our solar system, and what it takes to explore space.
Sun-Moon-Earth System Flashcards
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Middle School Science
