Moon

During the most recent total solar eclipse visible in the U.S., on Aug. 21, 2017, the skies darkened as the Moon crossed in front of the Sun. It blocked out all sunlight – except for that from a golden ring visible around the Moon’s shape, called the corona. Not surprisingly, solar power generation across North America plummeted for several hours, from the first moment the Moon began to obscure the Sun to when the Sun’s disk was clear again. On April 8, 2024, another total solar eclipse will track across the U.S., causing perhaps an even greater loss of solar power generation. Although this will be the second total solar eclipse visible in the U.S. in under seven years, these events are a rare occurrence. Nevertheless, they present a unique challenge to power grid operators. I am a space scientist with a passion for teaching physics and astronomy. Though I have seen many partial eclipses of the Sun, I have yet to witness a total solar eclipse. My road trip to...

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com. Why does a leap year have 366 days? Does the Earth move slower every four years? – Aarush, age 8, Milpitas, California You may be used to hearing that it takes the Earth 365 days to make a full lap, but that journey actually lasts about 365 and a quarter days. Leap years help to keep the 12-month calendar matched up with Earth’s movement around the Sun. After four years, those leftover hours add up to a whole day. In a leap year, we add this extra day to the month of February, making it 29 days long instead of the usual 28. The idea of an annual catch-up dates back to ancient Rome, where people had a calendar with 355 days instead of 365 because it was based on cycles and phases of the Moon. They noticed that their calenda...