What is a solar eclipse?

A solar eclipse is coming to North America on April 8, 2024. The moon will line up perfectly between the Earth and the sun, blocking out the sun’s light and casting a shadow that will pass over parts of Mexico, the United States and Canada. People in the path of totality will experience a few minutes of darkness during the day as the moon perfectly covers the sun. Those not in the path of totality in those countries will still experience a partial solar eclipse. In this episode, we’re answering questions about the eclipse and talking about how to keep your eyes safe if you’re watching it! We speak with Bridgewater State University solar physicist Martina Arndt, Fairbanks Museum planetarium director Mark Breen and Thomas A. Hockey, author of America’s First Eclipse Chasers.

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• An eclipse happens when one celestial body (sun, moon, or star) moves in front of another and blocks–or eclipses–some of that object’s light. 
• In a total solar eclipse, the moon is perfectly lined up between the earth and the sun to fully block the sun’s light. Whether you experience the total eclipse depends on where you are on earth.
• The path of totality is about 100 miles wide, and that shadow moves quickly across the earth’s surface. 
• People in the path of totality will experience up to 3 and a half minutes of darkness in this eclipse. If it’s not cloudy you may even see stars. 
• The moon moves between the sun and the earth every month as it orbits the earth, but because the moon’s orbit is slightly tilted, sometimes the shadow it casts is above or below the earth’s surface.
• In a partial solar eclipse the moon only blocks part of the sun.
• The moon is smaller than the sun, but it can block the sun because the moon is closer to the earth. To get a sense of how this works, hold your hand up in front of your face and see if you can get your thumb to block the light of a light bulb. If your thumb is far away from your face, it may not block the light completely. But as you move your thumb in towards your eye, it can block out the light completely.
• Sometimes the moon is far enough away from the earth that it doesn’t completely block the sun’s light. This is called an annular eclipse.
• During a total solar eclipse, you might be able to see the sun’s corona, its outer atmosphere. Researchers use eclipses to gather information about the corona, because the sun’s light is usually so bright it makes it difficult to conduct atmospheric research.
• You should always use eye protection when looking at an eclipse. If you want to look at an eclipse as it’s happening, you need to wear special eclipse glasses. Without them, you can cause permanent damage to your eyes. During totality, it’s safe to briefly remove your glasses, but you should ask an adult to let you know when it’s safe to take them off, and when you need to put them back on again.
• If you want to take pictures of an eclipse, you need a solar filter for your camera–even a cell phone camera.