Every year in early January, Earth reaches the closest point in its orbit to the Sun, a moment astronomers call perihelion. We are slightly nearer to our star and receiving more solar energy than we ...

Earth’s orbit around the Sun isn’t a perfect circle—it’s slightly elliptical. Each year, around July 2 or 3, Earth reaches its farthest point from the Sun, known as aphelion. Around January 2 or 3, ...

Much has changed in 250 years since the Declaration of Independence, but many aspects of astronomy look the same.