Every year in early January, Earth reaches the closest point in its orbit to the Sun, a moment astronomers call perihelion.

A company called Reflect Orbital wants to illuminate the Earth after sunset with orbital sky mirrors, raising alarm bells.

Add Yahoo as a preferred source to see more of our stories on Google. The sun shines above the Earth’s horizon. Perihelion, the point when Earth is closest to the Sun, occurs annually in early January ...

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, ...

Air pollution has a "dramatic" impact on the amount of sunlight reaching Earth’s surface, reveals new research. Solar radiative energy declined in large parts of the world from the 1950s to the 1980s ...