Seasonal affective disorder, or SAD, is the term used to describe a depressive mood that typically occurs in the winter months.

Earth is the only home humanity has ever known, yet most people are unaware of the incredible mysteries, extremes, and scientific wonders that make our planet unique. From hidden geological features ...

The pull of the planets sets Earth to wobbling in other ways as well. By changing the strength and timing of sunlight ...

The summer solstice marks the start of astronomical summer and the longest day of the year. Here we explore when the summer ...

The winter solstice, or the December solstice, is the point at which the path of the sun in the sky is farthest south. At the ...