NASA has shared a captivating image of the Earth’s terminator, the thin line separating day and night.

The picture, taken from the International Space Station (ISS) orbiting 267 miles above the Pacific Ocean, shows the breathtaking moment when a new day dawns on our planet.

The ISS, which completes 16 orbits of the Earth in 24 hours, offers a unique vantage point to witness the terminator, a phenomenon that occurs when the sun’s rays illuminate the Earth’s atmosphere, creating a distinct boundary between night and day. This boundary is visible as a thin, glowing line on the horizon, where the blue of the atmosphere meets the golden hues of sunrise.

Understanding the Earth’s terminator

The Earth’s terminator is the moving line that separates day and night on our planet, as per NASA. It is a result of the Earth’s rotation and its position relative to the Sun. It passes through most locations on Earth twice a day, once for sunrise and once for sunset, except for areas near the North and South Poles which experience long periods of darkness or sunlight during winter or summer months.

How Earth’s terminator affects/changes seasons

The Earth’s axis is tilted at 23.5 degrees, which causes the Northern and Southern Hemispheres to receive varying amounts of sunlight throughout the year. This tilt leads to the changing of the seasons, NASA says.

During the equinoxes (March and September), the Earth’s axis is perpendicular to its orbit, and the terminator is straight. Both hemispheres receive equal amounts of sunlight, resulting in milder temperatures and moderate weather.

The solstices (June and December) occur when the Earth’s tilt is most pronounced, and the terminator is curved. One hemisphere receives more daylight than the other, resulting in the longest and shortest days of the year.

The Earth’s tilt also affects the distribution of sunlight, impacting the length of days and nights. As the terminator moves, it alters the environment and influences natural processes.

The March equinox typically occurs around March 20/21, and the September equinox around September 22/23. The June solstice occurs around June 20/21, and the December solstice around December 21/22. These dates can vary slightly due to the Earth’s elliptical orbit and the gravitational pull of other celestial bodies.