This week marks a special moment in the sky: the March equinox is here.
The sky has its own version of Earth’s equator, known as the celestial equator. Our planet spins at an angle, not straight up and down, which means our relationship with the sun shifts throughout the year. During the times our half of the Earth faces the sun, it climbs higher in the sky, bringing us the warmth and long days of summer. Conversely, when we tilt away from the sun, it stays lower in the sky, leading to the cooler, shorter days of winter.
Summer brings the longest day, celebrated as the summer solstice, while the shortest day heralds the winter solstice. The transition between these extremes brings days when daylight and night are almost the same length. This happens because the sun aligns with the celestial equator. We witness this alignment twice a year, once in March and again in September. This year, the March equinox is set for the 20th of March at 03:06 GMT. Due to time zone differences, some places will experience the equinox on the 19th of March, local time.