According to calculations by the National Astronomical Observatory (OAN), spring in the northern hemisphere begins this Saturday, 20 March, at 10:37 a.m. EDT. This season will last 92 days and 18 hours and will end on 21 June, with the beginning of summer.
The sky at dawn will be dominated by Jupiter and Saturn. In the evening Mars will be visible, joined by Venus at the end of April and Mercury during the month of May. On 26 May a total lunar eclipse will be visible in eastern Asia, Australia, the Pacific and the Americas. And on 10 June an annular solar eclipse will be visible in North America, Europe and Asia. This last eclipse will be visible from Spain as a partial eclipse.
The beginning of the seasons is given, by convention, by those moments when the Earth is in certain positions in its orbit around the Sun. In the case of spring, this position is when the centre of the Sun, as seen from the Earth, crosses the celestial equator in its apparent northward motion. On the day when this happens, the length of day and night practically coincide. This is also called the vernal equinox: Equinox, from the Latin aequinoctium (aequus nocte), “equal night”.
Possible dates for the start of spring. Throughout the 21st century, the onset of spring may occur on at most three different calendar dates (19, 20 and 21 March). The earliest onset is in 2096 and the latest onset is in 2003. The variations from year to year are due to the way the sequence of calendar years (some leap years, some not) fits in with the length of each orbit of the Earth around the Sun (known as the tropic year).
Day length. Early spring is the time of year when the length of the day lengthens most rapidly. At peninsular latitudes, the sun rises more than a minute earlier in the morning than the previous day and sets more than a minute later in the evening. As a result, in early spring, the time the sun is above the horizon increases by almost three minutes each day.
Solar activity. Solar activity. The Sun’s activity is characterised by the presence of spots, flares and bulges on its surface, and on the Earth, it is seen in alterations in the propagation of radio waves and in an increased presence of polar auroras. This activity follows a period of approximately 11 years, and is associated with the Sun’s magnetic cycle. We are currently in solar cycle number 25, which began in December 2019 and is predicted to peak in July 2025. According to estimates made by NOAA and the Space Weather Prediction Center, during the spring the number of sunspots will reach values between 21 and 47. Graphs showing the number of sunspots in recent years and predictions of the evolution of cycle 25 can be found on the web.
For more information on the year’s astronomical phenomena, please consult the Astronomical Yearbook, a book published annually by the National Geographic Institute.
Original source: National Geographic Institute