Tomorrow, 20 March, is an equinox day. This means that for those in the northern hemisphere winter is ending and spring has ‘sprung’. For our counterparts south of the equator summer is ending and fall is beginning. From a geographical perspective we would describe the Sun as being over the Earth’s equator, and as this graphic shows there would be an equal amount of daylight and night on our planet as a result.
At the equator the sun is directly overhead and from that latitude you have no shadow, just a ‘blob-like’ shadow at your feet as this picture of my feet taken at mid-day in Quito Ecuador shows.
Northern hemisphere spring officially (well at least astronomically) begins at 11:57 am CDT (16:57 UT) Thursday 20 March when the Sun reaches the celestial coordinates of 0 hours and 0 degrees as it moves northward along the ecliptic crossing the celestial equator. To learn more about the celestial coordinates click here to read a previous post about seasons and the equinox.
Click here to see the online world sunlight map used to make the day/night graphic above.
Click here to go to the NASA Sun-Earth Days web site.
Here is a short series of hourly pictures taken during the day on the September equinox on the equator in Quito Ecuador at Collegio Menor San Francisco de Quito, a private school that I visited and did the SunShIP project with (Sun Shadow Investigation Project).
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.