The EU’s Interreg programme selected a project on the last continental sunsets (in which researchers from Ireland, France, Portugal and Spain participated) to celebrate European Interregional Cooperation Day in its Atlantic area. We organised the events on Friday on the Costa da Morte, as on that day the last European sunset can be seen in that area and at Cabo da Roca (Portugal).
The fact that there is more than one observation point for this phenomenon is a consequence of the inclination of our planet’s axis of rotation with respect to the plane in which we orbit around the sun. When the Earth was very young, it did not have this axial tilt (the solar system has a preferred direction of rotation, inherited from its formation process), but it was twisted after receiving a huge impact from a very large body (it is believed that the moon was formed from the fragments that broke off). The orientation of this axis remains fixed in our annual journey around the sun (ignoring long-term phenomena such as precession and nutation) but, as we orbit, the orientation of this axis looks different from the sun: it illuminates us in a way that varies considerably. Thus, in December, the northern hemisphere is less exposed to the sun: winter. Six months later, we are on the opposite side of the orbit, and the northern hemisphere is tilted more towards the sun: summer. This Monday, 22nd, although the axis remains tilted, it is positioned so that the northern and southern hemispheres are equally illuminated: the equinox.
Source: La voz de Galicia