Evolution of the orbital node position of comet C/1917 F1 during the last 50 thousand years. The red (blue) curve shows the shift in the descending (ascending) node that corresponds to the radiant northward (southward) of the ecliptic. The crosses indicate the starting positions (at the present) and the full triangles are the final position of the nodes in the considered period (only a part of the path of the descending node in a vicinity of the Earth’s orbit is shown). The orbit of the Earth is shown with the circle.