The path of totality is the narrow track the Moon's umbra traces across Earth during a total solar eclipse. Only inside it does the Sun disappear completely; everywhere else sees a partial eclipse. It is usually about 100 to 300 km wide but thousands of kilometres long, and the shadow races along it at over 1,700 km/h.
Understanding Path of Totality
Why the path is so narrow, and why it curves
The Moon is about 400 times smaller than the Sun but also about 400 times closer, so the two look almost exactly the same size in the sky. That is why the Moon's umbra only just reaches Earth: it is a long, thin cone whose tip lands as a spot usually about 100 to 300 km wide, larger when the Moon is nearer and when the Sun is low, because the shadow then strikes the ground at a slant. The Moon's shadow moves at about 3,400 km/h, while Earth's rotation carries the ground the same way at up to about 1,670 km/h at the equator. The difference is how fast the shadow sweeps west to east: at least about 1,700 km/h, and far faster near sunrise and sunset at the two ends of the path. Because Earth is round and tilted, the track looks like a curve on a flat map.
Centre line, edges and how long totality lasts
Totality lasts longest on the centre line, where the middle of the shadow passes overhead, and shortens towards the northern and southern limits. A few kilometres inside an edge it can last only seconds, while the mountains and valleys along the Moon's edge stretch out the Baily's beads and the diamond ring. That is why eclipse chasers aim for the centre line, and why each city page on Orbital Radar gives its own contact times and length of totality rather than one figure for a whole country. On 2 August 2027 totality lasts up to 6 minutes 23 seconds near Luxor in Egypt, the longest over land until 2114.
Along the path on 2 August 2027
How totality changes from place to place along one path, from the Atlantic coast of Spain to Arabia, in local time: