The actual diameters of the Sun and the Moon are vastly different. Their angular diameters are very similar, the very basis of a grand spectacle these give rise to whenever the Earth, the Moon and the Sun get so aligned as to cause an eclipse of the Sun by the Moon.
The orbits do not lie in a plane, that of the Moon is inclined by a little over 5° to the Earth’s,
and so a solar eclipse does not take place on every New Moon day. The eclipse of 22 July, 2009 had the longest total phase in a solar eclipse in the 21st Century: In fact, the totality of longest duration in any solar eclipse between 1991 and 2132.
The next eclipse that will surpass it in duration is due on 13 June, 2132 only. The 22 July 2009 eclipse offered a totality lasting several minutes all along the path, lasting for up to 6 min 39 sec in the ocean about 100 km south of Bonin Islands, southeast of Japan. The eclipse magnitude (the fraction of the Sun’s diameter was obscured by the Moon) was quite large, being at 1.0799.
The maximum theoretical duration for a total solar eclipse is 7 min 31 sec. The maximum width of the path of totality is about 250 km. The closer one is to the centre line of the path of totality the longer is the duration of totality.