There are many other research applications of solar eclipses, including global gravity measurements, investigations of ionization and radio propagation in Earth's atmosphere and studies of asteroid dust and cometary debris in the innermost solar system. The full range of research opportunities presented by a solar eclipse is too broad to review here. Suffice it to say that solar eclipses promise great value to scientific research for many, many years to come. If the Moon were slightly smaller than the Sun, the best eclipses would be annular ones with no dramatic corona or blackening of the daytime sky. If the Moon were slightly larger, the full glory of the chromosphere and prominences surrounded by the glowing corona would be lost.
Earth is the only planet in the solar system with spectacular solar eclipses.
Thanks to an apparently improbable coincidence, the Sun and the Moon are almost exactly the same size as seen from Earth. The Sun is 400 times larger than the Moon, but it is also 400 times farther away. The table below, adapted from The Sun in Eclipse by Maunder and Moore, shows that there is no other planet where the angular diameter of a satellite is so close to that of the Sun. Still the sizes of Amalthea and the Sun are quite different compared to the similarity between the angular sizes of the Sun and our own satellite. Another interesting case, noted by Maunder and Moore, is that of Mars's satellite Phobos, which subtends an angle up to 12.3 arcminutes as seen from the surface of the red planet.