ATCHISON, Kansas (OSV News) -- As Psalm 19 says, day in and day out, "the heavens declare the glory of God." But every now and then -- or sometimes every 50,000 years, to be more precise -- they can do it in a somewhat rare way. Comet C/2022 E3 (ZTF) -- more picturesquely referred to as a "green comet" because of its glowing green, icy nucleus -- will, according to NASA, make "its closest approach to the Sun on January 12, and then passes its closest to Earth on February 2." Having last visited in the stone age, the comet may never return to our solar system -- but if it does, it will take another 500 centuries. Some Catholic astronomers and institutions are using its arrival as a teachable theological moment for their students.