They don't, but they can reflect sunlight.
In Greek myth, both Io and Europa were maidens loved by Zeus, they are also related: Io being the mother of Epaphus who had with Memphis a daughter Libya who had with Poseidon: Agenor King of Phoenicia who with Telephassa or Antiope the parents of Europa.
Io Europa Ganymede Callisto
From Brightest to Dimmest: Ganymede Io Europa Callisto Use JPL's HORIZONS web ephemeris to look up apparent magnitudes of jovian satellites.
Neil Armstrong did not walk on either Io or Europa. Armstrong was the first person to walk on the Moon during the Apollo 11 mission in 1969. Io and Europa are moons of Jupiter and have not been visited by astronauts.
Europa, Ganymede, and IO :)
Europa is one of Jupiter's moons. Actally theres Europa, Callisto, Ganymade, and Io. :] Ganymede, Io, Europa and Callisto Jupiter has 67 moons, of which four are major. Those moons are Io, Europa, Ganymede, and Callisto.
Io, Europa, Ganymede and Callisto are the four satellites that orbit Jupiter.
Io and Europa are two of the 63 (known) moons of Jupiter. In Greek mythology, Io was a priestess of Hera and Europa was the queen of Crete; both were lovers of Zeus, whose Roman name was Jupiter. The continent of Europe is also named for Europa; the term has been in use since at least the 1st century CE (AD). The asteroid 85 Io is also named for Io.
Yes, Io is larger than Europa. Io has a diameter of about 3,643 kilometers (2,263 miles), while Europa's diameter is approximately 3,121 kilometers (1,940 miles). Both are moons of Jupiter, but Io is the most geologically active body in the solar system, which contributes to its larger size.
Armstrong visited the Earth's moon, not Enceladus (moon of Saturn), Io or Europa (moons of Jupiter).
The four largest moons of Jupiter discovered by Galileo are Io, Europa, Ganymede, and Callisto.
going by the magnitude scale, Callisto's the brightest. Io 5.5 Europa 5.7 Ganymede 5.1 Callisto 6.1