On the nights of January 7/8, 1610, Galileo...

On the nights of January 7/8, 1610, Galileo Galilei noted in his notebooks the discovery of the first 4 Jovian moons, which he named after the powerful Medici family, naming them Medicean I, II and III. The name Europa (above left) comes from Greek mythology-Europa was abducted by Zeus (the Greek name for Jupiter) in the form of a bull and bore him many children. Io is also named for a child of Zeus (Jupiter) the daughter of Inachus, who was raped by Jupiter. Jupiter, in an effort to hide his crime from his wife, Juno, transformed Io into a heifer. Calllisto (on the right) was named for another seduction of Jupiter. Callisto was the daughter of Lycaon, who was a follower of Artemis, famous as goddess of the hunt and for her chastity. To punish Callisto for lying with Jupiter, Artemis banished her. Without protection, Jupiter was forced to change Callisto and her son into bears to hide them from his wife Hera’s fury. Eventually, Jupiter placed them both in the sky as the Ursa Major and Minor, the Big and Little Bears (known today as the Big and Little Dippers). Ganymede was the fourth moon discovered by Galileo, named for the shepherd boy known for his incredible beauty and kidnapped by Jupiter. These names would not become common for several hundred years. Today, Jupiter has fifty named moons:

1. Io 2. Europa

3. Ganymede
4. Callisto
5. Amalthea
6. Himalia
7. Elara
8. Pasiphae
9. Sinope
10. Lysithea
11. Carme
12. Ananke
13. Leda
14. Thebe
15. Adrastea
16. Metis
17. Callirrhoe
18. Themisto
19. Megaclite
20. Taygete
21. Chaldene
22. Harpalyke
23. Kalyke
24. Iocaste
25. Erinome
26. Isonoe
27. Praxidike
28. Autonoe
29. Thyone
30. Hermippe
31. Aitne
32. Eurydome
33. Euanthe
34. Euporie
35. Orthosie
36. Sponde
37. Kale
38. Pasithee
39. Hegemone
40. Mneme
41. Aoede
42. Thelxinoe
43. Arche
44. Kallichore
45. Helike
46. Carpo
47. Eukelade
48. Cyllene
49. Kore
50. Herse

and an additional 16 provisional moons:

1. S/2003 J2
2. S/2003 J3
3. S/2003 J4
4. S/2003 J5
5. S/2003 J9
6. S/2003 J10
7. S/2003 J12
8. S/2003 J15
9. S/2003 J16
10. S/2003 J18
11. S/2003 J19
12. S/2003 J23
13. S/2010 J 1
14. S/2010 J 2
15. S/2011 J1
16. S/2011 J2

All images courtesy NASA. Thanks also to NASA for additional historical background