Galileo and the Jovian Satellites

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.