Before we jump into premature conclusion with easy answers as 'nothing at all' or 'at least they are both orbiting the Sun' perhaps we could do some quick research for just in case... With equatorial radius of Jupiter almost thirty times bigger than the same property on Mercury, obvious composition difference between one gas giant and small rocky planet and all the other major difference in mass, density, temperature, orbital inclination, orbit period and with almost everything we could compare the two, it is very hard to find the slightest similarity. Not to say that Jupiter in its arsenal is in possession of moons equal or even bigger in size than the smallest planet of our Solar system. However within past couple of seasons, what they had in common was the fact that they were under the spotlight of all of us who from time to time enjoy gazing the sky with naked eyes or through modest telescopes with strong feeling of being the witnesses of our own Solar system ...