Daily cosmobite: Jupiter at its brightest

The giant planet Jupiter is eleven times wider than the Earth and could fit 1300 earths inside it. Jupiter can be seen each evening after dusk low in the north-east sky. Tonight the planet is at opposition, that is, in a direction opposite to the Sun, and at its closest to Earth and at its brightest for the year.

5 responses to “Daily cosmobite: Jupiter at its brightest

  • i dont mean to be painfull but this is the second time in as many days i have seen comparrison sizes of the earth and another celestial object, from my perspective,given with seamingly incorrect results and i would just like to enquire as to how these results were calculated?
    from my understanding the cube of 11 would give the approximate result of 1300 earths fittign into the planet jupiter, and this was also the case with the other comparission i saw saying 1milling earths would fit into the sun being a body 100 times wider than our earth. Would not both of these comparisons require that the larger object in fact be a cube shape? I was thinking that a more appropriate method of simply calculatign the amount of earths fitting into, say jupiter, would be to cube the radius of the larger object (in this case cube of 5.5 being half that of the 11 times larger planet) and then multiply this resuly by Pi? Please let me know if im am on the right track with my reasoning as im gettign a little confused with the apparent dispatiry with my thought processes and the accepted scientific media releases that i have seen recently.

    • Hello Gerard. The volume of a sphere is 4/3*pi*radius cubed. So the ratio of the volumes of two spheres is the ratio of their radii cubed as the 4/3 and pi factors cancel out. This is equal to the ratio of their diameters cubed. So in considering how many times the volume of Jupiter is greater than that of Earth all we need to do is cube 11 with the approximate result of 1300.

      Of course, in reality if you were to pack 1300 earths into the volume of Jupiter there would be some empty space as well as they would not fit perfectly together and it maybe necessary to remove a few earths. I leave that calculation for the student.

  • Hi Nick, I wonder if you could tell me whether it was also Jupiter I saw this morning just before sunrise near the eastern horizon? It was an extraordinarily large star (or planet) and all references I can find online today mention Jupiter, so I can only assume that’s what it was. I also saw another bright object, not quite so large, but noticeably larger & brighter than anything else nearby, in a more north easterly direction, at the same time, any idea what that might have been? Not sure it makes any difference, but these observations were in Qld (so not DST) at approximately -26.36 S, 152.84 E
    thx in anticipation

    • Hello Jenny. You were not looking at Jupiter as it is at opposition, which means that it is opposite the Sun. So as the Sun was about to rise in the east, Jupiter was setting in the west. The very bright object you saw was the planet Venus that is currently visible in the eastern sky before dawn. Below Venus, towards the south, the planet Mercury would have been visible while above Venus, towards the north, you may have seen the planet Saturn. Alternatively, you may have seen the bright star Spica which is is above Saturn and to its north.

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