I'm surprised that the answer to 12 isn't "different planets at different times". When Mercury begins or ends a period of retrograde motion (as observed from Earth), it wouldn't seem to be moving "quickly across the sky, when observed from Earth".
I think this question is fine. Interpret it along the lines of "when a planet is moving as fast as any planet moves across the sky as seen from Earth, which planet is it?"
Superb video by Lemmino about the planets recently:
https://www.youtube.com/watch?v=LhfCietvDZo
Apparenty around Herschel's time most astronomers assumed that the moon and the other planets had civilisations on them, and Herschel himself believed that there were people living on the Sun! I don't know if that's an interesting fact yet but it certainly shocked me!
I'm only 20, but the fact that Pluto isn't a planet anymore still messes with me. I was in elementary school shortly after the IAU demoted Pluto to dwarf planet, but my teachers were on the older side so we still talked about Pluto as though it was a planet. If I have so much trouble accepting this, I imagine it must be infinitely more difficult for people who have lived their entire lives with Pluto as the 9th planet.
I'll always instinctively think there are 9 planets, but it's worth remembering Pluto was only discovered in the first place in the 1930s... and then Neptune before that in the 1840s. So it's always been in flux. Plus the "dwarf planet" category does make sense; there's what was previously classed as an "asteroid" in between Earth and Mars called Ceres which is a third the size of Pluto and, like a planet, is spherical. It's all a bit more complicated than they teach us in primary school.
I lived most of my life with the knowledge that Pluto was a planet, yet I had no problems accepting the new classification. Why? Cause it makes sense, and cause emotional attachments and tradition don't have a place in the natural sciences.
The closest planet to Earth question was really smart. I instinctively clicked Venus because Venus' orbit is the closest to Earth's orbit, forgetting that when Earth and Venus are on different sides of the Sun Mars and maybe even Mercury could be closer. Only one I got wrong
it has been proven that the orbits of both Uranus and Neptune cross over one another meaning that at different times Uranus is the farthest and at other times Neptune is the farthest
Farthest distance of Uranus from the Sun: 20.1 AU. Closest distance of Neptune to the Sun: 29.8 AU. Doesn't even come close. The pair you are thinking of is Neptune and Pluto, not Uranus and Neptune.
I was gonna say 'oh but Herschel discovered both planets' (or more accurately calculated Neptune) but I don't believe that happend in 1871 so you were indeed correct!
https://www.youtube.com/watch?v=LhfCietvDZo
Apparenty around Herschel's time most astronomers assumed that the moon and the other planets had civilisations on them, and Herschel himself believed that there were people living on the Sun! I don't know if that's an interesting fact yet but it certainly shocked me!
Cool quiz! 5 stars :)