Astronomical naming question

[Rogin the Armchair fan]

Why did Venus get the name of the brightest planet in the night sky and not Jupiter? Jupiter was the main God, after all. Did the Romans venerate (hmm, might have just answered my own question there) Venus more than Jupiter? One thing that occured to me is that Jupiter is always constant (in brightness), as its lit side always faces us and our relative orbits don't drastically affect its brightness, whereas Venus waxes and wanes over the year and Mars's brightness varies greatly depending on our relative orbital positions?

[hobbes]

Astronomical naming question

Right. Venus waxes and wanes as its orbit is inside ours.
Jupiter doesn't because it isn't.

The brightness of Jupiter does change quite a lot between apojove and perijove. But as it's so far away and you can only see it properly through a telescope, the difference isn't immediately obviously to the naked eye.
Venus is called Venus as it's beautiful, Jupiter is Jupiter as he was the king of the Roman gods and therefore the biggest. Which Jupiter is by a really long way.

[Guy Profumo]

Astronomical naming question

But was known Jupiter was the biggest planet?

Mercury was fast, Mars red, and Saturn slow.

Venus was the evening star / morning star, and Jupiter ruler of the night sky?

[Various Artist]

Astronomical naming question

I suppose you could say Venus is too changeable, for all its spectacular beauty – not only does it wax and wane, its confinement to the evening/dawn sky near the sun means its appearances are always rather more transient and fleeting.

Jupiter, on the other hand, is not only remarkably bright itself but it also stays visible and essentially unchanging in the sky, frequently dominating the celestial view for a great proportion of the night (seasons notwithstanding), for years on end due to its fairly slow movement against the background stars. So in that sense it's the most natural choice to name in honour of the king of the gods.

Edit: If I turn the room light off, for example, then I can see Jupiter quite clearly right now, riding high in the southern sky and shining straight through the window next to me, even though nothing else out there is visible – certainly not on a partially cloudy night with a certain amount of light pollution and glare from the computer screen. If I switch off the monitor and open the window to look out one or two stars come into view (like Spica in Virgo, near Jupiter right now), but nothing else begins to compete. The ancients couldn't have know just how much greater an astronomical body it is compared with the rest of the solar system, but they had already enough reasons to go on when they anointed it the king of the planets.

[Sits]

Astronomical naming question

One day I should learn this stuff. Even I can recognise Jupiter, sometimes Venus and occasionally Mars. Otherwise I'm floundering.

[hobbes]

Astronomical naming question

Well, the really gig one that you can see fairly often? That's the Moon.
And the big shiny one that only comes out in the daytime is the Sun.

[Various Artist]

Astronomical naming question

Sometimes you can even see both... at once! Really!

To fans of Bill Bailey's Qualmpeddler standup show, this is known as 'Chantelle's Paradox':

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[Evariste Euler Gauss]

Astronomical naming question

Well, that was educational from Mr Bailey. Not the sun and moon being two different things, I hasten to add. I knew that. Honest. But that you're not supposed to prick sausages these days before cooking (at least not decent quality ones). Learnt to do that in childhood in the '70s, from my Mum who herself had no doubt learnt it in the old days when it really was necessary due to the inferior quality, higher water content etc. A quick bit of googling confirms that Bill B is apparently correct. Mind you, cutting out the pricking will mean eating more fat.

[Various Artist]

Astronomical naming question

Heh, it is a highly educational sort of show. There's a great 'brick joke' at the end when Chantelle's Paradox returns while Mr Bailey is learnedly discoursing on JMW Turner's The Fighting Temeraire. Really.

Turner's masterpiece does indeed demonstrate the phenomenon admirably:

Of course, from Sits' side of the world all the astronomical bodies will appear upside-down. So the moon will be the wrong way up, and the sun appears underneath the water.