Venus, Jupiter and Moon – why so different from Australia?

moon_v_j-photo

It was a stunning event and fortunately the clouds held off until we were done observing. Unfortunately, my camera battery died – I had forgotten to check – and I didn’t have a spare with me. So I only got a few shots of the early stages. Later it was a brilliant, awesome display and hopefully others in our small group had better luck with their photos. Stay tuned. I hope to update this post. These are the three brightest objects in our sky after the Sun!

Ahhh! David Cole of Westport got a much better shot that evening – here it is. (Posted 12.11.08)

mjv_cole

And don’t forget to look tonight! No, the moon won’t be so close, but the planets still put on a great show and will for the next couple of weeks as they change position from night to night. Good way to get an intuitive understanding of why the ancients called these “planets” – a name which means “wanderers.” They’re also bright enough to see from even light-polluted suburban – and some city – skies.

Meanwhile, there are lots of good shots from Australia online here and this one was taken there by Guy Tunbridge. It’s interesting because the Australian alignment was much different than ours. Do you know why? Answer to come later, but feel free to add your explanation to the comments on this post. Note that not only is the moon oriented differently, but Venus and Jupiter have switched places.

moon_v_j_australia

Update 1: Does seeing them together help?

mvj_us_au

Ideally, your explanation will account for three changes:

  1. The side of the moon that is lit appears to change – or at leasr the orientation of it.
  2. In the US Jupiter is higher than Venus. In Australia this relationship is reversed.
  3. If you drew a line between Jupiter and Venus the orientation of the line would change.

If you stand on your head does it make any difference? (I no longer can do that so it’s a little hard for me to gather experimental evidence 😉

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4 Responses

  1. It’s because people in Australia are standing upside-down! (from my point of view)

    And they were viewing the event at a different time, when the moon is in a different location in the sky.

    So, there is a difference in both time and orientation.

  2. You’re right – the big change is in the time. The event happened about 15 hours earlier in Australia and that’s plenty of time for the Moon to move from one side of Venus and Jupiter to the other and thus present us with a frown rather than a smile. I’m sure of that part.

    But I don’t think folks in Australia are standing on their heads, relative to us. They’re more like lying down, though not quite that. However, here’s where I’m still puzzled. Yes, there’s a change in orientation, but I can’t really get my head around it.

    The numbers mesh nicely. This whole arrangement of Moon, Venus, and Jupiter swings through an arc of about 75 degrees. You can draw the arrangement on a piece of paper, then pivot the paper through a 75-degree arc and you’ll see this change. (If you include the moon you have to remember it jumps from one side to the other as well.)

    But we need to account for Jupiter being higher than Venus in our sky and lower than Venus when seen from Sydney, Australia. Pivoting the arrangement 75 degrees does that – and since we’re at roughly 41 degrees north latitude and Sydney is at roughly 34 degrees south latitude, that means the difference between us is 75 degrees.

    That’s nice and I don’t think it’s a coincidence – this is obviously related to latitude – but I still have trouble visualizing it. I can’t stand on my head, but I can lie down – and I can’t make this happen by simply doing that, so . .. I’m open for an entirely different explanation, or someone who can help me understand why this is the correct explanation 😉

    It’s funny – I know and fully understand how my view of the stars changes as I head either south or north – or for that matter, east or west – but this change of perspective with the planets and Moon is leaving my head spinning.

  3. […] Venus, Jupiter and Moon – why so different from Australia? […]

  4. […] – a frowney face over us – but by all means a spectacular sky event. (See this earlier post, and this one, and this […]

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