It’s all in the perspective

As I write this the sky is showing off.

We are witnessing the coming together in our sky of our two brightest planets – Jupiter and Venus.

The King meets a Goddess...Venus and Jupiter 13th March 2012

They have been moving closer all winter and now on a cool, early spring evening, after a spectacular sunset, they have reached conjunction.

But what is really going on?  As ever in astronomy it is never straight forward and this particular cosmic event is all a matter of perspective.

Jupiter and Venus are not meeting.  They can’t.  In fact Venus is closer to Mars which to see this evening you will have to turn around almost 180 degrees and face east.

Yes that’s right.

The bright red planet you can see to the east, behind you as you watch the conjunction is closer to Venus than Jupiter is.

It’s all in the perspective.

Tonight Venus is about 75,500,000 miles from Earth.

Mars is a mere 63,300,000 miles from us and 119,970,000 miles from Venus.

Jupiter on the other hand is a staggering 523,311,000 miles from Earth this evening, even further from Mars and over 447,000,000 miles from Venus.  A crude drawing of tonight’s positions looks something like this…

Yeah ok, very crude, but you get the point!

What we are witnessing is two planets ‘lining up’ from our perspective.  If you were to stand on Venus (not recommended) and look out at the sky, Jupiter would sit alone while in another part of the sky Earth and Saturn would appear in conjunction.

If you were in the vicinity of Jupiter then Earth, Venus, Mars and Saturn would all be appearing in a  stunning ‘super-conjunction’ if you could see past the suns glare!

Tonights 'super-conjunction from the surface of Europa! (screen shot from Stellarium)

Does this mean a conjunction is meaningless?  In some respects it is just a playing out of orbits and angles and tonight’s spectacular view is just a perspective unique to this particular time and position in the Solar System, but then surely that is itself pretty special.

Nowhere else in the universe and at no other time will people look up in the sky and see these two planets meet at these angles and mind-bending distances.  Maybe we are the only eyes in the universe contemplating such spectacles, either way it is still very beautiful and demonstrates the stunning mechanics of our Solar System.