Where we were November 11, 2006

I love trying to get a grip on reality - and it's not easy when it comes to looking at the sky from the perspective we get on the surface of this tiny planet. Really understanding what we are seeing and how all the pieces are moving and where they are at any moment is challenging.

The orrery - a clockwork mechanism - was invented a couple hundred years ago to demonstrate how the planets move around the sun and a computerized version of that helps. But what I really liked was combining an online orrery view with the Astronomy Picture of the Day - which today came from the SOHO satellite. (Credit: SOHO, ESA and NASA.) What the orbiting instrument has done is block out the glare of the sun so we can see four of the planets which from our perspective are very close to the sun - too close, in fact, for us to see any of them in our sky right now. The picture covers about 15-degrees - that's about half again as much sky as is covered by your fist held at arms length. Anyway, study it first.

Once you have that firmly in mind, then look at this "overhead" view of the solar system provided by the online orrery at "Solar System Live." (Links at end of post.) I added arrows and labels to the image.

This modified screen shot was taken from what the orrery shows as the planet positions at the same time as the SOHO image was taken. If you picture yourself on the Earth - best place to be in the solar system, I might add - and you imagine looking towards the sun (along the line of the arrow) it's easy to see that Mercury and Mars are to the right of the sun, from our perspective, and Jupiter and Venus to the left - just as the SOHO image shows. However, as the Orrery demonstrated, they are far from being in a straight line or any where's near one another - and that's just the kind of perspective I find fascinating.

Every time I look at the planets in our sky I try to get it firmly placed in my mind exactly where they really are in relation to us - build a 3-D mental model.

Great links related to all this:

SOHO Some incredible free stuff here - check out the links on the left of the page and get to know our nearest star better!

Astronomy Picture of the Day Always fun.

Solar System Live - One of my favorites and where I found the orrery, plus an explanation of the derivation of that strange word.

While looking for a more precise orrrery picture, I found an orrery that was a bit simpler here.