“Just So Science” – Eyes of the Heavens

By Elf Eldridge 15/05/2011


Yesterday I was given the opportunity to present to the 100 Level Astronomy class from Victoria University using the planetarium software and datasets we use up at Carter Observatory. It was great fun writing the talk, and performing it on the fly with no tests or dry runs for the scripts, and there were only a few *cough* operational errors on my part – so everything went relatively smoothly. Whilst I was researching it however, I stumbled upon a few awesome facts and infographics that I though I would share.

The first is that beautiful infographic above showing the scaled distances between the different sets of artificial satellites permanently falling around our little ‘blue marble’. They can largely be split into 3 zones: Low Earth Orbit (LEO), Mid Earth Orbit (MEO) and High Earth Orbit (HEO). The LEOs are mostly communication  and monitoring satellites, but the vast majority of manned spaceflight (i.e. the Vostok and MIR and ISS were/are all here) also occurred in this region. The MEO region is dominated by the GPS satellite networks, they need to be at this distance to permit triangulation with the maximum number of places on the earth. And finally we have the HEO satellites, those that are geosynchronous and so sit directly above a fixed point on the earth.

Cosmic Microwave Background - the edge of the observable universe
Cosmic Microwave Background - the 'edge' of the observable universe

And here’s the great thing about being human and being alive at this point in human history: look at the bottom of that infographic at how much further away the moon is. We went there. And it’s a hell of a long way, almost 400,000 kilometers – and hopefully one day we will go back. Come on China! Further out than that though are yet MORE satellites – 3 times further away even than the moon! One is the amazing satellite that generated the WMAP data (right), and one that will soon join it is the James Webb Space Telescope – the replacement for the old Hubble telescope.

Further out than that we have the various artificial satellites that are in orbit around Saturn, Jupiter, Mars etc plus the Voyagers – one of which has just entered the ‘heliosheath‘ – the part of our solar system where the effect of the Solar Wind from our Sun is almost completely lost….

Out past that is the ‘Radiosphere’, at a distance of about 70 light years it’s the bubble of radio signals that have been emitted by the earth since they first gained enough power to penetrate the ionosphere in the early 1940s. To give you some idea of scale this is about 14 times further away than the nearest star.

Earths Location in the Universe
Earth's Location in the Universe

Past that, just a little further past a few other ‘bits and pieces’ (see infographic above) at the distance of 13.75 BILLION light years lies edge of our observable universe – usually depicted using the WMAP Cosmic Microwave Background image shown above. This shows small temperature variations (blue = cooler, red = hotter) from the average in the universe when it first became transparent all those years ago…

And we can see ALL THAT. Phew, for tiny people we sure have seen a lot.

And I tried to fit it all into a 45 minute show. I feel such pity for those poor students right now. *Facepalm