Friday, 25 May 2012

A tour of the universe

As I have already said in this post and on Twitter (@scienceontoast), my recent adventures in the world of online science communication have rekindled a childlike enthusiasm for cool science that I have not felt for many years.

The unimaginably vast and mysterious universe is at our fingertips like never before thanks to fast internet, clever web content, and the power of social media and collaborative projects such as Wikipedia.

I've heard it said that the human mind simply cannot comprehend nor imagine the sheer size and scale of our universe. This may be true, but a clever web app by Cary Huang helps us get a little bit closer. (Thanks to Ashley Youett who originally sent me the link. It's been popular since on Twitter).

The Scale of the Universe 2 is a window with a sliding scale bar which the user controls to zoom through the length scales of the universe, starting out on our human scale and then delving down through the realm of the ant, the human ovum, bacteria and viruses, through our own DNA, atoms and molecules and right down to the nucleons, quarks and finally the Planck length, the fundamental quantum unit of length. Each object has a picture showing its relative size and potted info on each item is available with a click. I counted 12 empty orders of magnitude (a factor of 1000000000000) between the smallest elementary particle and the Planck length. To very tenuously paraphrase the great Richard Feynman, "there's plenty of room at the bottom". The universe really is an incredibly empty place.

Zooming back out quickly to the human scale again, we then start pulling back the camera to explore larger and larger objects. We learn that a marathon runner would have a good chance of running from pole to pole on a neutron star without stopping for lunch (but would succumb to some heinous gravity) and that the projected size of the moon is about the same as that of the continental USA (or Australia!).

The most fascinating part for me, though, is the stars. The stars cover sizes only a bit bigger than the Earth (the example is the white dwarf Sirius B), and in relative star sizes, the Sun is not really much bigger. Stars can really be stupendously large, with the largest red giants on the scale 10000 times bigger than the Sun!

We draw back further and swim through planetary nebulae, star clusters and galaxies. It astonishes me to think that in every single galaxy out there in the universe there are hundreds of billions of stars and I feel convinced that our there somewhere, perhaps even in our big sister Andromeda, there is intelligent life gazing out into space with the same sense of unfathomable scale and longing.

As we survey the galactic clusters that make up the larger superclusters and the filamentous structures that are formed by the distribution of matter in our universe, we eventually reach a limit: since light takes time to reach us, each distance further we can see takes us further back in time. We can see so far back in time, in fact, that distant universes are mere embryos, relics from much earlier in the history of the universe than we are in the present day. We can see so far back that we can see the very point at which the opaque soup of the universe first became transparent. Beyond this, we can see no more!! This is the limit of the observable universe, the curtain beyond which we can no longer reach the enquiring power of our telescopes. The nebulous grey beyond this in The Scale of the Universe 2 represents our uncertainty about exactly what comes before (although we have a pretty good idea right up to very, very early times in the formation of the universe, but for that we will have to talk about the Large Hadron Collider).

The Scale of the Universe 2 is by no means the first of its kind I’ve seen (and I assume there was a Scale of the Universe 1) but it is a fascinating tool to help us understand, in some small way, the true scale of the universe. It is also useful for one of my favourite pastimes... making my mind boggle, on purpose!

Monday, 7 May 2012

The Moon is fascinating, Super or not

I was treated to a celestial wonder this evening and this time, I was ready. The much-fabled Supermoon appeared out of the kitchen window glowing like a lantern, and I took to the streets with camera, zoom lens and tripod at the ready. The photo below was taken using a fairly standard digital SLR with a 55-250 mm lens at full zoom.

The Supermoon, which has attracted much attention in the online science world this week, is unusually large and bright and is caused by the conjunction of a full moon with the rocky satellite's closest approach to planet Earth for several years (although if you ask Wikipedia there are 5 Supermoons a year and there are plenty of pictures of one in 2011, so I may have missed a trick somewhere). The moon's elliptical orbit brings it periodically to this close approach or perigee.

Statistics vary but to pluck some from the air the Supermoon is claimed to be 14 per cent larger and 30 per cent brighter than at other times. I'm not usually cynical, but to the uninitiated however, I doubt somehow that the Supermoon would have illicited much of a reaction (unless seen in some dazzling context like rising above the minarets of Mecca or silhouetted by the Eiffel tower). The fact is, the Moon is pretty fascinating the whole time (less so when it's invisible of course) and I'm glad that the media attention from the Supermoon spurred me to point my camera skywards.

The next photo would probably draw peals of laughter from even the least experienced astronomer (or photographer for that matter). I decided to point the lens at a different part of the sky and give my Northern Hemisphere friends something a little special from Down Under, a little known constellation called Crux which I understand has some significance with the locals. OK, the photo is awful (there was a large street lamp metres away) but I was very pleased with the results considering the ease of taking the shot.

(For something a little more accomplished in this vein, have a look at these fantastic star trail pictures, thanks to Ben Kent for the link).

I am much indebted to the Supermoon for raising its 14-per-cent-larger head and inspiring me to peer up into the night sky. Having learnt this week that the Andromeda galaxy is 6 times wider than the full moon on the sky (provided you have the gear to see it), I am very excited about doing some stargazing in the very near future.