The scale of the universe

Not to long ago, I pointed to a rather effective illustration of the scale of the microscopic from cells to atom courtesy of the University of Utah.  In my opinion, though, it is the scales of the large that are truly mind blowing, but unlike the scales of the small, there isn’t one illustration that really gets the point across, but that doesn’t mean there is a scarcity of effective illustrations.

To start off, here’s something I made myself to show the size relationship between the eight planets of our solar system:

Solar system scale

I find it humbling to see that Jupiter has a permanent storm that is as wide north to south as the Earth is and even wider from east to west.  Imagining the immensity of the Earth is a task in itself.  Seeing the Earth as a relatively small planet really drives home how limited our viewpoint is.

But what takes it to the next level is not the size of objects on the grand scale, but the distances between them.

This is a representation of the distance between the Earth and Moon relative to their sizes (click to enlarge)

Earth moon distance

When I look up at the moon in the night sky, I can’t intuitively imagine it to be that far away.  It really is hard to imagine that there is the distance of 30 Earths between me and the moon.  But this is just the beginning.  That should be obvious when one compares the size of Jupiter to the size of the moon in the sky keeping in mind both the size of Jupiter and the Moon relative to the Earth and the size of the gap between the Earth and Moon.

A scale model of the distances present in the solar system can be seen at this web page*, where the sun is 562 pixels across.  The Earth is consequently 5 pixels across and just short of 60,000 pixels away.  If you properly page across the screen one click at a time, you can get a good idea of the scale involved.  It becomes very understandable that the fastest spacecraft ever launched from Earth started a journey to Pluto in 2006 that will take until 2015 to complete.

But the fun doesn’t stop there.  Compared to the nearest star, Pluto is ridiculously close to us.  If the distance between the Sun and Pluto were represented by a single pixel on your monitor, the distance to Proxima Centauri would be about 1.2 times the vertical height of my blog’s home page.

If we take that unfathomable distance to nearly the same proportion, we find the distance to to center of the Milky Way Galaxy.  If you want to get a good idea of the positions of objects within our galaxy and of galaxies beyond our own, I would suggest Where is M13?, which shows where objects in the night sky are relative to Earth along the galactic disk and plane of the Milky Way.

Another well done illustration of the size of Astronomical objects was done by Paul Stansifer and was uploaded in image form to the Wikimedia Commons by 84user. It starts will the scale of small planets and dwarf planets and moves up to 10 light years through powers of 10.

All in all, the scale of the universe exceeds the span of the human imagination many times over.  We can get a taste of the scales of the grand by comparing them to smaller yet still unimaginably immense objects, but in the end, I think that the only appropriate reaction to them is sheer awe.

*hat tip: Phil Plait


About Meng Bomin

Real name Benjamin Main, I am a graduate of Grinnell College with a degree in Biological Chemistry.
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