Another Blogging Blog

The Hubble Space Telescope (HST) has once again been peering into the dark depths of space and has delivered us another spectacular image of the farthest reaches of the observable universe¹. This image was taken using a recently installed wide field camera, which detects light in the near infra-red portion of the light spectrum, just beyond the red part of the spectrum and which is invisible to human eyes.

HST Ultra deep field image (click for larger view)

The space telescope stared intently at a tiny spot in the sky, which to the naked eye and even most telescopes would appear dark and empty. Over the course of 4 days of looking at that one spot, the individual photons of light exposed an image of hundreds of galaxies in the outermost regions of space.

If this image doesn’t blow you away, then perhaps you just need a little perspective. You might want to take a seat first. In Douglas Adams’ The Hitchhiker’s Guide to the Galaxy the process of achieving a sense of perspective in the universe was the most tortuous thing any sentient being could undergo and a machine was invented to do just that. It was called the Total Perspective Vortex and it gave its victims a true perspective of their place in the universe, which amounted to a “microscopic dot on a microscopic dot”.

I promise not to fry your brains, as the Total Perspective Vortex did, but will instead attempt to open your eyes to the awesome size of the universe. Let me start by describing what a galaxy is, by describing our own: the Milky Way. It is comprised of a few hundred billion stars, much like our own sun and a great many of which have planets orbiting them too. These are the stars we see when we go outside on a dark, cloudless night and look up at the sky.

To appreciate the size of the Milky Way galaxy, we measure it in terms of the time it would take a light beam to travel from one side to the other. In the vacuum of space, light travels at 300 000 km every second, yet it would still take 100 000 years to traverse the galaxy.

Now look again at that picture from Hubble. It contains hundreds of galaxies. And that is just a view of a tiny speck of sky. As far as we know, looking beyond the stars of our own galaxy, every other speck of sky would show the exact same thing: galaxies extending in all directions as far as we can see. And if we could look beyond all those galaxies in the picture, we would likely see more and more galaxies. Because the universe is expanding, the light from all the galaxies will never reach us, no matter how long we stare, but it is obvious that the little we can see is far from little.

If you still can’t wrap your head around what you’re seeing and want to try another perspective, watch the following video from the American Museum of Natural History. It starts with a view of planet Earth and proceeds to zoom out until the view encompasses all the known and observable universe. Hold on to your hats for a wild ride.

When it appears that those around you are busy staring at their proverbial navels, investing their time in the celebrity gossip pages or concerning themselves with how many angels could dance on the head of a pin, it is refreshing to stand back and appreciate the true magnificence of the wider universe in which we live. You may think the universe is something out there and far too distant and abstract to be regarded a part of our daily lives, but thanks to the incredible science and engineering that gave us tools like the HST, we are now able to visualise it, measure it and come to understand it. The universe is here and we are a part of it, and it is more incredible than anything our imaginations might conceive.

Notes and references:
1) Hubble’s Deepest View of Universe Unveils Never-Before-Seen Galaxies
2) Thanks to gfish for bringing this video to my attention.