Wednesday, 19 August 2009

Specks in Space

"Profound and humbling" is how this video describes the image that the Hubble Space Telescope came up with when pointed at a 'dead' part of space for ten days, and I couldn't put it any better. These two images of deep space have as big an effect on me as did understanding evolution for the first time. They make me feel insignificant and yet at the same time joyful at the amazing Universe we inhabit.

Enjoy and wonder!

Pinched from too many tribbles.


Coffeecup said...

Blows your mind doesn't it? I suppose if it's taken billions of years for the light to reach us then what we see now may no longer exist? It's looking straight into the very long distant past? Oh dear, too much for my feeble brain. How does a person try to understand infinity except in terms of their own insignificance within it?

Simply wonderous Puddock, thanks for sharing. xx

Puddock said...

I know what you mean Steph. My brain got a bit frazzled with the thing about the photon 'dying' when it hit the telescope. Did that mean, I wondered, that if we hadn't looked at that photon, it would still be travelling and 'alive'? I felt as if I was getting into 'tree in the forest' territory - if a tree falls in the forest and no-one hears it does it make any noise???

Having puzzled over this overnight I think I get it. Light is energy, like heat or sound. The fact that we see things because of it makes it difficult to be objective about it, I think. If we use rain as an analogy it's easier to understand (if I am getting the physics analogy wrong here I hope someone will correct me!)

Imagine you are standing at the top of a pointy tower. All around you it is raining. The fact that rain falls on you does not stop it raining. Obviously, it is still raining all around you. But it is true that the journey is over for the raindrops that hit you. They cease to be rain and instead become part of your dripping hair or soggy trousers. The raindrops that miss you will carry on being raindrops until they hit the ground far below.

It's the same with light. Light is emitted by a galaxy, like raindrops. The photons of light trundle along until something stops them and then they turn from photons into an image on the back of our eye or on a telescope. There are still loads of photons out there from the galaxy - not just the ones that have missed our telescope but also the ones emitted after the ones that hit our telescope. Does that make sense?

Anonymous said...

Mind-numbing. Mind-blowing. I feel insignificant and overjoyed at the same time. What wondrous sights exist out there in the Universe. We are lucky to be able to see it!

Wild Flora said...

This is a beautiful video. Thanks for posting it.

Your analogy of photons to raindrops is lovely and certainly explains why light from other galaxies continues to exist regardless of whether a few photons are absorbed when they hit a lens (be it that of a camera or that of an eye). However as photons are elementary particles (or waves -- they exhibit wave-particle duality), there are some differences between the way they behave and the behavior of entities at the macro level, such as a raindrop. Notably, when a photon hits a lens its electromagnetic energy excites electrons in the lens, elevating them to higher energy levels. In other words, the energy of the photon is taken up and transformed into another form of energy. As energy cannot be created or destroyed, while the photon itself may be said to have been absorbed or annihilated, the energy itself goes on.

This is incidentally why the "if a tree falls in the forest" question is basically silly. I've never understood why it's used as a Zen koan, unless the point of the exercise is to get people to realize that they are wasting their time pondering silly questions. The sound waves propagated by the falling tree exist until their energy is transmitted to an eardrum, which converts them to a different form of energy. Whether you choose to say that a noise has been made when the tree falls or when the sound is heard is entirely dependent on how you choose to define the word noise.

In contrast, when a raindrop hits your hair though there is some transfer of energy from your body to the rain and vice versa, mostly what happens is that the molecules composing the raindrop adapt to a different set of environmental constraints and adopt a different configuration. Your body doesn't absorb the water, though it may feel as though it has! The water composing the raindrops will continue to exist until the constituent atoms (the H and the O) are broken apart and used to make something else.

Is this a difference that makes a difference (to use a line from Gregory Bateson)? I have no idea. THAT might be a koan worth pondering.

Anonymous said...

Awesome. And to think, this is probably just the beginning. Imagine what more is actually out there that we still don't see -- that we still call "empty."