Saturday, 2 May 2009

A Question of Cosmology

I'd like to offer this question up to the search engines that may do the amazing job to which they were designed and find this page.

Considering the speed of light, or "c" as is the common denotation, is 299,792,458 metres per second, it does not travel fast enough to give us an accurate visual representation of where very distant objects in space actually are. The usual example is that where we see the sun in the sky is actually where it was about 8 minutes ago as it has taken that long for the light from it's surface to reach us. Saturn is seen where it was 84 minutes ago (at least at time of Cassini's arrival, this changes with it's orbit) and the moon 1.3 seconds in the past. Our nearest galaxy, Andromeda, is seen as where it was a massive 2.5 million years ago!

The Hubble Telescope's "Deep Field" picture taken in 1995 is an image that fascinates me due to the amount of "stuff", i.e. thousands of galazies and their contents, packed into one area. More food for thought is that due to the distance of these objects, what we are seeing is an image going back closer to the time of the Big Bang, almost 13 billion years ago!

One more important thing to consider before my question is that we know that the Universe is expanding and has done so ever since its creation. Not only is it expanding, but so too is the rate of expansion. Earlier thought would have it that it would gradually lose momentum from the Big Bang and possibly condense back together, but this would seem is not so. Without going into the reasons of why the expansion of the Universe is speeding up by plunging the topic of this text into the world of Dark Energy, I'll leave it there.

My question then, is that if the trajectory of our galaxy, the Milky Way, is known, could we then look back, deep along that trajectory to where it has been, to see our Galaxy in the distant past, possibly even to it's point of creation?