Sunday, 2 June 2013

Rivers Of Babylon

Before i take a look at the previous entry, here's this:

Click to tweet:  .  This is Sarada reciting her poem 'When The Rain Falls' (copyright us, 2013 - haven't decided about intellectual property rights yet) at Sing For Water, an annual choral singing event to raise money for the charity Water Aid ( http://www.wateraid.org/uk ) at the Riverside Festival on Bede Island in Leicester.

Short and to the point!  An unadorned video of Sarada (Liz), with no outro.

The slightly irritating thing about this video is that i had to exclude almost everything that happened at Sing For Water because of performing rights and privacy, which raises another question:  how the heck do people ever manage to make big videos full of crowds of people and so on without going through all that?  For instance:

Ooh look, it's Bing!  Anyway, clearly people don't go around getting consent and all that, but it seems a risk. Maybe i'm just too timid.

Now for yesterday's vid:

Click to tweet: http://clicktotweet.com/m187X .  People often ask, "what is the Universe expanding into?"  Whereas there may be a real answer to this, because of brane theory, even if that's true it may be an improper question reflecting a misunderstanding of the nature of space.

The idea of the Universe being like the skin of an inflating balloon is a popular metaphor but also probably misleading.  Space is indeed very likely to be expanding and that is definitely in a way like standing on the skin of an inflating balloon watching the rest of the Universe recede in all directions, except of course that it's in three dimensions rather than two.  The problem with that image is that it suggests that the Universe is situated in hyperspace and "blowing up" into a hyperspace which already exists.  This is an absolute view of space.

Gottfried Wilhelm Leibniz saw time as a relationship between events.  In his view, which has turned out to be wrong, relationships such as earlier, later and simultaneity are transient, and if X is later than Y and Y is later than Z, then X is later than Z.  Relativity shows this to be incorrect because time is more like love than height - X can love Y and Y can love Z, but it doesn't follow that X loves Z if X loves Y and Y loves Z, and time is similar.  Nonetheless, space can be seen as like time in this way, consisting of a relationship abstracted from direction and distance. To illustrate this, i introduce a thought experiment where he imagines a finite material Universe surrounded by infinite empty space, which is then shifted instantly to one side.  There would be no way to tell that this had happened, and therefore it can't.  This is said to be because space is a relationship between objects rather than a container for them.

Isaac Newton disagreed, pointing out that inertia and acceleration appear to demonstrate that an object "knows" it's moving through space, and that therefore space must indeed be like a container for objects, although a highly unusual one and unprecedented in science because it cannot be observed as such.

A few centuries later, along came Albert Einstein, who presented another experiment for our minds:  suppose a train is moving past us close to the speed of light and a light goes on in the middle of the train.  Since someone standing on a station next to the train will perceive light as moving at the same speed, they will see the light reach the back wall of the carriage before it reaches the front wall, but for someone standing directly under the light, it will seem to reach both ends at the same time.  In other words, simultaneity is an illusion.

Einstein also said space was curved.  This doesn't quite mean what it appears to.  Space in fact has properties which are not easily observed on this planet and the scale on which we live.  There is in reality a maximum possible distance between two objects which if "exceeded" will result in a change of direction between them.  Space is expanding in the sense that the maximum possible distance constantly increases.  This is completely different, though potentially compatible, with the idea that the Universe is expanding into some kind of mysterious void, and to consider that it is resembles the idea that there is something north of the North Pole - it makes no sense.

This is slightly complicated by the fact that 'brane theory may be corroborated, but even if it is and it does turn out that in some way the space we know is a membrane like an expanding bubble in hyperspace, that needn't alter the fact that space is a relationship between objects combining the ideas of direction and distance, and not a container for those objects.

I hope that makes sense.
This came out of one of those endlessly repeated questions on Yahoo Answers, this time from Astronomy and Space for once (the other question there is about the Apollo hoax (which it wasn't, of course)).  It's also an example of a question which sounds like it's about science but is more philosophical.  As a video, it's yet another example of one i may as well not have bothered to make because it won't get watched.  Ah well, at least the mpreg vlog's doing OK.