Archive for January, 2009
22 Jan 2009
NT Wright, speaking on Christmas Eve:
‘Unto us a child is born; unto us a son is given; and the government shall be upon his shoulders.’ [Isaiah 9] Unless you sigh with relief at those words, you haven’t really been listening. What we need just now, more obviously than ever in my lifetime, is someone to shoulder the burden, someone who can get under, pick up our multiple problems and carry them for us.
It should be obvious by now that nobody locally or globally has the slightest idea how to address, let alone solve, the crisis that has come swiftly upon us. And I’m not simply talking about the voting methods in Strictly Come Dancing. I’m talking about those admittedly lesser concerns, the problems of global power, global finance, global humanity as a whole.
We have of course just witnessed a kind of secular version of Isaiah 9. The election of Barack Obama has been hailed with wild delight around the world. ... The whole world was hungry for hope, and now Obama, who is indeed brilliant, charming, shrewd and very capable, is being told that the government of the world is upon his shoulders, and we expect him to solve its problems. Poor man: no ordinary mortal can bear that burden. Nor should we ask it of him. The irrational joy and hope at his election only shows the extent to which other hopes have failed, making us snatch too eagerly at sudden fresh signs. And that can only be because we have forgotten the Christmas message, or have neutered it, have rendered it toothless, as though the shoulder of the child born this night was simply a shoulder for individuals to lean on rather than the shoulder to take the weight of the world’s government.
Because this night, together with its senior cousin, the night of Easter, is the real night for which planet earth was waiting and to which it must look back if it wants to know the way forward. We place too much trust in our politicians because we place too little trust in God, and in the self-revelation of the living God in the child who is born to us. And when our politicians let us down, all we can think of is ... how to find another politician, who will get it right this time. ...
Jesus isn’t simply another politician on whom everyone can pin their hopes and who will then let them down. His way of establishing God’s justice and peace on the earth was different to Caesar’s, different to the usual power games and money games, different in source, different in method, different in effect. We are today hungry for exactly that difference, and Christmas night is the time to ponder it. ...
And Isaiah cries out, and Luke in his spectacular Christmas story cries out too, that it’s time for a different kind of world, a different kind of empire. What we need is a new economic system, a new way of doing global politics, a new style of leadership. That’s what the Christmas message is all about: ‘Unto us a child is born, a son is given, and the government shall be upon his shoulders. And his name shall be called, Wonderful Counsellor, Mighty God, Everlasting Father, Prince of Peace.’ Christmas is all about the coming of the world’s true king, the one who stops wars, who forgives debts, who establishes true justice and judgment in the earth.
20 Jan 2009
Astronomers spend a lot of time making computer simulations of the Universe. Some discussion on The e-Astronomer's blog has set me thinking about why...
- To help us work out whether the stars and galaxies in the Universe could have arisen from much simpler beginnings. The Universe is quite a complex and diverse place. How did it get like that? Did it start off simple and gradually grow in complexity? Or is that completely implausible? Of course, we'll never get a definitive answer, but computer simulations can give us some pointers. However, at some point you have to say enough is enough and decide whether the answer is probably "Yes" or "No". It seems to be "Yes", so do we really need to keep doing more and more simulations?
- To find or test the laws of physics. If we plug the laws of physics into a computer simulation and find that it reproduces the observed Universe perfectly, then that suggests we were right after all. But if not, maybe we should try tweaking the laws of physics to see if that improves things? Again, this is an exciting question to ask, but simulations are nowhere near good enough to be able to do this - and it's questionable whether they ever will be.
- To reproduce observations. We know from observations that galaxies have XYZ properties. After N zillion CPU hours, our expensive simulation is able to reproduce XYZ. Wahey! This suggests that the simulations are working, which is good for establishing number 1 above. But there will always be fresh observations for the simulations to replicate, so what's the point of continuing indefinitely?
- To give observers something to look for. Our simulation of XYZ suggests that galaxies will also have ABC properties. Please Mr Observer, is this the case? Give me a few billion for a shiny new telescope and I'll tell you... Yes it is! Wahey! (Or, No it isn't - go back to step 3 and reproduce what we actually found.) Again, this can help to establish whether or not simulations can work (point 1 above). But once that's been established, it's another unending road to nowhere...
- To reconstruct the history of the Universe. To my mind, this is by far the best reason to keep on with the simulations. It's not a competition between simulations and observations, each trying to stay ahead of the other, but it's both working together (along with a hefty dose of human intuition and creativity) to uncover the sequence of events that made the Universe what it is today. So the aim is not primarily to formulate a simple mathematical description of the Universe or to quantify things with great precision. But astronomers are on a quest more akin to that of a historian, an archaeologist or a forensic scientist - first to figure out what actually happened, and then to communicate the excitement and drama of that story to everyone else.
- To make pretty pictures and animations. Okay, I lied. This (and this) is what simulations are for.