Does the water-level in the pool rise or fall or stay the same?11 It is a very hot day so you open the refrigerator in your kitchen to cool the room – is this a good idea?12 In a future society, the postal service becomes so corrupt that anything sent unlocked will definitely be stolen by the postmen. You leave them outside for a day or two till they are only 98 per cent water. So how much does the sackful weigh now?5 Why do tapirs and parrots in the Peruvian jungle regularly eat clay?6 Given an evenly weighted coin with heads and tails, spun six times, which sequence is most likely: HHHHHHH; TTTTTT; HTHTHT?7 What role did basic science play in the invention of the aeroplane and steam engine?8 Why do healthy old elephants die?9 If I go into a perfectly flat field a with two bullets and fire one from a gun horizontally and drop the other at exactly the same time, which hits the ground first?10 You are in a small boat in a swimming-pool and there is a stone in the boat.You throw the stone into the water. One way or another, our picture of the universe is likely to change dramatically in the next few years !. I hope that my readers are so relaxed that they will want a little mental stimulation. So here are some puzzles that you might, I hope, find both amusing and interesting.
1 Why are your left and right sides reversed when you look in a mirror, but not your head to your feet?
2 Why do wheels make it easier to move an object?3 There is only one correct scientific explanation for any set of phenomena. True or false?4 You have a 100lb sack of potatoes; they are made up of 99 per cent water. We’ll have found our place in the universe, and in a sense there may be no more universe to find.” Of course, the universe could be too large to display topology, or it could turn out to be just singly connected. But even that discovery would be a leap forward in our understanding of the cosmos. “We gradually developed this Copernican notion that there is no special place in the universe – that every place is equivalent. And if we find this topology, we’ll discover that, no, every place actually isn’t equivalent.” Instead, he says, we’ll have found a kind of “You Are Here” sign for the cosmos “It will be the ultimate end of the Copernican revolution. On the other hand, just knowing that the Earth was round brought about a pervasive change in thinking.
Finding evidence for topology – especially any evidence for a multi-connected universe – could bring just such a change in our world-view.”It’s the end of a process that started with Copernicus,” muses Starkman. Granted, there may not be the sort of practical implications that Magellan’s discovery had for the 16th-century world; space travel over cosmological distances is almost certainly still centuries away. The other is the European Space Agency’s Planck satellite, due to get under way in 2005. The MAP satellite should be able to measure the microwave background radiation with a resolution of just 0.2 degrees (about half the angular size of the full moon), and Planck’s resolution may be two or thee times better still (by comparison, COBE has a resolution of just seven degrees).If their quest is successful, these cosmologists and topologists will bring about a profound change in the way we view our universe.
The models they have tested so far are not reflected in the COBE data – but there are many more models, still untested, that the COBE data do not rule out.What is really needed, however, is a clearer picture of the microwave background radiation, and this may come in just a few years’ time with the launch of two new satellites. The first is MAP, the Microwave Anisotropy Probe, a NASA mission set for launch in 2000. Pogosyan, together with Tarun Souradeep and CITA director Richard Bond, has been using computers to model various topologies in order to predict what patterns will be visible in the microwave sky. The best images so far come from the Cosmic Background Explorer (COBE), a highly success- ful Nasa satellite launched in 1989. For this reason, astronomers sometimes speak of the “observable universe”. But if we do live in a multi-connected universe, and it’s curved on a relatively small scale – that is, if the topology shows up on a scale that’s smaller than the size of the visible universe – then those matched circles would be awaiting discovery in the microwave background radiation.At the moment, however, we don’t have a map of the microwave sky with adequate resolution. The light from more remote objects – if they’re out there – has not yet reached us.
The universe may be topologically curved or twisted, but on a scale that’s simply too big to see. Remember, the light from the most distant objects astronomers can see has taken billion of years to reach the earth. (For rather technical reasons, these patches will be circular in shape.) It’s called a “pixelated search” – not a simple task, but within the reach of modern high-speed computers.”What we’re planning to do is to take these data – given to us as hot and cold spots around a balloon – and [extract] all of the possible circles you can draw on it,” says Cornish. By a careful analysis of this radiation, the scientists believe, it should be possible to decode the “signature” of the particular topology that governs our universe.The challenge that Cornish and his colleagues face, then, is one of pattern recognition.
