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| SCIENCE & TECHNOLOGY |
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Just 20 moves needed
to solve a Rubik’s Cube
Your mobile phone may be bugging you
Trends Prof Yash
Pal
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Just 20 moves needed
to solve a Rubik’s Cube
That might seem startling to anyone who has owned one of the classic toys for decades without being able to solve it just once – or has even resorted to peeling off the stickers and placing them back on in the correct pattern to pretend to their friends they have cracked it. But using one of Google’s supercomputers, an international team of square-eyed enthusiasts in California has confirmed that the puzzle need not take any time at all, no matter what its starting position. In fact, only 300 million arrangements – a small fraction of the total number – require a full 20 moves, with the majority of solutions taking between 15 and 19. It had already been thought that 20 was the maximum number of moves needed, after a previous estimate of 18 was disproved upon the 1995 discovery of a configuration that needed two more. Announcing definitively that 20 was the “magic number”, Professor Morley Davidson, a mathematician from Ohio’s Kent State University, said: “We were secretly hoping in our tests that there would be one that required 21.” Despite Google’s state-of-the-art technology, Professor Davidson said it would have been “completely hopeless” to try testing all of the combinations individually, and so the team studied duplicate and symmetrical patterns to reduce the number that required analysing. They began by splitting the configurations into 2.2 billion groups of 20 billion positions, which they were eventually able to whittle down to the 56 million groups of 20 billion combinations they analysed. Even then, their calculations would have taken a good desktop PC 35 years to work its way through them, but with Google’s equipment it took just a few weeks. More than 400 million Rubik’s Cubes have been sold since it was invented in 1974 by the Hungarian architect Erno Rubik, and Professor Davidson said his devotion to the project was because the puzzle had inspired his whole career. “It’s come full circle for me,” he said. “Rubik’s Cube was an icon of the Eighties when I was growing up and was the reason I went into mathematics. It’s the universal popularity of the puzzle – it’s probably the most popular puzzle in human history.” Professor Davidson carried out the work with John Dethridge, an engineer at Google, Herbert Kociemba, a maths teacher and Tomas Rokicki, a computer programmer from California. With the preliminary results now available online, the quartet are submitting their evidence to peer-reviewed journals for final confirmation among the mathematical community. Beyond that, they are considering looking at the Cube’s other mathematical mysteries or working on the four-layered version. By arrangement with The Independent
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Your mobile phone may be bugging you
A BRITISH internet security company has demonstrated how to turn the Palm Pre into a secret bugging device, ideal for corporate espionage, and issued hackers. In-house hackers at Basingstoke-based MWR InfoSecurity have created a bug hidden in an electronic business card, or vcard, which enabled them to use the Pre to record conversations and send the audio file back to them, whenever it is connected to a WiFi or 3G network - all without the user being aware anything at all is happening.
The company’s 26-year-old principal security researcher - who gives his name only as Nils, and who was hired by MWR last year after having been a freelance hacker since his teens - demonstrated the security flaw in the Pre to journalists and IT specialists this week, saying the phone was “easy” to break into. Hewlett-Packard acquired Palm two months ago, in part so it could use the Pre operating system on future smartphones. Nils also revealed that MWR found a serious security flaw in Google’s Android software, used as the operating system for a growing number of popular smartphones. The flaw allows a hacker to harvest all the usernames, passwords and browser history saved in an Android phone’s web browser. The vulnerabilities in the two operating systems took just two days for the determined hacker to discover, By arrangement with The Independent
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Trends
LONDON: Treating tumours with salmonella bacteria can induce an immune response that kills cancer cells, scientists have found—a discovery that may help them create tumour-killing immune cells to inject into patients. Researchers from Italy and the United States who worked with mouse and human cancer cells in laboratories said their work might help in developing a new drug in a class of cancer treatments called immunotherapies or therapeutic vaccines, which harness the body’s immune system to fight disease.
FBI laboratory has large backlog of DNA cases
WASHINGTON: The FBI’s laboratory has a backlog of more than 3,200 forensic DNA cases, which can prevent timely capture of criminals and prolong incarceration of innocent people, according to a U.S. Justice Department report released on Monday. The report by the department’s inspector general said the backlog, which has increased sharply in the past year, can cause delays in legal proceedings that must await DNA analysis results.
Spinal fluid proteins help diagnose Alzheimer’s
CHICAGO: Measuring certain proteins in spinal fluid can accurately diagnose Alzheimer’s and predict which patients with memory problems will develop the fatal brain-wasting disease, Belgian researchers said on Monday. And they may also help identify early signs of the disease in healthy people, the team reported in the Archives of Neurology.
— Reuters
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This universe
I have heard that initially, there was life on the Sun but because of continuous nuclear explosions there was too much heat and it turned it into a burning planet. Is it true?
What you have heard is pure nonsense. Unless the Sun was hot, you could not call it the Sun. The Sun is hot because of continuous generation of energy due to fusion reactions in its interior which is even more hot. No life can be possible when the temperature ranges from thousands of degrees at the surface to millions of degrees at the centre of the Sun. Whenever we buy a new watch, it shows the time as10:10. Why? Is there any scientific reason behind it? Once a scientist friend put the very same question to me. After some thinking I argued that the sales people felt that the two needles in a symmetric with respect to the time 1200 might have dictated their choice. So a sat down to discover times for which the needles could be symmetric. To my surprise I found several other combinations. After that I gave up except the thought that the salesman's choice was for a simple and traditional combination. Therefore I have no other explanation but some of you might try to discover the combinations that I did. Incidentally 10.10 is a fairly nice choice. I want to study about astronomy, astrophysics, space science and become a scientist in this field. After completing my B.Sc (my subjects are physics, maths and electronics), how can I study space science and from where? It seems that you have made the right choice for this time. Studying physics and maths in your BSc is a good preparation for becoming a space scientist. But you might have some distance to travel. You will need to join a good university like the Indian Institute of Science. But you can supplement this by visiting IUCAA in Pune even during undergraduate years. And let me also say that during your intense journey you might find some things that excite you but do not fall in the category of space science, do not overlook that. Creative meandering can often take you to exciting new journeys. I have observed many times that when we put ice cubes into normal water, a crackling sound is produced and the ice cubes develop cracks. Can you please explain the reason for this? I know why this question occurred to you. We all know that water expands on freezing. That is the reason that accounts for the fact that ice cubes float on water. But ice behaves quite normally, like other solids, after it is formed and cooled down to a low temperature; cold ice expands on being heated. Therefore when you put very cold ice cubes in water the ice cubes heat up. They expand before they have a chance to melt. Expansion of solid cubes cracks them and you do hear a crackling sound.Readers wanting to ask Prof Yash Pal a question can e-mail him at
palyash.pal@gmail.com |
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To be precise: there are 43,252,003,274,489,856,000 different possible configurations of the coloured squares on any Rubik’s Cube. Yet now researchers have calculated that you’re never more than 20 moves away from solving the famous puzzle.