?Time is free, but it?s priceless. You can?t own it, but you can use it. You can?t keep it, but you can spend it. Once you?ve lost it you can never get it back.?
Got the time?
It seems physicists aren?t concerned with owning or spending time, or even losing it. What really floats their boat is measuring it to the absolute smallest unit that they can find. That?s just the way they are…
Getting the time right, down to several fractions of a millisecond, is integral to many things that we consider routine nowadays. Precise navigation on earth (the flights you take) and in space, synchronising broadband data streams, GPS navigation and satellite trajectories, not to mention coordinating any sort of precise activity across the planet all require the precise use of time. Thus, using a clock that gradually loses time isn?t the best idea. Physicists from the US and Russia have found a way to compute, with unprecedented accuracy, a terribly tiny source of error in atomic clocks (the most precise time-keeping devices we have devised so far). This error comes into play in one of the world?s most precise atomic clocks, recently built by the National Institute of Standards and Technology, which has an uncertainty of one second per 3.7 billion years. This means that if the clock was started at the start of life on Earth (around 3.6 billion years ago), it would have lost only one second so far. Physicists, though, are terribly hard to please, and an error, however small, is anathema to them. The principle of the error is that any sort of heat expands the size of the electrons in an atom?in this case, in the Aluminium ion used in the clock?making precision measurements hard. Having measured this effect, the scientists can now factor it in, taking them closer to their goal of creating a clock with a lag of only one second in 32 billion years (several times the age of the universe).
What your food ate
There are many people who take what they eat very seriously. One of their biggest fears is that the food they are eating has been bred on unsavoury or unhealthy things?chemical fertilisers for plants, and corn for cows and pigs (to fatten them up). Also, with the coming of speciality meats, such as pasture-fed beef, the consumers want to be sure they are getting meat worth the premium price they paid. Many cattle farmers raise their cows on grass, but switch them to corn a few weeks before their trip to the slaughterhouse, but still label their beef as ?pasture-fed?.
Scientists have now come up with a way to track exactly what the steak on your plate ate before it died for your gastronomic pleasure. They say that by examining an animal?s muscle tissue and tail hair for proportions of oxygen, nitrogen, hydrogen and sulphur they can determine its diet. Specific diets, such as the example of the cow that was switched from eating mostly grass to a corn-based diet towards the end of its life, leave a distinctive ?fingerprint? of these elements in the cow?s tissue. This represents the cow?s diet throughout its lifetime. An analysis of the faster-growing tissue in tail hair reveals what the cow ate recently. So, the next time you order a speciality meat product, and they?re charging you the earth for it, you can now check to see if you?re getting your money?s worth.