Losing a second every 32 billion years

Written by Sharad Raghavan | Updated: May 13 2011, 08:17am hrs
Time is free, but its priceless. You cant own it, but you can use it. You cant keep it, but you can spend it. Once youve lost it you can never get it back.

Got the time

It seems physicists arent 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. Thats 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 isnt 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 worlds 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 atomin this case, in the Aluminium ion used in the clockmaking 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 thingschemical 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 animals 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 cows tissue. This represents the cows 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 theyre charging you the earth for it, you can now check to see if youre getting your moneys worth.