I thought it was a perfect cock,not a perfect clock, that got one laid.

I just tripped out the power cord... Just give me a sec to plug it back in.

Mines the one with 300 million year battery in the pocket.

I want one on my wrist. And that ASAP.

didn't we have to adjust the clocks last year just before New Years Eve because the world itself can't keep time ? 1 seconds every ten years or so isn't it ?

So after 300 million years this uber-clock will be out by 30 million seconds. Even FarEastern Rolex ripoffs are more accurate than that over their lifetime.

You know, after the first 299 million years I'm pretty sure that most people would have forgotten about the extra second anyway. Probably the sentient goo that we have evolved into by then will have transcended the notion of time altogether...

Actually the comment about strontium atoms being fermions is correct. Some atoms can be fermions depending on their constituent sub-atomic particles.

However, it's the line "resulting in a very impressive feat of not needing significant winding for more than 300 million years." that got my pedantic back up. Winding provides energy to power a clock, not its means of determining time. The clock will need powering for all the time it's in operation, but if you are happy with an accuracy of 1 second in 300 million years it won't need recalibrating within that period.

Paris, because she has plenty of energy but never turns up on time

...I'm willing to bet one 100 trillion of your US Dollars (or the US national debt, which ever is greater) that it loses two seconds before the 300 million years is up.

No, honestly.

It's being continually wound by that secondary red laser.

It might not need resetting though...

"Also, casually mentioning that you made a clock that's accurate to a second for 300 million years is almost guaranteed to get you laid."

I'm afraid that's a common geek misconception.

Lasers do not last for 300 million years... what happens when the laser goes kaput?

I think another knowledge band has been crossed - this one social. There are some people who can tell a girl that they have designed an atomic clock accurate to one second every 300 million years in such a way as to get laid. There are other people who can actually design such an atomic clock. But the overlap between these two groups of people is extremely small - in fact, I would guess it has roughly the same degree of smallness as the afore-mentioned one second in 300 million years...

How 20th century can you get?

Mine's the one with a Strontium mobile phone in the pocket!

Does it automatically switch over for Daylight Savings Time (Summer Time)??

You don't need one on your wrist. My £20 wristwatch synchronises to atomic clocks by picking up a radio broadcast. It also handles GMT/BST seasonal changes so doesn't need any adjustment until I travel to a different timezone. Interestingly, my computers now also synchronise to atomic time using NTP (Network Time Protocol) so I can read logged adjustments relating to when they have leap seconds, resulting from atomic time being more accurate than earth rotation time, needing a minute with 61 seconds every few years to keep the earth's rotation adjusted to atomic time.

Build it into a mems chip.

Fermions are just any particle/collection of particles with odd half integer spin i.e. 1/2 3/2 .....

As you correctly stated electrons, protons and for that matter neutrons are all fermions.

Now quarks are also fermions having a spin of 1/2, protons are a collection of 3 quarks and as such have a spin of 3/2 making them fermions.

So to work out if your atom is a fermion or a boson all you have to do is add all the spins of the constituent particles, if you get an integer value its a boson if not its a fermion.

OK so Strontium... goes of to wiki to check the atomic structure.. ah isotopes.

Most conman isotope SR 88(80% abundance) 50 neutrons, 38 protons and 38 electrons.

So that's 75 + 57 + 19.. whole number so a boson... doh.

OK so they must be using a different isotope and its got to be stable so they must be using SR 87(7% abundance), 49 neutrons, 38 protons and 38 electrons.

So that's 73.5 + 57 + 19... not a whole number so a fermion.

Of course if you ionise the atom you are removing an electron and so losing 1/2 spin...

... unless you have an even MORE accurate time source to compare it with.

Their clock has the claimed "accuracy" only because the DEFINITION of time has been arbitrarily defined to coincide with the method they're using to measure it.

Once upon a time, time used to be defined relative to the rotation of the earth. A definition that probably still makes the most sense to most people, because the primary purpose of time is to ensure we do things at the appropriate part of the day. If the earth were to mysteriously start rotating at half its normal speed, it would make no sense to use a supposedly "more accurate" time source that caused us to sleep only on alternate days.

Thus, the aim should probably be to find a time source which more accurately reflects the slightly-changing speed of rotation of the earth, so we don't have to artificially "increase" the year with leap-seconds whose very existence in effect proves "we got it very slightly wrong, but just like politicians it must be right because WE say it is".

... err, yes, but by the time I tell you, it'll be wrong...

Really? Highly contagious stuff this Strontium isn't it? So you don't want to father children, and you won't need the flourescent jacket when you go out at night either.

However, what's the point of this? Humankind won't last out this current century, never mind having a Timex which doesn't need winding for 300 million years. Future researchers will dig this stuff up and claim "pah! One second in 300 million years! What p1ss-poor quality!".

Paris because I fancy keeping a beat going.

Who wouldn't want a nuclear device on their wrist!

Simeon - you want perfect clock OR large ClOCK. Best is to have both.

You can have one on your wrist, there are some really nice watches which receive regular updates from the current generation of atomic clocks in Greenwich, I am sure that once this new generation of atomic clocks are available the timekeepers there will be upgrading.

http://www.zgwatches.co.uk/mens-casio-protrek-solar-watch-prw13001ver-p-876.html

A new super accurate clock was adjusted one hour ahead as boffins, who previously had refused to get out of bed earlier, no longer fear becoming discombobulated with a different prime time schedule.

Actually, the original explanation in the article was quite accurate as popular science goes.

A "fermion" is any particle - elementary or otherwise - with a half-integer total angular momentum. (For an elementary particle, its intrinsic angular momentum is "spin"). Turning a fermion around any axis by 360 degrees changes the sign of it's wavefunction. If particle's wavefunction does not change upon a 360-degree rotation, it is called a "boson", and has an integer spin. The total intrinsic angular momentum of a particle has important consequences at sufficiently low temperatures: two (or more) bosons can occupy the same quantum state (or be at the same place if you will). Two fermions cannot.

Whether a compound particle, such as an atom or a molecule, is a fermion or a boson depends on two things: the spins of it's constituent parts, and the way these spins are added together, or "coupled". The way these rules work is that a compound particle containing an even number of fermions (and an arbitrary number of bosons) will be a boson. A particle with an odd number of fermion constituents (and again any number of bosons) will be a fermion.

Strontium has 38 electrons (spin-1/2 particles). In its ground state, all its electrons are "paired", so that their spins cancel out, and total electron wavefunction has integer (zero) angular momentum. Most of the isotopes of its nucleus also have an even number of particles of each type (protons and neutrons), and thus integer spin as well. However, Strontium-87, which has natural abundance of about 7% has spin 9/2. As a result, the Sr-87 atoms have half-integer total angular momentum, and are fermions.

Yeah, right.

With another atomic clock making scientist, maybe.

(But what DO you do if you get bored at work? Watch the clock?)

Fundamental particles can be divided into fermions and bosons - fermions are those such as quarks and leptons with half-integer spin that obey the Fermi exclusion principle. The same distinction can also be applied to composite particles, such as protons and neutrons or atomic nuclei like carbon-13 and helium-3, you sum the spins of their components, and if there's an odd half left over they behave as fermions.

So it's quite valid to describe (some isotopes of) strontium as fermions.

They'll only have to put it back an hour in October...