Comments on: Ep. 117: Time

By: Tom

Tom — Thu, 01 Jan 2009 14:21:39 +0000

The explanation of atomic clocks isn't quite right. Cesium clocks are passive — they don't radiate when undergoing the transition between the states. This oscillation occurs because they are in a superposition of the two states (which are the hyperfine, or spin-orientation, states). The frequency information is "encoded" in the relative population of the two states when you make a measurement. The operation is not, as it is explained, because the atoms are excited and then spontaneously de-excite.

By: Colin

Colin — Thu, 11 Dec 2008 22:57:07 +0000

Fraser & Pamela

Fantastic show. I look forward to every episode.

Don't ever think about stopping!

Many Thanks & Best Wishes from England.

By: Alden Pearl

Alden Pearl — Thu, 11 Dec 2008 12:59:37 +0000

I enjoy the show & you do a wonderful job. Regarding Time (ep 117) I may have missed it but what about the "leap second" ( see http://www.skyandtelescope.com/news/wires?id=124150279&c=y) – how do we figure that out ??? I am familiar with the leap year and even the 400 yr rule but a second. Also some years 2 leap seconds are added ? Is this arbitrary – why not in some systematic way like we have for days every 4th year ?

Thanks Alden J Pearl MD

PS Please keep up these "brain hurting" episodes.

By: todd

todd — Wed, 10 Dec 2008 23:42:12 +0000

I've enjoyed this show since day one as well. Excellent work and one of them is canadian…naturally. I believe you are from the same area: I grew up is surrey BC and now live in Halifax.

Anyways, love the show.

By: Tim Reynolds

Tim Reynolds — Mon, 08 Dec 2008 01:28:38 +0000

Nice post. Thank you for the info. Keep it up.