Earlier quoted context omitted.
How do you know what time it is?
Look up a bit on your phone. ;)
Exactly that! :)
Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
21–30 of 34 posts
Re: Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
#22They're shockingly ugly (and expensive) beasts, but you can now get atomic wristwatches. (Actual atomic watches, not the "atomic" kind that simply receives the radio time signal.) https://www.hoptroff.com/collections/atomic-timepieces
Could atomic clocks provide more accurate GPS positioning for GPS receivers? It’s my understanding that GPS works by measuring tiny differences in the time it takes equivalent signals to reach the receiver from different satellites. It may be the case that other factors (like noise and refraction) dwarf any inaccuracies in the quartz clocks in our everyday GPS receivers.
We don't need super accurate clocks in the GPS receivers; instead, the GPS satellites carry atomic clocks with them, and include timestamps in their broadcasts. So you get two signals at the same time, compare the time the satellite said it sent each signal, and you've got the difference in travel time.
Re: Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
#23Earlier quoted context omitted.
Could atomic clocks provide more accurate GPS positioning for GPS receivers? It’s my understanding that GPS works by measuring tiny differences in the time it takes equivalent signals to reach the receiver from different satellites. It may be the case that other factors (like noise and refraction) dwarf any inaccuracies in the quartz clocks in our everyday GPS receivers.
We don't need super accurate clocks in the GPS receivers; instead, the GPS satellites carry atomic clocks with them, and include timestamps in their broadcasts. So you get two signals at the same time, compare the time the satellite said it sent each signal, and you've got the difference in travel time.
Oh, interesting. What’s the time granularity transmitted by the satellites? I assumed that the satellites broadcasted a course stream of times and the receiver had to finely measure its local time difference between receiving the same time from multiple satellites.
Re: Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
#24The description of their "high-pressure liquid chromatography" technique sounds an awful lot like how one would enrich uranium (you know, as one does.) Did they accidentally invent a better uranium enrichment process (or independently reinvent a classified one?) Or is there some difference between {C60, N@C60} and {U235, U238} that makes using HPLC to enrich it impossible?
HPLC separates molecules based on some chemical property. In this case, the N@C60 fullerenes are probably very slightly larger, distorted from pure icosahedral symmetry, or have different electronic structure to the plain C60. Chemically speaking, U235 is probably very much like U238 and the chemical compounds of the isotopes are probably chemically almost identical (since isotopic chemical reactivity depends basical…
It seem to me one could apply an RF field at the resonant frequency of the nitrogen to selectively heat the N@C60 molecules. Do this near their boiling point to distill them. Or maybe they'd break down before boiling off. This of course would not work for isotope separation.
Re: Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
#25Earlier quoted context omitted.
We don't need super accurate clocks in the GPS receivers; instead, the GPS satellites carry atomic clocks with them, and include timestamps in their broadcasts. So you get two signals at the same time, compare the time the satellite said it sent each signal, and you've got the difference in travel time.
Oh, interesting. What’s the time granularity transmitted by the satellites? I assumed that the satellites broadcasted a course stream of times and the receiver had to finely measure its local time difference between receiving the same time from multiple satellites.
My assumption, for example:
Receiver receives time “noon” from GPS satellite 1 at receiver-local time T=0.
Receiver receives time “noon” from GPS satellite 2 at receiver-local time T=2 nanoseconds.
Receiver receives a couple more “noon”s from other satellites, then uses its receiver-local time differences to trilateral its location.
Re: Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
#26Earlier quoted context omitted.
Nowadays wrist watches rarely have a point besides showing off your wealth.
I actually have a Casio watch that is identical to one that I used to have 30 years ago. No frills or whistles. Roughly the same price now as it was back then, too. Under ten pounds. (this obviously does not contradict your point - I mention it because I like talking)
I wore a Casio watch before I got a phone in the late 1990s. Really the best utility there is in the watch space. It's a done and dusted thing.
Re: Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
#27Earlier quoted context omitted.
Nowadays wrist watches rarely have a point besides showing off your wealth.
It's super interesting how even before phones, knowing the time was so important that we would put it on our wrists. We have clocks in most places. You could put a clock into your bag. But no, this is so important that we would place this on our wrists for instant access.
Time is only important if you have to synchronise events with other people.
Re: Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
#28So how precise would this make our location? Could I replace my 3D-mouse by a cellphone using this technique?
I’m not sure that is the goal. Having cheap and small atomic clocks simplifies time sensitive applications that can’t always rely on satellites or ntp. Clock synchronization is currently not a solved problem for the masses.
Re: Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
#29Earlier quoted context omitted.
How do you know what time it is?
Look up a bit on your phone. ;)
Ah so you take your phone out of your pocket to check the time? Like a pocket watch! Cool, now if only there was something you could keep on your wrist that told time.. Would be so much more convenient!
Re: Building the World’s Smallest Atomic Clock: A Nitrogen Atom in a Carbon Cage
#30Earlier quoted context omitted.
It's super interesting how even before phones, knowing the time was so important that we would put it on our wrists. We have clocks in most places. You could put a clock into your bag. But no, this is so important that we would place this on our wrists for instant access.
Time is only important if you have to synchronise events with other people.
Or if you want to keep track of your work schedule.