What is the smallest unit of time in D&D? (in-game only)

[Jon_Dahl]

"Let's meet in seven x."
"Let's meet here tomorrow/next month/next year at/in/on/etc. y."

Try to replace x and y with the shortest unit of time, increment of time or some concept of time. If possible, explain your choice.

[Coidzor]

By default rules, clocks exist. So areas with those will have some knowledge of seconds and minutes and hours. Reason: Because reinventing the wheel to come up with different names for seconds, minutes, and hours is a sign of a GM that has gone insane.

Areas where time is told by the position of the sun or a sun-dial should have some mental conception of periods of time beyond dawn, early morning, mid-morning, late morning, noon, and so on, but I couldn't point you towards any terms from real world history to use with certainty. I'd just use fairly inexact, varying ideas of what an hour or minute would be, though. Just like how everyone's "One Mississippi," method of counting is going to have variance. Reason: Ease of play.

A place like Mechanus would certainly know about units of time smaller than that smallest units of time that modern science has any use for, and have modrons dedicated solely to storing information about what those terms would even be called. Reason: Mechanus.

[Celestia]

A place like Mechanus would certainly know about units of time smaller than that smallest units of time that modern science has any use for, and have modrons dedicated solely to storing information about what those terms would even be called. Reason: Mechanus.
So, do the Modrons use a different term than Planck instant, or do they simply have a Modron conveniently named Max Planck? :smalltongue:

[OldTrees1]

So, do the Modrons use a different term than Planck instant, or do they simply have a Modron conveniently named Max Planck? :smalltongue:

Modrons probably know about time intervals smaller than a planck.

However I expect they would have the same term, just a different language's word for that term.

[Crake]

Modrons probably know about time intervals smaller than a planck.

However I expect they would have the same term, just a different language's word for that term.

I believe the planck time unit is supposedly the shortest discreet interval of time possible, there is no smaller unit of time.

[Dagroth]

I believe the planck time unit is supposedly the shortest discreet interval of time possible, there is no smaller unit of time.

That we are capable of understanding.

[MisterKaws]

I believe the planck time unit is supposedly the shortest discreet interval of time possible, there is no smaller unit of time.

That's what they want us to think.

[Pleh]

I believe the planck time unit is supposedly the shortest discreet interval of time possible, there is no smaller unit of time.

You're missing two words: physically and natural.

the planck time unit is supposedly the shortest discreet interval of time physically possible, there is no natural smaller unit of time.

In a universe where magic exists, all bets are off.

[Deophaun]

"Why measure things in Plank units when you can measure them in milliplank units instead?" The modron thought.

[OldTrees1]

I believe the planck time unit is supposedly the shortest discreet interval of time possible, there is no smaller unit of time.

IIRC planck time is based on the length of the shortest duration event that we IRL, as of 2017, know of. The length of the shortest duration event is not the same as the shortest possible span of time. Although perhaps that is what discreet means in this context?

So we can easily make smaller units of time, they are just not useful outside of thought experiments.

[Celestia]

You're missing two words: physically and natural.

the planck time unit is supposedly the shortest discreet interval of time physically possible, there is no natural smaller unit of time.

In a universe where magic exists, all bets are off.
Magic doesn't just do whatever you want because screw everything. I can't just say that there's a volcano that spews ice cream or that this piece of uranium decays without releasing radiation. Magic can bend reality, but it's still bound by it. Otherwise you just exist in a world of nonsense. There is no unit of time smaller than a Planck instant because once you go smaller than that, time ceases to be an identifiable concept. You can't just go "It's magic" and say that something is smaller. It makes as much sense as declaring that magic can make something colder than absolute zero.

[Flickerdart]

Magic doesn't just do whatever you want because screw everything. I can't just say that there's a volcano that spews ice cream or that this piece of uranium decays without releasing radiation. Magic can bend reality, but it's still bound by it. Otherwise you just exist in a world of nonsense. There is no unit of time smaller than a Planck instant because once you go smaller than that, time ceases to be an identifiable concept. You can't just go "It's magic" and say that something is smaller. It makes as much sense as declaring that magic can make something colder than absolute zero.

Energy/matter can't be created or destroyed...except with magic. Nothing can move faster than light...except with magic. But making an event take less time than a Planck unit makes you that angry?

[JoshuaZ]

There seem to be two distinct issues here. First, what is the smallest unit of time known. Second, what is the smallest unit of time in the D&D physical laws.

For the first one, minute or a small fraction of a minute is reasonable. It is worth noting that it took extremely developed clocks for seconds to be something that people could reasonably talk about. (https://en.wikipedia.org/wiki/Second#Based_on_mechanical_clocks). Most D&D settings aren't very consistent about their technological level; it is plausible that a setting with a high tech base like Eberron could have seconds as a unit or something of about the same size.

As for the second question: it doesn't really matter. It depends on what the base laws of physics in your setting are, and I doubt any major setting has paid any careful attention to that matter. Note by the way that the specific idea that the Planck time is the smallest unit of time measurable in our own universe is not really clear cut; we don't really have a good enough understanding of that scale of things to be very certain. Even our best experiments measure things which take multiple orders of magnitude more time than the Planck time. It isn't at all implausible that an eventual union of general relativity and quantum mechanics will revise our understanding here.

[johnbragg]

IIRC planck time is based on the length of the shortest duration event that we IRL, as of 2017, know of. The length of the shortest duration event is not the same as the shortest possible span of time. Although perhaps that is what discreet means in this context?

So we can easily make smaller units of time, they are just not useful outside of thought experiments.

Planck time is the time it takes light to move one Planck unit. One Planck unit is the smallest (theoretically) measurable, because below that threshold quantum effects make more precise measurement not so much impossible as unthinkable--the thing does not HAVE a specific position, it exists in a defined range of positions.

OR I could be totally misreading what I just learned on wikipedia.


Magic doesn't just do whatever you want because screw everything. I can't just say that there's a volcano that spews ice cream or that this piece of uranium decays without releasing radiation.

ACtually, if you're the DM/setting designer, yes you can.


Magic can bend reality, but it's still bound by it. Otherwise you just exist in a world of nonsense.

Imagination. There is no particularly logical reason why an imaginary universe in which some people can cast magical spells is based upon anything like modern physics.


There is no unit of time smaller than a Planck instant because once you go smaller than that, time ceases to be an identifiable concept. You can't just go "It's magic" and say that something is smaller. It makes as much sense as declaring that magic can make something colder than absolute zero.

Now that you mention it, in D&D, "Cold" is not just the absence of heat, it is its own energy type. So there's every reason to expect that in some cold-dominant outer or lower plane temperatures below -273 Celsius are entirely ordinary (locally speaking.)

IT's entirely reasonable to posit D&Dverses with different underlying principles of physics and metaphysics. I could and have spun out explanations based on mind being as fundamental a principle of D&D physics as mass is to our physics. (One implication is that, in my D&Dverse, Chuck Norris memes are literally true, at least locally.)

[Coidzor]

Modrons probably know about time intervals smaller than a planck.

However I expect they would have the same term, just a different language's word for that term.

Well, I'm sure the ones that can speak are all at least aware of the universal language: English. (https://youtu.be/hcL46NjFDJU?t=6m23s)

Planck time is the time it takes light to move one Planck unit. One Planck unit is the smallest (theoretically) measurable, because below that threshold quantum effects make more precise measurement not so much impossible as unthinkable--the thing does not HAVE a specific position, it exists in a defined range of positions.

OR I could be totally misreading what I just learned on wikipedia.

So it's less how many angels can dance on a pin and more how many modrons can fit inside of a planck unit.

[Flickerdart]

Nah, the universal language is ornithopters (http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=46016):


Regardless of the century, plane, or species, developing artificers never fail to invent the ornithopter.

[Deophaun]

Nah, the universal language is ornithopters (http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=46016):

Don't you mean Swedish Meatballs (https://www.youtube.com/watch?v=bVLkxSSvegc)?

[OracleofWuffing]

I, uh... Would have thought the answer was "The Duration of a Free Action." Which then got me kind of thinking, you know, you can take as long or as short as you can to say "one Mississippi," but then all standard action melee attacks are going to take as long as each other, and could be arguably more accurate a measurement, so you could have a setting where time is measured in slices and clobbers, and then-


By default rules, clocks exist. So areas with those will have some knowledge of seconds and minutes and hours. Reason: Because reinventing the wheel to come up with different names for seconds, minutes, and hours is a sign of a GM that has gone insane.
... Ooops. :smallredface:

[Telok]

Magic doesn't just do whatever you want because screw everything. I can't just say that there's a volcano that spews ice cream or that...

Ice cream volcano.
Ice cream.
Volcano.

I have a wizard in an ongoing game. It is now my goal to reach epic levels and craft the spell that raises an ice cream volcano.

Ice cream volcano.
I'm a wizard. I can totally do that.

[Dagroth]

Ice cream volcano.
Ice cream.
Volcano.

I have a wizard in an ongoing game. It is now my goal to reach epic levels and craft the spell that raises an ice cream volcano.

Ice cream volcano.
I'm a wizard. I can totally do that.

You just need a spell that creates a volcano. Then, Energy Substitution: Cold & Spell Thematics: Strawberries.

[Coretron03]

You just need a spell that creates a volcano. Then, Energy Substitution: Cold & Spell Thematics: Strawberries.

"And that kids, is why we learned the spell Detect insane wizards"

[Zombimode]

So, do the Modrons use a different term than Planck instant, or do they simply have a Modron conveniently named Max Planck? :smalltongue:

Considering the fact that there is a place in Mechanus called "Neumannus" I wouldn't be supprised.

[Pleh]

Energy/matter can't be created or destroyed...except with magic. Nothing can move faster than light...except with magic. But making an event take less time than a Planck unit makes you that angry?

+1. Excellent.


Magic doesn't just do whatever you want because screw everything. I can't just say that there's a volcano that spews ice cream or that this piece of uranium decays without releasing radiation. Magic can bend reality, but it's still bound by it. Otherwise you just exist in a world of nonsense. There is no unit of time smaller than a Planck instant because once you go smaller than that, time ceases to be an identifiable concept. You can't just go "It's magic" and say that something is smaller. It makes as much sense as declaring that magic can make something colder than absolute zero.

As so many others have said, yes I can. In D&D, magic >> physics. I can create characters who can research spells that do exactly what you said could not be done. I just have to get DM approval, which is no problem if I happen to be the DM.

If spells could only craft things that could have really happened anyway... well, casters might be better balanced, but there would be a ton of spells that no longer exist.

[stack]

"And that kids, is why we learned the spell Detect insane wizards"

Totally unoptimized. Plain old detect wizards is a level lower and gives exactly the same results.

[Manyasone]

The quantum cosmic tick
It is the shortest interval of time anything in the universe can occur

[Pleh]

The quantum cosmic tick
It is the shortest interval of time anything in the universe can occur

Introducing the all-new "quantum milli-tick." A thousand iterations in the standard quantum tick.

Get yours exclusively at your local magic spell.

[Necroticplague]

In-universe, I don't think published settings bother to bring up the small units of time. At best, the mention unites of time large enough to make up calendars (i.e, I know one setting has a 10-day week). Mechanically, it's undefined, because Free Actions are limited only by DM fiat.

[Deophaun]

All I really know is that, no matter how small the unit is, it's not getting anything more than a +16 to its Hide check.

[johnbragg]

The quantum cosmic tick
It is the shortest interval of time anything in this universe can occur

FTFY. Does not necessarily apply in universes whose fundamental rules allow magic, psionics, high level mundanes surviving falls from orbit, slow- and fast-time demiplanes, etc.

[dhasenan]

"Let's meet in seven x."
"Let's meet here tomorrow/next month/next year at/in/on/etc. y."

Try to replace x and y with the shortest unit of time, increment of time or some concept of time. If possible, explain your choice.

You're talking about practical scheduling units with your examples. The shortest practical scheduling unit in real life is about fifteen minutes.

A D&D peasant is unlikely to own a clock. There's no cantrip to tell the time. You might reasonably divide the day into six or eight watches and expect a peasant to be able to tell them apart, at least when it's not terribly cloudy.

Sundials and the like can provide more accuracy. However, you need them to be widely available to use the time units they provide to schedule things. Or you need to be living in a densely populated area and have some way of announcing the time.

We can also distinguish between the mechanics and the world.

Mechanically, we can look at the amount of time between two actions that occur in sequence. What's the smallest amount of time between two actions where one occurs after the other?

A round is six seconds. If I am the only person to act on a round, my actions take six seconds. If both you and I act during a round, I act first, then you act. We both take six seconds, and our actions together take six seconds. So how much time passes between my turn and yours? Negative six seconds.