# How to measure empty space

#### sushi

##### Active Member
how do you measure amount of space/nothingness,

is it quantifiable or unquantifialbe
what parameter can be used?

for example: how to measure the amount of "space" in the sky?

do standard measurements like mass, volume, energy, pressure, distance, area apply to this

standardized measurements is one of the things that gave birth to modern science, so I am thinking if empty space or void has amount or quantity that is measurable.

is the amount of empty space in an empty room equal to the room's volume, or is it something else?

#### elliptoid

##### the void is a lie
Good question!

To start make sure you are familiar with the Planck Length and then move onto mass-energy equivalence and uncertainty. At least have a layperson understanding of these entry level principles.

Then yes your answer is most certainly area or volume depending on the dimensionality of the projection you're using.

Measuring astronomical distances is very intricate and exciting process too. Learn about the parsec to understand more.

#### sushi

##### Active Member
Good question!

To start make sure you are familiar with the Planck Length and then move onto mass-energy equivalence and uncertainty. At least have a layperson understanding of these entry level principles.

Then yes your answer is most certainly area or volume depending on the dimensionality of the projection you're using.

Measuring astronomical distances is very intricate and exciting process too. Learn about the parsec to understand more.
let me think about that and do some research.

Is mass, energy, volume, distance, area not applicable in measuring space and nothing?

#### QuickTwist

##### Spiritual "Woo"
You can't measure space in a vacuum. You have to measure it in relation to objects that fill up that space. You have to have a total space amount and then find the area for the objects within that space and then subtract from the total space. At least this is what makes sense to me, but I might not really know what you are asking.

#### sushi

##### Active Member
You can't measure space in a vacuum. You have to measure it in relation to objects that fill up that space. You have to have a total space amount and then find the area for the objects within that space and then subtract from the total space. At least this is what makes sense to me, but I might not really know what you are asking.
you just say the exact opposite of what i mean.

if you can't measure how much black space and emptiness, how can the amount of empty space in the universe be measured?

#### Minute Squirrel

##### magician
I imagine it would depend on what kind of empty space you are talking about. If we're using the room example then it would be relayed terms volume. But ultimately I don't think we can measure it directly as our current understanding is that things fill empty space which is infinite. The universe is filling up empty space but there's still empty space inside it. Like if a jar would suddenly appear it would fill up an empty space while still having an empty space inside it as well.

#### Serac

##### A menacing post slithers
Just figure out the geometry of the space (e.g. Euclidean) and take measurements along its dimensions. Don't really see the problem.

#### kanteravir

##### Redshirt
Space is never entirely empty. Different patches of empty space can be measured to have a different energy density.
Is mass, energy, volume, distance, area not applicable in measuring space and nothing?
Space can be measured for existence of those properties, or their lack.

-How much space lacks energy defines how much of the energy can still fit inside of it, same with mass. Mass is non-linearly proportional to energy.
-Volume and area are directly proportional to distance. The relation is cubic and quadratic respectively. Or you could think in terms of diagonals, square roots of 3 and 2.
-Each unit of space can hold a finite amount of mass-energy ratio which is its energy density.

Space is something which can have properties, emptiness is the local value of those properties and to get a perception of the magnitude of the observed properties some places in space need to be different from others and compared against.