<p>Sadly, your question has no meaning unless you both posit a finite size for the particles (unlikely) and some magical way to defeat all 3 of the E-M, strong, and weak nuclear forces.  Otherwise you don't even define how "closely" the particles could be placed.  That's pretty much what StephenG is alluding to when he suggests a black hole -- the black hole itself has undefined dimension; the event horizon would pointless.</p>

CC BY-SA 4.0
2018-11-19T21:47:52.160Z
+1 for the undefined density and the pressure from non-gravity forces. A black hole may not be the best thought-experiment solution with such conditions... :-)
Chappo Hasn't Forgotten
CC BY-SA 4.0
2018-11-19T20:18:56.300Z
2018-11-19T20:18:56.300Z
Carl Witthoft
<p>First things first ...</p>

<blockquote>
  <p>Tachyons</p>
</blockquote>

<p>These are <em>entirely</em> hypothetical and no evidence for them exists.</p>

<blockquote>
  <p>How much does subatomic particles such as photons, <del>tachyons</del>, and electron being the biggest particles etc. occupy space?</p>
</blockquote>

<p>How long is a piece of string ?</p>

<p>There's no simple answer to what size an elementary particle is.  You can view them, depending on context, as having no size (point like) or being spread all over space (wave distribution).</p>

<p>We can't say how many free particles there are (i.e. particles not bound to other particles).</p>

<p>This is a lot more complicated by the current mainstream thinking that dark matter and dark energy make up most of the mass/energy content of the universe.  Whatever dark matter may be, if it turns out to be a particle or particles we don't know about yet (quite likely on existing evidence) then those particles will almost certainly exist as free particles (only gravitationally bound together) as current thinking is that dark matter does not interact much at all with other matter or itself.  And we have no idea what dark energy could be.  So with most of the mass/energy is in forms we cannot identify we can't really say anything much about what you're asking.</p>

<p>A very, very, very rough estimate on the amount of dark matter is about 25% of the mass-energy of the universe.</p>

<blockquote>
  <p>If put in a ball how big of a ball would that be?</p>
</blockquote>

<p>In a ball it would be (possibly) a huge black hole comprising anywhere from 25% to 95% of the mass-energy of the universe.  I won't even bother estimating the size of the event horizon as it's just a useless number.</p>

<p>However "how big a ball" could equally mean it was, as it is now, spread out over the entire universe.  So a perfectly correct answer is - universe sized.</p>

CC BY-SA 4.0
2018-11-16T21:49:52.303Z
"We can't say how many free particles there are." Actually, there are indirect ways to make estimates which are probably pretty good, perhaps within a factor of 2 and likely within a factor of 10. (E.g., we have good reasons to say that the baryonic matter density if around 4% of the critical density. We have a pretty good measure of the density of matter in stars, planets and black holes, and believe that most of the rest of it is a very hot and very thin plasma of electrons and protons -- by subtraction, we estimate their density.) Similarly for other particle types.
Mark Olson
CC BY-SA 4.0
2018-11-16T21:10:20.300Z
2018-11-16T21:10:20.300Z
StephenG - Help Ukraine
<p>How much does subatomic particles such as photons, tachyons, and electron being the biggest particles etc. occupy space? If put in a ball how big of a ball would that be?</p>

CC BY-SA 4.0
2018-11-16T16:21:17.083Z
This is more of a physics question than an astronomy one. In any case, the Standard Model treats particles as having no size so this question is kind of moot without more assumptions being applied.
zephyr
CC BY-SA 4.0
2018-11-19T02:24:18.510Z
How big is a tachyon? ;-)
Chappo Hasn't Forgotten
CC BY-SA 4.0
2018-11-19T15:41:49.647Z
@Chappo  it has negative size.   ;-)
userLTK
<astrophysics><universe><space>
How much of the Universe is subatomic?
Muze
# How much of the Universe is subatomic?

(Asked by: username_0 on 2018-11-16)

How much does subatomic particles such as photons, tachyons, and electron being the biggest particles etc. occupy space? If put in a ball how big of a ball would that be?

**Tags:** astrophysics, universe, space

> **Comments:**
> **username_1**: This is more of a physics question than an astronomy one. In any case, the Standard Model treats particles as having no size so this question is kind of moot without more assumptions being applied.  
> **username_2**: How big is a tachyon? ;-)  
> **username_3**: @username_2  it has negative size.   ;-)  

---

## 2 answers

### Answer by username_5 on 2018-11-16. Score: 8 | Accepted answer

First things first ...

> Tachyons

These are *entirely* hypothetical and no evidence for them exists.

> How much does subatomic particles such as photons, ~~tachyons~~, and electron being the biggest particles etc. occupy space?

How long is a piece of string ?

There's no simple answer to what size an elementary particle is. You can view them, depending on context, as having no size (point like) or being spread all over space (wave distribution).

We can't say how many free particles there are (i.e. particles not bound to other particles).

This is a lot more complicated by the current mainstream thinking that dark matter and dark energy make up most of the mass/energy content of the universe. Whatever dark matter may be, if it turns out to be a particle or particles we don't know about yet (quite likely on existing evidence) then those particles will almost certainly exist as free particles (only gravitationally bound together) as current thinking is that dark matter does not interact much at all with other matter or itself. And we have no idea what dark energy could be. So with most of the mass/energy is in forms we cannot identify we can't really say anything much about what you're asking.

A very, very, very rough estimate on the amount of dark matter is about 25% of the mass-energy of the universe.

> If put in a ball how big of a ball would that be?

In a ball it would be (possibly) a huge black hole comprising anywhere from 25% to 95% of the mass-energy of the universe. I won't even bother estimating the size of the event horizon as it's just a useless number.

However "how big a ball" could equally mean it was, as it is now, spread out over the entire universe. So a perfectly correct answer is - universe sized.

> **Comments:**
> **username_6**: "We can't say how many free particles there are." Actually, there are indirect ways to make estimates which are probably pretty good, perhaps within a factor of 2 and likely within a factor of 10. (E.g., we have good reasons to say that the baryonic matter density if around 4% of the critical density. We have a pretty good measure of the density of matter in stars, planets and black holes, and believe that most of the rest of it is a very hot and very thin plasma of electrons and protons -- by subtraction, we estimate their density.) Similarly for other particle types.  

---

### Answer by username_4 on 2018-11-19. Score: 3

Sadly, your question has no meaning unless you both posit a finite size for the particles (unlikely) and some magical way to defeat all 3 of the E-M, strong, and weak nuclear forces. Otherwise you don't even define how "closely" the particles could be placed. That's pretty much what username_5 is alluding to when he suggests a black hole -- the black hole itself has undefined dimension; the event horizon would pointless.

> **Comments:**
> **username_2**: +1 for the undefined density and the pressure from non-gravity forces. A black hole may not be the best thought-experiment solution with such conditions... :-)  

---

