Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

How Deep Does the Multiverse Go?

samzenpus posted about 2 months ago | from the beyond-the-beyond dept.

Space 202

StartsWithABang writes Our observable Universe is a pretty impressive entity: extending 46 billion light-years in all directions, filled with hundreds of billions of galaxies and having been around for nearly 14 billion years since the Big Bang. But what lies beyond it? Sure, there's probably more Universe just like ours that's unobservable, but what about the multiverse? Finally, a treatment that delineates the difference between the ideas that are thrown around and explains what's accepted as valid, what's treated as speculative, and what's completely unrelated to anything that could conceivably ever be observed from within our Universe.

cancel ×

202 comments

Sorry! There are no comments related to the filter you selected.

It's turtles all the way down (5, Interesting)

Anonymous Coward | about 2 months ago | (#47443907)

It's turtles all the way down.

Re:It's turtles all the way down (0)

gumbright (574609) | about 2 months ago | (#47444063)

I guess I should be happy this was the obvious response. I would have added a "...duh".

Re:It's turtles all the way down (4, Insightful)

Mikkeles (698461) | about 2 months ago | (#47444985)

But, is it turtles all the way up?

Many worlds (5, Funny)

Livius (318358) | about 2 months ago | (#47443913)

In one version of reality, this is a first post!

Re:Many worlds (0)

Anonymous Coward | about 2 months ago | (#47443975)

Not this one, though.

Re:Many worlds (1)

istartedi (132515) | about 2 months ago | (#47444091)

Except in the one where you posted saying it wasn't, but were mistaken because it actually was. That might not be too far from the one where I'm GWB, a frequent Slashdot poster. It's interesting to ponder the concept of what "infinity" really means when you consider all the possibilities on some mundane thing like that.

Re:Many worlds (1)

Anonymous Coward | about 2 months ago | (#47444195)

Seems you misunderstand infinity. It does not mean that everything (or anything) which is possible is somewhere actual or true.

Just imagine an infinite amount of worlds where everything is the same except for one thing which happens in infinite variations. For example, in this world I am "Anonymous Coward", in another "Anonymous Poster", in another "Nameless Coward", in yet another just "Anonymous", etc... There are an infinite worlds, yet in none of those you're GWB.

Re:Many worlds (2)

istartedi (132515) | about 2 months ago | (#47444231)

What is your criterion for restricting the variations? Why are "Anonymous Coward" and "Anonymous Poster" possible, but not "XFFSF Poster" and GWB as an active Slashdot user?

Re:Many worlds (4, Insightful)

narcc (412956) | about 2 months ago | (#47444771)

You've missed the point.

Try a different example. Consider that there are an infinite number of values between 0 and 1. While infinite, none of those values will be 2.

If that's not to your liking, consider something like Penrose tiling where a pattern formed from just two shapes can tile infinitely without repeating.

See, when you ask:

What is your criterion for restricting the variations?

There need not be any such criterion. See, just because a thing is possible does not mean it will necessarily be actualized even given an infinite number of universes.

One hypothesis of many (0)

Anonymous Coward | about 2 months ago | (#47444329)

The multi-world interpretation of quantum mechanics is not the only one, nor even the most accepted. It is just one that popular media has run with (and botched). The Copenhagen interpretation still holds its ground, and (as I understand) is still the most widely accepted in the scientific community. Many scientists have an emotional bias against it because of the special role that observation plays (and the implications that might have regarding consciousness), but that bias does not itself have any scientific basis (and neither does the mind-over-matter woo that trendy religious movements have imposed upon it). The evidence speaks for itself, and that evidence says Copenhagen is sound.

*I* have a personal bias against the word "multi-verse," from a linguistic perspective. The word "universe" already means exactly what we are using the word "multiverse" to mean. But nobody cares.

Re:One hypothesis of many (0)

Anonymous Coward | about 2 months ago | (#47444881)

*I* have a personal bias against the word "multi-verse," from a linguistic perspective. The word "universe" already means exactly what we are using the word "multiverse" to mean. But nobody cares.

Hey, I care. Just not very much.

Re:Many worlds (1)

TapeCutter (624760) | about 2 months ago | (#47445019)

There are an infinite worlds, yet in none of those you're GWB

At least that explains why in this universe GWB doesn't punch himself in the face every now and then.

Re:Many worlds (1, Funny)

Anonymous Coward | about 2 months ago | (#47444133)

in one version of reality, "first" means "second". In another version, "first" means "small" and "post" means "penis".

Re:Many worlds (1)

kruach aum (1934852) | about 2 months ago | (#47444107)

That depends on your concept of identity across worlds. Surely the first post in another multiverse cannot be entirely identical to one in this one, as it exists in a different multiverse, not this one. Furthermore, it also differs from "this" post in that it is first in reply to the article posted on Slashdot*, or /.*. It also differs in that it wasn't made by you, but you*, who further differs from you in such a way that allows him to make that first post where you failed. If you're already so different from you* as to fail where he succeeded, it would stand to reason that any post made by you* is sufficiently different from posts made by you that they do not qualify for identity. In which case, there really is no universe in which your post was the first post.

Re:Many worlds (0)

Anonymous Coward | about 2 months ago | (#47444687)

In a similar way, there is no universe in which you are fun at parties.

Re:Many worlds (0)

Anonymous Coward | about 2 months ago | (#47444539)

In another, this wouldn't be just more medium.com linkspam.

Re:Many worlds (0)

Anonymous Coward | about 2 months ago | (#47444567)

In a parallel universe, my posts are very witty.

Accelerated expansion (0)

Anonymous Coward | about 2 months ago | (#47443941)

The author of the article misses that the expansion is accelerating.

Re:Accelerated expansion (1)

ramorim (1257654) | about 2 months ago | (#47444161)

Well, and massively above speed of light in this early days ... If the theory of a dot-expanding-into-a-universe is real, we have a "46 billion light-years in all directions, filled with hundreds of billions of galaxies and having been around for nearly 14 billion years since the Big Bang". :D

Re:Accelerated expansion (0)

Anonymous Coward | about 2 months ago | (#47444641)

Why would it be massively above the speed of light? Do you somehow make the assumption that we are at this very moment able to see from or position in the marble-sized volume of space that expanded, to the edge?

Re:Accelerated expansion (0)

Anonymous Coward | about 2 months ago | (#47444799)

ftfa "In just a matter of 10^-32 seconds, a region the size of a subatomic particle would have expanded to be larger than our observable Universe is today."
I'm pretty sure that expansion from ~0 to >billions of light years is an infinitesimal fraction of a second is faster than the speed of light.

Re:Accelerated expansion (1)

TapeCutter (624760) | about 2 months ago | (#47445121)

Objects cannot move relative to each other faster than light but the space between them has no such restriction. Hyper Inflation lasted until the universe was about the size of a basketball. The big bang didn't end with (hyper) inflation, it is still happening and the universe is still inflating. The boundary to our modern universe is expanding away from us at the speed of light. So, two observers on opposite sides of our visible universe will be speeding away from each other faster than light. Only an observer in our position can see that the two observers at the opposite "edges" existing simultaneously.

Big fan of Starts with a Bang for many years, I must ask Ethan why cosmologists have ruled out the idea that our universe is the interior of a black hole. Neil deGrasse Tyson claims Einstein's equations can be interpreted to mean there is a different universe inside a black hole but he doesn't elaborate. If anyone else knows of a good reason as to why our universe can't be the interior of a black hole then I'd love to hear it.

Re:Accelerated expansion (0)

Anonymous Coward | about 2 months ago | (#47445065)

Of course. Galaxies are already moving away from us faster than c, this is well known in the science community. The fastest one discovered is over 2x faster than light. The problem is that pesky red-shift. It's hard to see light from object that are so red-shifted. Gamma Ray Bursts help a lot with that. Nothing can move through space faster than c, but space itself has no limitations. We assume it's expanding, because that's the simplest explanation.

Math? (5, Insightful)

meerling (1487879) | about 2 months ago | (#47443943)

"Our observable Universe is a pretty impressive entity: extending 46 billion light-years in all directions, filled with hundreds of billions of galaxies and having been around for nearly 14 billion years since the Big Bang."

The observable universe is observable because there has been time for the light to travel that far, which can not exceed the age of the universe. Therefor, if the universe is 14 billion years old, then the furthest we could see in any direction is only 14 billion light years, giving a maximum, diameter of 28 billion light years.
So why does the summary say it's 46 billion L.Y. across and only 14 billion Y. old?

Re:Math? (3, Insightful)

ledow (319597) | about 2 months ago | (#47443973)

If you assume a static, never-changing, fixed space... you might have been right.

Isn't this how we know it's expanding?

Re:Math? (0)

Anonymous Coward | about 2 months ago | (#47443981)

Because space also stretched during those 14 billion years.

Re:Math? (1)

Livius (318358) | about 2 months ago | (#47444145)

I've never heard the explanation as to why that makes light seem to go faster rather than seem to go slower.

Re:Math? (4, Informative)

Anonymous Coward | about 2 months ago | (#47444281)

Most people can understand this on their own, but since you need some hand holding:

Imagine an ant on a rubber band. Mark the start position with a dot, let the ant walk for 5 seconds, mark the end position with a dot. The distance between the two dots will be greater if the rubber band was stretching while the ant was walking on it.

Re:Math? (-1)

Anonymous Coward | about 2 months ago | (#47444423)

But why does stretching the rubber band make the ant's stride larger? Why does the ant move faster across a stretched rubber band?

You lose, you snarky little faggot.

Re:Math? (0)

Anonymous Coward | about 2 months ago | (#47444661)

The strides aren't larger and the ant isn't moving faster. The part of the rubber band behind the ant is getting longer and you should focus on that.

Re:Math? (0)

Anonymous Coward | about 2 months ago | (#47445029)

He should focus on why he is compelled to anounce on Slashdot that having a small penis makes him irritable.

Re:Math? (0)

uvajed_ekil (914487) | about 2 months ago | (#47444833)

Nice trolling - calling people out because you don't understand what is going on, then using an insensitive epithet. Way to do it anonymously, loser. Claim your posts, turd face.

Re:Math? (0)

Anonymous Coward | about 2 months ago | (#47445105)

I've never heard the explanation as to why a stretched rubber band becomes longer rather than shorter.

Re:Math? (1)

Livius (318358) | about 2 months ago | (#47444519)

Why does the rubber band carry the ant forward? Isn't it equally plausible that the rubber band moves underneath the ant's feet while her speed remains constant, decreasing her speed relative to the rubber band?

Re:Math? (0)

Anonymous Coward | about 2 months ago | (#47444525)

Why is your ant suddenly a girl?

Re:Math? (2)

Livius (318358) | about 2 months ago | (#47445135)

Suddenly? She was born that way, with the W chromosome and all.

Re:Math? (0)

Anonymous Coward | about 2 months ago | (#47445221)

I guess the ant's feet could slip if the rubber band is greased or if you stretch it too abruptly, but that's being contrarian. You're supposed to imagine the ant's feet keeping their grip and then the analogy works.

Re:Math? (2)

Livius (318358) | about 2 months ago | (#47445297)

That's called the luminiferous aether hypothesis.

Re:Math? (2)

MRe_nl (306212) | about 2 months ago | (#47443989)

Special relativity
http://en.wikipedia.org/wiki/S... [wikipedia.org]

Re:Math? (1)

archer, the (887288) | about 2 months ago | (#47444057)

Does that cover speed as well? 23 Billion Light Year radius and 14 Billion years old implies stuff is/was travelling at 1.6c. And if 46Billion LY was the radius, average speed becomes 3.2c.

Re:Math? (4, Informative)

wierd_w (1375923) | about 2 months ago | (#47444221)

Given a sufficiently large distance between two discrete points in the universe, the rate of hubble expansion between those points can exceed C.

http://www.universetoday.com/1... [universetoday.com]

You can think of it this way:

You have a ruler-- You can only move along the ruler at at most, 100 units per second. (we will use this as an analogue for going C) However, for every second, for every 1000 units distance on the ruler, a new unit of distance magically appears. If you have a distance between 2 points that is sufficiently large, (In this case, in excess of 1,000,000 units) more than 100 units will be introduced every second, which is faster than your maximum rate of traversal-- So you will NEVER reach the target-- it receedes faster than you can get to it.

http://www.universetoday.com/1... [universetoday.com]

Re:Math? (1)

Anonymous Coward | about 2 months ago | (#47445005)

Stop explaining things to people. Tell the guy who explained this to you the same thing.

Re:Math? (0)

Anonymous Coward | about 2 months ago | (#47445083)

http://arxiv.org/abs/astro-ph/0310808
http://en.wikipedia.org/wiki/Metric_expansion_of_space

Re:Math? (1)

wonkey_monkey (2592601) | about 2 months ago | (#47444753)

No.

Re:Math? (5, Informative)

NEDHead (1651195) | about 2 months ago | (#47443991)

Because the expansion of space is independent of the light traveling through it, and the light that has just arrived came to us in some cased from objects that are now much further away than 14B lightyears

Re:Math? (1)

NEDHead (1651195) | about 2 months ago | (#47443997)

That would be cases, not cased. My Apologies

Re:Math? (0)

Anonymous Coward | about 2 months ago | (#47444409)

I blame Slashdot for still not allowing edits in 2014. Your post was very informative.

not true, IIRC (1)

globaljustin (574257) | about 2 months ago | (#47444649)

Because the expansion of space is independent of the light traveling through it

nonsense statement...had to read twice to be sure, but this is just technobabble and not based on scientific definitions of "space" and "light"

and the light that has just arrived came to us in some cased from objects that are now much further away than 14B lightyears

if I understand you correctly, you're wrong...the whole point of GP, one which I think you're attempting to address, is that the only reason we know the universe's shape is because of "light"...wether the CMB or a GRB...

the CMB & the light from the most distant/oldest objects indicates the 14Billion number...if what you say is true, we'd have to revise the figure

in other words, **NO** there is not 'light' hitting us from 14B ly+ because if that were true we'd have evidence of an older universe, so we'd revise our figure of the age of the universe accordingly

Re:not true, IIRC (3, Informative)

wonkey_monkey (2592601) | about 2 months ago | (#47444749)

nonsense statement...had to read twice to be sure, but this is just technobabble and not based on scientific definitions of "space" and "light"

That's weird, I understood it perfectly as an (admittedly somewhat simplified) explanation of how space expands and how light travels through that expanding space. Don't blame your lack of understanding on what you imagine to be the GP's lack of clarity.

in other words, **NO** there is not 'light' hitting us from 14B ly+

No-one said there is. There is light hitting us which was emitted by objects which are now* more than 14 billion light years away.

*for a given value of "now," that is, but I'm not sure I'd enjoy trying to explain that to you.

Re:not true, IIRC (2)

NEDHead (1651195) | about 2 months ago | (#47444751)

Let me put it in terms you can understand: If you hold a rubber band with one end in each hand, and put an ant on the rubber band at one end headed toward the other, and the ant moves at a constant rate toward your other hand, and as the ant moves you stretch the rubber band, then your hands will be further apart than the ant has moved when the ant reaches your other hand.

If you have a favorite animal, I can rephrase to accommodate.

Re:not true, IIRC (2)

TapeCutter (624760) | about 2 months ago | (#47445187)

If you have a favorite animal, I can rephrase to accommodate.

Probably wouldn't work with my dog, it would just eat the rubber band.

Re: Math? (0)

Anonymous Coward | about 2 months ago | (#47443999)

The simple answer from an amateur is because of spacetime expansion, even though galaxies aren't locally exceeding the speed of light, there is more "stuff" being created in the space between them. So from a more global perspective, they appear to be moving faster than light even though it's just an illusion.

You religious people! (0)

Anonymous Coward | about 2 months ago | (#47444139)

Therefor, if the universe is 14 billion years old, then the furthest we could see in any direction is only 14 billion light years, giving a maximum, diameter of 28 billion light years.

You fundamentalists! Always insisting that the Universe is only 28 billion years old because the Bible says so.

Oh shit! nevermind.

Re:Math? (1)

Charliemopps (1157495) | about 2 months ago | (#47444183)

The universe is expanding like others said... but it's still an incorrect statement. All of our measurements so far suggest that the universe is flat, and extends in all directions infinitely. It has no size, it's unending. Even more mind boggling is that if the many worlds theory is true, then there are also an infinite number of other universe that are equally as vast. Long story short? There really are Ewoks somewhere.

Re:Math? (1)

wonkey_monkey (2592601) | about 2 months ago | (#47444765)

The universe is expanding like others said... but it's still an incorrect statement.

The statement did say "observable universe."

Grammar (1)

TapeCutter (624760) | about 2 months ago | (#47445229)

"Universe" = everything.
"universe" = everything observable.

But that grammatical rule breaks down if you put the word at the start of a sentence.

Re:Math? (1)

WaffleMonster (969671) | about 2 months ago | (#47444269)

The observable universe is observable because there has been time for the light to travel that far, which can not exceed the age of the universe. Therefor, if the universe is 14 billion years old, then the furthest we could see in any direction is only 14 billion light years, giving a maximum, diameter of 28 billion light years.
So why does the summary say it's 46 billion L.Y. across and only 14 billion Y. old?

The universe is expanding all while light is in transit to our bug-eyed telescopes.

For details: http://arxiv.org/pdf/astro-ph/... [arxiv.org]

Math? (0)

Anonymous Coward | about 2 months ago | (#47444663)

Why are you assuming the observable universe is all the universe that exists?..

When your mother hides behind something, does she no longer exist?

Re:Math? (0)

Anonymous Coward | about 2 months ago | (#47444821)

you are assuming we are at the point of original expansion not moving. You are also not taking into account attrition of photons due to intervening matter.

Re:Math? (2)

TapeCutter (624760) | about 2 months ago | (#47445155)

Yeah, confused the hell out of me too the first time I heard it back in the 80's. If you search the "starts with a bang" website you'll find a well written article that explains why. Oh and 46 is the radius from our POV, so it's actually 92 "across".

Re:Math? (1)

complete loony (663508) | about 2 months ago | (#47445307)

Because they *were* 14 billion light years away, and are now probably 46...

46 Billion Light-Years? (0)

Anonymous Coward | about 2 months ago | (#47443967)

How can we observe 46 billion light-years away if the light has had only 14 billion years to travel?

Re:46 Billion Light-Years? (0)

Anonymous Coward | about 2 months ago | (#47444337)

Putting this here because it's an unanswered version of the same question being repeated over and over in the thread.

People always raise something like this as a critique of the results of a theory and never seem to twig that *both of these statements are predictions from the same damned theory*. It is self-consistent if you accept the assumptions that go into it. If you don't accept the assumptions then that's fair enough, but a bit of respect for the people who have actually studied for upwards of ten years to be able to do this stuff professionally might lead one to believe that they haven't overlooked something so painfully obvious.

I don't understand... (1)

Miles Zarathustra (3745089) | about 2 months ago | (#47443987)

How can we see 45 billion light years away if the universe has only been here for 15 billion years?

Re:I don't understand... (5, Interesting)

vux984 (928602) | about 2 months ago | (#47444027)

The speed of light through space is distinct from the rate at which the universe itself expands. Weird fun things ensue. :p

Re:I don't understand... (0)

Anonymous Coward | about 2 months ago | (#47444043)

Oversimplified but relevant as a starting point: https://www.youtube.com/watch?v=XBr4GkRnY04

Re:I don't understand... (1)

uvajed_ekil (914487) | about 2 months ago | (#47444837)

Expansion, of course.

An idea (0)

Anonymous Coward | about 2 months ago | (#47444005)

I think there are different nexuses where different universes of the multiverse collide based on the most prominent energies available. I mean, it's just a rough idea. No idea if I'm way off. Think 12/21/2012.

Too bad (1)

Blaskowicz (634489) | about 2 months ago | (#47444103)

I was getting used to the notions of multiverse so broad there exists a copy of me somewhere with a penis in place of the nose and a nose in place of the penis. And that's far from the weirdest things out there.

Brian Green;'s multiverse book (2)

peter303 (12292) | about 2 months ago | (#47444213)

Some of the the mind blowing chapters consider an infinite universe in space and time. Our local area could exactly repeat on the average of 10^150 light years, Brian calculates. And there could many more variants than exact repeats.

Imagine an infinite number of exct copies of yourself, each sparated by immense distances. Image even more variants of yourslef, living slightly to greatly different lives.

Re:Brian Green;'s multiverse book (1)

taxman_10m (41083) | about 2 months ago | (#47444263)

Or maybe this life is as good as it gets for you and your multiverse you's.

Re:Brian Green;'s multiverse book (0)

Anonymous Coward | about 2 months ago | (#47445273)

once we reach the edge of the petri dish all bets are off?

Please explain (1)

StripedCow (776465) | about 2 months ago | (#47444293)

Consider the time axis, from minus infinity to plus infinity.
Somewhere along this axis the universe comes into existence.
Call this point t0.

Now why is t0 exactly t0? Shouldn't there be another universe, exactly equal to this one, with time t1 (!= t0).

Now even if time is created as part of a "big bang", there should be a "meta-time" for which this holds.

Re:Please explain (0)

Anonymous Coward | about 2 months ago | (#47444317)

Now even if time is created as part of a "big bang", there should be a "meta-time" for which this holds.

Why would you assume that? I suppose you will postulate a "meta-space" that existed before the universe too. Sounds like the universe just went ahead and existed 'before' it existed.

Re:Please explain (1)

pla (258480) | about 2 months ago | (#47445311)

I suppose you will postulate a "meta-space" that existed before the universe too. Sounds like the universe just went ahead and existed 'before' it existed.

Know how I can tell you didn't read TFA? Because he says exactly that - That inflation happened before the Big Bang, faster in fact than it did after

If it helps, you could consider the Big Bang the end of FTL inflation, though not 100% accurate (that "first 10^-32 seconds" thing assumes it lasted for a whole 10^-32 seconds, rather than starting at the rate mentioned and ending at a relative (no pun intended) snail's pace.

Re:Please explain (1)

RussR42 (779993) | about 2 months ago | (#47444361)

Time is a measure of change. Until something changy exists, even if there was some kind of "meta-time", it would be meaningless. So meaningless that positing it's existence is pointless...

Re:Please explain (1)

RussR42 (779993) | about 2 months ago | (#47444375)

goddamnit, *its. It's my first day with these new fingers.

Re:Please explain (1)

Charliemopps (1157495) | about 2 months ago | (#47444741)

Consider the time axis, from minus infinity to plus infinity.
Somewhere along this axis the universe comes into existence.
Call this point t0.

Now why is t0 exactly t0? Shouldn't there be another universe, exactly equal to this one, with time t1 (!= t0).

Now even if time is created as part of a "big bang", there should be a "meta-time" for which this holds.

No. Time is a part of this universe. There is no "meta" time, other universes do not necessarily have time. There is no t Minus infinity. We know exactly when time started (ok, to within a few trillionths of a second) You can no more go back further in time than that, than you can make a square circle.

It's something that's hard to talk about because our language is so wrapped up in the idea that time is endless, but it's not.

Re:Please explain (0)

Anonymous Coward | about 2 months ago | (#47444953)

"Meta-time"?
really?
smoking dope does not make you smart.

Good article (1)

WaffleMonster (969671) | about 2 months ago | (#47444341)

Especially liked raised BS flag on many worlds interpretation crackpottery.

Copyright And The Universe (0)

Anonymous Coward | about 2 months ago | (#47444407)

what's completely unrelated to anything that could conceivably ever be observed from within our Universe.

Mickey Mouse released to the public? Never in this universe!

Web 3.0 Bullshit (0)

Anonymous Coward | about 2 months ago | (#47444507)

Fuck that web 3.0 Metro-y bullshit. Why the fuck are webpages loading 5Mbyte background images and taking up the whole goddamn screen with content rather than presenting it in a field-of-view sized portion of it?

Here's the deal... (1)

djupedal (584558) | about 2 months ago | (#47444531)

As humans, we can't conceive of what's beyond, simply because we lack the mental capacity. Much like an amoeba is unaware of high interest rates.

Anybody noticed (0)

Anonymous Coward | about 2 months ago | (#47444569)

the serial medium.com self-promoting going on? Beyond the general unreadability of medium.com if you don't own a tablet, I thought that slashvertising was frowned upon. Maybe not. This a beta feature?

How deep? (1)

Gareth Iwan Fairclough (2831535) | about 2 months ago | (#47444573)

Very.

Speculative. (5, Insightful)

Oligonicella (659917) | about 2 months ago | (#47444575)

Anything dealing with multiverse is speculative. Math does not constitute evidence.

Re:Speculative. (0)

Anonymous Coward | about 2 months ago | (#47444897)

Agreed. Also;
1. There is only one "universe".
2. Making your arguments more convoluted, doen't make them more correct.
3. Things like singularities and infinity mean your math sucks. Nothing more.
4. "0" is a handy tool, until you start doing stupid things like dividing by zero. You cannot divide by zero. It is nonsense.

Re:Speculative. (0)

Anonymous Coward | about 2 months ago | (#47444907)

Anything dealing with multiverse is speculative. Math does not constitute evidence.

Tell it to the auditors.

This is just one person's (4, Informative)

Bob Hearn (61879) | about 2 months ago | (#47444667)

personal opinion of the status of the various ideas labelled "multiverse", inappropriately presented as fact. There is certainly not a consensus view that these opinions are correct, as you might mistakenly infer. In fact, "..., with different Big Bangs but very likely with the same fundamental laws and constants" -- it seems to me the weight of professional opinion is actually more on the other side here. His views on Everett's many-worlds interpretation are also counter to those of most people who accept it as valid in the first place. Perhaps most egregiously, if he is going to borrow (linking to) Tegmark's categorization of the different levels of multiverse, he should at least get them right. But he refers to Tegmark's level 1 as level 0, level 2 as level 1, and is a little confused about the distinction between 1 and 2. If you want a much more thorough, and objective, discussion of the various multiverse ideas, you want to read Brian Greene's The Hidden Reality. And of course Tegmark's Our Mathematical Universe is the latest entry into this field, a manifesto of sorts.

Wait a minute... (0)

cluening (6626) | about 2 months ago | (#47444823)

If the universe is 14 billion years old and 46 billion light years in radius, that means it has expanded at an average of about 3.29 light years per year since the big bang. But... shouldn't it be limited to expanding at a rate of one light year per year?

Re:Wait a minute... (5, Informative)

Anonymous Coward | about 2 months ago | (#47444853)

For fuck's sake. How many times must similar questions be asked?

http://science.slashdot.org/co... [slashdot.org]

These are all basically the same question, which reduces to "I'm going to assume that the people who spend their lives working on this can't do elementary arithmetic". Instead, they're working within the strongest theoretical framework they can encounter. In this case, that framework is general relativity and, specifically, Friedman-Lemaitre-Robertson-Walker spacetimes. A subset of the FLRW spacetimes are the de Sitter and anti-de Sitter spaces. These have exponential expansion or exponential collapse, and as one might imagine, this means that if you somehow attached little radar transceivers to fixed points in (anti-)de Sitter space then the distance between them will change far greater than the speed of light would imply. There is no contradiction here, because in general relativity, the "speed of light" means something propagating along null geodesics, paths along which the observed travel time is zero. Null geodesics basically map out spacetime. This is then entirely and totally distinct from any conception of "space expanding faster than light" - the question becomes meaningless.

Re:Wait a minute... (0)

Anonymous Coward | about 2 months ago | (#47444957)

Yeah, duh.

Re:Wait a minute... (0)

Anonymous Coward | about 2 months ago | (#47445199)

Well, in some ways that's kind of my point in the comment I linked to - people study ten years from the start of a Bachelor's to the end of a PhD just to be at the start of a career in this stuff. It's unlikely that everyone who has ever embarked on a career in relativity or cosmology could have overlooked something so straightforward. So the natural reaction to some odd-looking numbers should be to assume that the researchers probably know what they're talking about and see if they can explain it, rather than (as wasn't done here but has been done in other questions in this thread) to declare things as "nonsense"; or, as was even done here, to strongly imply people have somehow overlooked "ah but the speed of light is a speed limit!" They haven't. These numbers emerge from the theory, they are self-consistent given that theory.

And on a totally different tone, surely even someone who has never studied cosmology before must be getting pretty damned frustrated at seeing the same question reposed repeatedly. Every single cosmology article we get the same question, tens of times. It's answered, in various (sometimes even accurate) ways, each time, at a variety of levels ranging from the entirely intuitive to the fully technical. And *every* *single* *time* we get the same question, repeated again, and again, and again, and normally by people who if they even glanced at the current comments would see someone trying to answer it already.

Re:Wait a minute... (0)

Anonymous Coward | about 2 months ago | (#47445249)

(To clarify, "sometimes even accurate" refers mainly to the fact that almost any explanation that calls to intuitive concepts is going to be inaccurate. Sometimes explanations are dead wrong but for the most part it's people trying to transmit a mental picture of something the human brain simply cannot visualise. Also, to clarify the example I used in the earlier comment, cosmology is not based on de Sitter spaces but these are the extreme example of a universe filled with nothing but a cosmological constant, and they exhibit what at first sight looks like a strongly superluminal expansion. It is postulated, and almost universally accepted (no pun intended), that in the very early universe there was a period of so-called "inflation". This was a period in which the universe underwent quasi-de Sitter expansion, meaning that while it may not have been entirely composed of something acting like a cosmological constant, it was either composed entirely of something acting *almost* like a cosmological constant (as the simplest inflation models do; the only matter is a scalar field, rolling so slowly in its potential that it is basically constant), or there is something acting almost like a cosmological constant but other fields around diluting the expansion somewhat. A universe expanding under the influence of matter or radiation is similarly not restricted to expanding "faster than light" - which is a meaningless statement - but is far less extreme than a de Sitter spacetime.)

Still nonsense (-1)

frnic (98517) | about 2 months ago | (#47444825)

If there furtherest objects are 46B LY away, and the universe is 14B years old, and it all started at a point, then something moved faster than the speed of light.

Re:Still nonsense (3, Informative)

Anonymous Coward | about 2 months ago | (#47444877)

For the love of fucking GOD.

http://science.slashdot.org/co... [slashdot.org]

Read the fucking comments, you cretin, and try and avoid labelling something as "nonsense" which you evidently don't fucking understand.

Re:Still nonsense (0)

frnic (98517) | about 2 months ago | (#47444931)

My, aren't you the literate one. Such an expansive vocabulary to express yourself, my poor mind can barely comprehend what you meant to say.

Re:Still nonsense (0)

Anonymous Coward | about 2 months ago | (#47445039)

Read the comment I linked to then, you prick. You might learn something.

Re:Still nonsense (3, Informative)

thrich81 (1357561) | about 2 months ago | (#47445181)

Although he is a bit abusive I'd cut the AC a bit of slack; your question/comment has been asked several times on this thread and in past ones. The short answer is that space itself can expand faster than the speed of light and so events we observe from a long time ago can be further than c times the time it took for the light to get here. Even events occurring 'now' from regions in space expanding away from us faster than c will eventually become observable to us, although the concepts of distance and time and 'now' can get really tricky under General Relativity. It is all prescribed by General Relativity, or more properly, by some of the easier solutions of the General Relativity field equation which appear to apply to our Universe. You can't use intuition from Special Relativity when the distances and times involved get cosmological. Sorry I don't have a good reference right now, but it's all in Wikipedia (try General Relativity or Hubble Constant or Age of the Universe, maybe). I looked it all up a while back when I got burned (on /.) using my Special Relativity intuition where it didn't apply.

How Deep Does the Multiverse Go? (1)

whitelabrat (469237) | about 2 months ago | (#47445011)

It doesn't. That shit it cray cray.

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>