The universe is flat or a glob?

[nec208]

Okay is the universe flat or a globe like earth? I was talking to someone and they where saying the universe is a globe like earth.All the stars and planets are in this globe and 90% of the mass is dark matter.

Out of this globe is The Infinite Nothing Zone the eternal zone where "nothing exists". The globe can expand or contract.Has of now the globe is expanding.


Other quetion is how big of a rock can hit earh before doing harm to city like LA or New York ? A rock the size of bus can do harm to city like LA? How big to country or earth is wipe out ?

 

[MeteorWayne]

Since these are two unrelated topics, they would have been better off in two different threads. I will answer one in each of two responses, then probably split the thread up.

Regarding asteroids, it depends to a large extent on the impact speed and the composition of the object, but roughly a 30-100 meter object can wipe out a city.

100 meters to about 1 km can effect a continent.

Somewhere above 1 km in size will have global consequences, and above about 10 km will threaten much of the life on earth.

 

[neilsox]

Most indications point to glob or globe rather than flat or disk shape for the universe.
The 30 to 100 meter size are much more abundant than the over one kilometer size, but the smaller ones often disintegrate at altitude of about 100 kilometers. This produces a great light show, but rare surface damage. Large chunks however, that reach 50 kilometers or lower behave like an air burst H bomb, sometimes destroying hundreds of square kilometers. The over 100 meter size sometimes disintegrate at 100 kilometers or higher, but there are almost always some big chunks that reach lower altitude damaging a million or more square kilometers of the surface. There are a variety of opinions about the exact numbers I mentioned, partly because these events are rare, and very brief. Keep in mind that a one kilometer asteroid has about 1000 times more material than a 100 meter asteroid due to the cube relationship between diameter and volume. Neil

 

[dragon04]

I saw a better image than this one, but I don't remember where I found it. This one will do though.. It's a 3D representation of 9300 galaxies that were mapped. The scale here is off the hook. That "box is billions of LY on a side. Looks strangely like depictions of interconnected neurons I've seen.

 

[nec208]

Than the glob theory is false if that is the case.

 

[nec208]

Since these are two unrelated topics, they would have been better off in two different threads. I will answer one in each of two responses, then probably split the thread up.

Regarding asteroids, it depends to a large extent on the impact speed and the composition of the object, but roughly a 30-100 meter object can wipe out a city.

100 meters to about 1 km can effect a continent.

Somewhere above 1 km in size will have global consequences, and above about 10 km will threaten much of the life on earth.

Where are the holes in the ground of asteroids slamming into earth? Has there even bean a 1KM asteroid holes?

I did not make other thread because I did not think this thread will make it past 8 posts.If this thread gets busy than split it up in 2.

 

[MeteorWayne]

Ever heard of Meteor Crater in Arizona? That was a small (but dense) meteor impact ~ 49,000 years ago.

Here's a good reference.

http://www.solarviews.com/eng/tercrate.htm

The largest easily visible one is the Manicouagan, Quebec, Canada one, about 100 km across.

The Chixalub (dinosaur killer) crater is larger but harder to see, since the crater is undersea and is only detectable by using gravity measurements...though it has a clear signature.

 

[CommonMan]

The shape of the universe seems to still be determined. I went to a couple of websites and none of them are certain, they only give you information on what it could be. Try this one:
http://en.wikipedia.org/wiki/Shape_of_the_Universe
and this one says the shape is Dodecahedron.
http://goldennumber.net/universe.htm

 

[jasonpply]

on the same subject. my understanding is that we can only see as far as 14-17 billion lightyears which is around the time of the big bang. my question is can we see this far in all directions or is the plane of sight different on all sides? my guess is that since we a apart of an ever expanding universe that the line of sight would change..

 

[MeteorWayne]

Since the Universe is expanding everywhere, there are no differnt sightlines, we can see the same distance, about 13.4 light years in all directions.

 

[jasonpply]

see thats what confuses me. wouldnt that make us the center of the universe? also wouldnt there be a specific spot where the bigbang would have occurred? i know we can see alot of the universe in its infancy,. but wouldnt there be a specific spot of birth?

 

[MeteorWayne]

I understand it's a hard concept to get. But if you go, say 10 billion light years away, they can also see 13.4 billion light years in all directions. In fact, due to the expansion of the Universe, there are parts of it that we can't see, they are now further away than light has been able to travel in that time.

Trust me, it hurts my brain too

 

[jasonpply]

lol your right on the brain hurting. one last question then. if we can see 13.4 billion ly's in any direction wouldnt that make the universe 26.8 billion years old, because that amount of area would cover that distance if you drew a straight line from one end to the other?

 

[MeteorWayne]

LOL, no it doesn't work that way. The first light was created about 300,000 years after the big bang, that's why I use 13.4 billion year (assuming big bang was 13.5 billion years ago, the current estimate). But we can see 13.4 billion light years in any direction.

Let me take a rest here; I am not the best at explaining it. There are a few other regulars who have much better comminucation skills on this issue. I'm sure they will chime in when they see the thread.

I need an ice bag for my head...

 

[jasonpply]

sorry about giving you a bad head. lol i just dont get it if there was a big bang which caused so much energy and heat i would have thought that it would be something we could see. :evil: also dont we travel through space @ a great deal of speed? planet, sun and galaxy. would changes in our local change what we can see? so say one million yrs from now wouldnt other sights start to appear in the distance ie: galaxies or large bundles of hydrogen clouds? this is not a question for wayne. his head hurts!!!!!! :lol:

 

[tampaDreamer]

We can "see" only the echoes of the big bang, google 'cosmic background radiation', I believe that's the correct term.

Imagine all of space as a leaf. You are thinking that the leaf is growing from the center and so the oldest parts are on the edge and the newest parts are in the middle. However that is not right. The leaf is growing from everywhere, so that if you and I are ladybugs on the leaf, no matter where we stand we will continue to get farther away from each other. And since it is growing from everywhere, the farther away we start from each other, the faster we will recede because the more 'everywhere' there is between us to grow.

Hope that helps! I struggle with this stuff too and I just hope I can pay forward some of the time others have spent explaining this stuff to me.

 

[nec208]

That can't be right .If you think of a doughnut the new parts are by the center and the old parts are by the outer layer.How can there be old and new parts in the center?

If space was big ball of mass (gas) that exploded the parts are moving away very fast.The older parts are more away than the center parts.

It works when we explode things .So you are saying space is different?

And how can space have shape be flat ,blob,globe or whatever if there was big explosion?

 

[MeteorWayne]

That's the big problem. Once the idea of an explosion gets in your head it's hard to get out. It's not an explosion. Space if forming as it expands, so nothing is being pushed away from anything else. The piece of paper the objects are drawn on is getting bigger, but nothing is being pushed away from anything else (except by dark energy, which is a small effect); in fact due to gravity any dots on the paper are attracting each other, as the paper itself gets bigger.

 

[derekmcd]

Unless something has changed, the age of the universe is 13.7 billion years. The surface of the last scattering occurred approximately 3-400 thousand years after the big bang. Subtract 400K from 13.7 billion and you get 13.66 billion years. Round up, as most do, both the age from T=0 and the amount of time light has travelled is still referred to as 13.7 billion. Not 13.4.

MeteorWayne has the right idea. One needs to imagine our existence on a manifold. The surface of a balloon (or any sphere) is a 2 dimensional manifold (2-manifold). There's no inside or outside. Our existence in the universe is described as a 4-manifold (3 spatial dimension plus one of time). Place yourself on that manifold and as it expands and try to describe the center... it can't be done as all reference frames are equivalent. Everyone sees themselves as the center.

The only thing you can measure are the increasing distances between whatever coordinates you choose to measure from/to. No matter what coordinates you choose to begin your measurement from, you will see everything receding from you based on the Hubble constant which only varies over time, but not distance.

 

[jasonpply]

i find this concept hard to grasp. because you are taught in school of the big bang theory as well as drilled into your head via most articles in science magazines. it hard to understand that if all was created via an enormous force (explosion) by the big bang. then its hard to get the fact that everything in the known universe is moving away from each other in all different directions. personnally i find that odd.

i have read alot of articles on other theories ie; string, multiverses so on and so on. the fact that the unverse may be infinite i find hard to believe. strictly because of the vaccuum of space itself. wouldnt there have to be a closed in enviroment for there to be such a vaccuum? again i could be be wrong. could these radiowaves emitting from this big bang just be left overs from our own galactic core swallowing everything in its own vicinity then re-birthing our own galaxy? after all arent radiowaves slower than the speed of light and would take longer to reach us from such an event than the light itself of even 400 thousand years after the event??????

 

[MeteorWayne]

Sorry, about the timing, bad math on my part. I was subtracting 300 million for 13.7 billion, not 300,000. So as derek said, 13.7 billion is right.

Light is nothing more than radio waves that we have little receivers for those frequencies mounted in our head. What is called "the speed of light" is really the speed of electromagnetic waves from radio through infrared, light, ultraviolet, X-rays, and gamma rays etc.

 

[weeman]

That can't be right .If you think of a doughnut the new parts are by the center and the old parts are by the outer layer.How can there be old and new parts in the center?

If space was big ball of mass (gas) that exploded the parts are moving away very fast.The older parts are more away than the center parts.

It works when we explode things .So you are saying space is different?

And how can space have shape be flat ,blob,globe or whatever if there was big explosion?

Nec said: It works when we explode things. So you are saying space is different?

You are correct, the big bang model is completely different in its mechanics than the black cats you blow up on the 4th of July!

I think you're thinking too 3-dimensional about the situation. Keep in mind that the greatest misconception about the big bang is that it was an explosion of matter that happened within pre-existing space. This is not the case. Instead, the big bang was space! There was no space or matter before the big bang. Additionally, on intergalactic scales, it is not the galaxies themselves that are moving farther from each other, rather it is space itself that is expanding, thus moving galaxies apart.

Think of it like a loaf of bread with raisins. When the bread is a ball of dough, the raisins are closer together. Now throw it in the oven, wait a while until it's cooked, and take the loaf out. What do you observe about the raisins? Well, they've moved farther apart, but not under their own power; instead, it was the bread between the raisins that was moving them farther from each other.

As for the "center" of the universe, well, there is no center! The big bang, and cosmic expansion, mean that every point of space expands away from every other point of space. We can't look to a point in space and find the center, because the center of space essentially exists everywhere, if that makes sense. Here's an example:

Example 1: A---B---C---D

Here are 4 galaxies represented by 4 letters. Right now, each galaxy is 1 billion lightyears apart. Now lets expand them:

Example 2: A----------B----------C----------D

Each galaxy is now 5 billion lightyears away from its nearest neighbor. This is when increased distance means increased expansion rate. Lets look at Example 1 from Galaxy A's perspective. Galaxy B is 1 billion lightyears from Galaxy A, and Galaxy D is 3 billion lightyears from Galaxy A. Now lets compare Galaxy A's perspective in Example 2. Galaxy B has moved away to a distance of 5 billion lightyears, yet Galaxy D has moved away to a distance of 15 billion lightyears. From Galaxy A's perspective, B moved just 4 billion lightyears away in the same amount of time that D moved 12 billion lightyears away.

This basic idea is where the argument comes that distant galaxies appear to expand away from us at speeds that are close to that of light (C). If we flip the two examples and look at everything from Galaxy D's point of view, it will be exactly the same as Galaxy A's.

I hope this post helps put things into perspective! Did anyone ever tell you to look at things more 3-dimensionally? Well, in astronomy you have to do that, except it's probably better to look at things 4-dimensionally! Surrendering your basic ideas of dimension here on Earth will give you a more open mind to understand cosmic expansion.

 

[jasonpply]

Wow ty weeman that was an awesome explanation. You guys all rock here @sdc. can anyone explain why we have the vaccuum effect in the universe????? But you guys all rock

 

[MeteorWayne]

Not sure what you mean by "the vacuum effect" can you explain a little more?

 

[Mee_n_Mac]

i find this concept hard to grasp. because you are taught in school of the big bang theory as well as drilled into your head via most articles in science magazines. it hard to understand that if all was created via an enormous force (explosion) by the big bang. then its hard to get the fact that everything in the known universe is moving away from each other in all different directions. personnally i find that odd.

It is an "odd" thing to think about and envision. The name "big bang" doesn't really help as it implies an explosion (something we have as part of our "everyday" experience) vs an expansion. But as said above don't think explosion, think expansion. The old 1 dimensional rubber band analogy works well so long as you don't stretch it too far.

i have read alot of articles on other theories ie; string, multiverses so on and so on. the fact that the unverse may be infinite i find hard to believe. strictly because of the vaccuum of space itself. wouldnt there have to be a closed in enviroment for there to be such a vaccuum? again i could be be wrong. could these radiowaves emitting from this big bang just be left overs from our own galactic core swallowing everything in its own vicinity then re-birthing our own galaxy? after all arent radiowaves slower than the speed of light and would take longer to reach us from such an event than the light itself of even 400 thousand years after the event??????

I'm not sure why you'd think there would have to be a closed environment, perhaps you can elaborate ? As for radiowave emanting from our galactic core .... what's is measured are radio waves coming from all directions that are almost exactly equal in strength / power. If the CMBR was due to something happening (or happened a while ago) in our galaxy you'd expect that it would be very strong coming from the direction of the core (ie - looking towards the Milky Way) and weak to non-existent looking in different or the opposite direction(s).

And radio waves are light .... just light at a much lower frequency on your radio dial ! Radio waves travel at the speed of light though the speed of light depends on the stuff it's traveling through.