Large Hardon Collider

[Kaylia]

There is no inbetween, that is arbitrary.

If it is not prohibited, then it will be prolific. This is how the Universe works.


You're still missing what I'm saying about the water.

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I mean literally INSIDE the rock, in the spaces between the molecules of the rocks, are spots where water tends to slide in and make itself at home.

It's fucking plasma or high temperature liquid/gas. Molecular link are gone, and water is free.

The rocks and regolith that make up the lunar surface are about 45 percent oxygen (combined with other elements as mostly silicate minerals). The solar wind — the constant stream of charged particles emitted by the sun — are mostly protons, or positively charged hydrogen atoms.
If the charged hydrogens, which are traveling at one-third the speed of light, hit the lunar surface with enough force, they break apart oxygen bonds in soil materials, Taylor, the M3 team member suspects. Where free oxygen and hydrogen exist, there is a high chance that trace amounts of water will form.

Explanation like this are much more interesting, and actually make sense.

There is no inbetween, that is arbitrary.

If it is not prohibited, then it will be prolific. This is how the Universe works.

You can't make statement like this. Your feeling about the universe is not science.

[Max™]

Spoiler: show

http://upload.wikimedia.org/wikipedi.../Big_Slash.gif

http://www.novacelestia.com/images/e...n_creation.jpg

In the latter image of a more direct impact, yes, most of it would be vaped.

There is water in the mantle of the Earth which is full of molten rock.

You're forgetting the entire concept of impact excavation, it isn't like this object simply smashed into the Earth and vaporized everything.

There would have been utterly pulverized material, yes, but there would have been a huge amount of relatively intact material hurled into space, or else it wouldn't have lingered in the Earth's path.

Lighter, pulverized material would fall inwards or be blown outwards, larger material, from dust/pebble sizes and upwards, would have coalesced.

[Kryssan]

Not going to touch too much on the geosciences here because it isn't my field, but you're misnomering fission a bit. What occurs in the earth's core is not fission caused by neutrons, it is fission caused by radioactive decay (mostly, with a small amount generated by cosmic rays), as annotated by other sources. This fission is called spontaneous fission, and does not require any outside affect and is not particularly influenced by any outside reaction. However, in order for it to occur, you need a rather heavy element (note, not the commonly accepted Nickel-Iron core - recently hypothesis have been made about an inner inner core containing uranium or some other heavy actinide(s)) and the chances of it occurring are rather small, some on several orders of magnitude. I'm sure you can use your google skills to find some examples so I'll save myself the trouble of writing them in here.


While it is possible to initiate a chain reaction via spontaneous fission and generate nuclear fission (the process that uses neutrons to split atoms), you need to have an intrinsic critical mass on hand as well as favourable conditions to sustain that reaction. I've seen no evidence of the earth containing large volumes of elements at ready-to-go critical mass ratios, and more importantly, I see no moderator or poison process available to control the reaction. A runaway criticality in the earth's core - assuming conditions were available to support the chain reactions - as Max pointed out, would be a very bad day for the virus known as humanity.


U-235 exists in very limited amounts in the world today, the most predominant isotope of uranium is U-238, which is a fast fuel. The further process of the breeding caused by the fissioning and transuranic decay of isotopes yields more fast fuels that are then burned in place of the starter U-238. However, here's the kicker about fast fuels - the hotter they get, the less reactions you get, which is one of the reasons they are being fielded in the Generation IV reactor designs. The hotter your core gets, the more it shuts down. So this concept of reactor control thereby almost completely negates the idea of a nuclear fission reaction occurring in the supposed/theorized ball of uranium located in earth's core. You have no moderator materials to allow for thermal fission, and the very heat and pressure of the earth's core will negate a fast fission reaction. That leaves you only with spontaneous fission and cosmic ray induced fission as your 'fission' occurring in the earth to generate heat. While it is possible some of the neutrons from these fission events could generate a nuclear fission event, the necessary factors in making it happen are an extreme probability, and the ability to generate a chain reaction, especially an ongoing chain reaction for millions of years, isn't a valid theory with the current data that we have concerning the earth's construction.






I'm ok with you using the term 'radioactive decay' for two reasons: its applicable, and its correct for your current discussion. And hey, it also makes heat! This is where 'decay heat' comes from in a nuclear reactor when you shut it down. So it will actually work for your discussion as such. 'Fission', on the other hand, will not. But nice use of wikipedia skills to try and take a large wealth of 'maybes' and attempt to develop a theory with it.

[Tristam]

Hit-and-Run planetary collisions of the sort that produced the moon, even if the earth's mantle were watery at the time, would be expected to produce dry bodies according to the modelling paper below. What you said earlier, that water can "slide into" rock is true, but it can also "slide out" which it is much more likely to do at low pressure. For water to accumulate in the way you're suggesting would require very rapid formation of a core, which probably isn't how our moon formed. Sorry I'm not including figures, but I think the paper is open access even though it's NPG? It's possible I'm reading the paper incorrectly, so if anyone can dig into it better by all means correct my guesses.

From what little I know (which is very little, this isn't even close to my field), there are other, much more likely scenarios for how water got on the moon. In any event, this is really cool.

Nature 439, 155-160 (12 January 2006) | doi:10.1038/nature04311; Received 13 July 2005; Accepted 6 October 2005

When impactors and their removed materials depressurize from pre-impact equilibrium conditions, they might degas. Figure 4 shows equilibrium equations of state computed for molten early mantle containing 1, 5 and 10 wt% water—plausible conditions for young planetary embryos. The limited solubility of water in silicate liquids at low pressures means that the mantle of a hot primitive embryo is probably degassed at shallow levels, whereas the deep mantle can retain abundant water. Planetary embryos suffering severe mass loss, spin-up or fragmentation might, according to Fig. 2b, experience a global hydrothermal event in the hours during and following depressurization. According to Fig. 4, a core-mantle pressure drop of 50% in a water-bearing Moon-sized object would initiate extensive deep-mantle degassing. As for materials no longer bound to an impactor (Figs 2a and 3), there is little if any post-encounter pressure support. Removed materials would be almost totally unloaded from their equilibrium pressure, and if molten would efficiently degas throughout—a recipe for dry, igneous, fine-scale meteoritic debris.

[Woozie]

Tristam, what field are you in, just out of curiosity. You seem to know a lot about a variety of different subjects.

[Tristam]

Tristam, what field are you in, just out of curiosity. You seem to know a lot about a variety of different subjects.

My undergrad was in biochemistry, and I studied protein-lipid interactions in cholesterol metabolism. Then in grad school I moved into biophysics, and while I kept an interest in metabolism and energetics, I worked mostly on studying the mechanics of proteins at the single-molecule level. I developed a general interest in evolution, because the protein superfamily I study is an amazing example of evolution at work.

As a postdoc I'm trying to take what I've learned about protein mechanics and apply it to a more complicated biological system, so I'm studying members of the same protein superfamily in the context of the brain.

I know a little about modeling because that's what alot of biophysicists do, many make computational models to attempt to explain systems on a higher-order level that isn't really easy to address directly with the tools/time available. Nothing that is really discussed on the board is close to what I do, and I'm better trained in biology than physics, so I tend to stay out of the more theoretical physics-oriented discussions. I've collaborated with, and have many friends who are, much better studied on the physics side of things, so on occasion I get to hear them talk about theoretical astrophysics and the like, but it's just not where I am professionally.

That being said, everywhere I go I've taken advantage of institutional subscriptions to Science and Nature especially, and the awesome thing about those journals is the editors really try to force the authors to write in a level that is usually generally understandeable to anyone with some background (I've heard they wouldn't allow someone to use the "Pi" symbol in text once without referencing exactly what it is). So I really think that when it's available, it's the best way to dig into things, and from time to time I find something that's relevant here.

[Woozie]

Wow, I may need your help with some things.

Right now I'm working on modeling interactions in protein or polymer structures. I know very little about chemistry (and thus, nothing about proteins or polymers). Right now I'm only using a Lennard Jones potential between different proteins (which are all somewhat helix shaped, by the way) and any other forces involved are being approximated by some simple harmonic oscillators.

The reason I'm approximating them this way is because I have absolutely no clue how the interactions between different molecules of a protein work. I remember learning in thermal physics that certain solids can be approximated as sets of SHO's if the temperature is low and certain conditions are met. I can think of a trillion reasons that wont work in my model. I need to learn more about the actual interactions between the building blocks of proteins or a molecule. Obviously I can't just use the columb potential and solve the Schrodinger equation for a system of a few hundred many-electron atoms, so there must be some other way.

What do I need to study to learn this in more detail? I've taken a year of chemistry so far. What books (or courses, or peer-reviewed journals) would you recommend I go into so that I can understand this a bit better? To be honest, I don't care too much about the details of the force. I'm more interested in techniques or numerical methods used to model such forces in computer computations. Like with the carbon nanotube research, I focused a lot more on solving problems my professor gave me, and left the physical interpretation of the results up to him. I've been studying carbon nanotubes for two years now and I still don't really know more about them than when I started despite the fact that I have enough done to get published (and I will be submitting it for publication soon). For carbon nanotubes, I was able to find a TON of methods in books and journal articles. For what I'm doing now, I don't know where to start.

Edit: I'm using matlab mostly, btw, and I'm also familiar with the finite element method (which I doubt would apply here unless I find some model involving partial differential equations). But if you know of any books or articles that use something else, that's fine. I have access to a ton of journals. Which do you think would be most useful to me?

[Mizango]

That is one thing I like about this thread, we pretty much have all the bases covered in regards to almost all aspects of science.

This is right up Tristam's alley.

[Woozie]

Oh, and I forgot to mention that I have access to a lot of different software as well, if you have any recommendations. For part of the carbon nanotubes research, I used this program that actually let me build the tubes and their structure and model their heat properties based on what I built. My professor doesn't want me to use that for the protein structures. He said I'd run into a brick wall later on if I tried, though I don't completely understand why. He may have been saying that due to my own limitations as a programmer. I started out using Femlab, which was incredibly easy, but when I moved onto the smaller scale stuff, it took me months just to learn a lot of basic programming stuff. I'm not sure if he's making me use matlab now because it's easier for me or because it's a better way to do the problem.

Are you experimental, or do you do just the modeling part, or both? What programs do you use in your research?

[Tristam]

Wow, I may need your help with some things.

Right now I'm working on modeling interactions in protein or polymer structures. I know very little about chemistry (and thus, nothing about proteins or polymers). Right now I'm only using a Lennard Jones potential between different proteins (which are all somewhat helix shaped, by the way) and any other forces involved are being approximated by some simple harmonic oscillators.

The reason I'm approximating them this way is because I have absolutely no clue how the interactions between different molecules of a protein work. I remember learning in thermal physics that certain solids can be approximated as sets of SHO's if the temperature is low and certain conditions are met. I can think of a trillion reasons that wont work in my model. I need to learn more about the actual interactions between the building blocks of proteins or a molecule. Obviously I can't just use the columb potential and solve the Schrodinger equation for a system of a few hundred many-electron atoms, so there must be some other way.

What do I need to study to learn this in more detail? I've taken a year of chemistry so far. What books (or courses, or peer-reviewed journals) would you recommend I go into so that I can understand this a bit better? To be honest, I don't care too much about the details of the force. I'm more interested in techniques or numerical methods used to model such forces in computer computations. Like with the carbon nanotube research, I focused a lot more on solving problems my professor gave me, and left the physical interpretation of the results up to him. I've been studying carbon nanotubes for two years now and I still don't really know more about them than when I started despite the fact that I have enough done to get published (and I will be submitting it for publication soon). For carbon nanotubes, I was able to find a TON of methods in books and journal articles. For what I'm doing now, I don't know where to start.

Edit: I'm using matlab mostly, btw, and I'm also familiar with the finite element method (which I doubt would apply here unless I find some model involving partial differential equations). But if you know of any books or articles that use something else, that's fine. I have access to a ton of journals. Which do you think would be most useful to me?

Wow, congratulations on getting your work almost submitted, it's an awesome thing to see your work hit print.

For protein polymers, I've done very little work on them, and only in the context of biology. So beyond general energy minimization to determine protein structure, even for things like helical actin filaments, I'm at a bit of a loss. Honestly though, I think most protein structural modelling is done using such energy minimization and comparing those models to experimental data such as x-ray diffraction patterns. I can send you a couple links about using such info to derive structure of helical proteins. Sometimes they have their code submitted as supplemental info.

If you're looking for general protein-protein interactions and how biological protein structure is stabilized, I'd be willing to bet physical chemistry courses would be helpful, I took P-chem for biologists looong ago, so most of it is forgotten, but the textbook I use is Tinoco et al, it will have introductory chapters on protein structure and interactions. Embarassingly, I left my copy in my old lab, so I can't address any direct questions about the text until I get a chance to pick it up in october.

Amazon.com: Physical Chemistry: Principles and Applications in Biological Sciences (4th Edition) (9780130959430): Ignacio Tinoco, Kenneth Sauer, James C. Wang, Joseph D. Puglisi: Books

Honestly though, that might be a bit too general for you. For journals, JACS and Nano-letters are a couple of publications that the more physics-oriented guys in the lab would frequently read. Proteins are alot like Rube Goldberg machines in the way that they work, noncovalent interactions comprise the majority of the discussion whenever one shows a detailed structure of a protein.

Sorry I can't be more help, but your work sounds interesting, good luck with it! If you want, I can PM you links to a couple of my articles to get a better idea of exactly what I've done. I'm actually in the process of submitting a paper but we got rejected from our top choice lol.

[Tristam]

Oh, and I forgot to mention that I have access to a lot of different software as well, if you have any recommendations. For part of the carbon nanotubes research, I used this program that actually let me build the tubes and their structure and model their heat properties based on what I built. My professor doesn't want me to use that for the protein structures. He said I'd run into a brick wall later on if I tried, though I don't completely understand why. He may have been saying that due to my own limitations as a programmer. I started out using Femlab, which was incredibly easy, but when I moved onto the smaller scale stuff, it took me months just to learn a lot of basic programming stuff. I'm not sure if he's making me use matlab now because it's easier for me or because it's a better way to do the problem.

Are you experimental, or do you do just the modeling part, or both? What programs do you use in your research?

I'm all experimental, all of our programming was done in house in LabView 7.1. For modelling, what we do isn't really structural, we have a biochemical pathway for how we think our system works, and we have data that is limited to one or a few particular steps in that biochemical pathway. Our model is the reaction pathway, and the parameters are the rate constants, some known via other measurements and some derived potentially through our experiments. So for what we've done, it's very little actual structural data.

Now, that's not to say we're not interested in structure, we're actually looking at a nifty protein that is specifically modified in vivo in a way that we show will directly change the mechanical properties of the motor by changing the length of a structural element of the protein (actually, part of what I did was prove that this element behaves as a rigid rod).

The cool thing, for me at least, is that changing this element changes how this protein responds to forces, in this case tension resisting the motion of one part of the protein changes the biochemistry in another part. We're very interested in how that structural change from tension in one end is relayed, but we're not there yet.

Edit: Wow I'm an idiot, I just remembered one of my good friends did his thesis work on modeling interactions between helical transmembrane domains in proteins. I think his thesis might be freely accessible online, if you think that'll help, I'll gladly send you that link. Theses are generally very very comprehensive, so that should have a really good treatment of the sorts of interactions youre looking for.

[Kaylia]

Not going to touch too much on the geosciences here because it isn't my field, but you're misnomering fission a bit. What occurs in the earth's core is not fission caused by neutrons, it is fission caused by radioactive decay (mostly, with a small amount generated by cosmic rays), as annotated by other sources. This fission is called spontaneous fission, and does not require any outside affect and is not particularly influenced by any outside reaction. However, in order for it to occur, you need a rather heavy element (note, not the commonly accepted Nickel-Iron core - recently hypothesis have been made about an inner inner core containing uranium or some other heavy actinide(s)) and the chances of it occurring are rather small, some on several orders of magnitude. I'm sure you can use your google skills to find some examples so I'll save myself the trouble of writing them in here.

My bad if I was missusing the word (I thought nuclear fission was the general term that include Spontaneous fission (decay), and every other form of nucleus that go through fission).

I was simply pointing out that radioactivity is at the source of the strong heat at the core. Nothing more.

In the latter image of a more direct impact, yes, most of it would be vaped.

There is water in the mantle of the Earth which is full of molten rock.

You're forgetting the entire concept of impact excavation, it isn't like this object simply smashed into the Earth and vaporized everything.

There would have been utterly pulverized material, yes, but there would have been a huge amount of relatively intact material hurled into space, or else it wouldn't have lingered in the Earth's path.

Lighter, pulverized material would fall inwards or be blown outwards, larger material, from dust/pebble sizes and upwards, would have coalesced.

If material is accelerated to space with a single "instant" push, there is a good chance it will be deformed greatly, to the point where the quantity of "intact rock" you mentioned is insignificant.

After that, the material is getting a suntan for thousand of year, while gravity do her thing. If Moon can't retain water on the surface, I don't need to draw you a picture to explain why this material has even less of a chance to keep strong quantity of water.

[Khamsin]

There is no inbetween, that is arbitrary.

If it is not prohibited, then it will be prolific. This is how the Universe works.

Unless the rate at which something happens (or probability that it will) is low enough that its rare, but exists. Or exists in small quantities here and there.

If something is not prohibited, then it may become prolific given enough time, but the universe is only a finite few billion years old (whether that be ~13 or ~40) with a potentially infinite future. In 802919281294891 vigintillion years, something that's rare now may be prolific then.

[Max™]

The Universe is old, we are strangely near the end of the fertile star production years, if there is life here by now, it must be elsewhere, but there is probably something that pushes everything back down to pondscum on some periodic timescale, if anything.


As for the water and moon rocks, I hadn't seen the paper mentioned above and I concede that it may not be as viable as I had understood it to be, but should also point out that the paper cited is not conclusive either, we still haven't dug down into the moon much yet.

[Cruzizzle]

Call it what it is, we are just that. Which is why I am afraid to take some of these bat shit crazy people into space. I would be more than content leaving them here waiting for the day they've prophesied about (Wrongly every time might I add) for thousands of years.

I mean to each his own and all but you're right, think of the advancements we would have made and still be making if we all were on the same page.

This is probably WAY out of context (i'm working through this thread and am only on page 22 atm ><) but I had to comment on this because reading this reminded me of the family guy episode that was on this past week and needed to share.

stewie invented a multi dimensional transporter and takes brian to a dimension that he describes as: "same year same time but in this universe christianity never existed which means the dark ages of scientific repression never occurred and thus humanity is 1000 years more advanced"

aaaand I don't have 10 posts yet but just google "family guy road to multiverse" for the whole episode it's hilarious!

[Mizango]

lol I remember that episode and kudos to you for reading all of these pages, holy cow.

[Eliseos]

Yeah, my mind would have wandered off trying to reread all this lol.

[Kryssan]

Why can't we sticky this? That way I don't have to make threads everyday.

Guess we don't need a sticky when noone lets the thread fall off the front page, heh.

lol I remember that episode and kudos to you for reading all of these pages, holy cow.

Yeah, my mind would have wandered off trying to reread all this lol.

What's wrong with a wandering mind? The only problem I have is your lack of further contributions ~ 4 days with no content? For shame. I'm to blame too, I guess, though. Oh well. Nothing ever happens in nuclear power. *yawn*

[Kryssan]

Oh well. Nothing ever happens in nuclear power. *yawn*

Damn, here I go and make a liar of myself. Posted today on ITER:

Making Progress ITER Oct 2

[Cruzizzle]

Yeah, my mind would have wandered off trying to reread all this lol.

didn't say i was doing it *quickly* lol (i had to make a bookmark just for this thread...)

but its one of the most interesting threads on this board so worth the time!