pavelcherepan

I'd have to check my info but IIRC dust particles start forming prior to sun starting thermonuclear reactions and once it does, particles are a bit too large to get dragged around by the solar wind easily. Also, it's important to understand that even though solar wind moves very fast but it consists mostly of single protons and electrons and the particle density is extremely low, so much that to us it's a very high quality vacuum. It can, over time, make inner system depleted of light gases but can't really affect larger particles so much.

Generally most models show that initial coalescence of planetesimals is due to collisions of dust particles moving on highly elliptical orbits. Only when they're big enough - 10-1000 km in diameter a runaway growth labelled "oligarchic growth" stage begins where gravity is the leading cause of accretion. ccwebb, have a look at these studies. I think they might help: http://www.pnas.org/content/108/48/19165.full http://books.google.com.au/books?hl=en&lr=&id=VlSVmxgPgGYC&oi=fnd&pg=PA297&dq=terrestrial+%26+formation&ots=-qic0--Ttp&sig=T-Wqi7VJr7XcQUhyO-Y1D3GH_d8&redir_esc=y#v=onepage&q=terrestrial%20%26%20formation&f=false http://iopscience.iop.org/0004-637X/642/2/1131/pdf/0004-637X_642_2_1131.pdf Robittybob1, I'd suggest you keep your unproven ideas away from accepted science forums.

I guess that was simply to save space because on your updated graph the top part has no information at all. Although cutting at 60% is uncool too, gives a wrong impression, you're right.

Usually you'd be using U-Pb radiometric method for older granites and granodiorites and for younger rocks U-Th method can be used. But this probably won't be possible for you. If you could answer studiot's question it will help a lot. fiveworlds, using ice core samples will help us exactly how? Also, I don't think it's an ice core in the picture, looks like a normal PQ size drill core.

The lake sediments that ACME has shown in his picture have a different sedimentation history, regime and rate compared to chalk cliffs. You can't use 500ky number for layers on his picture. Also ACME explained how it was sedimented with yearly layers.

I can't answer in length now, but still a few points: - not previous ice age, but current. We're still in it - if arctic ocean is warm enough to not be frozen, how come in latitudes south of it it snows heavily? - I don't think ice ages are getting shorter. Could you show where you found this assumption? - can you give a link to the paper you're referring to?

Any evidence to support this? Torus... How can an entire torus form an accretion disk? You might need to clarify your 'torus idea', some drawings or pictures will help. Given the latest comment I can't figure out what it looks like. And some information for you to check:

overtone, you've been asked long ago to provide evidence. You haven't done that so far and it seems to me that you can't do so and now, having nothing of significance to offer to the actual topic of discussion, you keep arguing about wording and making straw men. Your idea is filled with logical holes, fallacies and you can barely be falsified, because there's no evidence. Das ist nicht nur nicht richtig, es ist nicht einmal falsch! W.Pauli (It's not only not right, it's not even wrong!)

OK. I see your point and indeed it is valid, but still there are some inconsistencies. For starters, there is evidence to support that outer giant and ice giant planets have formed from such an accretion disk but they all share one feature that is not present in inner planets - all of those have large and developed systems with dozens of natural satellites and rings (however tiny those may be). Some of those satellites may have been captured asteroids and comets but all the larger satellites of giant planets are thought to have formed with the planet and from the same accretion disk. What do inner planets have? Mars has two satellites, but they are captured asteroids, most likely; Earth has one, but the theory of formation of Earth/Moon from the same material is even less supported than the theory of Moon capture; Venus and Mercury both have no satellites. Also, all giant planets are theorized to have a core composed of silicate rocks and ice, so even for those, the formation of rocky center of accretion precedes accretion of gas cloud. Current models mainly show that such rocky centers are created mostly by collisions of initial dust and rock particles. And, finally, by the time rocky planets were forming the inner Solar System was already quite severely deprived of gases and volatiles so even if accretion disks were present in the formation of inner planets, these wouldn't be large and dense and majority of mass gain was from collisions between small rocky bodies on highly elliptical orbits,

studiot, I've read about this one but this is not a discovery per se, but just an attempt to re-classify the known extinction to be on a separate list. Look, for example, at the chart below. The peak of extinction just before the Permian-Triassic "Great Dying" is the one that they want to re-classify. It's already been known and the scale of it is known as well. So this is similar to re-classifying Pluto or Ceres to a dwarf planet. Not really a science, just some administrative work I would also like to correct your scoreboard: Mass extinctions: 6 Lifeforms: Gazillion

Yeah, I saw that one before, but what is different from your idea is that in this photo dark bands represent areas of the original protoplanetary disk that have been depleted of material and where proto-planets have already formed. Hence before the formation of those we'd be looking at a fairly uniform disk of some 2000 AU in diameter rather than tori you're talking about. The reason why they haven't pointed them out is because planets are tiny compared to the entire disk and very dim so they are not clearly visible. The diameter of the entire disk is about 2000 AU = 300*109 km, then a planet the size of Earth will be (2.1*10-7)% of this diameter. BTW, why are you talking of yourself in a third-person?

It seems to me a bit strange to think of an accretion disk as something solid or so dense that it can be impacted on. How dense do you think it was?

I have said it already in a PM but will repeat again. I don't think this idea is valid. The 'extremely flattened' and 'slowly rotating' accretion disk can apply to the entire Solar System when it was forming, but doesn't seem to be applicable to the formation of planets. First of all, it seems highly unlikely to have a 'torus' of material at the exact current orbital distance of the Earth. What could cause such torus to form? What would cause 8 separate tori to form? Or was formation of the Earth different from all other planets? How does this idea explain highly elliptical orbits of near-Earth asteroids and the fact that orbits of a lot of bodies in SS are highly tilted to the plane of ecliptic? If it was a rotating accretion disk that obviously implies some sort of center of mass, why wasn't this disk perturbed by gravitational influence of the Sun and other forming planets? This 'asteroid chunks' you're talking about - were they all exactly equal size, evenly distributed and moving with the same exact angular velocity in the orbit? If they weren't equal size and evenly distributed, their orbits would change over time due to interaction with each other? On the other hand, if they were evenly distributed how come they started accreting to form Earth? Your whole idea of how 'some pieces will hit the disk from outside and some will hit it from the inside' is based on exactly what? Sorry, but you don't get to choose what features can be discussed. I, for example, want half a dozen questions answered that I've formulated above. And no, you didn't present a model, just a collection of random guesses, unsupported by any kind of evidence same as what we've seen in your other threads about formation of Theia and Earth. But coming to your discussion points: 1. 2. Are you implying that centrifugal force is responsible for the loss of hydrogen, helium and other volatiles? 3. Moon capture hypothesis has been more or less disproved by now. The mass ratio Moon/Earth is the biggest of all planet/satellite systems in SS and it's highly unlikely that Earth could've captured the Moon. Also isotopic composition doesn't support it. 4. Tidal effect doesn't have to be related to oceans. The Earth's crust and Moon crust experience tidal effects as well. Same things I've told you in all your other threads pertaining to formation of Earth/Theia - your ideas are based exactly on zero evidence and can't explain observed phenomena.

It seems to me that you're trying to compare apples with pickaxes. Planets orbit the Sun, Sun orbits the center of Milky Way, Magellanic clouds orbit our galaxy and the entire Local Group of galaxies move around common barycenter due to gravitational interaction. So on a small scale and on close distances galaxies can be both red- and blue-shifted depending on whether they move towards or away from us. On such a small scale expansion of space that causes red-shift proper is hardly noticeable and gravitational attraction plays major role. On a larger scale, once we look further than several megaparsecs all galaxies are receding from us due to expansion of space. But that doesn't mean that on a local level a couple of nearby galaxies can't be gravitationally bound and can easily collide and merge. Obviously also current theories suggest that there's no center of expansion. Everything is receding from everything else. <Balloon analogy> If you really want, you can assume a zillion of Big Bangs, but what would be the observable effects of those? How can we distinguish your idea vs the general idea of one BB? Any mathematics to prove it? Also, unfolding space implies some level of curvature on a global scale, but current theories suggest that on a global scale the spacetime is flat.

Unless your cooling system uses liquid tritium as a coolant and it's leaking you probably shouldn't expect much radiation to come from your computer If you're worried about radiation exposure so much the better option would be to encase your PC and your TV and most importantly, the microwave oven in leaded glass. It is transparent so you'll still see stuff but it would block even the gamma radiation to some extent. An even more efficient and cost-effective solution to radiation issues would be to encase yourself in a box of lead glass But then you'll still have high-energy cosmic rays to deal with and a whole lot of neutrinos... On a more serious note, that's how zeolite is used to absorb radiation: As you can see, it's just physical absorption of radioactive material, but it doesn't absorb radiation itself.

Doesn't really matter what period you take. I still can't see coincidence, because a coincidence by definition is: while all events and circumstances surrounding humanity are connected and inter-connected in some way. Let me ask you again - what are you referring to as the "mother Duck"?

I haven't noticed that idea coming up, but I can't see how it's viable, anyway. How would you explain preferential accretion at the equator? This doesn't make sense statistically and maybe that's the reason it hasn't been argued before.

How so? LOIC and HOIC have been used quite successfully in massive co-ordinated DDOS attacks. But obviously, just as John pointed, it's not really hacking as it requires literally no knowledge of computer architecture, networking or programming. Yet media, even reliable and respected news companies are happy to release yet another headline like "Hackers from Anonymous group attack *\ insert website name *\", which could be because an alternative headline "A bunch of school kids take down a major government website" is a bit too scary.

This has nothing to do with the distribution of elements. The problem is that due to 62Ni (and 58/56Fe) having the highest nuclear binding energies synthesis of any elements heavier than iron/nickel via fusion is inherently an endothermic process, i.e. it doesn't release energy but consume it. And as a result no normal star in normal circumstances does produce any heavy elements. With the supernova on the other hand there is such a dramatic amount of excess energy that in the final moments of its existence the star manages to produce a bit of very heavy elements too. In fact any element around us that is heavier that 62Ni is a result of a supernova explosion in which case Moby's song "We're all made of stars" makes perfect sense And coming back to your initial question again. Most of stars will produce Fe in some amounts, but few of them will go bada-boom! And it all depends mainly on two things - mass of the star and its metallicity. <Stellar evolution>

Yeah, yeah, yeah 'bursting to capacity'. Even in small and over crowded Japan over 90% of population live in 5 major metropolitan areas which take up less than 13% of the total area of the country. Over 60% of the territory has population density under 200 people/km2 and the entire island of Hokkaido is less than 100 people/km2. And this is the very crowded Japan. This is not what I call 'bursting to capacity'. It's not really an instability, but rather 'inequality'. And I'm not sure what you refer to as 'mother Duck'. I think as a species in general we're just going with the flow and unless pretty much all of us get killed in a very short period of time we'll keep going, we'll invent means to provide food and energy to sustain growing population, we'll find means to better utilise resources of the planet, but we'll persevere until the bitter end (which is not now).

I have to say that I'm speechless because I never quite expected such argumentation. Now I need to put on my thinking hat and try to figure out what this riddle means

This happened to me too. Avast just went nuts and blocked scienceforums. I had to add an exception to the rules to stop this madness.

I'm not into cause and effect either. I don't care what is the driving factor, whether it is that technological advancement results in increase of population or the other way around. What I'm saying is that it's no coincidence at all. As long as technology advanced we were meant to get to the current population levels and as long as technology advanced we were meant to get to the stage where we can send craft into space (unless everyone died in the nuclear holocaust). Do you see a coincidence? Because I don't. And no plan. Just as evolution has no plan same applies to the the advancement of humanity as a whole. It just happens. Entropy has to increase

Not a coincidence at all. At all times human population on the planet was limited by the available resources mostly. At 35000 BCE the population is estimated at 3 million, because they were hunter-gatherers and had limited resources. At 10000 BCE the population increased to some 15 million due to development of agriculture. There couldn't have been more due to limited resources and rudimentary technology. Then further in time at some 4 CE the population of Roman Empire alone was 40-60 million due to advances in agriculture, technology and medicine. Do you see the trend? As technological level increased so did the population. So at any time in the world history one could say "the world is getting full and the supplies are running out" and then what, it would be a great coincidence at any time in human history? In that case it's not a coincidence, it's related to many other factors and these are not random. Your whole original assumption is flawed, I'm sorry to say this.

What does this have to do with anything? It only really allows us to see full solar eclipses. We have reached the Moon (you know, "That's one small step..." and so on), Mars and asteroids (although unmanned only), but at current technology level space mining is expensive and can't compete with mining on the Earth itself. It costs some $25-40 to produce a tonne of iron ore, but it costs $10000 for a kilogram on low-Earth orbit and some $16000-27000 to get to GSO. And after you get your equipment in space, you still need to reach asteroid you're planning to mine, dig some stuff and send it back to Earth. Very expensive. Also very-very prone to failure. Also governments are not willing to spend so much because it gets in the way of developing weapons to kill people