Robittybob1

Why is there no Dark Matter in and around our Solar System?

Have you seen a miracle then?

It might be unproductive for you but I have learnt a lot. Give your insights please, but I get annoyed with your attitude. I prefer if you just contribute to the science. I am not arguing that the Earth's age is underestimated.

I have largely been trying to answer Swansont's persistent questions, and they have lead the thread along this path. We are trying to see the events that heated the Earth in the beginning so to me it is very relevant in the overall answer to the speculation.

There are definitely varying timelines for the Iron Catastrophe, this one mentions 50 million years. http://www.pbs.org/wgbh/nova/education/programs/3111_origins.html This alternative model has a better timeline but it still requires heating to set it in motion. http://en.wikipedia.org/wiki/Rain-out_model This model allows for a preformed core and further melting at the time of the GI. Quite an extensive timeline is detailed in this webpage: http://carbonomics.net/MCcarbon/Carbonomics/13c10/13c10c.html

I won't be insisting on anything really for as I have already said I prefer the Moon Capture Theory. But as you have noted there is definitely an inconsistency in the Giant Impact theory for they need the impact to occur "after a few tens of millions of years" but the Iron Catastrophe (IC) appears to occur much later, yet the heating that occurred during the Giant Impact would have immediately set the IC in motion at the very least. There definitely appears to be something incompatible between the two ideas.

There seems to be a bit of confusion between my view and quoted views of other people (scientists?). I have never tried to determine when the iron core of the Earth formed so that statement "concentrated in the core after a few tens of millions of years" must have been a quote from another source. OK can you heat the material in the Mantle, as it is today, and get liquid iron metal just to separate out of it? That is how I picture the iron catastrophe working. After the iron has separated and settled in the core then I'd say the "mantle was already low on iron" not before "the Iron Catastrophe" event took place. I plan to look into the timing of these events soon and see if they can be coordinated for at the moment the timing order seems to be reversed. If you were a Moon capture theory advocate none of this is that important, for the relative proportions of iron in the Moon and the Earth have another cause altogether.

Yes I think you have hit the nail on the head. There was nothing stopping the surfaces, where all the forces would be initially applied, reaching phenomenal temperatures. But once I start allowing small amounts of material turning to plasma and radiating away I'm never going to estimate the overall average effect. Looking at sources that mention "vaporization of rock" http://en.wikipedia.org/wiki/Giant_impact_hypothesis This plasma and radiation is not going to radiate unless it able to escape instantaneously as might happen in an atomic explosion, turning matter into energy. If all that kinetic energy was releasable as light, that seems impossible to imagine, yet an artistic impression is given http://en.wikipedia.org/wiki/Giant_impact_hypothesis#/media/File:Artist%27s_concept_of_collision_at_HD_172555.jpg So it might be possible that there is an extreme jet of material escaping sideways. Radiating out in a 360 degree field. Only now am I realizing that this picture shows a small planet impacting a larger one, but if they were both of similar mass sharing the kinetic energy there would be an extreme flattening and material would be flung out into space orthogonal to the line of impact. That would be useless material in the ultimate Moon formation process, for ultimately we are going to need the material to be in the ecliptic and truly averaged on the Moon's final inclination. So for this type of collision the other planet would have to be sourced out of the Solar System to get the ejected material in the right plane to form the Moon. (That seems to be ruled out just because it is so improbable.) [As an after thought about the play on words of hitting a nail on the head, you sometimes get this effect when hitting nails on their heads they will fracture into small extremely hot pieces of iron flying off from under the hammer head. Sparks are an example of this.] "Re: What is the heat of vaporization of Earth's crust?" http://www.madsci.org/posts/archives/mar2002/1015040902.Es.r.html All that energy would be enough to vaporise 1/8 the mass of the Moon. So vaporisation would be a way to deal will a sizable chunk of the heat. With the incoming relative speed of 7.9 km/sec it would not be hard to imagine liquified rock being blasted away a higher than escape velocity. http://en.wikipedia.org/wiki/Escape_velocity

The concentration of iron in the Mantle would have dropped (being already concentrated in the core). As I understand the GIT the core of the Moon is predominantly from the core of the impactor. The glancing blow does not rip iron out of the Earth's core, but there is an exchange of Mantle and Crustal components. I could be wrong about this for I personally prefer the Moon Capture theory but it is not getting the support it needs. True as I found out the other day. The Mars sized planet is around 9 times larger than the Moon, so it basically left 8/9ths of its mass here on Earth if the theory is correct.

That is the problem. There would be nothing left for the iron catastrophe to do if the Giant impact occurred ahead of it. Somehow we have to get the Iron Catastrophe to occur before the Moon formation. Otherwise they couldn't say things like this In that analysis the Iron Catastrophe had already occurred before the Giant Impact.

Using the above equations the relative velocity due to gravitational attraction would be 7.9 km/sec. That is quite fast, but that is if the other planet came in from infinity. If it just starts falling from the other side of the Sun it might not get to be going so fast. An interesting figure was the Kinetic Energy /unit Kg = 1.56E+07 Joules/kg. Seems too much heat That is enough heat to bring the whole Earth to an average temp of nearly 18,000 degrees! Rocks would be evaporating at those sort of temperatures.

Could you please paraphrase what you are saying? I was thinking if the Iron Catastrophe occurred before the Giant Impact then the events are in the right sequence. Do you disagree with that?

Still seems a bit confusing to me. Why would they be concerned how quickly a Mars sized object cools? If it happened as early as this then the timeline looks better, for the Iron Catastrophe would precede the Giant Impact. I'll see if there is any reference to support this.

Can you prove your last sentence please? If Ve = sqrt(2*G*M)/r) (I can see where Enthalpy converts this to V^2 = 2*G*M/r ) Get rid of the square root by squaring both sides V^2 = 2*G*M/r Divide BS by 2 1/2 * V^2 = G*M/r Multiply BS by m (mass of incoming body) 1/2 * m * V^2 = G * M * m / r In the case where the two masses are equal and they will form a combined mass the size of the Earth so r = radius of the Earth. 1/2 * m * V^2 = Kinetic Energy = G * M ^ 2 / r Do you agree with that?

"the (relative) impact speed is at least as large as the escape velocity" It could be a lot higher than that too. Let them start at opposite sides of a similar sized orbit around the Sun if you like. Just to see what the acceleration due to gravity would do to start with please. One planet could just catch up with the other so even though the whole process is taking place at something like 30 km/sec it is the relative motion that will determine how much kinetic energy will heat the planets.

This post results from the problem posed in another thread: http://www.scienceforums.net/topic/88301-earth-what-is-the-real-age/page-6#entry861043 If two planets each 1/2 the mass of the Earth collide what is their terminal velocity? This would depend if one planet was falling toward the Sun so it could have a velocity over and above that caused by the mutual attraction. (So we will have to ignore this additional velocity in the meantime.) I saw one statement that said: https://books.google.co.nz/books?id=0iggAwAAQBAJ&pg=PA427&lpg=PA427&dq=potential+energy+planets+colliding&source=bl&ots=MQYOmb0bj2&sig=cLZQMP-V8pwzhPi220UakLldSVA&hl=en&sa=X&ei=TTYaVZ-iBYXxmAWc8oD4BQ&ved=0CEQQ6AEwBzgK#v=onepage&q=potential%20energy%20planets%20colliding&f=false "the (relative) impact speed is at least as large as the escape velocity" Ve = sqrt(2*G*M)/r) (I can see where Enthalpy converts this to V^2 = 2*G*M/r below) r being the sum radii of the two planets for they would be touching at that point. There would be additional potential energy being released as they merge together. Please, can anyone help me estimate the speed that the 2 half Earth-sized planets would impact each other and what the kinetic energy would do to the mass of the two planets (assume they were on average 1000 degrees Kelvin to start with)?

Is there a really good timeline for the first Gy of Earth's existence? That article on the Iron Catastrophe said it was 500 My after formation, so I take that to mean the Earth was reasonably solid (maybe partially molten) till the iron poured into the center of the Earth. When does Theia impact fit around that? Presumably it was after the Iron Catastrophe. It is time for me to do some homework on this. Well this article gives me a clue: http://www.space.com/25322-moon-formation-wild-theories.html So it was after the Iron Catastrophe according to that! But because the Moon and Earth rocks date back to an early age they can't have the Moon forming 0.5 Gy after the Earth forms. There seems to be an even newer theory, where two bodies of roughly equal mass collide. http://www.nasa.gov/topics/solarsystem/features/moon_formation.html Nothing is easy but with this you get a total blending of the isotopes make the Earth and Moon of similar composition. Now that sort of Impact would presumably be a total meltdown. Ek = 1/2 * M1 * V1^2 + 1/2 * M2 * V2^2 M1 = M2 approximately. Would the velocities of these two bodies be in similar or opposite directions?

Well the Earth isn't solid even today, and apparently neither is the Moon. I wouldn't be surprised if Venus wasn't liquified in the center as well (opinion only). Mars with its cold surface, small volume and little atmosphere cooled and "froze" the core and hence lost its magnetic field. So "cooling" must be related to surface cooling only, and having the surface cool enough for living organisms to survive. Unless there was some water to cool things by evaporation or conduction/convection the early earth would have been a very dangerous place to live on (volcanoes, mud pools, geysers).

Mars! Now that finally makes sense.

Sounds high to me.

what was the answer?

OK 1 ppm = 1 mg/kg. So if you found the result being 51 ppm or 51 mg/kg what more do you need? Your pill doesn't weigh a kg so you have to bring that down. OK

PPM would indicate a number of molecules, so would you need to know the molecular weight of Riboflavin? What is it? You would think the concentration should not be altered by the amount of material (weight). Do you agree? That could be wrong if the amount of material is dissolved in a set amount of solvent. What does C value mean?

Thanks for clearing that up David. So looking at those ratios if an incoming mass the size of the Moon is enough to melt the Earth what would a Mars sized mass (that is a mass 8.7 times as large) do?

So the same pill when crushed was a fraction lighter, is that correct?