Prime-Evil

As for what gravity is, I am not sure. I can only suspect that it is one of those things that itself defines both space and time, and is itself defined by them.

Here they estimate the Earth mass, but don't discuss effect of distributed mass of Earth:

http://www.wonderquest.com/calculation-mass-of-earth.htm

 

So I think I have to go straight to the source, Sir Isacc's Law of Gravity, and see where he says that the distribution of mass doesn't matter unless you become surrounded, i.e, dig towards center of earth.

 

But here it only talks about a binary system without discussing distribution of mass. I need to see where Newton broke out his calculus. I presume he took care of this somewhere along the way, and that it was either one of the more bring bits, to him anyways.

http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html

 

Aha. Now I see. Newton's hollow earth paradox. Two cones.

So he did manage to get the job done without calculus after all.

http://www-spof.gsfc.nasa.gov/stargaze/StarFAQ2.htm#q29

If that is the case then there would be no difference.

That's what I have been told, but I haven't quite figured it out.

 

If you use the simple formula, and a mid-latitude radius, and neglect the small stuff like rotation, time of day, and tides, then it seems to work out pretty close to 1 kg weighing 9.81N.

 

F = G m1 m2 / r^2

 

G = 6.6742E-11 [N.m^2/kg^2]

m1 = 1 [kg]

m2 = 5.9742 x 10^24 [kg]

 

r = 6,371,000 [m], F = 9.823 [N]

r = 6,375,000 [m], F = 9.811 [N]

r = 6,378,000 [m], F = 9.802 [N]

 

Pretty close eh? So I suppose it doesn't prove much.

 

But why doesn't all that mass out to the sides cause of weight to be reduced? I suppose it is countered by some of the mass directly beneath us being closer and some of it being farther away and the fact that r is squared, not linear. Has anyone seen an actual proof of this?

 

Is this what the estimate of the Earth's mass is based upon?

 

When I changed the mass of the earth into 6 or more descrete masses it did seem to make a difference, so I'm thinking whatever you do does have to approximate a sphere maybe. Can anyone help me out on this? Time to break out the old calculus maybe, or just use more discrete blobs and approach a sphere and use brute force and shear ignorance, which is sort of what calculus is anyway.

If all the mass were to be confined to a smaller radius' date=' it would cause the [i']weight[/i] to be higher because the average distance between all the mass and you would be less. If compressed far enough, past the Schwarzschild radius, it would become a black hole. So yes, the weight would increase if the distance was lowered. The mass would stay the same.

Think about mass on the other side of the earth from you, it exerts less gravity on you than the earth below your toes. If you brought all the mass as close to you as possible, your weight would increase. Don't think of the earth as one object, think of it as trillions and trillions of atoms.

If all the mass was at the core and you were somehow suspended where the old radius was it would still be higher. All the gravity would pull down whereas before some pulled at an angle (mass close to surface 1/4 of the way around earth in either way.)

That wasn't exactly my question was it? My question was what if you changed the distribution of the Earth's mass but kept your distance from the Earth's center of gravity constant.

"I've got this theory, and the only cure, is more cowbell."

 

Most human population models are of two kinds.

1. There are the friendly models, popular with the UN, where all the countries of the world eventually achieve mutual prosperity and stable fertility rates and the world population eventually reaches a steady state where the new people being born is in balance with the number of people being 'lightly killed'.

2. There are the fruit fly models, popular with others, where all of the people of the world breed like fruit flies until they use up all of there resources and then their population crashes, assuming of course they are not able to escape and find more fruit in another bell jar in a galaxy far far away.

 

What about a third model, with humans, where instead of reaching a stable steady state or have an appocolyptic crash we instead enter a period of extreme oscillations, resulting from the destabilizing effect of conflicts over resources with periods uncontrolled of regional and global population growth intersperced with periods of extreme regional and global die-offs due to war, famine, pandemics, embargoes, riots, revolts, genocide. You know, civilized homo-sapien stuff. I'm thinking population increases of 50-100 million per year, balanced by die offs of as many a 1 billion people at a time every 20 years or so, or at least within a 5 year period due to some related cause. We've never had that many people die at once before. That's a lot of people. But we have never had 10 billion pyromaniacs run out of stuff to burn before either.

Yeah, I was hoping you would find them tough for high school, since I don't have the answers. I am still not even sure about the first one, though I have a hunch. Still, I think you may have missed my caveat:

 

"I think when you finish high school you should have more questions than answers, and at least two answers to most questions. Isn't that the real point of science and education after all?"

Are people in this thread still naked.

Put some clothes on for crying out loud.

 

Definitely one of the funnest threads.

Which came first, the skinny dipping, or the blushing?

Scepticism is good. But you also need to be sceptical of your scepticism.

My guess is two.

One to mix the drinks and one to call the hired help.

 

We are talking Victorian England after all.

That's what the liars want him to think.

 

Look at these graphs

 

Atmospheric CO2 is higher then it's ever been in all our record keeping.

I think you meant to say that CO2 is higher then it's ever been in all our record keeping since 1962, and higher than ever in our current geological epoch based on indirect measurement and analysis of data dating back 400,000 years. I don't think you meant to imply that we have been keeping records for 400,000 years. The glaciers have, but of course we haven't.

 

Anyhow, I am quite convinced we are in for a wild ride when we hit 400ppm by 2020 and 500ppm in 2100, and run out of most of our easy fossil fuels in the process as India and China try and catch up to our own madness and we try and stop them from doing so. What I don't understand yet is what our policy makers are really planning on doing. I don't believe for a minute that they believe the rhetoric that they are spewing out. I think that is all just a somescreen for something else. Whatever that is, I can only guess and fear.

The rhetoric is indeed very funny. I get a kick out of this one.

To think that ONE species of animal can drastically change weather patterns and mess with the entire planet's ecosystem is nothing short of disgustingly egotistical.

This is from the same people that for the past 3,000 years or more have been claiming that we have some sort of divinely granted dominion over all the Earth. It is a little late no with 6,500,000,000 pyromaniacs at the top of the food chain to deny any accountability.

 

That said, the original poster needs to show his old man a little more respect. There is always some wisdom to be found with our parents, even if we can't always see it right away. But the business as usual crowd; Yeah, they can go flood themselves.

Cool.

 

I often wonder if non living material, like simple and complex polymers, and even some inorganic material in our internal and external environments, play a much larger role in who we are, how we thing and behave, and how we adapt and evolve. Like aluminum and PCBs and stuff. Or maybe I'm just getting pissed off because I'm growing old and losing my mind and growing man breasts.

This means that the virus can basically be passed down to your ancestors.

Don't you mean 'from' you ancestors. Otherwise that really would be spooky shat.

 

Interesting thread. I've often wondered how much of our evolution depends on the evolution of all of our hosted organisms. In a sense, we exist as a species within nature, and without nature, with both an external environment, and an internal invironment, both of which we are codependant upon. I am also unsure what is evolution, what is devolution, and what is adaptation to current circumstances using pre-existing genetic material and relationships with internal and external micro-organisms and even non-organic materials in our internal and external environments.

Sure Enough.

 

With all that coal about I would like to know where I could get myself a ton or so of the stuff. Not exactly environmentally friendly, but perhaps no worse than using electricity for heat and hot water. I think if you were careful, and frugal, and used a combination of coal and wood, you could get very good use of both and use the money you saved to add some more insulation and solar heating. Where can a person buy coal?

 

It would be interesting also if you could produce liquid fuel for you car from coal at home and recover heat from the process to heat your home and hot water, and perhaps generate some electricity along the wat also. It is interesting to research what can be done on a small scale, because most research is done for applications on a large scale.

OK here are my 10 questions:

 

Part 1 - Physics:

 

1. Classical Mechanics

Would a mass on the surface of the Earth weigh more or less than it does now if the Earth's mass was concentrated at it's core, or of uniform density, or concentrated evenly about the Earth's crust like a hollow shell?

 

2. Quantum Mechanics

What causes gravitational force?

 

3. Relativity

If a quantity of pure matter at rest was able to accellerate itself by consuming its own mass and turning it into energy in a closed system without losses, what would its final velocity be?

 

4. Modern / Theoretical Physics

If two neutrinos were separated alone at rest in deep space at a distance of one light year apart and allowed to accellerate towards one another under the force of gravity and other forces, what velocity would they have when they eventually collide?

 

5. Astronomy and Cosmology

If time and space are relative, did the universe have an actual beginning or only a theoretical one, and will there be an actual end, a theoretical end, or no end?

 

 

Part 2 - Chemistry:

 

6. Inorganic Chemistry

What would be the most useful synthetic liquid fuel for vehicle transportation that is not a hydrocarbon and how might it be produced from sunlight or electricity?

 

7. Organic Chemistry

What would be the most useful synthetic liquid fuel for vehicle transportation that is a hydrocarbon and how might it be produced from sunlight or electricity?

 

 

Part 3 - Biology:

 

8. Evolution, Morphology and Exobiology

What role has viruses played in the evolution and lifespan of complex multicelled plants and animals, including humans, over the past 100,000 years, and particulary in the past 10,000 years with the advance of the human species?

 

9. Ecology and the Environment

What is the best estimate of the historical levels of total global biomass broken down into plants, animals, and dead organic matter, in soil, above ground, and in the oceans over the past 100,000 years, and particulary in the past 10,000 years with the advance of the human species?

 

10. Biochemistry and Molecular Biology

What role has inorganic chemicals played in the evolution and lifespan of complex multicelled plants and animals, including humans, over the past 100,000 years, and particulary in the past 10,000 years with the advance of the human species?

 

 

I think when you finish high school you should have more questions than answers, and at least two answers to most questions.

 

Isn't that the real point of science and education after all?

"i take electrical engineering classes and our instructor wants us to create a project that includes a hardware and software component, preferably using the pic microcontroller..."

 

How about a solar hot water heater with a solar powered circulation pump and valves for drain down at night, and software that automatically controls the timing of the drain down and refilling and circulation based on hot water temperature and use, outside temperature, and solar insolation?

My superficial guess is that carbon dioxide will distribute itself quite uniformly even if it is overproduced in the Northern Hemishere. Positive feedbacks like land use and snow and ice cover will vary North and South, but current carbon dioxide levels should indicate that climate change is a global problem, even if global warming advances more quickly in the Northern Hemisphere.

 

It raises an interesting question though. What might happen to critical equatorial regions like the Saharah and Indian Ocean if there is a change in the temperature gradient between Africa and Eurasia? Also ocean currents in the Pacific.

I have solved all the potential problems with evolution to my satisfaction.

The difficulty is in convincing women that I am right.

No, that guy doesn't seem to understand selective breeding.

Hey. That's nobody's business but the two species involved.

So then roughly:

Biomass Heat ===== $0.03/kwh ~ $10/MillionBTU ~ $150/cord ~ $1.25/gallon gasoline

Biomass Fuel ===== $0.06/kwh ~ $20/MillionBTU ~ $300/cord ~ $2.50/gallon gasoline

Biomass Power ==== $0.12/kwh ~ $40/MillionBTU ~ $600/cord ~ $5.00/gallon gasoline

Wind Power ====== $0.12/kwh ~ $40/MillionBTU ~ $600/cord ~ $5.00/gallon gasoline

Hydrogen Fuel ==== $0.12/kwh ~ $40/MillionBTU ~ $600/cord ~ $5.00/gallon gasoline

Solar Power ====== $0.24/kwh ~ $80/MillionBTU ~ $1200/cord ~ $10.00/gallon gasoline

Solar Hot Water === $0.12/kwh ~ $40/MillionBTU ~ $600/cord ~ $5.00/gallon gasoline

Solar Passive Heat = $0.06/kwh ~ $20/MillionBTU ~ $300/cord ~ $2.50/gallon gasoline

 

One of the downsides of hydrogen fuel from wind power is that even though it is a fairly efficient conversion, there is an exergy loss, since hydrogen is only about 50% as efficient as electricity in producing work. They do generally outperform batteries however, in efficiency, weight, and cost, expect perhaps in very small and short duration applications. It might be difficult for hydrogen to be cheaper that ethanol and biodiesel in the long run however, unless hydrogen engines prove to be more efficient, or simply more available.

I never had much faith in this hydrogen economy nonsense, since to my hydrogen is just an energy storage medium and not an energy source. But when you consider the yield per acre of Wind Power vs Biomass, and the problems associated with land use, and the fact that Wind Power is compatible with agriculture, I think a hydrogen economy combined with electric power generation does make more sense. I think solar power will be more useful in the lower latitudes below 30-45 and wind power will be more useful in the higher lattitudes above 30-45, with both useful in between.

 

It is true that wind power will kill birds, but if it allows more natural habitat to left alone from forestry and agriculture then this cost can be mitigated and corrected. The important this is that 'alternative' energy is not used as 'additional' energy, which currently it is.

Solar power can be used to produce hydrogen directly by electrolosis. The yield per acre is considerably higher than wind and biomass, but the capital cost is also correspondingly higher. Also, I think the life cycle energy cost of producing the solar cells is about 60% to 75% of the energy obtained over a 20 year life span. Not great, but comparable to ethanol from corn and uses less acres and therefore make more area available for forests.

 

Relative yield/acre/year

 

Biomass Heat: 4 ( 1-10, ie 1 cords wood, 3 tons of corn or canola, or 10 tons switchgrass)

Biomass Fuel: 2 ( 50% conversion )

Biomass Power: 1 ( 25% conversion )

Wind Power: 10 x the power at perhaps 20 times the cost per acre

Solar Power: 100 x the power at perhaps 400 times the cost per acre

 

e.g.

Biomass Heat: 1.5 cords of wood sustained yield = 24 MillionBTU/acre

Biomass Fuel: 3 tons of dry corn converted at 50% = 24 MillionBTU/acre

Biomass Power: 6 tons of biomass converted at 25% = 24 MillionBTU/acre

Switchgrass Fuel: 10 tons converted to ethanol at 50% = 160 MillionBTU/acre

Wind Power: 30kw/acre x 0.36 = 92,000 kwh/year = 320 MillionBTU/acre

Solar Power: 3000 m2/acre x 4kwh/m2.day x 15% = 2,200 MillionBTU/acre

Solar Hot Water: 3000 m2/acre x 4kwh/m2.day x 50% = 7,500 MillionBTU/acre

Solar Passive Heat: 3000 m2/acre x 4kwh/m2.day x 85% = 12,500 MillionBTU/acre

 

I think the cost goes up more than linearly, but you save on land. Also, traditional biomass heat and passive solar heat are considerably cheaper than producing liquid fuel or electricity, but of course the 'available energy' is correspondingly less. I think a combination of all of these technologies is best, but some particular attention needs to be put on re-storing and sustaining higher levels of biomass and biodiversity. The bottom line no matter what you do is that you need fewer people, and they need to consume less energy.

Yes, but what about my point that current carbon dioxide levels are now sufficiently high to cause global warming significantly above the background variability, even given our limited understanding.

 

This is perhaps the simplest proof of global warming:

http://en.wikipedia.org/wiki/Earth%27s_energy_budget

I am not sure the cockroaches would consider this evolution.

Due to time zone differences' date=' I have been out of this for over 12 hours, and a lot of replies have come in.

 

I am really replying to Herpguy's earlier posting.

 

Herpguy.

Sorry, but my facts are real. Yes, I have been to a glacier (in fact, many). The pattern is widespread. When a glacier moves forward (with increasing cold), it pushes a pile of rubble ahead of it. This includes many fragments of organic matter which can be carbon dated. When climate changes, and things start to get warmer, it leaves this large pile of rubble in place (now called the terminal moraine). By carbon dating lots of organic matter in this rubble, and using the youngest as the date, we can be pretty sure when the glacier started to retreat. ie when things began to warm up. By repeating this test in many places world wide, we get global warming beginning about the year 1750.

 

Admittedly, if a different method of measuring temperature (eg tree rings) is used, we get weird differences in results. This allows people to 'select' their science to suit their politics.

 

Greenhouse gas in the atmosphere suffers no ambiguity at all. The results are very clear cut. Before 1920, there was very little change. From then, there was a major change.

 

We are still faced with the incongruity that global warming began in 1750 and greenhouse gases in 1920. No-one has yet given the explanation. If greenhouse gas increase causes global warming, the increase MUST come before the warming.[/quote']I believe there are a few explanations for that. It is true that carbon dioxide levels started rising, perhaps 1750, before fossil fuel burning really go underway, perhaps as late as 1950. One possible reason is that from 1750 to 1900 there was a lost of deforestation, charcoal burning, and in general, biomass destruction. The other possible reason for the anomoly is that up until recently, like the last 20 years, carbon dioxide levels have not been high enough to cause global warming that was sufficiently high be statistically significant compared with background variability and noise. But today 380ppm is proof enough of global warming.

 

This is perhaps the simplest proof of global warming:

http://en.wikipedia.org/wiki/Earth%27s_energy_budget