How did Halley realised the magnetic poles were constantly moving. During the 1700s what device did he use to determine that? Did his realisation come form mere speculation?

The people circumnavigate the world those days. Hailey probably heard the account from sailors that compass needles goes haywire when they approach the north and south pole. Sometimes is happens earlier and other times it happens later. He forgot a minute (1/60 degrees) at the center of the earth becomes an arc 1 nautical mile in length on the surface. There must be some margin of error for something of this size.

I think that if there was another magnet of different polarity just below each other we would have serious problems since this magnet is attached to the soil of our earth. It will not be as simple as compass needles going haywire. I think I will reject Halley's speculation or realisation.

This post has been edited by faceless: Sep 15 2010, 04:29 PM

What are the odds of that ?

We are all still here. Since thousand and thousandsS of year, when the Dinosaurs rule the earth, the Ice Age and when the great flood.

lol this theory has been long unproven and failed.
1st, if the centre of gravity is not concentrated near to the core,
and it's around the outer sphere like the one in the rubber earth crust's case,
the resultant gravitational force will way much different.

the hollow core earth will also result in different distribution of mass and density,
leading to a huge change in its moment of inertia,
and furthermore causing totally different rotation angular velocity.

a hollow planet this size?
dude planet is formed naturally through the clumping of dust and asteroids, and earth was melted during its formation,
thus a solid sphere will be formed, not hollow.
the heavy substances such as heavy metal will sink to the bottom and the lighter one emerges on the surface.
to get a hollow core earth?
there must be some highly intelligent and advance race intervening in the act of creation and hollow out the core,
and putting a sun inside.

as you must know too,
the formation of star require certain critical mass and enough density of gas, with sufficient rotational kinetic energy as they are racing around the centre, as the gases are being concentrated at the centre, temperature continue to rise and the critical temperature for nuclear fusion will be reached, fusion happens and the star shines. the burning of star sends out wave of solar flare, solar wind and etc, carrying away the dust and asteroids without enough inertia to stay in orbit.

a burning sun will not collapse into black hole because it is balanced by the pressure created by the heat of the nuclear fusion.
trying to resist the heat of a star with the earth's thin layer of crust, analogue to the skin of basketball?
not quite, it will just melt, or collapse under the strong gravity a star should have, or getting blown out by the pressure created by the sun to balance the sun's gravity.

these are just some fact, little of from the ones that support filled-core earth postulate.

ah, my second long post after my reply to the thread regarding Hawking's denial of God's intervention in the creation of universe.
read it here! http://forum.lowyat.net/index.php?showtopi...post&p=36264943

BUT, to a point where nature can balance it out. Ecological system require to recycle bad content that was very very abudent at that time and pollution of simple basic smoke, feces and pee water.
Today its chemical A to Z type plus less the LARGE amount of forest.

I think this statement is as good as the statement that the earth is hollow.

How did the dust start clumping to each other? Earth is so dusty but there are no giantic dust ball floating around.

I think we need to keep an open mind. We should not discredit hollow earth from the precpective of a widely accpeted theory. We should discredit it from looking at inconsistencies from within itself.

lol u misunderstood me.
yup at the early age we regard those tiny particles as dust.
comet is a dust ball, so are the asteroids. and the sun too.
dust clumps together due to gravitational pull, as every body that has mass exert this property.
the sun's gravitational pull is highest, as it is in the centre of the solar system, where most dust will spiral towards it and concentrate.
the thing that is different with sun it that, it shines, it burns.

normal planets formed by almost the same principle,
where dust clump for form rock, rocks clump to form larger asteroids and then planets.
you might wonder why do we see rocks but not a huge and unstable dustball.
well i mentioned that the earth was melted.
melted particles of rocks and etc just mixed together and when they cooled, we see a huge chunk of rock in space, not dustball.

read up more on the theory on the formation of stars and planets yourself if you are really interested,
as the real thing is always long to be explained here.

however,
READ FROM RELIABLE AND CORRECT SOURCE,
maintained by those widely recognized,
as you know internet nowadays don't just give you information,
it gives you flawed or incorrect ones, or those deviated from the truth and mainstream.

of course, most important of all, be wise and sensible and know how to choose to read.
book is still the best of course =)

what is this point of balance, nature does not have a opinion on what is the optimum condition, many period in earth history the environment are not suitable to human and in future i may change again to be too hostile for human for live in. that may be the end of human but not the end of the earth, earth will keep moving on until maybe it was destroy by an massive asteriod or the sun become red giant and swallow the earth.

i think you have a case of Chemophobia by making assumption that chemical are bad, the fact is everything in nature are chemical, air, water, gold and all the natural incurring toxic material. this is also a case of appeal to nature where all things natural are consider good and artificial are bad, but the fact are many natural stuff can kill you, for example cocaine are a all-natural plant extract from coca plant, but would you think it is good for your body to take.

yup indeed we as human are mostly egocentric.
we can see that from normal people's point of view,
their thinking often deviated and self-oriented.
seeing 'optimum condition' as the condition for human survival.
now we have changed the planet by a little,
and if human race were to be wiped out the nature will still progress on its path without even bothering about the existence of human or without us.
these things are dead, have no emotion but just follow the evolution of the condition from time to time and change accordingly due to certain reasons, by following the law of nature, that is physical laws.

people are often influenced to think that 'chemical' is something bad for us.
we are all made up of chemicals too.
it's just harder for human to have a neutral or non-oriented thinking and not being egocentric.
but proper education will change this.

Common enough for the invention of antibiotics to raise the average life expectancy of humans.

Of course we're still here. A reduced life expectancy only means people live shorter lives. It doesn't mean extinction.

I laugh at your small impact craters and present to you-The Giant Impact Hypothesis. The shortened version of this theory is that the moon was formed when a Mars sized object collided with the earth. An impact that size is bound to deform or create a hole in the side of the planet if it was hollow.

Seeing as how the moon has 0.01 the mass of earth and Mars is around 0.1 the mass of earth, the earth gained mass in the violent exchange. This would have resulted in a lop sided mass distribution on the planet which destabilize your rotating hollow sphere.

So hawking stated in his book,
there are 3 possibilities for discovering the complete unified theory:

1. There really is a complete unified theory, which we will discover someday if we are smart enough.
2. There is no ultimate theory of the universe, just infinite sequence of theories that describe the universe more and more accurately
3. There is no theory of the universe; events cannot be predicted beyond a certain extent but occur in random and arbitrary manner.

1. Now.. How random does a molten core get to be a planet? Scientices always say that planet are constently being bombarded by meteor. But only theorize the melted earth?
2. " events cannot be predicted beyond a certain extent ".. to an extent that no one have ever seen how earth was born.

"yup at the early age we regard those tiny particles as dust.
comet is a dust ball, so are the asteroids. and the sun too.
dust clumps together due to gravitational pull, as every body that has mass exert this property.
the sun's gravitational pull is highest, as it is in the centre of the solar system, where most dust will spiral towards it and concentrate."

So where is the fusion reaction to start a sun? If its from dustball, wouldnt the sun be just a big dustball?
the thing that is different with sun it that, it shines, it burns.

"dust clumps together due to gravitational pull, as every body that has mass exert this property.
the sun's gravitational pull is highest, as it is in the centre of the solar system, where most dust will spiral towards it and concentrate."

But What if.. there is a mini sun doing the same thing as the Sun would have done but clump it around is gravitational field until it form a crust around it? It would be the same as other planet that spin around collecting space dust. Because of the Big Bang Theory, shape and size of the stars or sun is unknown and at random. Same as meteorite, it could come in a small scale or a big scale or an earth size scale.

"READ FROM RELIABLE AND CORRECT SOURCE"
Where is the correct and reliable source? The Goverment? The Paid Goverment 3rd party? That would be like asking Najib about 1Malaysia Concept.

Astronomers observed the universe for a reason: to learn how stars and planets were formed and how it will eventually end. Evidents suggest that planet like ours were form with a core.

Ancient people is not as tough. The lack of proper sewage, easily bring about and spread disease.

"Hawkling prefers another possibility: that there are other forms of intelligent life out there, but that we have been overlooked. If we should pick up signals from alien civilizations, Hawking warns,"we should have be wary of answering back, until we have evolved" a bit further. Meeting a more advanced civilization, at our present stage,' Hawking says "might be a bit like the original inhabitants of America meeting Columbus. I don't think they were better off for it." - Coming from Stephen Hawking

As the well reknown theorist say this and people will and must believed him.
ALIEN DO EXCIST.
Reject The Hollow earth theory and believed in Aliens, or until he acknowledge it.

---

Added on September 15, 2010, 7:16 pmI laugh at you Giant Impact Hypothesis. Wouldnt it knock earth out of orbit?

This post has been edited by ScrewBallX: Sep 15 2010, 07:16 PM

This does not follow. What hawking stated, as i understand it, means unification of existing laws of nature. This unification is a great thing because it brings us closer to the fundamentals of nature, it gives a better picture what reality is. So as we probe deeper into nature, some events display disturbing behavior that seems to suggest some manner of randomness or arbitrariness. It does not mean we would not know how earth is born. There are many evidences that support the current theory how earth was made. The problem you have is it does not support a hollow earth.
There is a critical mass required before a lump of matter ignites into a shinning sun. Otherwise you would see saturn or jupiter shinning like a smaller sun but you don't. For the earth and other planets to rotate around the sun, that means gravitationally these planets are falling into the center of gravity all the time, but they keep missing it all the time too. So the theory of hollow earth can be resolved easily, because you need a mini sun to shine for at least millions of years, earth to rotate furiously around the mini sun that is inconsistent with it's current rotation, an escape velocity much smaller than what we know today that somewhat prevents matter from falling directly into the inner sun. So where are the calculation and evidence?

Unless of course you invoke magic or arbitrary unknown laws of nature, which then makes this theory a wild speculation wouldn't it?

'MIGHT' is a more proper word.
we are alien, life form in this universe.

ScrewBallX, just another question,not trying to offend you,
are you educated under the main science stream?

and possibilities are often listed or provided together,
even it is less likely to happen.
this is just as s step to protect oneself and of course,
not restricting human's thinking to just one main branch.

but then for the public's concern and for human to learn,
we often take the most likely one and establish it as the basic of our knowledge.
the 3 possibilities that hawking stated, and I repeated,
the 1st one is what we are aiming and believe this is possible in the future.
the 2nd one is, to our experience so far, true.
the 3rd one is also still unknown, just like the first one.

and these are stated for the discovery of Unified Theory,
not simply to apply to anything even though the postulate has already been busted.

the power of speech, or one's way of talking/conveying message is a very powerful tool,
and it can even be used for spreading the wrong understanding of something.
that is why in ancient time people believe in witches and shaman etc.
but now, the properly educated one doesn't trust them,
it is because they have learnt the truth, which they believe in those more than the magic and mystical power. that is science.

i'm not saying the hollow earth theory is 100% wrong.
yep we still can't penetrate to the core and see what's inside.
but observations and measurements plus inductive reasoning had lead us to the conclusion that the earth is not hollow, and has been established as the model of the earth for long.

we need to accept new ideas and changes, yes, but up to certain limit.
we only accept them when we've learned that it is more correct than the previous one, and matches our logic and observation.

for now, being in the main stream,
I would say the hollow core earth postulate is very less likely to be true, or to be established as the model of the earth.

sun?
by the way do you really mean sun, a burning star in earth's core under the hollow core earth model?
or you just mean the molten core of earth?

core of the earth can be seen as the inner sun since its hot enuff to provide heat

He meant a real sun that probably have nuclear fusion happening inside earth.

who is saying alien do not exist, the universe is so big with so many planet, it is only reasonable to believe some of the planet have develop inteligent life form. but there is a different from believing alien exist to believing alien have already landed on earth and are making all kind of experiment on human.

Why do aliens have to be organic and then have head, hands, legs and others? Cant alien be something we never imagined b4?

let's open a new thread on alien?
LOL
of course it can be something out of our imagination.

and perhaps they don't have to be carbon-based.

hawking thinks that, if life can exist on earth,
why not on other planet in the universe?
cause planet earth is just another normal planet in this universe.

btw there's a mathematical formula to calculate the potential number of existence of extraterrestrial in this universe.
here:
http://en.wikipedia.org/wiki/Drake_equation