Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: tamo kangujam on 17/02/2014 10:09:50
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how does earth has magnetic power or gravitational power? will the other planets also has the same with the same direction and field lines? if so what could be the north pole and south pole of the universe?
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The Earth has a gravitational field, just as any other mass like an asteroid, a planet, a star or a galaxy. The Earth's gravitational field will remain intact as long as the Earth remains intact.
The Earth also has a magnetic field. This is thought to be due to convection of molten metal in the center of the Earth. This is not a stable field, but one that changes chaotically in direction and polarity over long periods of time. The current "dynamo" is expected to stop working when the molten core cools down, leaving an extremely weak magnetic field, like the Moon. Other bodies like the Sun, Jupiter and Neutron Stars also have strong magnetic fields, pointing in different directions, and produced by different mechanisms than the Earth.
You cannot use a gravity or magnetic field as a permanent source of power.
If you look at photos of galaxies in the sky (http://www.nasa.gov/multimedia/imagegallery/image_feature_142.html), the axis if the different galaxies is somewhat random. So there doesn't seem to be an obvious North and South pole for the universe as a whole.
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Thank you Evan.
So, the gravitational force of the earth is due to the presence of molten metals, right? Then why are those non-metallic materials got attracted by the earth's gravitational force? Also according to Newton, every particle attracts every other particles(even those non-me talic) how this will be possible?
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Thank you Evan.
So, the gravitational force of the earth is due to the presence of molten metals, right?
Yes, the gravitational force of the earth is due to the presence of molten metals plus all the other mass and material and energy in and on earth. This means that the molten metals contribute to earth's gravity, but are not the sole source of earth's gravity.
Then why are those non-metallic materials got attracted by the earth's gravitational force? Also according to Newton, every particle attracts every other particles(even those non-me talic) how this will be possible?
Correct (about Newton), every particle and every photon (referring to your other question on the wave and particle natures of light) have mass, and hence they all attract each other. This is why the great mass of our sun measurably bends starlight that passes near it.
The cause of attraction between particles of matter and also attraction between light and matter is currently a great mystery. Some scientists have calculated that sub-atomic things they call "gravitons" may exist and may cause gravity, but this has been neither proven nor disproven. Maybe you will find a way to prove it or disprove the existence of gravitons someday.
Science is such a fun place, because the deeper we dig, the more we realize just how much we don't know. Scientists make it seem like they know a lot, by providing a lot of quick answers to our questions. But in reality, we have more questions than answers, and what we know and what we can measure is not even 1% of what exists. For Example: Dark energy is thought to make up 68% of the universe, and dark energy + dark matter together are now thought to make up 96% of the universe. So stuff we cannot see and cannot measure is what we think most of the universe is made of.
Scientists, like Evan had no idea of either dark matter nor dark energy just 30 years ago, which means they thought they knew about gravity and light and matter, but in reality, they knew about less than 4% of what was around them.
All of this not-knowing can be simultaneously exciting and humbling, especially when it pushes us to work to figure out the what's and why's of the world.
So, when your science teacher or professor or some person on the internet tells you: "This is what ..." or "This is why..." Instead, know they are just making their best guesses based on observations and hypotheses (opinions), and smile inside, because you know that we will likely know much more, and possibly have very different understandings in just a few more years.
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So, the gravitational force of the earth is due to the presence of molten metals, right?
No. The gravitational field is due to the presence of everything that has mass. It attracts anything else that has mass.
The metallic core of the earth provides a magnetic field which is entirely independent of the gravitational field. It attracts other para- or ferro-magnetic materials and repels diamagnetic materials.
A lump of lead has a measurable gravitational field but no magnetic field. The two phenomena are not the same.