# Tag Info

14

Is it possible for Earth to experience Polar Shift? Yes, and it has happened before. In the past 80 million years it happened over 150 times. The last time this happened was around 800 thousand years ago. A quick note about what a polar shift is, more properly termed a geomagnetic reversal. Earth's magnetic is such that a compass points to a certain ...

11

Positive lightning is indeed very interesting. According to the National Weather Service, the reason why it has a higher amperage and voltage is due to the due to the amount of air it must get through to reach the ground. Otherwise, it would never reach the ground. Since it originates in the upper levels of a storm, the amount of air it must burn ...

10

You can definitely see a large geomagnetic storm with a compass, if you have the timing to catch one and the patience to sit and stare for a few minutes. If you look at these minutely measurements from Lerwick observatory for one of the more recent large storms (the 2003 Halloween storm), you can see a roughly 4.5 degree swing in declination (labelled "D", ...

10

Yes, it is not just possible, but highly probable. Detailed palaeomagnetic data have revealed how the Earth's magnetic field changes in a polarity shift. In relative terms (time scale inaccurately known) there is a slow decrease to <10% of the normal field intensity. After an uncertain interval the field intensity picks up to some 20 or 30% of the normal ...

10

Yes, the earth emits electromagnetic radiation. It emits infrared radiation with wavelengths of about 1 µm to 1 mm. This is heat, essentially, and much of it radiates into space: Most if not all of the earth's rocks are radioactive (e.g. because of minerals containing isotopes in the uranium decay chain, such as potassium-40) and emit gamma radiation with ...

7

Sandstorms occur in dry areas, particularly deserts. The sand particles are fairly uniform in size. As the dry sand moves due to the wind it begins a leaping process known as saltation. Quoting the Wikipedia article: the initial saltation of sand particles induces a static electric field by friction The sand particles become polarized and as the ...

5

The short answer to your question is yes all charge particles (positive or negative), independent (like electron, proton) or attached to other materials like cloud droplets, molecules, atoms, etc. when in motion produce magnetic field. If two charged particles of same charge are moving in opposite direction then they cancel out each other's magnetic field. ...

5

The electricity you're talking about is the man-made kind, which is completely independent of any charge the Earth has relative to its atmosphere. Man-made power sources are almost all referenced to the Earth as zero volts, as established by connecting the "ground" to a conductive rod driven into the ground. Each house's electrical system is also grounded in ...

4

Short answer: 0.2 times the total length of your cable(s). 100m rollout --> ~20m depth Bear in mind that the deeper you get, the more you have to be careful with your data interpretation. Also if you do a roll-along your depth doesn't get deeper. Long answer see Bernard J (2003): Short note on the depth of investigation of electrical methods. Heritage ...

3

When the solar wind is funneled into the Earth's magnetic poles, those particles excite the electrons of molecules in the atmosphere which then bumps those electrons up into another orbital. When the electrons fall back down into their native orbital, they produce a photon of a particular wavelength whose energy is equal to the difference between the energy ...

3

Does the image of the pushbroom scans a path perpendicular to the direction of satellite travel? Not really. There is no "scanning" in a push broom sensor. A push broom sensor does not have any moving parts; compare with the related whisk broom sensor which does indeed scan a path perpendicular to the satellite's motion. The difference between the two is ...

3

No. If that were the case, the Sun would eventually develop a net charge. Let's imagine that's the case and the Sun develops a net positive charge. That charge would eventually stop negative particles from flying away and facilitate the ejection of positive ones. This regime would then restore the neutral charge of the Sun. This negative feedback makes sure ...

3

You are looking at $\nabla \vec B$-drift here (spoken: grad-E drift). This type of motion can be explained in a simplified way, when imagining a 2-D plane, separated at y=0 with two different magnetic field strengths, $B_z$. Let us say that for y>0, $\rm B_z$ is large and for y<0, $\rm B_z$ is weak. The strong field imparts a small gyro-radius for the ...

2

Could you be specific in your question as to what data you need on storms? Do you just need dates when storms occurred, or global geomagnetic index activity levels, or ground magnetic field measurements? Are you interested in the storm effects at Earth, or do you want space-borne measurements of solar activity? You can find lists of some basic info for the ...

2

Think of the electric current as a fluid, and a battery or some other source of current as a pump. Change the earth for the ocean. I don't know about the negatively charged earth's surface, but those -500,000 coulombs are an absolute measure of charge. That charge is distributed over some surface, and the earth's surface is pretty big.

2

As described in the question there are two similar coils, one radiates the AC magnetic field ("transmitter") and the other picks up the weak radiated AC magnetic field produced by subsurface electrical currents induced by the primary field. Sensitivity vs. Depth There are two modes of operation. The following two figures are from Section 4.1 of GEONICS ...

2

Disturbance storm time index is a measure of the weakened horizontal component of Earth magnetic field during great magnetic disturbances. The depression is often flanked by peaks, that initiates and ends the storm. Dst is published by Kyoto University and more information about the methods and references are available on the web page. The Dst index ...

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