New answers tagged earth
5
Not really. A magnetic field alone doesn't create electricity. A changing magnetic field does. The Earth's magnetic field does change a tiny bit but not enough to really generate much.
The other option is to move the inductor in the magnetic field. The Earth's magnetic field is quite homogeneous over short distances though so the coil would need to move ...
1
Okay, This question has assumed a lot. I think you're aware that Earth's (spin) rotational velocity (around 30 m/s) is the left over velocity after the Earth had formed from the dust clouds and matter. If on the contrary, you were to assume its spin to be multiplied by 10k x suddenly: first - the outer layers would wither off. Finally, you'd be left with ...
0
Its called specific weight and water has smaller specific weight than rock, if you find water between rocks that only because it is replacing the air in the fissures that would be there otherwise. It is the same question to ask why hot-air balloons fly. Same thing because hot-air has a smaller specific weight than cold air.
1
This link answers the question well:
http://en.wikipedia.org/wiki/Bertrand%27s_theorem#Radial_harmonic_oscillator
It sidesteps some of the difficulties you would otherwise have with this class of problem by looking at the potential, which is a metric of the square of the radius, which eliminates the square root, which can then be isolated with each ...
3
What you're looking for is Bertrand's theorem which states that for central force field in $1/r^p$, only $p=2$ (newtonian field) and $p=-1$ (harmonic field) give closed orbit whatever the initial conditions are (and assuming you are bounded to the field).
For sure you can find some initial conditions that give closed orbits (for example, all $p\in[-1;2]$ ...
4
For future reference, if you even have only the most basic understanding of the physics behind it, you can guess that the fastest the mag field would drop off would be order $1\over r^2$. And you can guess that it originates from the center of Earth. Since we're sitting pretty at ~6371km, adding another 100-1000 km would not even decrease it by half, let ...
0
First of all, I think that you should formalise what a reference frame is. Some people say that it is the same thing as the coordinate system, but stated this way, it is something physically senceless. Somewhere I heard the following definition of a reference frame:
A reference frame is an observer with a device that can measure the relative position of ...
1
If Earth had 0 inclination to the ecliptic, then life could still exist and there would be no change in seasons. In fact, at latitudes greater than $-23.5^o$ and less than $23.5^o$, the seasons are already irregular compared with the rest of the planet; they have two points where the Sun shines directly on top of them, effectively making them have two ...
0
I think it is , start running with an acceleration on earth such that it opposes your acceleration due to earth's rotation , and thus in net your acceleration will get 0 ,and you'll be an inertial reference frame . However , then obviously you'll see earth to be accelerating as you are inertial reference frame now .
0
I can't understand why you ask, whether we can create something which is totally mathematical and not some physical "thing". A reference frame is totally for our convenience to measure the parameters like position, time or orientation of some object relative to a co-ordinate system we've preferred.
So, No - It's not possible in any known way.
I suggest you ...
1
I might have misunderstood your question. If you mean, is there an absolute "motionless"? The answer is No, because all motion is relative.
Inertial reference frames are reference frames that are not accelerating - two inertial reference frames move at a constant velocity with respect to each other. Whilst there is no absolute motion, there is absolute ...
3
David H provided a good answer, but the short answer to your question is "yes", other shielding (passive) exists. A Mu-Metal ($\mu {-metal}$) has a very high magnetic permeability and can be used to provide magnetic shielding. Some call these "Zero gauss chambers". These essentially "channel" the magnetic field around the center of the chamber.
3
There is one and only way to cancel something: add its negative to itself. However, there is an alternative to cancellation for shielding a region from external electromagnetic fields.
Generally speaking, methods of isolating a region from external electromagnetic fields (EM shielding) can be divided into two categories, passive and active. A passive shield ...
0
Best example of plasma on earth is lightning. It's, natural. plasma exists at high temperatures. Those temperatures don't usually exist here. But, they do for a brief second in a bolt of lightning
Sun
Solar wind
Auroras
Nebulae
Fluorescent lights
Neon signs
1
Although considered a viable alternative hypothesis in the past, the expanding earth hypothesis is now generally considered to be obsolete, given the overwhelming evidence in support of plate tectonics. The following paper uses geologic evidence and a classical physical analysis of the earth-moon system to show there is no evidence that the earth's radius ...
2
Gravity. As nearly as possible, the materials of the earth have migrated vertically so as to approach an arrangement closer to hydrostatic equilibrium. Liquid water or water vapor is much less dense than rock, and can flow through connected porosity in the earth's crust. In rock at depth, the weight of the overlying rock deforms the rock, collapses pores, ...
5
One has to study the geologic structure of the earth:
Figure 1: The interior structure of the Earth, with a close up of the lithosphere/asthenosphere boundary. Redrawn from Plummer & McGeary, 1997.
There exists the Oceanic crust, which is the boundary between the bulk of water and the lithosphere. It has very low permeability and thus the oceans ...
2
I think the answer to this is actually pretty complicated, and has to do with chemical changes that take place in rocks during subduction. Rocks generally do like to absorb water (they become hydrated), but under the intense pressure and temperature of the subduction zone, the water molecules and the minerals become separated. I don't know exactly why this ...
Top 50 recent answers are included
