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Author Topic: Does anyone here feel qualified to discuss electricity in space?  (Read 3842 times)

Offline Joe L. Ogan

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Does anyone here feel qualified to discuss electricity in space.  We know that it exists but we do not know very much about it.  I find the subject very intriguing but I know very little about it.  Thanks for comments.  Joe L. Ogan


 

Offline Pmb

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Does anyone here feel qualified to discuss electricity in space.  We know that it exists but we do not know very much about it.  I find the subject very intriguing but I know very little about it.  Thanks for comments.  Joe L. Ogan
Everything is known about it. What would you like to know?
 

Offline Joe L. Ogan

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What is its' relation to astronomy?  Thank for comments.  Joe L. Ogan
 

Offline CliffordK

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I'm not sure one would say that everything is known about anything.

We know a bit about planets with atmospheres, and the potential for atmospheric electrical storms.  We also know a bit about liquid core planets as they relate to electricity. 

Our sun, as a stellar exemplar emits a tremendous amount of positive and negative ions into space, and Earth receives ions from outside the solar system. 

We also know that our sun flips magnetic fields about once a decade, yet we don't know if that was also occurring 20,000 years ago, nor even whether it was occurring during the late 1600's and early 1700's.  The causes of the solar magnetic field fluctuation are still speculative.

Apparently Voyager 1 may have finally left the heliosphere during the last year or so, and now is collecting interstellar data.  At least so some astronomers believe.  But, with barely 1 year of data just outside of our heliosphere, there are undoubtedly new frontiers to discover.

Anyway, I'm sure a lot is known about the interaction of ions in space, but undoubtedly there is more to learn as we observe our sun, or galaxy, and distant stars, galaxies, and supernovae. 
 

Offline evan_au

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We know that there are currents circulating around the Earth in various radiation belts.

Most matter near the surface of the Sun is in the form of a plasma, made of positive and negative ions. These tend to spiral around whatever magnetic field is present, but mostly the positive and negative ions tend to move together, so it is a motion of charged particles, but when the + & - particles move in the same direction, you wouldn't really call it an "electrical current".

The Earth's magnetic field can change when it is buffeted by a Coronal Mass Ejection, which causes electrical currents to flow in the Earth, and can overload power transformers.
 

Offline Pmb

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What is its' relation to astronomy?  Thank for comments.  Joe L. Ogan
That question is to vauge to answer. What exactly are you looking for? Electrodyanamics includes optics and that plays are large role in observational astronomy. Planets and stars have magnetic fields. Stars are basically large balls of plasma which is described using electrodynamics.
 

Offline Pmb

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Quote from: CliffordK
I'm not sure one would say that everything is known about anything.
I agree. But being exact in answers like that don't get anyone anywhere. What I meant when I said that is that all phenomena that we have observed to date can be adequately described using electrodyanmics. There are no more questions or mysteries in the field that haven't been answered using it.

What remains is those things which people haven't figured out how to apply electrodynamics too, not that they've done and failed. There's a big difference in that respect. The laws and theory of electrodynamics is complete.
 

Offline JP

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I'm not sure if this is what you're getting at, but this topic gets brought up a lot in relation to the so-called "electric universe theory," which is widely promoted on internet fora.  A user gave a very good account of why this theory isn't considered viable by mainstream cosmology:
http://www.thenakedscientists.com/forum/index.php?topic=28589.msg298990#msg298990
 

Offline Joe L. Ogan

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What keeps us from using it as a source of energy on earth?  Thanks for comments.  Joe L. Ogan
 

Offline Joe L. Ogan

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Is electricity in space the same as radiant energy?  If it is we already use radiant energy in certain things such as heating water, heating the house etc.  But we have no direct connection to use it as an electrical source.  Is this possible?  Just because it has not been done as yet doesn't mean that it is impossible.  It just means that we have not discovered a way to use it as yet.  Thanks for comments.  Joe L. Ogan
 

Offline JP

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They are quite different things.  In electricity, we generally either push electrons along a wire by forcing them to go from high energy to low energy (DC current) or we cause electrons to oscillate in a wire and extract energy from this oscillation (AC current).  We can't easily get DC current to flow in outer space because objects in space are generally electrically neutral overall, so getting electrons to flow from one to another isn't going to work.  AC current won't really work because you'd have to connect a conductor between the earth and a distant object so that oscillations in that object could cause oscillations in electrons here on earth.

Some objects, such as stars, will fire out charged particles including electrons at high energies, but they don't do so at a high enough rate to really be useful, nor is this really a form of electricity.

Radiant energy is made of photons, which are not charged particles.  They are generated when charges accelerate and can travel easily through empty space.  These are created in huge numbers by stars, since the heat within a star causes electrons to wiggle about wildly, emitting photons constantly in all directions.  Since these photons easily travel through space, we can catch them on the earth and convert their energy into electrical energy. 
 

Offline Joe L. Ogan

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Do you believe then that people are wasting their time in trying to devise a system whereby they can use radiant energy as a means of electricity for general use?  Thanks for comments.  Joe L. Ogan
 

Offline yor_on

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Can you have entangled electrons :)
 

Offline JP

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Radiant energy is what's being used for solar energy.  From what I know of it, I think it's a viable technology, though there are obstacles to be overcome to make it efficient and cheap enough to be widely useful.
 

Offline Pmb

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Quote from: JP
They are quite different things.
This is why I said that the question is vague. Different people mean different things when they use the term electricity. If you look the term up in a dictionary youíll see various definitions of it. For example: from Merriam-Webster Online Dictionary
http://www.merriam-webster.com/dictionary/electricity
Quote
a : a fundamental form of energy observable in positive and negative forms that occurs naturally (as in lightning) or is produced (as in a generator) and that is expressed in terms of the movement and interaction of electrons
b : electric current or power
2: a science that deals with the phenomena and laws of electricity
3: keen contagious excitement <could feel the electricity in the room>
I myself interpreted his question as possibly referring to sense 2, i.e. the science of electrodynamics.

Quote from: JP
In electricity, we generally either push electrons along a wire by forcing them to go from high energy to low energy (DC current) or we cause electrons to oscillate in a wire and extract energy from this oscillation (AC current).  We can't easily get DC current to flow in outer space because objects in space are generally electrically neutral overall, so getting electrons to flow from one to another isn't going to work.
JP Ė I have to say that Iím quite surprised to see you said this. Normally youíre extremely smart and are always spot on (Donít let that go to your head. LOL!!). But in this case I canít imagine what you mean by it. Charges will flow quite easily, i.e. with zero resistance, in a vacuum. Think of a cathode ray tube or a vacuum tube.

Quote from: JP
AC current won't really work because you'd have to connect a conductor between the earth and a distant object so that oscillations in that object could cause oscillations in electrons here on earth.
Again, we donít know what he means by ďin outer space.Ē If you pass an electron beam through a magnetic field the current will alternate the direction it takes in space (tongue in cheek of course).

It doesnít necessarily mean that heís only talking about regions of space where there is no material present. Thereís no reason why you canít place a magnet in a vacuum and run electrons through the field. In fact when you think about it, when we study or talk about electrodynamics weíre often talking about them in a vacuum. Only when someone asks us about EM in a material medium, i.e. a conductor, dielectric etc., do we talk about them.

Quote from: Joe L. Ogan
Is electricity in space the same as radiant energy?
Radiant energy is part of the science called classical electrodynamics. Since you havenít yet told us what you mean by electricity or clarified your question about what youíre referring to when you speak of electricity in outer space Iím going to assume that youíre using the term in this sense and will continue to do so unless you specifically state otherwise and state which part of the definition from the dictionary quoted above youíre referring to.

Quote from: Joe L. Ogan
If it is we already use radiant energy in certain things such as heating water, heating the house etc. 
For the most part, all energy we have available on earth came from the radiant energy of the sun. (which is a star). Earlier stars created heavy metals such as uranium, plutonium etc. which we use for nuclear fusion. Plant use the sun for energy through photosynthesis. We get oil from fossilized plants (fossil fuel) and of course solar energy (solar cells, heat etc.).

Quote from: Joe L. Ogan
But we have no direct connection to use it as an electrical source.
Says who? Solar cells take radiant energy from light sources, such as the sun, and covert it to electrical energy in the form of current or stored energy in a battery.

Quote from: Joe L. Ogan
Is this possible?
Not just possible. Nature has been using it for billions of years.

Quote from: Joe L. Ogan
Just because it has not been done as yet doesn't mean that it is impossible. It just means that we have not discovered a way to use it as yet
Thatís correct. However sometimes things havenít been done because itís known to be impossible to be done. Science is about learning from nature and learning what is possible and what isnít possible. For example; itís impossible for a fly to throw a baseball and hit the moon.
 

Offline JP

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Pete, I was responding to Joe's question about electricity vs. radiant energy (which would make the sun the primary useful source).  It's absolutely true that you could fire an electron or a proton beam in space easily and consider that an electric current, but you'll notice I mentioned that most sources are electrically neutral (or close to it) overall.  This means that generally you don't see them firing beams into space.  Moreover, if one happened to get charged, it would easily release charges into space, but these would generally not be collimated in a beam.  This spray of particles in all directions wouldn't have much relation to electric current as we use the term here on earth.

Similarly, you'd have trouble finding a naturally occurring AC current that propagates through space, and certainly this type of thing doesn't commonly reach the earth.

Of course, the sun does fire all sorts of particles at us, and the charged ones tend to be blocked by the atmosphere and earth's magnetic field.  I'd have to check the numbers, but I suspect the flux is too small to be very useful to us.

Radiant energy is a completely different beast which is generated by hot objects, even if they're electrically neutral.  Since this describes all stars including the sun, it's a much more readily accessible form of energy.
 

Offline Pmb

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Quote from: JP
This means that generally you don't see them firing beams into space.
Iím still confused. Are we talking about outside the earthís atmosphere or are we simply talking about physics in a vacuum? In the former case the sun releases charged particles.  In the later case every picture tube uses an electron gun.

Quote from: JP
Similarly, you'd have trouble finding a naturally occurring AC current that propagates through space, and certainly this type of thing doesn't commonly reach the earth.
Charges in motion are currents, just not the kind that youíre speaking of. But it should be kept in mind, for the benefit of our readers that all charges in motion are currents, whether itís a single charged particle or a current flowing through the car battery.

In the case of the sun pumping out charge, when it hits the earthís magnetic field near the poles they move on a spiral trajectory causing radiation and thus the Northern Lights. However, while the change direction and in this sense only are they alternating, theyíre not alternating in the sense of AC house current.

Quote from: JP
I'd have to check the numbers, but I suspect the flux is too small to be very useful to us.
No no no no! Donít forget! Pretty pretty pretty north lights pretty pretty. :D

Letís not forget the cosmic microwave background radiation too.
 

Offline CliffordK

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Certainly there are a lot of magnetic fields in space.  Typically inducing a current into a wire or a coil requires a change in the magnetic field.  One doesn't really have anything in space that is at a fixed point, so the magnetic fields would necessarily be somewhat changing, and thus one would bet some current induction.  A tumbling space craft might even get essentially AC current. 

Of course currents induced by the Earth's or Sun's magnetic field would be small for a small coil, but it should be detectable enough to aid with orienting the spacecraft, or for research.

Are either the solar wind, or cosmic rays affected by the various magnetic fields?  Of course, Earth's magnetic field does provide it some protection from the solar wind and cosmic rays.  Also, as Voyager passes out of the solar system, it is detecting an increase in cosmic rays, and thus the sun, and sun's magnetic field does protect the solar system somewhat from cosmic rays.
 

Offline RD

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Of course currents induced by the Earth's ... magnetic field would be small for a small coil, but it should be detectable enough to aid with orienting the spacecraft, or for research.

More useful than that ... https://en.wikipedia.org/wiki/Electrodynamic_tether
« Last Edit: 08/08/2013 04:00:37 by RD »
 

Offline evan_au

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I heard today that the Sun's 11-year magnetic reversal induces currents in a current sheath which flows around the Sun. Sometimes this current flows in the vicinity of Earth's orbit.

As the Sun's magnetic field is expected to switch direction over the next few months, this affects the currents circulating around the Sun, and this is thought to affect the number of cosmic rays reaching the Earth.

This is an AC current, but it is such a low frequency that we would consider it DC.

One problem with tapping electricity in planetary space is that conductive ions have a very low density, which makes space a pretty good insulator. There is large amounts of energy available, but the source impedance is very high, which makes it hard to harness this energy.

For now, harnessing the Sun's power through solar cells , photosynthesis, wind power, hydro power and tidal power seems more predictable than capturing the somewhat erratic electrical currents from the Sun we can intercept on Earth with our current technology. Perhaps a space mission inside Mercury's orbit may be able to draw more energy from the denser plasma close to the Sun? 

Have a listen to the first 10 minutes of: http://mpegmedia.abc.net.au/science/podcast/starstuff/starstuff20130807.mp3
« Last Edit: 08/08/2013 22:06:46 by evan_au »
 

Offline evan_au

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With our present technologies, we prefer electrical sources with a consistently low electrical impedance. This lets us draw as much power as we like, without the source voltage changing much, and dissipating most of the power in our load, rather than in the source.

In a battery with a high source impedance/resistance, the output voltage collapses as soon as you try to draw any useful power. Lightning charges in thunderclouds store large amounts of energy, but initially the impedance is too high to draw any useful power. But when the air breaks down into a lightning bolt/plasma, the impedance drops to a very low value, and all of the energy is dissipated in just microseconds - too fast for us to collect it in a controlled manner.

There is a large amount of electrical energy in space, but it is spread out over an extremely large volume. To draw useful amounts of power in space, you need a very large collecting antenna, positioned where the plasma currents are highest. Local eddies in the current would need to be locally converted into useful energy.

It takes a lot of energy for a space rocket to approach the Sun, so perhaps magnetic braking could be used to spiral inwards towards the Sun, while collecting some electrical energy from the plasma?
 

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