Sustainable Planetary Magnetic Fields May Be Very Rare

Recently articles have thrown cold water on the notion that any planet about earth size would have a enduring magnetic field. That's bad news because these fields protect the planet and any developing life on it from solar flares and cosmic radiation. Also they slow the loss of atmospheric gas molecules to space. According to the articles you need iron in the core to combine with elements that do not like to combine with it. this requires a sulfur reduced form of these elements to keep oxygen from getting into the way. on earth this only happened because of a mercury sized interloper that collided with and got ate by the earth.

www.sci-tech-today.com...

so how rare would this sort of serendipitous events be in planetary evolution?

sounds rare to me. hopefully i am wrong but (admittedly without any data to support one way or another) it seems to me that this discovery greatly reduces the number of truly earth like planets.

a reply to: stormbringer1701

I suppose there is no way of really knowing. I personally would assume that collisions between early planets in a forming solar system is quite common. Also, magnetic fields are actually quite common amongst planets and their moons in our own Solar System, so it's reasonable to assume this would be the norm elsewhere.

It's an interesting theory, but I don't think it rules out any other planets having "sustainable magnetic fields", as many planets we know of already do have them.

the issue is whether those bombardments are the right mass and composition to enable the chemistry that makes the uranium thorium and potassium settle in the core. you can have all the collisions you want and it won't do what it is supposed to do if the other factors aren't right. also while it's true that other planets have magnetic fields they do not compare to earth's magnetic dynamo.

originally posted by: stormbringer1701
the issue is whether those bombardments are the right mass and composition to enable the chemistry that makes the uranium thorium and potassium settle in the core. you can have all the collisions you want and it won't do what it is supposed to do if the other factors aren't right. also while it's true that other planets have magnetic fields they do not compare to earth's magnetic dynamo.

Out of the 8 "planets" in the Solar System, 6 have magnetic fields, so it certainly seems that it is more common that it is not, so I'm going to disregard the "requirement" for a special radioactive mix and put it down to it being the "norm". It might just be that this particular mix gave us an usually long lived and powerful field, unlike Mar's which cooled much quicker and the dynamo stopped.

As for "comparing" to Earth's dynamo, out of the planets with magnetic fields, ours is the second weakest - only beating Mercury in terms of field strength.

So I think the thrust of the argument of this paper is that this is an explanation as to why we still have our field when our sister planets lost theirs eons ago, rather than pointing out that our planet is unique, which it is not.

In fact, the article you linked in your OP mentions nothing about "Sustainable Planetary Magnetic Fields May Be Very Rare" - that seems to be your take on it.

It is an inference I made. A logical one. if that mix is why we have an enduring and strong magnetic field and the occurrence of circumstances that created it are rare then earth-like magnetic fields are rare in terrestrial class planets. That is to say rocky worlds of around one earth mass or less. obviously gas giants may be different. Mars lacks a dynamo and its magnetic field died early. all that is left is a residual field. Earth's field isn't massively strong. Roughly half a gauss. but it is apparently rare for such a field on such a planet to endure for as long as it has and will.

things that are affected by the magnetic field:

solar and cosmic radiation exposure
atmospheric retention
deep hydrological cycling responsible for maintaining the gas mix and the oceans.

Potentially there are biological dependencies on species evolved in it. might be responsible for proper bio chemistry or even partially for long term function. it would be subtle stuff and hard for research to suss out.

Life always find a way.

originally posted by: Abednego
Life always find a way.

This is true. but it is hardly comforting if you want to make new home worlds for humans and transplanted biomes and suitable planets aren't very easy to find.

Yes Earth is rare, mars is normal short lived core same as all moons. It is of the utmost importance as life needs the billions of years active core to create and sustain atmosphere and other protections. Mars is a desolate waste with dead core, dead tectonics, and thinned out atmosphere, high solar radiation. There will never be life like Earth on Mars, only enclosed bases same as we could accomplish on the moon. This is why Mars is a waste of time except for studying, Moon bases would accomplish more for less for harvesting resources.

I'm sure that planets like earth are very rare. But I feel that we are not alone in this universe.

originally posted by: Abednego
Life always find a way.

I agree with this.

While a planet with a weak or non-existent magnetic field may not be hospitable to humans, I think life on that planet may evolve a way to deal with the increased radiation.

I often hear some people say that the conditions on Earth for humans to evolve into humans is just so fined tuned (such as our Moon or our magnetic field) that without those things, we humans would probably not be around. However, that's not to say that life on Earth would not have evolved in different ways in the absence of those things, and very different species of life would have been the result -- maybe even other intelligent life in lieu of humans.

a reply to: Soylent Green Is People
We humans have a great ability to adapt or at least make the most out of the environment we live in. If we take a look at a world map, is easy to see that we can live in the hardest of places.
I think that the way our body is configure is the most closest to perfection to live here on Earth and anywhere in the universe.

originally posted by: stormbringer1701
Recently articles have thrown cold water on the notion that any planet about earth size would have a enduring magnetic field. That's bad news because these fields protect the planet and any developing life on it from solar flares and cosmic radiation. Also they slow the loss of atmospheric gas molecules to space. According to the articles you need iron in the core to combine with elements that do not like to combine with it. this requires a sulfur reduced form of these elements to keep oxygen from getting into the way. on earth this only happened because of a mercury sized interloper that collided with and got ate by the earth.

www.sci-tech-today.com...

so how rare would this sort of serendipitous events be in planetary evolution?

sounds rare to me. hopefully i am wrong but (admittedly without any data to support one way or another) it seems to me that this discovery greatly reduces the number of truly earth like planets.

Strong magnetic fields are rare? 1:1,000,000,000? Pick your number. The universe is still so big, it makes intelligent life almost a certainty.

originally posted by: stumason
a reply to: stormbringer1701

I suppose there is no way of really knowing.

There's almost always a way of knowing.

Though it may be that we have to wait for much better telescopes for direct imaging of terrestrial sized exoplanets before we can know.

a reply to: JadeStar

No telescope is going to tell you much, if anything, about the magnetic field from an exoplanet - you'll have to wait even longer until we have FTL to know for sure

originally posted by: stumason
a reply to: JadeStar

No telescope is going to tell you much, if anything, about the magnetic field from an exoplanet - you'll have to wait even longer until we have FTL to know for sure

Ermm... Actually light is an amazing thing. It can tell you a lot of things about a planet and that now includes if it is likely to have a magnetic field.

See: How to estimate the magnetic field of an exoplanet?

Scientists used the observations of the Hubble Space Telescope of the HD 209458b in the hydrogen Lyman-alpha line at the time of transit, when the planet crosses the stellar disc as seen from the Earth. At first, the scientists studied the absorption of the star radiation by the atmosphere of the planet. Afterwards they were able to estimate the shape of the gas cloud surrounding the hot Jupiter, and, based on these results, the size and the configuration of the magnetosphere.

Cool, of course this technique only works for Hot Jupiters but there are others which can work for more temperate terrestrial sized planets.

No need to wait for unobtanium. Build telescopes.

a reply to: JadeStar

Ah cool I guessed there probably would be a way with telescopes, but the best way has to be up close and personal As it says in your link, they can only "estimate" the field.

Sod telescopes, we'll have FTL one day. Like some film said, it's the difference between wanting to be an astronomer or an astronaut. Some are content looking, others want to go and have a poke. I am a poker

originally posted by: stumason
a reply to: JadeStar

Ah cool

I guessed there probably would be a way with telescopes, but the best way has to be up close and personal

As it says in your link, they can only "estimate" the field.

Sod telescopes, we'll have FTL one day. Like some film said, it's the difference between wanting to be an astronomer or an astronaut. Some are content looking, others want to go and have a poke. I am a poker

Would we have gone to the moon if we couldn't see it? Would we care so much about going to Mars had it not been for Percival Lowell thinking he saw canals through his telescope?

Telescopes have value in firing the imagination and giving us hints of what awaits. You have to fire the mind before you fire the engines.

Warp drives may never actually exist but we can find out a LOT about neighboring planets with telescopes.

Read this....Forget Space Travel, Build this Telescope

Excerpt:

There's a lot of talk about interstellar travel, and whether we will ever be capable of rocketing to other stars. It's a tough thing to do.

However, if the type of telescope described here can be built, then the tyranny of distance is vanquished. You can forget deep space probes and their long travel times. We could explore alien worlds in the comfort of our own homes, as our laptops scroll and zoom through data sets collected by a mammoth, space-based telescope array.

It would also, quite obviously, be a whole new way to search for extraterrestrial life ... just look for it, or its artifacts (like cities).

You might like this video from my other thread:

originally posted by: rickymouse
I'm sure that planets like earth are very rare. But I feel that we are not alone in this universe.

If the universe is teaming with life as some believe, where is the evidence? The universe would be saturated with artificial electromagnetic signals yet all evidence shows it to be entirely strerile of intelligent life other than ourselves.

It may be so rare that two intelligent species may never exist in the same million year time frame some say, well the distances that vary from stars and galaxies make up the entire spectrum of time steps, from thousands of light years to billions of light years and no signals.

This leaves one possibility, that we are existing in a special era of the universe where only till now was there possible the correct mix of stardust for intelligence to arise. This leaves the only option where life out there exists but the distances are too vast for us to detect yet. If we are at the beginning of this wave of appearing intelligence, we may never know.

a reply to: TinfoilTP

Just because we do not have any evidence YET that there are other inhabited planets does not mean that they do not exist. Two hundred years ago we were not sending out any radio signals, yet people were still intelligent. If you would have told people two hundred years ago that we would be walking around talking to little flat boxes you would have gotten thrown in some sort of sanitarium or burned at the stake for being a witch or warlock.

Finding another world with beings using frequencies we use for communication would be rare. Even if they did, how long ago would that signal have originated? They would be long gone and replaced by other beings just as we replaced the neanderthals and other species of hominids.

But I still feel that life like here on earth is rare. There might be a little diversity of small organisms on multiple planets all over the place though. Look at all the different species we have here, hopefully we do not kill off most of them.

exciting news though; a 4 newton QVPT which is in the realm of near term possible TRL can get to alpha proxima in 29 years.