Alien life on Super-Earth can survive longer than us due to long-lasting protection from cosmic rays

Life on Super-Earths may have more time to develop and evolve, thanks to their long-lasting magnetic fields protecting them against harmful cosmic rays, according to new research published in Science. Space is a hazardous environment. Streams of charged particles traveling at very close to the speed of light, ejected from …

[Pascal Monett]

"Earth’s magnetic field will disappear in 6.2 billion years or so"

By that time, ou Sun will have already entered its Red Giant phase and either we are cooked, of the change in the sun's density will have moved our orbit outwards - hopefully to a new Goldilocks zone.

And by that time we definitely need to have colonies on other planets and moons, as well as large space stations harvesting minerals in the Kuiper Belt. I would also hope that, in a few billion years (if we live that long as a species), we will have a presence in other solar systems.

Because if we don't, there's every chance that there's a large, dense asteroid out there with our address on it, and that'll be the end of us.

[heyrick]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

Well, this planet has already had five extinction events so far, so it would be foolish to think another won't happen.

(conveniently, Netflix just released a movie about that...)

[Bartholomew]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

Don't look up ?

[DJV]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

Wear a larger, very wide-brimmed hat.

[EricB123]

Wear a Wide Brimmed Hat

That was what Mr. James Watt (Prez Regan's secretary of the Interior) had to say. Along with sunglasses as to more radiation from the developing hole in the ozone layer.

Different frequency of radiation, but you get the idea. Science above politics always.

[Blank Reg]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

That won't save you from tectonicly driven catastrophes. While killer asteroids get all the press, modern civilisation is more likely to be wiped out by a particularly energetic volcano. A decade of global cooling would result in mass starvation and societal collapse.

Or just a really big burst from the Sun could wipe out the electrical grids around the world. Again society collapses.

We're not getting off this planet, we won't last that long

[DS999]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

We're already in the sixth extinction event, it just isn't caused by something outside the planet this time.

[Joe W]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

The first one was caused by life itself. Some crazy bacteria managed to figure out photosynthesis, poisioning everybody else with theit excretions (Oxygen).

But yeah, the current one is a big one as well. And the bacteria likely lacked an understanding of what was happening, which I would say the humans actually (should) possess. Thus I would not compare these two events.

[The Man Who Fell To Earth]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

Yep. Solar evolution of this star system limits life on Earth to only another 700 million years or so. While that is quite a bit shy of the Earth being engulfed by the Sun, long before that, due to the earliest stages of the Red Giant phase, solar intensity will have increased enough to have killed off all life on Earth.*

* "The Life and Death of Planet Earth" by Peter D. Ward and Donald Brownlee

[Youngone]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

What? Shit!

Only another 700 million years! Why are we not doing something?

[Psmo]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

We are; we're trying to make sure we blow ourselves up first to take away the problem.

[Psmo]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

This comment has aged better than I'd hoped.

[Little Mouse]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

We are #2:

We're already regarding super-earths with envious eyes.

Then slowly, surely, we'll draw our plans against them.

[Loyal Commenter]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

But the chances of anything leaving from Earth are a million-to-one...

[Vometia has insomnia. Again.]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

Convenient; as Pratchett observed, a million-to-one chance is an absolute certainty.

[The Man Who Fell To Earth]

Re Little Mouse: "Earth’s magnetic field will disappear in 6.2 billion years or so"

Yea. Humans are worse than any alien predator the movies have ever devised. We are like locusts. We can & do eat everything else on this planet. We can & do live everywhere on the land of this planet. We breed like rabbits so can die by the millions and we replace our ranks rapidly. Our only natural predator of any consequence is others of our own kind. Besides which we are pretty hard to kill in large numbers without using high technology. And all of that was as true back when we were hunter-gatherers as it is today.

We are a scourge. Best thing any aliens who happen to notice us could do for interstellar peace is nuke us from orbit before we spread. It's the only way to be sure.

[Loyal Commenter]

Re: Re Little Mouse: "Earth’s magnetic field will disappear in 6.2 billion years or so"

We don't breed like rabbits, though. Rabbits have a pregnancy that lasts about 1 month, with multiple births and have the ability to suspend a pregnancy if times are lean, to be resumed later. The kits are rapidly independent, and reach sexual maturity at 4-5 months.

Humans, on the other hand, generally only give birth to a single infant, after a 9 month gestation. The infant is helpless at birth and for a long time afterwards, can't even walk, and doesn't gain any sort of independence for years, doesn't reach sexual maturity for anything up to 15 years, and typically doesn't start breeding until some time after that (exceptions apply).

The human breeding cycle is actually atypically long for animals of our size, and is pretty much the antithesis of "breeding like rabbits". This is largely down to the combination our large brains, and bipedal locomotion, which means there is a limit on the level of development that can happen in the womb, with the baby's head still fitting through the birth canal. Evolution has stretched this pretty much to the limit, which is why birth mortality in unassisted births is still appreciable, and until relatively recently in our history, getting pregnant was one of the main causes of death for women. Because there is a limit to how much humans can develop in the womb, we are born with soft skulls and continue to develop after birth, being essentially helpless. Compare that to pretty much any other large mammal, where one of the first things the infant does is stand up and start to walk about.

[the Jim bloke]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

Then slowly, surely, we'll draw our plans against them.

Like we did with Brexit?

and how we managed the pandemic?

and how we manage every other aspect of our "civilisation"..

.

..

ROFLMAO!

[ThatOne]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

> in a few billion years (if we live that long as a species)

Don't mix up astronomical and evolutionary timescales. Hominids appeared about 2 million years ago, so even in the unlikely event nothing bad happens to us, chances are that in less than a million years humanity will have evolved into something else, not necessarily superior.

_{Latte-drinking attention-deficient adipose blobs would be my bet.}

[DJV]

Re: "Latte-drinking attention-deficient adipose blobs would be my bet"

A couple of decades then...

[Blank Reg]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

I recall reading a theory that because stupid ugly people tend to marry other stupid ugly people, and because smart attractive people tend to marry other smart attractive people that we will eventually split into two separate races.

Unfortunately it seems that the stupid ugly people tend to breed more prolifically, and far too often end up in politics. So we're all screwed.

[jmch]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

"And by that time we definitely need to have..."

"We" as a species have existed about a million years, and as any sort of culture for maybe 10,000. Given the way things are going we'd do well to last another 10,000 let alone a million.

And by that time who knows where evolution + genetic engineering will take us. Homo sapiens will have gone the way of neanderthalis.

[42656e4d203239]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

The conceit of man has always amused me....

One often does well to remember that T. Rex (Cretaceous) is closer, chronologically, to the iPhone(Quaternerary) than to the Stegosaurus(Jurassic).... Homo-whatever, and descendents, are mere blinks of an eye in those terms.

Those Lizards (I know) had this evolution thing cracked.

[Loyal Commenter]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

I'm pretty sure there's no cladistic link there though...

[jason_derp]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

"...and that'll be the end of us."

...Good?

[Neil Barnes]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

the change in the sun's density will have moved our orbit outwards

I'm missing something here: irrespective of the sun's density it's centre of mass remains the same, right? So why would the orbit change?

(I am not an astronomer and don't know the answer to these things)

[Pascal Monett]

From what I understand (not an astronomer, much less a scientist), an objects density has a direct correlation with how well its gravitational field can attract other things.

You know that a black hole gobbles up light, right ? That's because its density is insanely high (to not use the word "infinite"). A stellar-mass black hole (supposing there are any that exist) would still be a black hole, would still have the mass of the Sun, but would be much, much more dense.

So, the Sun balloning up in size will reduce its overall density, and there are some scientists that think that that could change our orbital distance.

At least, that's what I understood.

[Anonymous Coward]

This is incorrect. If Sun was replaced by BH of same mass no planet's orbit would change (assuming replacement process was quiet),

[Steve K]

Black holes

Not a physicist either but:

A black hole "gobbles up light" only because light cannot travel fast enough along the spacetime infall to escape once inside the Event Horizon. It's a bit like trying to swim up a waterfall.

Light does not have mass, so that's not what is causing it (directly).

The sun will be losing so much mass (i.e. much more than the sunshine/coronal mass ejections we know and love presently....) at the Red Giant stage that Solar System planetary orbits will shift outwards due to this change in gravitational mass from the sun.

If the mass stayed the same then the density change wouldn't matter (unless we were then in the solar atmosphere in which case drag would send the smoking ember that was Earth spiralling in to the sun)!

[Anonymous Coward]

Re: Black holes

This is correct with tiny caveats: close to BH event horizon orbits become highly relativistic and strange (for instance is radius below which no stable orbits exist) and in some of those regions BH essentially does 'gobble light' to some extent. However Earth would not be close to horizon of solar mass BH.

Also light does have mass in a useful sense: photons have no rest mass (since have no rest frame cannot!) but they do have energy and this do deform spacetime since RHS of field equations is energy-momentum tensor. Indeed if you get enough light in a small enough space you will get a horizon and thus a BH, this is a Kugelblitz (almost certainly only theoretical toy!).

These are tiny caveats however: your point is good.

[Eclectic Man]

Re: Black holes

Esteemed readers of the Register, one thing I know about both General Relativity and Quantum Mechanics is that they are (to me) highly counter-intuitive. On another forum* there was a discussion about the properties of Black Holes, and I was not sure of what was being posted, so I thought to myself, those LIGO Boffins probably know a bit about Black Holes, and I found:

https://www.ligo.caltech.edu/page/ask-ligo

I was very pleasantly surprised to receive a detailed, coherent and, for a layman (well lapsed Mathematical Logician) easily understandable response explaining most of the fallacies the people had posted. Really well worth asking them about anything to do with LIGO or Black Holes, as most of what I read on that other forum was incorrect, according to current understanding.**

*Astronomy Picture Of the Day: https://apod.nasa.gov/apod/archivepix.html

**No names - no pack drill, but generally APOD is well worth a look, including the discussion threads.

[M.V. Lipvig]

Incorrect The Sun's mass will not be staying the same. In the time it took me to type this post the Sun lost tons of mass because it is a great flaming ball of burning hydrogen. Eventually it will burn off enough fuel that it will no longer have the gravity to keep itself together, and that is why it will grow into a red giant. Assuming Earth's mass remains, Earth's orbit will go wider and wider until we're far enough and fast enough to break loose, at which time we'll head out to interstellar space to try somewhere else. Well, I SAY we. We'll be long gone by then. The Moon is heading away from us now at a couple of inches per year. and when it finally breaks loose, there goes our magnetic shield. The Moon's gravitational influence is what keeps Earth's core hot and moving, moreso than planets that spend years opposite the Sun from us.

[Anonymous Coward]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

You are right. Shell theorem due to Newton means that for spherically-symmetric mass distribution only mass inside given radius counts and you can treat it as point mass at CoM. Earth's orbit could change if Sun lost a lot of mass (would rise), or obviously if Sun got big enough that Earth was inside atmosphere (would fall).

[Blank Reg]

Re: "Earth’s magnetic field will disappear in 6.2 billion years or so"

If the density is uniform then I should think it wouldn't make a difference. But the density is not uniform and will further change as the Sun evolves.

Also the diameter of the Sun vs the distance to the earth makes a difference. It's current diameter is around 1% of it's distance from earth. So differences in density won't have a big impact. But as it grows then we'll see greater effects from the matter on the near side and less from matter on the far side. If it were all uniform then I guess it would balance out. But the Sun is a swirling ball of atoms so I expect we'll get much larger perturbations of the gravitational field as it expands.

[Chris Gray 1]

Huh?

To quote the El Reg article:

"In other words, the cores Super-Earths need to be cooled to much lower temperatures before they solidify. Their larger-sized cores also mean they lose heat at a slower rate than Earth’s too."

But, the article also says that the higher pressure in super earths makes their iron melting point *higher*, meaning less cooling to reach solidifacation. The first sentence in the above has it backwards. Or am I missing something?

[KarMann]

Re: Huh?

I came here for exactly that, so no, it's not just you.

[Spherical Cow]

Re: Huh?

There are many mangled sentences in this article, far too many to report via the corrections link. The author just needs to proof-read before pressing the publish button.

[Joe W]

Re: Huh?

Came to comment on the temperature issue as well - and I did stumble over a bunch of sentences, though I usually attribute that to me being stupid OR not having enough caffeine in my system yet. However, the two "however" in the last sentence of the second paragraph, however, are probably a mistake.

(yes, we all know how this happens, writing something, then rewriting, then restructuring, rewriting once again, and failing to find mistakes when proofreading because your brain knows what you intended to write and will adjust perception accordingly).

And I'm sure that this post contains several glaring mistakes, grammatically or spelling, which is referred to as "Muphry's Law".

[Loyal Commenter]

Re: Huh?

The melting point is elevated due to the pressure, but the temperature is also higher (things heat up as they are compressed), and rate of heat loss lower (proportionate to surface area divided by volume, so inversely proportional to radius).

Of course, another big factor in how long a core of a planet can remain partially molten is the composition. Whilst the Earth's core is largely iron and nickel, it, and the mantle, also contain radioactive metals which produce heat from their decay, which is why the Earth hasn't cooled completely already.

[Eclectic Man]

Earth's core

See: https://en.wikipedia.org/wiki/Earth%27s_inner_core for a slightly more detailed description of the current theory of the Earth's core composition.

Strangely I'd have thought that there would be amounts of heavy radio-active elements also mentioned (Uranium, for example), as these are keeping the core hot, and have been for billions of years.

[the spectacularly refined chap]

Re: Earth's core

There are, in theory at least, along with lots of other economically interesting stuff (gold, platinum etc) since the heavy stuff sinks to the bottom as the planet differentiates. We are talking trace amounts compared to iron, nickel and the lighter elements though, to the point that they are not seismically detectable. It doesn't need a lot of the transuranics to keep things nice and toasty since a couple of thousand km of rock works as a nice thermal blanket.

[saif]

Needs a moon of decent size

The presence of a large moon relative to the planet size also produces enough tidal energy to sustain a molten core... without which Mars and Venus lost their magnetic personalities

[heyrick]

Re: Needs a moon of decent size

Mars doesn't have a moon, it has a low orbit potato.

[Phil O'Sophical]

Re: Needs a moon of decent size

Fission chips?

[Anonymous Coward]

Re: Needs a moon of decent size

...it has a low orbit potato.

I wouldn't say it's that low. If I were living on Mars, I probably wouldn't have to duck occasionally while walking to the shops.

[Neil Barnes]

Re: Needs a moon of decent size

True. But you might not want to wear a tall hat.

[Rich 11]

Re: Needs a moon of decent size

It's not something to fear.

[ian 22]

Re: Needs a moon of decent size

Or panic..

[the spectacularly refined chap]

Re: Needs a moon of decent size

The presence of a large moon relative to the planet size also produces enough tidal energy to sustain a molten core... without which Mars and Venus lost their magnetic personalities

Not really. In tidal heating scenarios it is the smaller body that receives the majority of the heating and the Moon is a little far rmemoved from the Earth (and the ordit too cicular) for significant tidal heating on either body.

The current consensus is the Moon is no longer even in hydrostatic equilibrium: though it clearly was in the past it has cooled too much since then. That is to say, if the Earth wasn't here the Moon would not qualify as a planet in its own right.

The mechanism on Mars is well understood, it is simply too small barring a particularly efficient insulating layer as we are now theorising at Pluto after New Horizons. Venus is a little more open but the volcanic activity indicates it is still hot: current best guess (yes, it is little more than that) is the lack of a magnetic field is due to tectonic activity being shut down by the lack of water to lubricate the plates, and therefore nowhere for the heat to go aside from the periods of global volcanic eruption which act as a pressure valve.

[Spherical Cow]

Re: Needs a moon of decent size

What's this you say about the moon not being in hydrostatic equilibrium? It is 3475km across, surely that's more than enough??

[the spectacularly refined chap]

Re: Needs a moon of decent size

Apparently not for a cold, rocky body. It has been in the past (why it is round) but it has cooled and it is now believed to be rigid enough to no longer qualify. One of the problematic issues of the planet definition, although I have no intention of debating that issue here.

Icy bodies or rock/ice mixes can be a lot smaller and remain in hypostatic equilibrium, but that doesn't describe the Moon.

[Eclectic Man]

Re: Needs a moon of decent size

I cannot find a link on the Internet, but I believe that as the Moon cooled, the gravitational attraction for the Earth caused it to bulge, and distort away from the expected oblate spheroid. I think it was Lagrange who calculated the size fo the bulge on the 'dark side' of the Moon. (Register astronomers, please advise)

(Any search for Moon and Lagrange is swamped by references to the Lagrange points.)

[Anonymous Coward]

Re: Needs a moon of decent size

Obviously once one body (the Moon) is tidally locked to the other it will experience only tiny tidal heating due to libration and elliptical orbit, both of which will go away over time. At that point all tidal heating will be in larger, not-yet-locked body. Would be extremely surprised if tidal heating of Moon is higher than of Earth at present.

[Joe W]

Re: Needs a moon of decent size

Doesn't the moon also help to shield us from asteroids? It definitely helps the Earth to spin more stable, if I recall correctly.

[KittenHuffer]

Re: Needs a moon of decent size

I believe that theory has been shot down now. It came about because there are far more craters on the far side of the moon. So the idea was that side was getting hit, and saving the Earth from those impacts.

It's now been simulated that when the Earth/Moon system formed they were close enough together (and hot enough) that the near side of the Moon stayed molten for a long time due to the heat being given off by the Earth. So the impacts that happened as the Earth/Moon system were settling down could still be seen on the far side which solidified early, but would splash into one of the still molten mares on the near side. By the time the near side solidified the rate of impacts had dropped, so that we can still see the flat plains (mares) as they were when they formed.

[Paul Crawford]

Nice, but then such a planet would not allow escape velocity to be reached based on chemical rockets either, would it?

I guess if some sort of warp drive is possible they might get out to explore, though it is bad form to try and take off using your warp drive...tends to kill off life (or maybe start it in the first place).

[Anonymous Coward]

...but then such a planet would not allow escape velocity to be reached based on chemical rockets either, would it?

You'll need (a lot) more fuel to escape the gravity well of a Neptune sized planet, but it's not impossible.

[Spherical Cow]

"such a planet would not allow escape velocity to be reached based on chemical rockets either, would it?"

A heavy planet with a strong magnetic field probably has a deep dense atmosphere, which is good for launch systems which fly before rocketing, e.g. Vigin Orbit LauncherOne or possibly even Skylon. Reaching orbit is easier once you've got high enough that wings don't work any more even when going very fast.

Conversely, a small planet with no magnetic field probably has bugger-all atmosphere (e.g. Mars) and would not be suitable at all for launch systems involving wings. For those planets you just use a rocket.

[KSM-AZ]

What about...?

Danny Dunn's anti-gravity paint?

[Loyal Commenter]

Re: What about...?

I think you need to use Cavorite.

[Anonymous Coward]

Life, human or alien

Under all theories of the universe that I am aware of all life in this universe is doomed. All matter will decay into some form of energy.

The longest term survival strategy would probably require a Kardashev Type 2 civilization (we are not even at Type 1) which has abandoned their home star system and created a Dyson ring with habitats around a white dwarf. That would get you up into the hundred billion year range.

A Type 3 civilization might add some percentage more but, ultimately, the survival of life in this universe depends on it leaving this universe and setting up shop in another, younger universe. Over and over again. Ad infinitum.

[Rich 11]

Re: Life, human or alien

All matter will decay into some form of energy.

Unless you're positing some sort of Big Rip scenario I don't see how your average iron atom is going to be reduced to pure energy.

[Anonymous Coward]

Re: Life, human or alien

Either nucleon decay, or if nucleons do not decay then eventually BH's form due to quantum events and then they decay via Hawking radiation. This takes ... a long time.

[Loyal Commenter]

Re: Life, human or alien

Short answer: black holes.

Eventually, everything "clumps together" enough to fall into singularities, which evaporate over the eons (orders of magnitude longer than the current age of the universe, in the order of 10¹⁰⁰ years) as Hawking radiation.

That, or the "Big Rip", which you mention. The expansion of the universe has been measured to be accelerating (we call this "Dark Energy" because we don't know how or why). Eventually, this could reach a point where the acceleration prevents atomic nuclei holding onto their electrons, and after that, it will even overwhelm the forces that hold nuclei together, and then beyond that, their component subatomic particles. If this theory is correct, then this will happen on a much shorter timescale (around 10¹¹ years).

[Rich 11]

Re: Life, human or alien

But there's a middle ground where the rate of expansion exceeds gravity's ability to bring all matter together, and where my favoured iron atom doesn't end up in a black hole. Also you forget that Hawking radiation consists of particles which themselves don't end up (given expansion) annihilating with a suitable anti-particle or getting dragged into another black hole.

[Mike 137]

Re: Life, human or alien

"require a Kardashev Type 2 civilization"

The problem will be that by the time you decide to create the ring you won't have the resources to do so. Even if you plan to strip your home world of everything material required to do it, you're unlikely to have the energy need to build it and populate it. Let alone maintain it, as Larry Niven's Ringworld pointed out decades ago. Only in science fiction is infinite energy available free of charge.

In any case, just like all others have been, we're certainly a transient species. There's no reason to think otherwise, particularly considering the damage we continue to inflict on ourselves through uncontrolled consumption.

[ThatOne]

Re: Life, human or alien

> require a Kardashev Type 2 civilization (we are not even at Type 1)

We're actually more a Kardashian Type civilization, and therefore mostly immune to any concerted and sensible undertaking.

[JassMan]

Just a non-biologist type question

But how do they know that life would develop at all on those super earths without the benefit of a few cosmic rays kick starting the formation of amino acids and stuff in the primordial soup? Its not much use having the potential to live longer, if you don't get born at all.

Also without a bit of radiation, surely speciation is also likely to be a lot slower.

Or are the authors creationists and believe that God creates living beings directly without evolution.

[ThatOne]

Re: Just a non-biologist type question

> without the benefit of a few cosmic rays kick starting the formation of amino acids

Not a specialist but I guess there are other ways of adding energy to that primordial soup to create the chemical bonds (volcanism and natural radioactivity come to mind).

Also the magnetic shield, no matter how strong, isn't tight, there are necessarily those holes in the poles. So I guess there will always be some amount of solar wind and cosmic rays coming in through those holes.

[Falmari]

Re: Just a non-biologist type question

@JassMan "But how do they know that life would develop at all..." They don't mention anything about life or having longer to evolve in the paper. So you are being unfair in your speculation of their beliefs.

I have read the scientific paper linked in article ‘MEASURING THE MELTING CURVE OF IRON AT SUPER-EARTH CORE CONDITIONS and that is what it is about.

So, while the reason for doing this study is because “size of the liquid metal core, is an important factor for understanding the potential for generating a radiation-shielding magnetic field” the paper is purely scientific in nature.

They experimentally determined the high-pressure melting curve and structural properties of pure iron up to 1000 GPa. Performed experiments to emulate conditions iron descending to the core of a super-earth would see.

More experiments lots of maths some assumptions which results in this “super-Earth cores will take up to 30% longer to solidify than Earth’s core, where this model predicts Earth’s core will solidify in 6.2(3.4) billion years (Gyr)”.

The whole speculation on “Life on Super-Earths may have more time to develop and evolve” by this article’s author is based on this ““While there are a lot of requirements for a habitable planet, such as a surface temperature that enables liquid water, having a magnetosphere that can protect against solar radiation for long periods of time could offer long durations of time for life to evolve,” Richard Kraus, lead author of the paper and a physicist at the LLNL, told The Register.”

Now what prompted this comment is unknown, but I would hazard a guess that this article’s author latched onto the final sentence of the paper “Assuming the solidification time scale sets the time scale for dynamos, the results lead to the notable finding that super-Earths are likely to have a longer duration of magnetically shielded habitability than Earth.”. Then asked a question about that sentence speculating life would have longer to evolve.

[Joe W]

Re: Just a non-biologist type question

Good analysis! Have one -->

[Loyal Commenter]

Re: Just a non-biologist type question

I'd just like to point out that your comment contained the answer in the phrase "longer duration of magnetically shielded habitability". Longer habitability = more time for life to evolve. It's a fair bit of paraphrasing, to be sure, but if that's a quote from the paper, then it's right there.

[Falmari]

Re: Just a non-biologist type question

@Loyal Commenter “It's a fair bit of paraphrasing, to be sure” yes it is, sure you could extrapolate Longer habitability to = more time for life to evolve but IMHO Longer habitability means just Longer habitability. But I take your point. :)

@Joe W thanks for the beer but to be honest my analysis does not do the paper justice as a lot of it went over my head.

[Loyal Commenter]

Re: Just a non-biologist type question

I think the paper is using "habitability" in the astronomical sense, as in the body falls within the parameters that we think can support carbon/water-based life, in terms of temperature, radiation, and chemical parameters. That gives a timescale within which life has the opportunity to arise and evolve. Given that there is evidence of life in rocks that are almost 4 billion years old, the sun is only 4.6 billion years old, it took about 150 million years for the Earth to form, and it's fair to assume that it took a while to cool and the conditions for life to arise, this implies either that once the conditions are right, life arises pretty quickly (within 10s of millions of years), or that very primitive life may have seeded the Earth from interstellar space. Given how hostile interstellar space generally is, I'd tend to go for the first option.

[Falmari]

Re: Just a non-biologist type question

I'd would go for the first option also.

Also, I forgot to say in my earlier reply, excluding the quote from the Register article the quotes in my original post are from the paper. I really should have made that clear in my original post. My bad. :(

[Grikath]

Re: Just a non-biologist type question

The biologist-type answer to that is that our universe is pretty much set up to make life happen, eventually, etc.

Young planets are basically huge chemical reactors, and produce a lot of the basic elements of what we currently assume are needed for life. If the right conditions are there: mostly liquid water, pressure and a bit of heat at the right range, all those basic elements follow the dance of chemistry and random chance and both RNA and proteins will form. Some of that will have their own chemical properties, and....

A lot of that sequence depends, etc. But the conditions needed for it aren't that extreme, and still exist around volcanic areas here until this day. And are used by us ( under controlled conditions, but the chemistry is the same..) for those PCR tests we're all bothered by currently.

And cosmic rays don't kickstart anything. They are so energetic they smash things to bits. To the point of shooting right into our planet and going right through it only slowing it down a bit on occasion. Our magnetosphere doesn't do much to protect us from that, really. What it does do is prevent our planet from being stripped bare and terminally irradiated by the solar wind.

Venus has an atmosphere because of its gravity well and the fact that the main atmospheric components are CO2 and sulphuric acid. Heavy stuff. Mars, being much smaller, didn't stand a chance, and while it may have had some microbial life in its historical oceans, those have been stripped while the planet was still relatively warm. Else it would still have plains of ice instead of just desert. Pluto does have plains of ice, but even that far out the solar wind strips away its atmosphere in "summer" when it actually has one. That's how important a geomagnetic field is: It keeps the water in.

[Anonymous Coward]

Re: Just a non-biologist type question

And cosmic rays don't kickstart anything. They are so energetic they smash things to bits. To the point of shooting right into our planet and going right through it only slowing it down a bit on occasion. Our magnetosphere doesn't do much to protect us from that, really. What it does do is prevent our planet from being stripped bare and terminally irradiated by the solar wind.

This is very wrong. Cosmic rays are mostly completely ionised atoms (so protons, alpha particles etc) with a small proportion being electrons and I think some tiny number being positrons / antiprotons etc. They are charged and so interact intensely with everything in sight. Many cosmic rays are stopped by Sun's heliosphere, more are stopped by Earth's magnetic field, still more in the atmosphere, producing what people call 'secondary cosmic rays' which is shower of crud particles after cosmic ray collides with nucleus in atmosphere. Some make it to surface, think it is ~few thousand per m^2 per s. Chance of cosmic ray passing through Earth is epsilon for very small value of epsilon indeed, zero really.

Think you are may be thinking of neutrinos, which really do hardly interact with anything.

Cosmic rays are certainly mutagenic: have been studies and disputes about whether cancer rates go up with altitude (more cosmic rays). Not a biologist so can't answer question as to whether they influence evolution rate but would not be surprised if they do.

[Grikath]

Re: Just a non-biologist type question

Errrmmm... no? Cosmic rays are indeed charged particles, which, like the general ionised soup of the solar wind would be beholden to the vagaries of anything a magnetic field would do to them.

However... They are charged particles that have been accelerated to a speed just short of c by the processes that are supposed to spawn them. Which, as a certain mr. Einstein teaches us, means their virtual mass is quite impressive, and means they tend to be less than impressed by magnetic fields they encounter, unless that field is really strong. And they pass by really close.

Of course, if something slows them down even a tad, they shed a lot of that virtual mass really fast. But by that time we've stopped calling them cosmic rays, as they slip into a different energy band.

So yeah.. cosmic rays smash stuff.

And no.. Neutrinos are neutrinos.We shower in those 24/7 and they don't seem to do much.

And as far as mutagenic power goes.. The worst culprit, by far, is Oxydane. Followed by the fair amount of gamma and Röntgen radiation from our own star. Followed by spontaneous A-T and C-G conversions. Followed by.... Cosmic rays don't even make the top 10 when it comes to mutagenesis on a planet where life as we understand it would actually be possible.

[Anonymous Coward]

Re: Just a non-biologist type question

So you know when you put electronics in space it has to be rad-hard, especially above LEO? That is because in space there are many, many more cosmic rays than under atmosphere, which is because almost all cosmic rays which reach Earth are absorbed by atmosphere and many more by magnetosphere. And if you want to measure cosmic rays what do you do? You put your experiment in a balloon or a spacecraft. Why do you think that is? Gosh.

And yes, they are deflected by heliosphere and magnetosphere, whatever you may think (and you seem now to have dropped obviously stupid claim that they go right through planet). Perhaps quote from Wikipedia first paragraph on cosmic rays might be useful.

Cosmic rays are high-energy protons and atomic nuclei that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own galaxy,[1] and from distant galaxies.[2] Upon impact with Earth's atmosphere, cosmic rays produce showers of secondary particles, some of which reach the surface; although the bulk is intercepted by the magnetosphere or the heliosphere.

I mean you could look this up rather than inventing things to suit yourself.

[Potemkine!]

The intense radiation can strip atmospheres and cause oceans on planetary surfaces to dry up over time

So why have Venus suck a thick atmosphere when it has such a weak magnetic field?

[Anonymous Coward]

This is interesting question. One partial answer is that Venus does in fact have an induced magnetic field, which is result of ionisation of its upper atmosphere from solar UV and then this interacts with solar wind. I think this is not completely understood but may be part of the mechanism by which Venus lost its water and other light gases.

[Uncle Ron]

Driver?

Aren't cosmic rays one of the prime drivers of evolution? A planet with intense shielding wouldn't have this driver, no?

[Uncle Ron]

Zombie Cells

I have recently become deeply interested in the concepts surrounding "Zombie Cells," also known as senescent (aging or deteriorating) cells. They stop dividing, and they also stop working, i.e., doing their job. Think about it: Diabetes, arthritis, immune system--all of it would be affected. Life on any planet that has figured out how to target them and either get them back to doing business, or getting rid of them, would become ageless. Maybe Methuselah figured it out. Anybody smart about this? What's the latest?