'Super-Earths' May Lack a Magnetic Field -Exist as Dead Zones

Rocky planets a few times heavier than Earth that were thought might be life-friendly may lack  a protective magnetic field that originates from an iron core that is at least partly molten.

A simulation of super-Earths between a few times and 10 times Earth's mass suggests that high pressures will keep the core solid, according to Guillaume Morard of the Institute of Mineralogy and Physics of Condensed Matter in Paris, France. Without a magnetic field, the planets would be bathed in harmful radiation, and their atmospheres would be eroded away by particles streaming from their stars.

The present-day Mars is a prefect example of a planet that lost its magnetic field. Planetary magnetic fields are created by massive molten metal currents within the planet's core.  A flowing current creates a magnetic field, even when the current is massive volumes of charged liquid metal moving under the influence of temperature gradients (convection).  But magnetic analysis of Martian sites by Berkeley researchers show that the red planet's protective field was switched off half a billion years ago.

Without the magnetic field Mars and perhaps Super Earths in the Milky Way are defenseless against the radiation that constantly pours in from space. Earth is thought to have survived the same space-bombing because of our superior size, with our dynamo maybe stuttering a little but - very importantly - not stopping.

So life would have trouble getting started on super-Earths, even if they lie in the habitable zone around their stars.

However, Vlada Stamankovic of the German Aerospace Center in Berlin reckons it is too soon to rule out molten iron cores - and magnetic fields - for super-Earths. Their interiors might get hot enough to melt iron, he says. "Actual temperatures could be much larger than assumed - we simply do not know."

About 500 exoplanets are now known, but most of these have been hot giants circling too close to their stars, because they are easiest to find. As techniques have been refined, smaller planets have come into view, and a recent survey by University of California astronomers, Andrew Howard and Geoffrey Marcy, concluded that about a quarter of all Sun-like stars should have Earth-size planets.

Analysis of the Kepler Mission "400," may soon reveal Earth-size planets as well as the existence of magnetic fields and the possibility of life-bearing habitats.

Casey Kazan via newscientist.com

Comments

[velocity.wave]

I agree that without a magnetic-field, it would mean that things could be difficult to impossible for land based life (as we know it) to get started on these super-Earths.

But what about ocean-based life on these super Earths?!

Water acts as an excellent shield!

Just think of Jupiter's Moon Europa. Europa has no magnetic field to act as a shield.

Europa gets heavily bombarded with cosmic radiation, solar radiation, and a large amount of radiation emitted by Jupiter. Yet, we still believe there is a reasonable chance of life within Europa's ocean.

So why couldn't there also be life in the oceans of these super Earth's?

The oceans of these super-Earths could, in theory, be teaming with aquatic life -- including large sized creatures, and possibly intelligent creatures (think dolphins or whales).

And who knows if there is aquatic life, then perhaps they might have evolved their own body-shielding to allow them to gradually creep and crawl onto the land and take over the land.

If nature can find a way to allow bacteria to live happily on top of nuclear fuel rods... nature might also be able to find a way on those super-earths as well.

[voldemort]

good thinking velocity.wave

[Ivar Nielsen]

Magnetic fields depends on the excistant of any kind of atmosphere that can be magnetized/ionized.

- There is no magnetic bar in the Earth - all magnetism cease to function at a much lower heat that the one measured inside the Earth.

- The Sun creates magnetic fields on the Earth and the very same goes on anywhere else in cosmos where stars are radiating eletric forces onto their planetary satellites.

Natural Philosopher Ivar Nielsen

[cacarr]

Ivar:

You are demonstrably wrong, and, furthermore, a complete nutter.

[Havarti]

Velocity.wave makes total sense, couldn't agree more.

Ivar: I actually laughed out loud at your comment.

[Baja]

@Ivar: And the Sun is running on cold fusion. Right?

[Holo]

screw you jerks who bad mouth an exceptionally knowledgeable natural philosopher. Ivar's ideas are scientific and based on logic. He has published an arxiv paper and has a great website. Don't feel bad if your work is found by some foolish skeptics like here on the daily galaxy. I gave these jerks up and am happy without their behind kissing remarks that my website needs cleaning up. The thing that needs to be cleaned up are the advertisements here and most of the comment posters.
Halo