Why CMEs may have sabotaged our plans to colonize Gliese-581g

This is a followup to my posts about the Goldilocks planet, Gliese-581g, in a way.

It’s expected, according the book Chasing the Sun (I read an article by NPR which cited the book), that the next couple years may well be the start of another active season for coronal-mass ejections. CMEs are when stars explode a little bit, to oversimplify a bit, and launch a bit of the star’s mass into space. In the case our sun, Wikipedia says that “coronal mass ejections reach velocities between 20km/s to 3,200km/s with an average speed of 489km/s. . . . The average mass is 1.6×1012kg.” That’s almost 1.8 billion tons of matter being shot out by a giant nuclear cannon. Being shot at about a million miles per hour. No, actually: 489 km/s = 1,093,861.85 miles/h

Here’s a nice, ultraviolet-spectrum video from NASA. The big one is at 1:05; the white spots you see are bits of the sun.

Basically, we’re going to be approaching another solar maximum, and as you might guess this means solar activity will peak. Which isn’t much of a danger to us. Because we have something very nice to protect us: the magnetosphere.

Artistic depiction of Earth's magnetosphere

These magnetic fields, caused by the iron core of our planet, protect us from the sun's onslaught.

This is all very cool stuff; Earth has a strong-enough magnetic field to protect us almost entirely from radiation and charged particles. Except for the auroras, visible near the North and South magnetic poles, we don’t often get a close-up look at the stuff.

Sometimes, exceptionally strong CMEs can interfere with our power grids and radio signals. They have caused power outages in the past, but the last really really big ones came before Electricity was really around.

In any case, we’re mostly safe. It’s not going to be the end of the world, for us.

But what about this new planet, Gliese-581g?

The most recent skeptic’s argument against the feasibility of planets like Gliese-581g being able to harbor life is that they might lack the magnetic field that Earth has.

Earth has an iron core, which is partly molten. But Gliese-581g, which is speculated to be a fair amount more massive, may have internal pressures high enough to keep the core–if it is even iron– solid. Which would mean it would have no magnetic field.

Without a magnetic field, the planet would likely be stripped of its atmosphere. Radiation can kind of put a damper on things, too. So maybe this isn’t our miracle planet.

Read the article that inspired this post.


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