Io Volcanoes Go Hyperactive
The volcanoes on Jupiter’s moon are bursting out at record rates, and nobody knows why. Is it the new normal?
A press release from NASA’s Jet Propulsion Laboratory says it was a “hellacious two weeks” last summer on the innermost large moon of Jupiter, Io (about the size of Earth’s moon). This most volcanic body in the solar system strutted its stuff with three massive, super-hot outbursts in August 2013:
“These new events are in a relatively rare class of eruptions on Io because of their size and astonishingly high thermal emission,” [Ashley] Davies said. “The amount of energy being emitted by these eruptions implies lava fountains gushing out of fissures at a very large volume per second, forming lava flows that quickly spread over the surface of Io.“
All three events, including the largest, most powerful eruption of the trio on Aug. 29, 2013, were likely characterized by “curtains of fire” as lava blasted out of fissures perhaps several miles long.
Super-eruptions may not be all that rare. NASA’s Astrobiology Magazine quotes a scientist who said, “We typically expect one huge outburst every one or two years, and they’re usually not this bright.” This new discoveries, based on careful analysis of photos from the Keck II telescope, are leading him to think this may be the new normal. “Here we had three extremely bright outbursts, which suggest that if we looked more frequently we might see many more of them on Io.”
Huge outbursts were measured by the Galileo spacecraft (in orbit 1995-2003), the New Horizons spacecraft (2007) and earth-bound telescopes, including record bursts in 2001 (10/04/01), March 8, 2003, and 2007 (4/23/07, 12/03/07) and 2010. No energy source was mentioned in these new articles, particularly one that could persist for billions of years.
Back in September 27, 2002, in Science Magazine, planetary scientist Alfred McEwen said this:
If Io’s typical heat flow over geologic time is just 10% of today’s value, then we can expect 1012 km3 of silicate melt over the last 4000 million years—40 times the volume of Io. There should thus have been sufficient heat to melt 10% of Io’s volume 400 times. After just four episodes of such partial melting, Io should have formed a low-density crust ∼50 km thick. High-temperature, dense mafic or ultramafic lavas could only rise through the thick low-density crust under extraordinary circumstances.
His way out was to propose a magma ocean under the crust; that idea has gained traction in 2011 from analysis of Galileo data (NASA, see 5/14/11). Still, the lavas would have erupted hundreds of times over in billions of years, according to what McEwen just said. Material is also continuously lost to a torus around Jupiter, so after a few times through the recycler, one would expect the material to be depleted in the lightest elements. Brian Thomas at ICR responded in 2011 that the magma ocean theory is insufficient to account for Io’s heat output. The problem stems entirely from secular astronomers’ refusal to consider a younger solar system, one that is far less than 4.5 billion years old.
In 2000-2002, the enormous output of this moon already exceeded what the scientists could account for by tidal flexing (8/16/00), 9/27/02). Since then, planetary scientists tried to rig downward the heat output measurements, while sticking to the public story, as found on Wikipedia, that tidal flexing is sufficient to account for the energy output (occasionally the truth leaks out; see “Too hot to handle,” 6/12/12, also admission in 7/29/11). None of the latest theories, though, have addressed the problem of erupting 40 times Io’s entire mass through the volcanoes, or the problem of a growing crust stifling further eruptions. Tidal flexing appears to be a convenient, but insufficient, theory. Just last year, a study showed that locations of Io’s eruptions based on tidal flexing models do not match predictions (see “Bimbo eruptions in the solar system,” 4/06/13). Another admitted that Io’s heat is several times higher than tidal flexing models can explain (2/02/13).
The 2013 outbursts, if the new normal, may revise upward the total heat output, straining further the notion that tidal flexing is sufficient. Since planetary scientists typically shun the idea that we happen to be living in special circumstances (2/02/13), the latest news from Keck may have planetary scientists singing a new verse of Io, Io, It’s Off to Work We Go (5/04/04).
Well, we rig rig rig
Well, we rig in our minds the whole day through
Rig rig rig, that is what we like to do
And it ain’t no trick to get sick quick
If you rig rig rig, with a paradigm shtick
Rig rig rig, the whole day through
Got to rig rig rig, it’s what we like to do in our mind, in our mind
With 4 billion years assigned;
We got to rig rig rig, from the morning till the night
Rig rig rig up everything in sight
We got to rig rig rig, in our mind, in our mind
Rig scenarios by the score
A thousand stories, sometimes more
But we don’t know what we are riggin’ for, yeah
It’s off to work we go
We keep on sweating all day long
Got to make your troubles go
Well, we keep on sweating all day long