The key point of contention is the satellites crunchy ice covering. We know that the Jovian moon is coated in kilometers of frozen material, but that sort of handwaving figure can get you in trouble - exactly how many kilometers there are can make all the difference. We believe that the European core is heated by the massive tidal forces applied by Jupiter - but how does that heat radiate into space?
Most scientists believe that the subEuropan seas are locked under tens of kilometers of ice. Heat is then conducted from the warm core by bulk convective motion of ice - huge chunks of frozen material literally carrying the heat away with them as they move up through the icy layer, shuffling and refreezing as they dump heat into space.
Professor Richard Greenberg believes that the crust is thin, only a kilometer or so, and heat is carried out by simple conduction - much slower, but providing a constant flow of energy through a relatively fixed underwater region bordering the immense cliffs of ice.
Greenberg does weaken his case by accusing a "Big Ice" cabal of scientists of suppressing his results, holding back his views to favor their own established model. The thing is, when you start talking about a conspiracy against you it doesn't matter if you're right or wrong: you sound a bit crazy. Especially when that "cabal" isn't a hidden core of ultra-billionaires, but probably about twenty guys with tenure who meet twice a year to talk about space moons.
On the upside, it seems the shadowy Europa lobby can't keep him silent and he's printing a book, "Unmasking Europa", putting forward his views and setting up the mother of all "I told you so"s if it turns out he's right. Again, he slightly weakens his case by fantasising an entire Europan ecosystem based on a few flybys of the Galileo probe, and it's not as if popular opinion will actually sway the scientists investigating the issue.
What is important is that such issues do now percolate to the public, one way or another. Science is no longer the preserve of those either rich enough to afford it or trying to build missiles out of it. Beside the cook books and crime novels you can find imaginings of the stars, controversies of the cosmos, and books about the entire universe. Which are slightly more interesting than "Five things you can do with leftovers" by Dolores Housewife.
Posted by Luke McKinney.