Jupiter is Stranger Than We Thought

On the one hand, it's hardly surprising that an enormous gas giant doesn't work the way we first thought it did. It's space. Conventional logic is usually wrong. On the other hand, it's still surprising. It's not like Jupiter is a complete unknown to us, with Galileo fulfilling the same role Cassini is currently (though not for much longer) performing around Saturn. It was a big flagship space probe that orbited Jupiter for nearly 8 years, and in doing so vastly expanded our knowledge of Jupiter and the Jovian system.

(Brief aside: Cassini and Galileo may be very similar space probes, but I don't think there's a question that Cassini was by far the more successful of the two. Galileo suffered several technical issues that hindered its abilities and orbited for 8 years, whereas Cassini has suffered no such problems and has orbited for 13 years.)

It's been nearly 14 years since Galileo took its final dive into Jupiter, and once again, a space probe orbits Jupiter. Juno is a space probe designed to learn more about Jupiter itself rather than its moons, and from polar orbit it has done a very good job of this. For one thing, the Jovian polar regions don't match the rest of the planet. You think of Jupiter, you see the red, brown, and white stripes, but in fact, the poles are mostly blue. And that's just an obvious thing we learned because we finally got a chance to look at Jupiter's poles (Jupiter has almost no tilt, so it was impossible to get an image of them without sending a probe into polar orbit).

Suffice to say, a gas giant that bears almost no resemblance to Earth has an atmosphere that operates in ways entirely different to our own. For one, the enormous Jovian auroras work in reverse, caused by electrons leaving the polar regions, rather than entering them as they do on Earth. It also appears that the sun is not the primary driver of weather on Jupiter, and once you drop below the upper atmosphere, things don't quiet down. The lower parts of the atmosphere are just as diverse as the upper parts. A big band of ammonia orbiting the equator was particularly interesting, as there is no good reason why it should be there at all.

Things don't get quieter even further down in Jupiter's central regions. There are noticeable fluctuations in Jupiter's gravitational and magnetic fields, indicating a non-uniform interior and deep convection within the planet. The article concludes with a quote that I find rather appropriate, both to this current situation and to astronomical science in general: "In hindsight, it’s hard to imagine why would we have ever thought it would be simple and boring." Indeed.

Is Cosmic Inflation Theory Wrong?

Sometimes, even fairly basic scientific concepts get questioned. This is a good thing. If there's enough room in a theory for questioning, there's a good chance the theory is either wrong or incomplete. Take the Big Bang. It's a fairly uncontroversial theory in the scientific community. All the matter in the universe started from one single point, it explodes, and we get the universe. But there was a problem with that concept. The universe is flat, as in, the matter is spread out incredibly thin and space is basically empty. That's fine as far as it goes, but there was no way the Big Bang could have been powerful enough on its own to spread the matter of universe so thin. There must have been another factor, and into the breach came inflation. This inflationary energy is what cause the universe to become what we see today.

Of course, a theory is nothing without evidence, and we have significant evidence of inflation. There are the ripples in the cosmic background radiation, the existence of dark matter (though we still don't know what dark matter is), as well as another type of gravitational radiation called B-Mode polarization, found in 2013 using data collected from the Planck satellite. Case closed, right?

You know where this is going. Three scientists took issue with the Planck data, saying that it fit the most convenient theory of inflation, not the simplest one. And that leads into one of inflation's biggest problem. It is so broad a theory, with so many hypotheses contained within it, that all new data can be made to fit. Nothing can disprove it. And that's a problem. If it can't be disproved, it's not science, it's philosophy. And we're not dealing with a bunch of philosophers here, we're dealing with physicists. And pro-inflation physicists (the vast majority, let's remember) are not happy with this suggestion. They say they need more time and more data, that it's just taking a very long time to eliminate hypotheses. The anti-inflation physicists say that more than enough time has been spent on inflation, nothing will prove it, and new data will just cause the theory to stretch even further.

Inflation has another big problem, and that is inflation seems to require a multiverse. And once again, the existence of multiple universes would be impossible to prove and is therefore not science.

That begs a question, though. If inflation is wrong, how did the universe get the way it is today? The anti-inflation physicists suggest something called "the Big Bounce", a process wherein the universe grows out of a point, reaches a certain point, then collapses back on itself, only to repeat the process again and again. This is also not a new idea, and like inflation, it has a big problem. The Big Bounce has always required the existence of naked singularities. And once a theory requires naked singularities, it's done. Nobody likes naked singularities. Our intrepid trio anti-inflation physicists claim they've managed to figure out a Big Bounce theory without a singularity, but that claim's been made before, and has always been disproved.

So where does that leave us, the non-physicist audience? Well, if you want to be democratic about it, inflation has the support of almost everyone, while anti-inflation is thought of as being pretty fringe science. I'd say if you're ever at a party, and someone asks about your opinion on the formation of the early universe, just say inflation. It would require less explanation.

Cassini Has Been Good for Astrobiologists

As you may (or may not) be aware, Cassini's mission around Saturn will be coming to an end this year. For 13 years, Cassini has orbited Saturn, and has discovered a lot. I think that I'll make a more comprehensive post about Cassini closer to October, when Cassini performs its death dive into Saturn, but for now, I want to highlight this. It is interesting how a planet a billion miles away from the sun possesses two moons with the potential of hosting life. Enceladus especially has been a huge surprise. I don't think anyone was expecting Enceladus to be anything more than a ball of ice. But here we are today, with photo evidence of massive geysers spewing organic material out into space. Cassini doesn't have the capability to detect life, but the ingredients are there.

Then, of course, there's Titan. Titan is a fascinating place. A thick atmosphere, a methane cycle that mirrors Earth's water cycle, large methane seas hundreds of feet deep, even rivers of methane, Titan really does resemble an Earth in deep freeze. No one knows if life can use methane instead of water, there are pros and there are cons. But it would be very interesting to find out. Life on Enceladus would be, well, different to life on Earth, but not that different. It would be recognizable to us, and would probably resemble deep-sea life on Earth. But life on Titan? It would be a truly alien biochemistry.

Basically, we need to go back to Saturn. And soon. Enceladus and Titan are just too inviting as targets to resist. Mars is closer, and Europa is basically just a bigger Enceladus, but for my money, if there's life in the solar system, it'll be around Saturn.