The Week in Space and Physics: Jupiter's Changing Spot
On the Great Red Spot, nuclear fusion, the first launch of the Ariane 6 and Starliner
According to the official story, the Great Red Spot of Jupiter has been around for centuries. It was there, they say, when Robert Hooke peered through his telescope in May 1664, and then when the artist Donato Creti painted the planet in 1711. It was definitely there in February 1979, when Voyager 1 flew past and snapped a photo, and still there in 2022, when the Webb captured a magnificent view of the giant planet.
Except, perhaps it wasn’t. Jupiter’s Great Red Spot, a team of researchers now think, has not lasted as long as once believed. True, Hooke probably saw a spot in 1664, and Cassini certainly saw one in 1665, but there is no evidence that this was the same spot we see today. Indeed, the researchers point out that there is a long gap in the records - lasting over a century - in which nobody apparently saw the spot at all.
Jupiter’s spot is known to be a gigantic storm, big enough to swallow the Earth and featuring winds of hundreds of miles an hour. How it came to be, and why it has lasted for so long, is poorly understood: but we do know the spot fluctuates over time. For the past half century or so it has been shrinking, and gradually becoming more circular in shape. Eventually, perhaps, it may disappear altogether.
The question, now, is whether this has happened before - and if so, if the Great Spot is rather younger than once thought. The spot of the seventeenth century, as seen by Hooke and Cassini, was then known as Jupiter’s Permanent Spot. Data from the time is sparse, and photographic evidence, of course, non-existent. Yet the drawings that do exist show a dark circular spot in roughly the same place as today’s Great Spot.
The researchers point out, however, that the Permanent Spot seems to be much smaller than today’s spot, and - crucially - much smaller than the one seen in the late nineteenth century. Between 1713 and 1831, they say, there were no observations of the spot, and thus no evidence it existed. Even if it did, the storm would have had to have grown quickly, rapidly swelling in size over a century to match the storm seen in the 1830s.
That’s not impossible, others say, and it is anyway risky to rely too much on long ago images seen through early telescopes and then drawn by hand. But if the spot did disappear, and then a new one appeared, it suggests there might somewhere be observations hinting at how the storm came to be in the first place.
Possibly this happened when several smaller storms merged, a process that has been seen to form other spots on Jupiter. Yet the Red Spot seems too large for this explanation, and the merging storms would probably have been visible from Earth anyway. Instead the spot might have formed as a whole, thanks to a disturbance in Jupiter’s atmosphere. If so, the researchers say, Jupiter’s great spot may indeed disappear in the next few decades. Astronomers, however, might then see another one form to take its place.
Nuclear Fusion Delayed Again
Nuclear fusion, the old joke has it, is always twenty years from reality. It is, at least, an enticing vision. If it works, the technology could offer almost endless clean energy, harnessing the same power that fuels the Sun to drive modern civilization.
Getting it to work, however, is easier said than done. Fusion, at least as we best understand it, involves temperatures of hundreds of millions of degrees, a heat that no material can withstand. Containing a fusion reaction therefore requires sophisticated magnetic fields, and complex reactor designs to control and harness the resulting plasma. This has been done, but never yet in a way that has generated more power than it took in.
Only one experiment, in the United States, has ever reached a point known as ignition, after which a reaction is theoretically self-sustaining. Even then, however, the reaction lasted for less than a second, and cannot easily be scaled up to provide useful amounts of energy. The hope for that, instead, currently lies in a facility being built in the south of France, known as ITER.
ITER, when it begins operations, should be the first large-scale fusion plant capable of outputting large amounts of energy. Scientists think the facility will be able to generate at least ten times the energy put in, resulting in at least half a gigawatt of fusion power. That would be good enough to begin building a series of actual power stations, and thus to realise the long sought dream of a world powered by nuclear fusion.
Yet work on ITER has not gone smoothly. The facility is fantastically expensive, with a price tag of over fifteen billion dollars. Plans to build it were first unveiled in 1987, but construction only began in 2010. It should, had all gone to plan, have been ready to start reactions in 2016. Time after time, however, that date has been delayed.
Now project managers have admitted that it will not be ready until at least 2034. Its first experiments - where scientists begin perfecting nuclear fusion - will not happen until 2039. And on top of all that, the price tag has risen by another five billion dollars.
Fusion, then, is still twenty years from reality. And even if ITER does get finished, and does produce the hoped for results, it will still take decades more for the technology to become widespread. Fusion may well one day change the world. But that day will not come any time soon.
Ariane Prepares for Lift-Off
The launch of Europe’s new Ariane 6 rocket finally seems to be in sight. After four years of delays - and a full year of relying on SpaceX - the continent may restore its independent access to space with a lift-off on July 9th.
The rocket’s predecessor, the Ariane 5, was considered one of the best in the world. Over more than two decades of operation the launcher reached orbit more than one hundred times, sent probes to Jupiter and Mercury, and lofted the James Webb telescope to its vantage point a million miles from Earth.
Its successor, the Ariane 6, is supposed to be cheaper to fly and quicker to build. Yet it is unlikely to dominate the market in the same way that the Ariane 5 did. SpaceX’s Falcon 9 is cheaper still, and now flies several times a week. Only those determined not to use SpaceX are likely to turn to the Ariane 6.
Perhaps fortunately for Europe, that still seems to be a large market. Not only will the rocket launch European scientific and defense missions, of which plenty are planned in the years ahead, but it will also launch hundreds of Amazon’s Kuiper satellites. They, the tech giant hope, will form a network to rival SpaceX’s Starlink. Other work could in time come from the IRIS2 project, an effort to build a European space communications system.
At the same time, Europe is also trying to encourage a new generation of rockets able to properly rival SpaceX. A crowd of startups are busy building and testing launchers of their own. The next few years, indeed, may see many more maiden launches from European spaceports.
Starliner - Stranded in Orbit?
After reaching the space station in June, Boeing’s Starliner capsule was supposed to head back to Earth after a stay of less than two weeks. Instead the capsule is still there, docked to the station, along with the two astronauts it carried onboard.
At blame is a set of faulty thrusters on the capsule’s service module, a component that supports the capsule in orbit but is dumped before it re-enters the atmosphere. As Starliner approached the station, several of those thrusters temporarily stopped working. Controllers managed to get most of them back online again, but the reason why they acted up is unknown.
Since the service module doesn’t return to Earth, engineers from Boeing can only troubleshoot the problem in orbit, and that is easier to do while docked to the station. What this doesn’t mean, however, is that the capsule is unable to return to Earth, or that the astronauts are “stranded” in orbit. The service module, and thus the faulty thrusters, are jettisoned before re-entry. Any astronauts onboard, barring another problem, would thus be able to safely make it home.
Interesting info on the Jupiter great red spot! Years ago I used to think of it as a swirl or part- like people have in their hair at the their crown and the connection this has to the "hairy ball theorem" of topology. Then later, I started thinking of it as a manifestation of processes of anisotropic heat distribution occurring very deep in the planet atmosphere: a moving hot spot, much like a moving magma dome under the Earth's crust like at Yellowstone that stimulates volcanism at the overlying surface. The info you provide lays to rest both my mathematical and geological analogies!