Not only did NASA’s David Williams reply, but he drew some awesome diagrams of Europa.
Jupiter is the largest planet in our Solar System, and the competition really isn’t even close. It’s an absolutely massive planet and it helped define what a gas giant planet truly is. Because of its size, it might be hard to imagine a time when Jupiter had a problem growing, but new research suggests that the planet spent millions of years as a relatively modest world.
In a new paper published in Nature Astronomy, a team of researchers presents a detailed timeline of Jupiter’s first few million years. The scientists used meteorite data that has been amassed over time which hinted at the fact that Jupiter has long played a “gatekeeper” role for the planets that orbit closer to the Sun.
When the planet reached between 20 and 50 times the size of Earth it began divide the massive disk of dust and debris that was circling the Sun at that time. It effectively split the Solar System into to sections, and by studying meteorites researchers can determine when that split happened.
By building a timeline of meteorite activity, researchers can make some impressively advanced models that show the birth and earliest years of our system and the planets. Using a wealth of meteorite information collected over many years the team calculated when Jupiter began growing rapidly, and how long it took for it to reach its current size.
The model shows that Jupiter was born a baby. That’s true of all planets, so it’s not particularly surprising, but what the data also shows is that the planet grew incredibly slowly for its first few million years of existence.
“During the first stage the pebbles brought the mass,” Yann Alibert, lead author of the paper, explains. “In the second phase, the planetesimals also added a bit of mass, but what is more important, they brought energy.”
That first phase of growth, which lasted around a million years, allowed a solid core to form. The two million years that followed was slower in terms of growth, but the high-energy impacts created an incredible amount of heat to the would-be gas giant. At the three million year mark the planet was only about 50 times the size of Earth, but that’s when things began to speed up. The millions of years that followed were a bit of a growth spurt for Jupiter as it began to draw in more and more gas and balloon up to its current mass which is over 300 times that of Earth.
Of all the planets in our Solar System, Jupiter is probably the most interesting to look at. It’s just a big ball of fast-moving gasses in all kinds of wild colors. The planet hosts storms that could swallow the entirety of Earth, and while we can see lots of neat things happening near the planet’s cloud tops it’s a lot more difficult to determine what is actually going on deeper inside the planet.
Now, thanks to some fancy calculations and jet stream models inspired by Earth’s own weather patterns, researchers have a new theory on just why Jupiter’s crazy bands seem so perfectly arranged.
In the study, which was published in The Astrophysical Journal, scientists explain that the jet streams on the planet are likely cut off by magnetized gasses deeper within the planet. The jet streams control the flow of gasses around the planet’s outer atmosphere where colorful bands of ammonia twist around the planet. These jet streams stretch many miles into the planet, but stop once they reach the magnetized gasses closer to its center.
“The gas in the interior of Jupiter is magnetised, so we think our new theory explains why the jet streams go as deep as they do under the gas giant’s surface but don’t go any deeper,” Dr. Jeffrey Parker of the Livermore National Laboratory explained in a statement.
We know jet streams on Earth work in a roughly similar way, but the difference between Jupiter and our own planet is that the streams on the gas giant don’t have a rocky surface underneath to disrupt them. We know that the clouds on Jupiter stretch for thousands of miles into the planet thanks to observations by NASA’s Juno probe, and the planet’s strong magnetic field is thought to play a role in how they are arranged.
If you want to dive into the nitty gritty of the work, put on your thinking cap and prepare for plenty of calculations. It’s some very deep stuff.
Here on Earth, electromagnetic waves around the planet are typically pretty calm. When the Sun fires a burst of charged particles at the Earth we are treated to an aurora (often called Northern Lights), but rarely are they a cause for concern. If you were to head to Jupiter, however, things would change dramatically.
In a new study published in Nature Communications, researchers describe the incredible electromagnetic field structure around two of Jupiter’s moons: Europa and Ganymede. The invisible magnetic fields around these bodies is being powered by Jupiter’s own magnetic field, and the result is an ultra-powerful particle accelerator of sorts, which might be capable of seriously damaging or even destroying a spacecraft.
“Chorus waves” are low-frequency electromagnetic waves that occur naturally around planets, including Earth. Near our planet they’re mostly harmless, but they do have the capability to produce extremely fast-moving “killer” particles that could cause damage to manmade technology if we happened to be in the wrong place at the wrong time.
Jupiter’s magnetic field is many thousand times larger than the Earth’s, and that means that moons like Europa and Ganymede actually orbit within their host’s magnetic field while also producing their own. This results in chorus waves that are incredibly strong, and scientists now believe that the Ganymede is surrounded by waves a million times more intense than anything we’ve seen on Earth. The skies around Europa host waves that are “only” around 100 times more intense.
“Chorus waves have been detected in space around the Earth but they are nowhere near as strong as the waves at Jupiter” Professor Richard Horne, co-author of the work, explains. “Even if small portion of these waves escapes the immediate vicinity of Ganymede, they will be capable of accelerating particles to very high energies and ultimately producing very fast electrons inside Jupiter’s magnetic field”.
If enough of these “killer” particles were to strike a spacecraft things could go sideways very quickly. I guess it’s a good thing that mankind has very little interest in visiting Jupiter in person.
Exoplanets orbiting distant stars might be our best chance of finding advanced, complex life forms, but there’s still a handful of places in our own Solar System where life could still be hiding, we just have to find it. Jupiter’s moon Europa is one of those places, and while we’ve gotten some great glimpses of its surface there’s a good reason why we haven’t seen signs of life: It’s probably inside the planet itself.
Europa is a massive watery world covered by a layer of icy crust. That ice is hiding what scientists believe is a vast ocean, and that ocean may very well having something living in it. A new study published in Nature Astronomy explains how we might go about detecting that life, and it actually sounds a bit easier than you might think.
The paper focuses on how far we’d have to dig into the moon’s ice layer in order to harvest samples that would provide proof of life in the water beneath. The ice, of course, is made of the same water that rests beneath, and if there’s life in that water the ice likely holds frozen biological material that a spacecraft could test.
However, scientists believe that radiation from space and Jupiter’s atmosphere is probably wreaking havoc on any biological material on the surface. That’s bad news, because it could cause that material to break down over time, making it essentially useless to researchers.
That’s a bummer, but the researchers say that finding usable samples will actually still be fairly easy. According to the paper, a lander won’t have to dig very deep to find a clean sample that hasn’t been tainted by radiation.
“Radiation processing and destruction of potential biosignatures is found to be significant down to depths of ~1 cm in mid- to high-latitude regions, and to depths of 10–20 cm within ‘radiation lenses’ centred on the leading and trailing hemispheres,” the scientists explain. “These results indicate that future missions to Europa’s surface do not need to excavate material to great depths to investigate the composition of endogenic material and search for potential biosignatures.”
Put simply, radiation should only be a problem within the first inch of the surface, and maybe as deep as 8 inches in certain areas. A lander or rover capable of drilling into the planet (similar to how NASA’s Mars Curiosity rover drills into rocks on the Red Planet) should have no problem snagging some useful samples and potentially proving the existence of life deep within the planet’s ocean.