Once a week.
Subscribe to our weekly newsletter.
A new theory explains Jupiter’s perplexing origin
A new computer model solves a pair of Jovian riddles.
- Astronomers have wondered how a gas giant like Jupiter could sit in the middle of our solar system's planets.
- Also unexplained has been the pair of asteroid clusters in front of and behind Jupiter in its orbit.
- Putting the two questions together revealed the answer to both.
Jupiter's long been a puzzler to astronomers. Planet formation theory holds that a gas giant forms far away from its star then moves inward over time until it's in a tight orbit around the sun. Jupiter, though, sits right in the middle of our solar system's planets, between Mars and Saturn. And that's not all that's odd: There's an unexpectedly asymmetrical pair of asteroid clusters — known as the Trojan asteroids — preceding and trailing Jupiter in its orbit. The group in front is 50% larger than the one in back. The most widely accepted idea was that Jupiter formed near the Sun and moved outwards.
That's now been turned on its head by a team of scientists from Lund University who ran a series of models to try to identify a plausible origin story for Jupiter. They discovered that the planet and its clusters would be where they are under only one scenario: Jupiter forming way out near Uranus — as gas giants are supposed to do, after all — and moving slowly toward the Sun, attracting and accreting the asteroids that now form its core, with the leftovers trailing behind. Lead author Simona Pirani says, "This is the first time we have proof that Jupiter was formed a long way from the Sun and then migrated to its current orbit." Including the mystery of the asymmetrical Trojans in the simulations was the key.
Jupiter, right in the middle of everything.
The model that lands Jupiter where it is today, along with its thousand of Trojans, begins four times further away from the Sun than Jupiter currently orbits, just inside of Uranus' orbit. Jupiter first took form about 4.5 billion years back as an icy planetary seedling, an ice asteroid, no bigger than Earth. Somewhere between two and three million years later, the future giant began spiraling slowly inward toward the Sun, pulled by gases circulating throughout the solar system. It took about 700,000 years to get where it is now. Along the way, before it developed its gaseous atmosphere and massive size, Jupiter's gravity pulled the Trojans in — the researchers expect Jupiter's core to be composed of materials similar to the Trojans. They're believed to be rich with dark carbon compounds, and likely rich in water and other volatile materials beneath an outer layer of dust.
Lucy in the sky with Trojans
Trojan clusters held in place by the Sun and Jupiter
(Astronomical Institute of CAS/Petr Scheirich)
In October 2021, NASA plans to launch its Lucy mission to study the Trojans. It's believed that they're very old time capsules from the universe of four billion years ago. The craft will study seven of them: one from the solar system's main asteroid belt, and the remaining six from the clusters leading and following Jupiter in its orbit.
Those two Trojan groups are held in place at stable LaGrange points by the combined gravitation pull of the Sun and Jupiter acting together as a single centrifugal force acting upon them.
NASA has high hopes for the mission as chance to get a closeup look at the type of materials from which our planetary bodies formed.
Meanwhile, Jupiter's seeming a little bit less mysterious now, at least in terms of its origin. It may also be that ice giants Uranus and Neptune, as well as Saturn, have a similar history.
Why are so many objects in space shaped like discs?
- Why Don't Gas Giants Have Gas Moons? Bill Nye Explains - Big Think ›
- NASA's Juno probe detects unexpected lightning on Jupiter - Big Think ›
These alien-like creatures are virtually invisible in the deep sea.
- A team of marine biologists used nets to catch 16 species of deep-sea fish that have evolved the ability to be virtually invisible to prey and predators.
- "Ultra-black" skin seems to be an evolutionary adaptation that helps fish camouflage themselves in the deep sea, which is illuminated by bioluminescent organisms.
- There are likely more, and potentially much darker, ultra-black fish lurking deep in the ocean.
The Pacific blackdragon
Credit: Karen Osborn/Smithsonian<p>When researchers first saw the deep-sea species, it wasn't immediately obvious that their skin was ultra-black. Then, marine biologist Karen Osborn, a co-author on the new paper, noticed something strange about the photos she took of the fish.</p><p style="margin-left: 20px;">"I had tried to take pictures of deep-sea fish before and got nothing but these really horrible pictures, where you can't see any detail," Osborn told <em><a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">Wired</a></em>. "How is it that I can shine two strobe lights at them and all that light just disappears?"</p><p>After examining samples of fish skin under the microscope, the researchers discovered that the fish skin contains a layer of organelles called melanosomes, which contain melanin, the same pigment that gives color to human skin and hair. This layer of melanosomes absorbs most of the light that hits them.</p>
A crested bigscale
Credit: Karen Osborn/Smithsonian<p style="margin-left: 20px;">"But what isn't absorbed side-scatters into the layer, and it's absorbed by the neighboring pigments that are all packed right up close to it," Osborn told <em>Wired</em>. "And so what they've done is create this super-efficient, very-little-material system where they can basically build a light trap with just the pigment particles and nothing else."</p><p>The result? Strange and terrifying deep-sea species, like the crested bigscale, fangtooth, and Pacific blackdragon, all of which appear in the deep sea as barely more than faint silhouettes.</p>
David Csepp, NMFS/AKFSC/ABL<p>But interestingly, this unique disappearing trick wasn't passed on to these species by a common ancestor. Rather, they each developed it independently. As such, the different species use their ultra-blackness for different purposes. For example, the threadfin dragonfish only has ultra-black skin during its adolescent years, when it's rather defenseless, as <em>Wired</em> <a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">notes</a>.</p><p>Other fish—like the <a href="http://onebugaday.blogspot.com/2016/06/a-new-anglerfish-oneirodes-amaokai.html" target="_blank">oneirodes species</a>, which use bioluminescent lures to bait prey—probably evolved ultra-black skin to avoid reflecting the light their own bodies produce. Meanwhile, species like <em>C. acclinidens</em> only have ultra-black skin around their gut, possibly to hide light of bioluminescent fish they've eaten.</p><p>Given that these newly described species are just ones that this team found off the coast of California, there are likely many more, and possibly much darker, ultra-black fish swimming in the deep ocean. </p>
Using machine-learning technology, the genealogy company My Heritage enables users to animate static images of their relatives.
- Deep Nostalgia uses machine learning to animate static images.
- The AI can animate images by "looking" at a single facial image, and the animations include movements such as blinking, smiling and head tilting.
- As deepfake technology becomes increasingly sophisticated, some are concerned about how bad actors might abuse the technology to manipulate the pubic.
My Heritage/Deep Nostalgia<p>But that's not to say the animations are perfect. As with most deep-fake technology, there's still an uncanny air to the images, with some of the facial movements appearing slightly unnatural. What's more, Deep Nostalgia is only able to create deepfakes of one person's face from the neck up, so you couldn't use it to animate group photos, or photos of people doing any sort of physical activity.</p>
My Heritage/Deep Nostalgia<p>But for a free deep-fake service, Deep Nostalgia is pretty impressive, especially considering you can use it to create deepfakes of <em>any </em>face, human or not. </p>
How long should one wait until an idea like string theory, seductive as it may be, is deemed unrealistic?
- How far should we defend an idea in the face of contrarian evidence?
- Who decides when it's time to abandon an idea and deem it wrong?
- Science carries within it its seeds from ancient Greece, including certain prejudices of how reality should or shouldn't be.
Plato used the allegory of the cave to explain that what humans see and experience is not the true reality.
Credit: Gothika via Wikimedia Commons CC 4.0<p>When scientists and mathematicians use the term <em>Platonic worldview</em>, that's what they mean in general: The unbound capacity of reason to unlock the secrets of creation, one by one. Einstein, for one, was a believer, preaching the fundamental reasonableness of nature; no weird unexplainable stuff, like a god that plays dice—his tongue-in-cheek critique of the belief that the unpredictability of the quantum world was truly fundamental to nature and not just a shortcoming of our current understanding. Despite his strong belief in such underlying order, Einstein recognized the imperfection of human knowledge: "What I see of Nature is a magnificent structure that we can comprehend only very imperfectly, and that must fill a thinking person with a feeling of humility." (Quoted by Dukas and Hoffmann in <em>Albert Einstein, The Human Side: Glimpses from His Archives</em> (1979), 39.)</p> <p>Einstein embodies the tension between these two clashing worldviews, a tension that is still very much with us today: On the one hand, the Platonic ideology that the fundamental stuff of reality is logical and understandable to the human mind, and, on the other, the acknowledgment that our reasoning has limitations, that our tools have limitations and thus that to reach some sort of final or complete understanding of the material world is nothing but an impossible, <a href="https://www.amazon.com/dp/B01K2JTGIA?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank" rel="noopener noreferrer">semi-religious dream</a>.</p>