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Mystery of the gigantic Oort cloud from deep space explained
Astronomers possibly solve the mystery of how the enormous Oort cloud, with over 100 billion comet-like objects, was formed.
- The Oort cloud is a gigantic "cloud" at the edge of the solar system, about 3,000 times the distance between the Earth and the Sun.
- Astronomers used computer simulations to reconstruct the first 100 million years of the Oort cloud's existence.
- The Oort cloud may consist of the "leftovers" from the solar system's formation
Astronomers have calculated the first 100 million years of the history of the gigantic Oort cloud – a theoretical entity that contains 100 billion or so comet-like objects and forms a giant spherical shell around the sun and the rest of the solar system. NASA describes it as "a big, thick-walled bubble made of icy pieces of space debris the sizes of mountains and sometimes larger."
The Oort cloud was named after Dutch astronomer Jan Hendrik Oort, who discovered it in the 1950s. He was looking to understand why some comets in the solar system have elongated orbits. Scientists now believe the Oort Cloud is the source of most such comets.
The cloud is believed to be extremely far from the sun, many times more distant than the outer reaches of the Kuiper belt, the area of the solar system past the orbit of Neptune that contains comets, asteroids, and small icy space bodies as well as the dwarf planet Pluto.
According to NASA, the inner edge of the Oort cloud is likely between 2,000 and 5,000 AU (astronomical units or Earth-Sun distances) from the sun. The outer edge is probably 10,000 to 100,000 AU from the sun. By comparison, the Kuiper belt is about 30 to 50 AU away from the sun.
Oort cloud: the leftovers of the solar system
In a preprint article (accepted for publication in Astronomy & Astrophysics), a team of astronomers from Leiden University in the Netherlands describe how they used sophisticated computer simulations to determine how the Oort cloud formed.
They took a new approach by starting from separate events that might have happened in the early days of the universe and connecting them together. This allowed them to map out the full history of the origins of the gargantuan cloud.
As explained in their press release, the scientists used the ending calculations from one event as the starting calculation for the next event.
Protoplanetary disk.Credit: Pat Rawlings / NASA
Their simulations confirmed that the Oort cloud is what remained of the protoplanetary disk of gas and debris from which it is believed our solar system formed about 4.6 billion years ago.
The cloud has comet-like objects made of debris from two places in the universe. Some of them are from nearby parts of the solar system, such as asteroids expelled by giant planets like Jupiter. Another group of objects in the Oort cloud comes from a thousand or so stars that were around when our sun was born, eventually drifting apart from each other.
"With our new calculations, we show that the Oort cloud arose from a kind of cosmic conspiracy," said astronomer and simulation expert Simon Portegies Zwart from Leiden University, adding, "in which nearby stars, planets, and the Milky Way all play their part. Each of the individual processes alone would not be able to explain the Oort cloud. You really need the interplay and the right choreography of all the processes together."
He added that the Oort cloud was ultimately produced by "the interplay and the right choreography of all the processes together."
As it is so far away, humanity hasn't yet built a telescope powerful enough to see the small, faint objects of the Oort cloud directly. By some estimates, it would take telescopes that are 100 billion times better than what we currently have to see into the cloud. Even the new James Webb Telescope that's launching later in 2021 is unlikely to be able to see that far, confirmed Nobel laureate (and James Webb Telescope scientist) Dr. John Mather.
It would also take humanity a long time to reach the Oort cloud. As NASA estimated, even if you consider that the Voyager 1 probe can cover about a million miles every day, it would take it about 300 years to reach the inner edge of the Oort Cloud. And to get all the way through, it would likely require another 30,000 years.
- The sun may have had a long-lost companion star - Big Think ›
- The view from Voyager 1, humanity's furthest spacecraft - Big Think ›
So much for rest in peace.
- Australian scientists found that bodies kept moving for 17 months after being pronounced dead.
- Researchers used photography capture technology in 30-minute intervals every day to capture the movement.
- This study could help better identify time of death.
We're learning more new things about death everyday. Much has been said and theorized about the great divide between life and the Great Beyond. While everyone and every culture has their own philosophies and unique ideas on the subject, we're beginning to learn a lot of new scientific facts about the deceased corporeal form.
An Australian scientist has found that human bodies move for more than a year after being pronounced dead. These findings could have implications for fields as diverse as pathology to criminology.
Dead bodies keep moving
Researcher Alyson Wilson studied and photographed the movements of corpses over a 17 month timeframe. She recently told Agence France Presse about the shocking details of her discovery.
Reportedly, she and her team focused a camera for 17 months at the Australian Facility for Taphonomic Experimental Research (AFTER), taking images of a corpse every 30 minutes during the day. For the entire 17 month duration, the corpse continually moved.
"What we found was that the arms were significantly moving, so that arms that started off down beside the body ended up out to the side of the body," Wilson said.
The researchers mostly expected some kind of movement during the very early stages of decomposition, but Wilson further explained that their continual movement completely surprised the team:
"We think the movements relate to the process of decomposition, as the body mummifies and the ligaments dry out."
During one of the studies, arms that had been next to the body eventually ended up akimbo on their side.
The team's subject was one of the bodies stored at the "body farm," which sits on the outskirts of Sydney. (Wilson took a flight every month to check in on the cadaver.)Her findings were recently published in the journal, Forensic Science International: Synergy.
Implications of the study
The researchers believe that understanding these after death movements and decomposition rate could help better estimate the time of death. Police for example could benefit from this as they'd be able to give a timeframe to missing persons and link that up with an unidentified corpse. According to the team:
"Understanding decomposition rates for a human donor in the Australian environment is important for police, forensic anthropologists, and pathologists for the estimation of PMI to assist with the identification of unknown victims, as well as the investigation of criminal activity."
While scientists haven't found any evidence of necromancy. . . the discovery remains a curious new understanding about what happens with the body after we die.
Metal-like materials have been discovered in a very strange place.
- Bristle worms are odd-looking, spiky, segmented worms with super-strong jaws.
- Researchers have discovered that the jaws contain metal.
- It appears that biological processes could one day be used to manufacture metals.
The bristle worm, also known as polychaetes, has been around for an estimated 500 million years. Scientists believe that the super-resilient species has survived five mass extinctions, and there are some 10,000 species of them.
Be glad if you haven't encountered a bristle worm. Getting stung by one is an extremely itchy affair, as people who own saltwater aquariums can tell you after they've accidentally touched a bristle worm that hitchhiked into a tank aboard a live rock.
Bristle worms are typically one to six inches long when found in a tank, but capable of growing up to 24 inches long. All polychaetes have a segmented body, with each segment possessing a pair of legs, or parapodia, with tiny bristles. ("Polychaeate" is Greek for "much hair.") The parapodia and its bristles can shoot outward to snag prey, which is then transferred to a bristle worm's eversible mouth.
The jaws of one bristle worm — Platynereis dumerilii — are super-tough, virtually unbreakable. It turns out, according to a new study from researchers at the Technical University of Vienna, this strength is due to metal atoms.
Metals, not minerals
Fireworm, a type of bristle wormCredit: prilfish / Flickr
This is pretty unusual. The study's senior author Christian Hellmich explains: "The materials that vertebrates are made of are well researched. Bones, for example, are very hierarchically structured: There are organic and mineral parts, tiny structures are combined to form larger structures, which in turn form even larger structures."
The bristle worm jaw, by contrast, replaces the minerals from which other creatures' bones are built with atoms of magnesium and zinc arranged in a super-strong structure. It's this structure that is key. "On its own," he says, "the fact that there are metal atoms in the bristle worm jaw does not explain its excellent material properties."
Just deformable enough
Credit: by-studio / Adobe Stock
What makes conventional metal so strong is not just its atoms but the interactions between the atoms and the ways in which they slide against each other. The sliding allows for a small amount of elastoplastic deformation when pressure is applied, endowing metals with just enough malleability not to break, crack, or shatter.
Co-author Florian Raible of Max Perutz Labs surmises, "The construction principle that has made bristle worm jaws so successful apparently originated about 500 million years ago."
Raible explains, "The metal ions are incorporated directly into the protein chains and then ensure that different protein chains are held together." This leads to the creation of three-dimensional shapes the bristle worm can pack together into a structure that's just malleable enough to withstand a significant amount of force.
"It is precisely this combination," says the study's lead author Luis Zelaya-Lainez, "of high strength and deformability that is normally characteristic of metals.
So the bristle worm jaw is both metal-like and yet not. As Zelaya-Lainez puts it, "Here we are dealing with a completely different material, but interestingly, the metal atoms still provide strength and deformability there, just like in a piece of metal."
Observing the creation of a metal-like material from biological processes is a bit of a surprise and may suggest new approaches to materials development. "Biology could serve as inspiration here," says Hellmich, "for completely new kinds of materials. Perhaps it is even possible to produce high-performance materials in a biological way — much more efficiently and environmentally friendly than we manage today."
Dealing with rudeness can nudge you toward cognitive errors.
- Anchoring is a common bias that makes people fixate on one piece of data.
- A study showed that those who experienced rudeness were more likely to anchor themselves to bad data.
- In some simulations with medical students, this effect led to higher mortality rates.
Cognitive biases are funny little things. Everyone has them, nobody likes to admit it, and they can range from minor to severe depending on the situation. Biases can be influenced by factors as subtle as our mood or various personality traits.
A new study soon to be published in the Journal of Applied Psychology suggests that experiencing rudeness can be added to the list. More disturbingly, the study's findings suggest that it is a strong enough effect to impact how medical professionals diagnose patients.
Life hack: don't be rude to your doctor
The team of researchers behind the project tested to see if participants could be influenced by the common anchoring bias, defined by the researchers as "the tendency to rely too heavily or fixate on one piece of information when making judgments and decisions." Most people have experienced it. One of its more common forms involves being given a particular value, say in negotiations on price, which then becomes the center of reasoning even when reason would suggest that number should be ignored.
It can also pop up in medicine. As co-author Dr. Trevor Foulk explains, "If you go into the doctor and say 'I think I'm having a heart attack,' that can become an anchor and the doctor may get fixated on that diagnosis, even if you're just having indigestion. If doctors don't move off anchors enough, they'll start treating the wrong thing."
Lots of things can make somebody more or less likely to anchor themselves to an idea. The authors of the study, who have several papers on the effects of rudeness, decided to see if that could also cause people to stumble into cognitive errors. Past research suggested that exposure to rudeness can limit people's perspective — perhaps anchoring them.
In the first version of the study, medical students were given a hypothetical patient to treat and access to information on their condition alongside an (incorrect) suggestion on what the condition was. This served as the anchor. In some versions of the tests, the students overheard two doctors arguing rudely before diagnosing the patient. Later variations switched the diagnosis test for business negotiations or workplace tasks while maintaining the exposure to rudeness.
Across all iterations of the test, those exposed to rudeness were more likely to anchor themselves to the initial, incorrect suggestion despite the availability of evidence against it. This was less significant for study participants who scored higher on a test of how wide of a perspective they tended to have. The disposition of these participants, who answered in the affirmative to questions like, "Before criticizing somebody, I try to imagine how I would feel if I were in his/her place," was able to effectively negate the narrowing effects of rudeness.
What this means for you and your healthcare
The effects of anchoring when a medical diagnosis is on the line can be substantial. Dr. Foulk explains that, in some simulations, exposure to rudeness can raise the mortality rate as doctors fixate on the wrong problems.
The authors of the study suggest that managers take a keener interest in ensuring civility in workplaces and giving employees the tools they need to avoid judgment errors after dealing with rudeness. These steps could help prevent anchoring.
Also, you might consider being nicer to people.