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Top 4 candidates in our solar system for terraforming
When it comes time for humanity to pick a new home, where will we go?
- Regardless of whether you think the Earth will suffer some catastrophe or not, most individuals believe that humanity will eventually have to live on another planet.
- There is no nearby planet that can support human life, however; we'll have to pick a good candidate and terraform it.
- Each celestial body presents its own unique challenges and requirements. Some need more carbon dioxide, others need less; some would become water worlds, others more Earth-like; and so on.
Whether you're feeling optimistic or pessimistic about humanity's long-term chances on Earth, most of us agree that we should colonize other planets. Whether that's out of humanity's sheer pioneering spirit or the pragmatic survival instinct to spread out so that a catastrophe on Earth doesn't wipe out the species, establishing a colony on a nearby planet seems like a must.
Trouble is, our neighboring celestial bodies are constantly bombarded by deadly radiation, lack water or oxygen, rain sulfuric acid, swing from extreme heat to cold, and possess many other inhospitable characteristics. No matter where we go in our solar system, we'll have to engage in one of the largest projects imaginable: terraforming. Depending on the environment we want to transform into a more Earth-like one, the nature of this project will vary tremendously. Here's some examples from some of the most likely candidates for terraforming in our solar system.
An artist's depiction of Mars' gradual transformation via terraforming.
Mars has always been an appealing target for terraforming, as it is arguably the most Earth-like planet in the solar system. It goes through similar seasons to Earth, has a relatively similar atmospheric composition, its day-night cycle is extremely close to our own, it possesses abundant water in the form of ice, and it lies in the Sun's habitable zone.
But the biggest problem with Mars is that it has no magnetosphere. Without an envelope of shielding magnetism, solar wind will blow away any atmosphere before it can accumulate. Proposals to create the right kind of atmosphere on Mars — like Elon Musk's flashy idea of nuking the polar ice caps to release stored CO2 and water vapor, thereby heating the planet up — won't work long term without a magnetosphere to protect the planet against solar wind. With Mars' current, flimsy atmosphere, between 1 and 2 kilograms of gas are lost to space every second. Not to mention that the lack of this protective magnetosphere also exposes the planet and all life on it to deadly radiation from the sun.
One proposal is to place a gigantic magnetic shield in orbit between Mars and the Sun to recreate the effects produced by, for instance, Earth's rotating iron outer core. This would be an incredible engineering task, likely requiring regular maintenance and fuel to keep the magnet powered. But it would be the first step to ensuring that Mars could be made habitable. Even prior to that point, Mars gradual growth of an atmosphere would make future exploration on the red planet easier and easier.
An artist's depiction of Venus if it were terraformed.
Compared to Mars, Venus has very little going for it. The surface temperature is 462°C, or 864°F; it has the opposite problem as Mars, with an atmosphere more than 90 times as dense as that of the Earth; and it's got no breathable oxygen. Not to mention that it's covered in volcanos and rains sulfuric acid. On the other hand, it's our closest planetary neighbor, and its gravity is about 90 percent that of Earth's compared to Mars' 38 percent, meaning our muscles and bones wouldn't atrophy while living there.
While Venus also suffers from a lack of a sufficiently strong magnetosphere, it's abundance of atmosphere means that concern can be put aside for a while in our hypothetical terraforming project. Venus's major problem is its excess of CO2, which makes the surface of the planet too hot for life and too heavy for humans.
One approach would be to use autonomous robots to expose Venus's underground deposits of calcium and magnesium, resulting in a chemical reaction that would store CO2 in a magnesium carbonate. This would need to be supplement by a bombardment of those elements mined from asteroids as well in order to remove enough carbon from the atmosphere for human life.
There are a variety of other methods, but they all rely on removing CO2 from the atmosphere rapidly. Seeing as how our inability to do that on Earth may be one of the biggest reasons to find another planet, Venus may not be the ideal target for terraforming in the future. An alternative to terraforming, however, would be to build a floating city in the Venusian clouds, a feat that isn't too far-fetched technologically.
A full-color image of Callisto as captured by NASA's Galileo spacecraft/
NASA/JPL/ DLR(German Aerospace Center)
Many of the Jupiter's Galilean moons are attractive targets for terraforming due to their high abundance of water, but only Callisto lies far enough away from the radiation belts generated by Jupiter's magnetosphere. On Earth, we're exposed to about 0.066 rems of radiation per day. In contrast, Ganymede receives 8 rems of radiation per day, Europa receives 540 rems per day, and Io receives a whopping 3,600 rems. Callisto, in contrast, is exposed to about 0.01 rems per day, which humans can tolerate.
The process of terraforming these moons would all follow essentially the same recipe. First, heat up their icy surfaces either through giant mirrors, nuclear devices, or some other method. Then, let the radiation from Jupiter split the resulting water vapor into hydrogen and oxygen — the hydrogen will be blown into space by solar wind, while the oxygen will settle close to the surface. Use bacteria to convert the moons' ammonia into nitrogen, and there's a breathable atmosphere.
Of course, these planets would be completely covered in oceans hundreds of kilometers deep, and Callisto wouldn't have its own magnetosphere to keep that atmosphere in place long term, but their abundance of water makes it an attractive target nonetheless. More concerning is the possibility that life already exists beneath the Galilean moons' icy surfaces, in the warm waters by thermal vents. If we were to discover such life, would it be ethical to disrupt the only alien life we have ever known?
A composite image of Titan in infrared as seen by NASA's Cassini spacecraft. Because Titan's atmosphere is so hazy, viewing it in the wavelengths of visible light is not possible. Using the infrared spectrum enables us to see through the clouds to the moon's surface.
The appeal of terraforming Titan lies in its vast reservoir of resources. Its hydrocarbon reserves (such as petroleum) are several hundred times greater than all known reserves on Earth. It's covered in a wide variety of organic compounds, particularly methane and ammonia, as well as a great deal of water. And its atmosphere is primarily nitrogen as well — a composition that scientists believe resembles that of early Earth's.
Together, these ingredients would be of significant benefit to any terraforming project. If Titan's atmosphere does resemble early Earth's, then transitioning to an atmosphere that resembles modern Earth would be (relatively) straightforward. One proposal would be to position mirrors in orbit to direct focused sunlight onto the moon's surface. Since the surface ice contains many greenhouse gases, this could warm Titan up considerably, releasing water vapor and consequently oxygenating the atmosphere. It also spends most of its time within Saturn's magnetosphere, protecting its atmosphere from the solar wind.
But perhaps more so than any other body in our solar system, Titan could already have extraterrestrial life owing to its abundance of organic chemicals. And, if all of Titan's ice were melted, it would become an ocean planet 1700 km deep, or over 1,000 miles deep, making the establishment of fixed, permanent structures a challenge.
There are challenges common to all of these potential candidates for terraforming. The big one, of course, is getting there. Many of these targets are incredibly distant. For a comparison, it took Voyager 1 a little over three years to get to Saturn, where Titan, the most distant candidate, is located, and a ship with all of the necessary equipment, people, and resources would be significantly slower than a lightweight probe. Then, there's the issue of establishing a semipermanent colony while the long work of terraforming goes on. It's difficult to speculate about the capabilities we'll have at our disposal when terraforming a planet becomes a feasible project, but it could be hundreds, possibly thousands of years before any of these planets are completely terraformed. And these are just some of the known issues: a project of this scale is bound to have unexpected problems and consequences. Despite these major challenges, the vast majority of humanity believes that establishing a second home in our solar system is a necessity — the question is, which will it be?
- Terraform Mars? How about Earth? ›
- How bacteria can make Mars livable - Big Think ›
- Venus' clouds shows signs of alien life, MIT scientists say - 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.