Hey Bill Nye! Why Don't Gas Giants Have Gas Moons?
A very small person asks a very big question: why aren't the moons of gaseous planets also made of gas?
Bill Nye, scientist, engineer, comedian, author, and inventor, is a man with a mission: to help foster a scientifically literate society, to help people everywhere understand and appreciate the science that makes our world work. Making science entertaining and accessible is something Bill has been doing most of his life.
In Seattle Nye began to combine his love of science with his flair for comedy, when he won the Steve Martin look-alike contest and developed dual careers as an engineer by day and a stand-up comic by night. Nye then quit his day engineering day job and made the transition to a night job as a comedy writer and performer on Seattle’s home-grown ensemble comedy show “Almost Live.” This is where “Bill Nye the Science Guy®” was born. The show appeared before Saturday Night Live and later on Comedy Central, originating at KING-TV, Seattle’s NBC affiliate.
While working on the Science Guy show, Nye won seven national Emmy Awards for writing, performing, and producing. The show won 18 Emmys in five years. In between creating the shows, he wrote five children’s books about science, including his latest title, “Bill Nye’s Great Big Book of Tiny Germs.”
Nye is the host of three currently-running television series. “The 100 Greatest Discoveries” airs on the Science Channel. “The Eyes of Nye” airs on PBS stations across the country.
Bill’s latest project is hosting a show on Planet Green called “Stuff Happens.” It’s about environmentally responsible choices that consumers can make as they go about their day and their shopping. Also, you’ll see Nye in his good-natured rivalry with his neighbor Ed Begley. They compete to see who can save the most energy and produce the smallest carbon footprint. Nye has 4,000 watts of solar power and a solar-boosted hot water system. There’s also the low water use garden and underground watering system. It’s fun for him; he’s an engineer with an energy conservation hobby.
Nye is currently the Executive Director of The Planetary Society, the world’s largest space interest organization.
Aria: Hi Bill Nye. My name is Aria. My question is where do all moons come from and why do gas giants not have gas moons?
Bill Nye: Wow. That is a great question Aria. Wow. First of all I was alive when people figured out or satisfied themselves as to where our moon came from. And it's generally agreed that our moon was created when the earth was hit with another pretty big thing, another asteroid. And the impact was very hard and the energy of the smashing was converted to heat and both the earth and the moon were hot and molten and they both cooled off and here we are with this other separate thing in orbit around us. Now why do gas giants not have gas moons is a great question and the answer is almost certainly because of gravity.
So when you have these little things that spun off of, let's say Jupiter or Saturn, they were too small to sustain themselves as just balls of gas. The gas shrunk down, gravity pulled it down and formed a solid thing. Whereas on Jupiter and Saturn there's so much spin, so much heat created that these are held in the gaseous state or what we call gaseous state by the energy that's coming out of them, where as the smaller ones cooled off so much that they turned solid. It is just a fantastic question, Aria. And astrophysicists or planetary scientists speculate about this all the time, but what a fantastic thing that you made this observation. The moons of Jupiter, the big ones Io, Callisto, Europa and Ganymede those big moons are cooled off. They're not gaseous like Jupiter, what they orbit. That is fantastic. Wow. And maybe more will be learned about this.
And I gotta tell you, Aria, it's very reasonable that in your lifetime we will send the right spacecraft to Europa and the moon of Saturn, Enceladus and Titan, and look for signs of life. Instead of being a gas giant, in this one example, Europa is the moon of Jupiter that has twice as much seawater as the earth and that water is under a layer of ice. And I mention it because it's evidence of how things cool off when they're in space and they're small – or relatively small. The ice forms because the heat of creation, things smash together and that heat is radiated into space so there's a crust of ice, but the water underneath is kept liquid by the gravitational exercising of its orbit around Jupiter. It's amazing. What an observation. Aria, you're making my day. I hope you will be involved in missions to Europa and you will look for signs of life below the ice. I mean who knows if you have an ocean for four and a half billion years things are going to happen. There could be living things there. There could be Europanians out there, fish people that you'll interact with. Keep us posted. Thank you.
It took a very small person to ask a big question, one that planetary scientists pondered for a long time. There are four gas giants in our solar system – Jupiter, Saturn, Uranus and Neptune – but why are their moons not made of gas? They’re solid, unlike the planets they orbit.
As always, Bill Nye is on standby to explain the workings of the world and universe around us. The widely accepted theory on how Earth’s moon was created is known as the Giant Impact Hypothesisis. It states that a very young proto-Earth was struck by an asteroid, and in that collision both Earth and the debris that chipped off it became molten. They both cooled off, and now we have a moon; nicely spherical (although not perfectly) and solid, in orbit around us.
So why don’t gas giants have gas moons? The simple answer: gravity. When Jupiter or Saturn have undergone similar collisions or events that resulted in a fragment being spun off into their orbits, those new moons were too small to sustain themselves in a gaseous state. Gravity pulled the gas down until it formed a solid sphere. A gas giant, on the other hand, stays gaseous because of its size; there is so much heat generated from its spin that it cannot cool down into a solid state. Jupiter, for example, has 67 known moons and even the bigger ones like Io, Callisto, Europa and Ganymede, have cooled off – they're non-gaseous, unlike Jupiter itself.
Much can be learned after we know the state of moons; we now know that Europa has twice as much seawater as Earth, but that the water is under a crust of ice. One day, we may find life in those oceans – they’ve been around for 4.5 billion years, so it’s likely Europanians may be living there, says Nye.
Bill Nye's most recent book is Unstoppable: Harnessing Science to Change the World.
The week-long global protest, which is calling for an end to the age of fossil fuels, is taking place in more than 160 countries today.
SOPA Images / Contributor / Getty
- Millions of people around the world are taking to the streets to demand more urgent action on climate change.
- The protests come just days ahead of the 2019 UN Climate Action Summit.
- Although it's unclear exactly how many people are participating, it's likely to be the largest climate protest ever.
Most elderly individuals' brains degrade over time, but some match — or even outperform — younger individuals on cognitive tests.
- "Super-agers" seem to escape the decline in cognitive function that affects most of the elderly population.
- New research suggests this is because of higher functional connectivity in key brain networks.
- It's not clear what the specific reason for this is, but research has uncovered several activities that encourage greater brain health in old age.
At some point in our 20s or 30s, something starts to change in our brains. They begin to shrink a little bit. The myelin that insulates our nerves begins to lose some of its integrity. Fewer and fewer chemical messages get sent as our brains make fewer neurotransmitters.
As we get older, these processes increase. Brain weight decreases by about 5 percent per decade after 40. The frontal lobe and hippocampus — areas related to memory encoding — begin to shrink mainly around 60 or 70. But this is just an unfortunate reality; you can't always be young, and things will begin to break down eventually. That's part of the reason why some individuals think that we should all hope for a life that ends by 75, before the worst effects of time sink in.
But this might be a touch premature. Some lucky individuals seem to resist these destructive forces working on our brains. In cognitive tests, these 80-year-old "super-agers" perform just as well as individuals in their 20s.
Just as sharp as the whippersnappers
To find out what's behind the phenomenon of super-agers, researchers conducted a study examining the brains and cognitive performances of two groups: 41 young adults between the ages of 18 and 35 and 40 older adults between the ages of 60 and 80.
First, the researchers administered a series of cognitive tests, like the California Verbal Learning Test (CVLT) and the Trail Making Test (TMT). Seventeen members of the older group scored at or above the mean scores of the younger group. That is, these 17 could be considered super-agers, performing at the same level as the younger study participants. Aside from these individuals, members of the older group tended to perform less well on the cognitive tests. Then, the researchers scanned all participants' brains in an fMRI, paying special attention to two portions of the brain: the default mode network and the salience network.
The default mode network is, as its name might suggest, a series of brain regions that are active by default — when we're not engaged in a task, they tend to show higher levels of activity. It also appears to be very related to thinking about one's self, thinking about others, as well as aspects of memory and thinking about the future.
The salience network is another network of brain regions, so named because it appears deeply linked to detecting and integrating salient emotional and sensory stimuli. (In neuroscience, saliency refers to how much an item "sticks out"). Both of these networks are also extremely important to overall cognitive function, and in super-agers, the activity in these networks was more coordinated than in their peers.
An image of the brain highlighting the regions associated with the default mode network.
How to ensure brain health in old age
While prior research has identified some genetic influences on how "gracefully" the brain ages, there are likely activities that can encourage brain health. "We hope to identify things we can prescribe for people that would help them be more like a superager," said Bradford Dickerson, one of the researchers in this study, in a statement. "It's not as likely to be a pill as more likely to be recommendations for lifestyle, diet, and exercise. That's one of the long-term goals of this study — to try to help people become superagers if they want to."
To date, there is some preliminary evidence of ways that you can keep your brain younger longer. For instance, more education and a cognitively demanding job predicts having higher cognitive abilities in old age. Generally speaking, the adage of "use it or lose it" appears to hold true; having a cognitively active lifestyle helps to protect your brain in old age. So, it might be tempting to fill your golden years with beer and reruns of CSI, but it's unlikely to help you keep your edge.
Aside from these intuitive ways to keep your brain healthy, regular exercise appears to boost cognitive health in old age, as Dickinson mentioned. Diet is also a protective factor, especially for diets delivering omega-3 fatty acids (which can be found in fish oil), polyphenols (found in dark chocolate!), vitamin D (egg yolks and sunlight), and the B vitamins (meat, eggs, and legumes). There's also evidence that having a healthy social life in old age can protect against cognitive decline.
For many, the physical decline associated with old age is an expected side effect of a life well-lived. But the idea that our intellect will also degrade can be a much scarier reality. Fortunately, the existence of super-agers shows that at the very least, we don't have to accept cognitive decline without a fight.
Are tiny homes just a trend for wealthy minimalists or an economic necessity for the growing poor?
- The tiny home movement has been popular on social media sites, often portraying an idyllic lifestyle that's cheaper and better for the environment without sacrificing aesthetics.
- But tiny homes may become the answer to a growing population and growing inequality.
- As the movement continues to build up steam, one has to wonder whether it's a housing crisis solution with a new coat of paint.
Tiny homes. They're the watchword of the Home & Garden network, at once an Instagrammable, envy-inducing lifestyle and an unfortunate necessity for a generation struck by a recession, historically high inequality, and loans taken out for an ostensibly necessary education that's failed to really net any benefits.
But the question is, which are they? A symbol of a smarter, more environmentally-conscious, humbler generation — or a symbol of one that's had to make do with less than its predecessors? (See: "Millennials buy the things their parents did — but they're much poorer.")
Downsizing housing and hubris
Image source: Mike Morgan / For The Washington Post via Getty Images
Will tiny homes look like this in the future -- smaller and more efficient but still beautiful?
In the U.S., things are just bigger, and houses are no exception. The median size of a single-family home in the U.S. peaked in 2015 at 2,467 square feet. Compared to other parts of the world — particularly Europe — this is a massive figure. There's a variety of reasons for this; one, for example, is that Americans began driving early and often, which transformed the design of their cities and suburbs. Developers could build outside of urban centers where the land was cheaper and more plentiful, enabling bigger houses to be bought.
In addition, the idea of having a lot of space seems to be an appealing one to the former European colonies — where Europeans have often lived in more cramped, repurposed older buildings, Australians, Canadians, and Americans had the opportunity to seize land (despite it already being occupied) and build new, sprawling settlements throughout it. The prosperity that the America saw in the 20th century didn't hurt, either; why not build big if you've got the money to spare?
But a considerable amount of this space is wasted. A UCLA study found that the majority of people spend their time in the kitchen or around the television and very rarely use the living room or porch. As a result of these extra, unused spaces, more resources are wasted on construction, and energy consumption is double what a family would need if their house only had the rooms that they actually use.
Smaller, more energy-efficient houses are appealing to a growing population of minimalists and resource-conscious individuals. In 2017 alone, the sales of tiny homes increased by 67 percent. Coming in at under 400 square feet on average, these houses are also understandably cheap — for tiny homes on wheels, the average cost is $46,300, while those with a foundation cost on average $119,000. As a result, 68 percent of tiny homeowners don't even have a mortgage.
Downsizing out of necessity
Image source: George Rose/Getty Images
A community of tiny homes for homeless people known as "Nickelsville" in Seattle.
On the other hand, the group of people drawn to tiny homes isn't just homogenously composed of wealthy minimalists looking to reduce their consumption while still appearing trendy. In 70 percent of the U.S., the average worker can't afford a home, one-third of adults are a $400 bill away from financial difficulty, and a quarter have no retirement savings whatsoever.
Under these conditions, downsizing may be the only viable method to survive. Consider, for instance, how cities such as Seattle, Detroit, and Denver are constructing tiny homes as emergency shelters or transitional housing for the homeless. There are also the many retirees that had their savings wiped out by the Great Recession who now live nomadically in RVs and modified vans. This tiny-living trend also has its Instagram cheerleaders, but the reality of it is less idyllic. Journalist Jessica Bruder and author of Nomadland related an anecdote to MarketWatch illustrating the nature of nomadic tiny living:
"I talked to one couple, Barb and Chuck. He had been head of product development at McDonald's before he retired. He lost his nest egg in the 2008 crash and Barb did, too. One time, Barb and Chuck were standing at the gas station to get $175 worth of gas and the horror hit them that their account had $6 in it. The gas station gentleman said 'Give me your name and driver's license and if you write a check, I will wait to cash it.' He waited two whole weeks before he deposited it."
This might become a reality for more people in the future as well. Inequality widens when the rate at which wealth grows — say, your stocks or the price of your house — grows faster than the rate at which wages do. Research suggests that wealth is growing at a breakneck pace, keeping in line with economist Thomas Picketty's prediction of a dramatically inequal future.
Solutions for this will need to be found, and many municipalities or private individuals may find such a solution in constructing tiny homes. Homelessness is a powerful, self-perpetuating force, and having shelter is an obviously necessary step to escape poverty.
Regrettably, if tiny homes are being driven primarily by resource-conscious but fundamentally economically secure individuals, we can expect the trend to remain just that; a trend. In a few years, fewer and fewer tiny houses will be constructed and sold, and eventually there will just be a small contingent of diehard proponents of the lifestyle. If, however, the tiny home trend is being driven primarily by economic inequality, then we can expect it to stick around for a while.