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kottke.org posts about science

Slipping the Surly Bonds of Earth

Shuttle Endeavour rising through the clouds

I love this photo of the Space Shuttle Endeavour rising through the clouds on a plume of smoke during its last launch in 2011. We are but infinitesimal specks on a tiny rock orbiting a small star in an ordinary galaxy among trillions in an endless universe. And yet we’ve pushed our way into that vastness, just a little bit. I wonder where we’ll end up?


Richard Feynman and the Myth of Separating Science from the Scientist

In Surely You’re a Creep, Mr. Feynman, science historian Leila McNeill writes about the difficulty in separating science from the behavior of the scientist.

In addition to cataloguing the trespasses of individual scientists who abuse the cultural power of their position, we have to dismantle the structures that have allowed their abuses to continue with little to no disruption. Just for starters, this means abandoning the myth that the science can be separated from the scientist.

The conversation about separating the person from the practice has been slower to surface in science than it has in the literary, film, journalism, and art worlds. It might seem that there is less distance between an artist and the thing they create than for their counterparts in the sciences because art is often positioned as subjective and abstract. It’s easier to draw a clear line from a writer like Junot Diaz who has displayed abusive behaviors to women in real life and his male characters who do the same. Scientists, however, have been framed as objective observers of phenomena while scientific practice itself has been seen as empirical, measureable, stable, and separate. This typical framing disconnects science from the rest of the world, allowing it to be perceived as a disembodied conduit for unadulterated knowledge. But science isn’t just a body of knowledge; it’s an institution and a culture with material connections to a lived-in world. Its practitioners are makers of and participants in that institution and culture.


Our Unbounded Finite Universe

I’ve always had a hard time wrapping my head around the idea that the universe could be both finite and infinite at the same time (or something like that *takes bong rip*), but this passage from Coming of Age in the Milky Way by Timothy Ferris succinctly explains what’s going on:

General relativity resolved the matter by establishing that the universe could be both finite — i.e., could contain a finite number of stars in a finite volume of space — and unbounded. The key to this realization lay in Einstein’s demonstration that, since matter warps space, the sum total of the mass in all the galaxies might be sufficient to wrap space around themselves. The result would be a closed, four-dimensionally spherical cosmos, in which any observer, anywhere in the universe, would see galaxies stretching deep into space in every direction, and would conclude, correctly, that there is no end to space. Yet the amount of space in a closed universe would nonetheless be finite: An adventurer with time to spare could eventually visit every galaxy, yet would never reach an edge of space. Just as the surface of the earth is finite but unbounded in two dimensions (we can wander wherever we like, and will not fall off the edge of the earth) so a closed four-dimensional universe is finite but unbounded to us who observe it in three dimensions.

In the terms of Edwin Abbott Abbott’s Flatland: A Romance of Many Dimensions, we are Flatlanders living in a Lineland world who, with the aid of mathematics, have been able to peer into Spaceland.


Can You Start a Fire with Moonlight and a Magnifying Glass?

Equipped with only a magnifying glass and the light of the Sun, it’s pretty easy to start a fire.1 So, with a much bigger glass, could you start a fire with moonlight?

First, here’s a general rule of thumb: You can’t use lenses and mirrors to make something hotter than the surface of the light source itself. In other words, you can’t use sunlight to make something hotter than the surface of the Sun.

There are lots of ways to show why this is true using optics, but a simpler — if perhaps less satisfying — argument comes from thermodynamics:

Lenses and mirrors work for free; they don’t take any energy to operate.[2] If you could use lenses and mirrors to make heat flow from the Sun to a spot on the ground that’s hotter than the Sun, you’d be making heat flow from a colder place to a hotter place without expending energy. The second law of thermodynamics says you can’t do that. If you could, you could make a perpetual motion machine.

In a better world, Randall Munroe would be writing middle school science textbooks.

  1. A few summers ago when I was showing my kids how to do this, I started futzing with the small pile of tissue paper and pine needles we’d assembled and forgot about the magnifying glass I was holding…until I felt a searing pain in my leg and looked down to see a bit of smoke curling up from my slightly toasted thigh. Kids, do as dad says, not as he does.


How to Build a Dyson Sphere

Perhaps the most fundamental way to think about the Universe is in terms of energy. Even when you get away from physics and chemistry (where energy is obviously central) and into a topic like human history or economics, following how and where energy flows can be enlightening. In 1964, Soviet astronomer Nikolai Kardashev proposed thinking about the progress of human civilization in terms of how much energy we were capable of harnessing. On the Kardashev scale, a Type I civilization would be capable of using all of the energy available on their planet, a Type II civilization could use all the energy from their local star, and a Type III civilization could harness all the energy in a galaxy.

According to an equation suggested by Carl Sagan, humans are currently sitting at ~73% of a Type I civilization. But once we reach that milestone in perhaps a few hundred years (assuming we don’t blow ourselves up in the process), the construction of a Dyson sphere or, more likely, a Dyson swarm around the Sun is probably the key to eventually hitting Type II. In the video above, Kurzgesagt explores what would go into building some type of Dyson structure capable of harvesting most of the Sun’s energy. For starters, we’d probably have to completely dismantle the planet Mercury in order to have enough raw materials to build the swarm.


Life-Size Stone Mosaics Based on 16th-Century Anatomical Drawings

John Unger Anatomy

Sculptor John T. Unger is making a series of life-size stone mosaics based on anatomical drawings by the 16th-century Italian scientist Bartolomeo Eustachi.

Bartolomeo Eustachi, one of the first modern anatomists, is also considered the first comparative anatomist, as he was the first to use examples from the animal realm for comparison and clarity. Eustachi was a contemporary of Vesalius, and they share the credit of having created the science of human anatomy. In 1552 (nine years after Vesalius published his Fabrica) Eustachi completed a series of anatomical illustrations so accurate that had they been published in his lifetime, a modern understanding of anatomy might have come to pass two centuries before it was attained.

Unger has completed about half of the mosaics and is doing a Kickstarter campaign to help finish the rest of them. The first public showing of the finished artworks will be at the Carrie Haddad Gallery in Hudson, NY starting in June 2019.


Ultra-Precise Ice Core Sampling and the Explosive Cause of the Dark Ages

536 AD was an exceedingly bad year for humanity, perhaps even “the worst year to be alive”.

A mysterious fog plunged Europe, the Middle East, and parts of Asia into darkness, day and night — for 18 months. “For the sun gave forth its light without brightness, like the moon, during the whole year,” wrote Byzantine historian Procopius. Temperatures in the summer of 536 fell 1.5°C to 2.5°C, initiating the coldest decade in the past 2300 years. Snow fell that summer in China; crops failed; people starved. The Irish chronicles record “a failure of bread from the years 536-539.” Then, in 541, bubonic plague struck the Roman port of Pelusium, in Egypt. What came to be called the Plague of Justinian spread rapidly, wiping out one-third to one-half of the population of the eastern Roman Empire and hastening its collapse, McCormick says.

For Science magazine, Ann Gibbons writes about a new ice core sampling technique that is providing new insight into the causes of the fall of the Roman Empire and the Dark Ages in Europe.

Mayewski and his interdisciplinary team decided to look for the same eruptions in an ice core drilled in 2013 in the Colle Gnifetti Glacier in the Swiss Alps. The 72-meter-long core entombs more than 2000 years of fallout from volcanoes, Saharan dust storms, and human activities smack in the center of Europe. The team deciphered this record using a new ultra-high-resolution method, in which a laser carves 120-micron slivers of ice, representing just a few days or weeks of snowfall, along the length of the core. Each of the samples — some 50,000 from each meter of the core — is analyzed for about a dozen elements. The approach enabled the team to pinpoint storms, volcanic eruptions, and lead pollution down to the month or even less, going back 2000 years, says UM volcanologist Andrei Kurbatov.

Wow, this is like time travel! You should read the whole piece…it’s not long or technical. I loved the bit about how lead pollution provides evidence for the rise of the merchant class in medieval Europe. (via @tylercowen)


Hear the First Sounds Ever Recorded on Mars

NASA’s InSight mission recently landed on Mars and like other missions before it, the lander is a equipped with a camera and has sent back some pictures of the red planet. But InSight is also carrying a couple of instruments that made it possible to record something no human has ever experienced: what Mars sounds like:

InSight’s air pressure sensor recording the sound of the wind directly and the seismometer recorded the sounds of the lander’s solar panels vibrating as Martian winds blew across them.

Two very sensitive sensors on the spacecraft detected these wind vibrations: an air pressure sensor inside the lander and a seismometer sitting on the lander’s deck, awaiting deployment by InSight’s robotic arm. The two instruments recorded the wind noise in different ways. The air pressure sensor, part of the Auxiliary Payload Sensor Subsystem (APSS), which will collect meteorological data, recorded these air vibrations directly. The seismometer recorded lander vibrations caused by the wind moving over the spacecraft’s solar panels, which are each 7 feet (2.2 meters) in diameter and stick out from the sides of the lander like a giant pair of ears.

The sounds are best heard with a good pair of headphones.


Computer Simulations of Black Hole Mergers Observed by LIGO

As of December 1, 2018, the LIGO experiment has detected gravitational waves from 10 black hole merger events. In the computer simulations shown in this video, you can see what each of the mergers looked like along with the corresponding gravitational waves generated and subsequently observed by the LIGO detectors.


The End of Space Travel?

Remember Alfonso Cuarón’s Gravity? A missile strike on a satellite causes a chain reaction, which ends up destroying almost everything in low Earth orbit. As this Kurzgesagt video explains, this scenario is actually something we need to worry about. In the past 60 years, we’ve launched so much stuff into space that there are millions of pieces of debris up there, hurtling around the Earth at 1000s of miles per hour. The stuff ranges in size from marbles to full-sized satellites. If two larger objects in low Earth orbit (LEO) collided with each other, the resulting debris field could trigger a chain reaction of collisions that would destroy everything currently in that orbit and possibly prevent any new launches. Goodbye ISS, goodbye weather satellites, goodbye GPS, etc. etc. etc. The Moon, Mars, and other destinations beyond LEO would be a lot harder to reach because you’d have to travel through the deadly debris field, particularly with crewed missions.


The Effects of Pollution on Human Cognition & Performance

While I am not a big fan of shifting to an economic argument for things that are already plenty bad for other better reasons (see diversity in the workplace, immigration policy, healthcare, etc.), this article by Austin Frakt on the economic cost of pollution reports on the results of a number of studies linking pollution to low performance in work and school. This study of baseball umpires was particularly troubling:

Pollution may also affect the quality of work, which is much harder to measure. An intriguing study in the Journal of the Association of Environmental and Resource Economists got at this issue by examining how accurately baseball umpires called balls and strikes under different pollution conditions.

Since 2008, pitch calls have been checked by Major League Baseball with an electronic system. In a typical game, an umpire makes 140 ball/strike calls. When there was a 150 percent increase over average carbon monoxide levels or the same increase in small particulate matter, the study found an average of 1.4 additional incorrect calls. Levels of pollution that high occur in about one in 10 games.

Imagine what the rest of us, especially kids, are getting wrong when we’re in polluted areas (i.e. many American cities). (via @tylercowen)


Watch It Live: NASA’s InSight Probe Lands on Mars Today

After a seven-month journey covering over 300 million miles, NASA’s InSight probe will land on the surface of Mars today around 3pm. The video embedded above is a live stream of mission control at NASA’s Jet Propulsion Laboratory that starts at 2pm and will be the best thing to watch as the probe lands. (See also this live stream of NASA TV.) The landing will occur around 2:47pm ET but the landing signal from Mars won’t arrive on Earth until 2:54pm ET at the earliest. And no video from the landing itself of course…”live” is a bit of a misnomer here but it still should be exciting.

NASA produced this short video that shows what’s involved in the landing process, aka how the probe goes from doing 13,000 mph to resting on the surface in just six-and-a-half minutes.

The NY Times has a good explainer on the InSight mission and landing.

NASA’s study of Mars has focused on the planet’s surface and the possibility of life early in its history. By contrast, the InSight mission — the name is a compression of Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport — will study the mysteries of the planet’s deep interior, aiming to answer geophysical questions about its structure, composition and how it formed.

I love this stuff…the kids and I will be watching for sure!

Update: The Oatmeal has a great comic about the InSight landing.


Chinese Scientists Are Creating CRISPR Babies

In an article for MIT Technology Review, Antonio Regalado reports that researchers in Shenzhen, led by He Jiankui, are recruiting couples for a study to produce the first genetically edited human babies. They are hoping to use the CRISPR gene editing technique to “eliminate a gene called CCR5 in hopes of rendering the offspring resistant to HIV, smallpox, and cholera”.

The birth of the first genetically tailored humans would be a stunning medical achievement, for both He and China. But it will prove controversial, too. Where some see a new form of medicine that eliminates genetic disease, others see a slippery slope to enhancements, designer babies, and a new form of eugenics.

“In this ever more competitive global pursuit of applications for gene editing, we hope to be a stand-out,” He and his team wrote in an ethics statement they submitted last year. They predicted their innovation “will surpass” the invention of in vitro fertilization, whose developer was awarded a Nobel Prize in 2010.

A follow-up by the Associated Press indicates that He’s program is already underway and has resulted in a successful birth of twins earlier this month.

The researcher, He Jiankui of Shenzhen, said he altered embryos for seven couples during fertility treatments, with one pregnancy resulting thus far. He said his goal was not to cure or prevent an inherited disease, but to try to bestow a trait that few people naturally have - an ability to resist possible future infection with HIV, the AIDS virus.

He said the parents involved declined to be identified or interviewed, and he would not say where they live or where the work was done.

Update: He is now under investigation for legal and ethical misconduct.

On Sunday, the Shenzhen City Medical Ethics Expert Board said it would begin an investigation of He’s research and released a statement saying that HarMoniCare “according to our findings … never conducted the appropriate reporting according to requirements.” The former medical director of the private hospital, Jiang Su-Qi, told Southern Capital News he had no recollection of approving He’s research while he was on its ethics committee.

“These two children are the guinea pigs. They will go through their whole maturing process having not understood the risks ahead of time,” said Liu Ying of Peking University’s Institute of Molecular Medicine.


Studying Humpback Whales to Better Communicate with Aliens

In this video, a pair of scientists talk about their work in studying the communication patterns of humpback whales to learn more about how we might someday communicate with a possible extraterrestrial intelligence. No, this isn’t Star Trek IV. For one thing, whales have tailored their communication style to long distances, when it may take hours to received a reply, an analog of the length of possible interplanetary & interstellar communications. The scientists are also using Claude Shannon’s information theory to study the complexity of the whales’ language and eventually hope to use their findings to better detect the level of intelligence in alien messages and perhaps even the social structure of the alien civilization itself.

P.S. Fascinating whale facts are sprinkled throughout the video. Humpback whales “have had the Ocean Internet for millions of years” and can communicate directly with each other up to 1000 km away. That means that a whale off the coast of Portland, OR can chat with another whale near San Francisco. (via @stewartbrand)


This Holiday Ad Featuring Elton John Might Make You Cry

Sure, I know this is a television commercial for a UK department store and therefore should be afforded a certain level of emotional detachment, but only the most cynical folks out there will still be stone-faced at the end of this holiday advert starring Elton John.

After watching it, I thought back to my childhood for a gift that turned out to be more than just a gift. The closest I could come is a telescope1 my dad got me when I was maybe 8 or 9. While I didn’t grow up to be a celebrated astrophysicist or anything like that, that telescope solidified my love of science, encouraged my curiosity, and fostered my growing worldview that the universe could be wondrous without being magical. I could see sunspots on the Sun, the rings of Saturn, the moons of Jupiter, and shadows cast by craters on the Moon with my own eyes just as well as I could see the blades of grass right in front of me. Those objects moved around out there according to the same simple physical laws as the Earth moved, as did the baseball my dad & I played catch with, the rocket that shepherded astronauts to the Moon, and the waves on the ocean.

Seeing that all of those things were tied together across massive distances by a single system made a powerful impression on me. There was no need to say “well, I don’t know how that works so it must be some magical force or being”. I could go to a book and look up how Saturn’s rings formed, where the Moon’s craters came from, and why we only ever see one side of the Moon from Earth. And if the answer to a question didn’t exist, you could take that curiosity and go find out yourself, no permission necessary, and contribute to the collective human understanding of our existence. I switched away from a career in science shortly after entering grad school, but the spirit of scientific inquiry and curiosity has never left me or my work. I’ve loved being a designer, technologist, writer, and curator who still thinks like a scientist, like a little kid peering through his telescope at the rings of Saturn for the very first time and wanting to know everything about them.

  1. The telescape was a Jason model 311. I was old enough to know that it wasn’t made specifically for me, that didn’t stop me from feeling a little bit special owning a telescope with my actual name on it.


The Remarkable Brain Waves of High Level Meditators

What’s going on in the brains of people who meditate? Anecdotal evidence suggests that meditation does something to people’s minds and bodies…quiets and calms them. In this video, Daniel Goleman reports on research done by his colleague Richard Davidson, a neuroscientist at the University of Wisconsin–Madison. Davidson brought a number of “Olympic level meditators” into his lab and hooked them up to a brain scanner. He found that the brains of these expert meditators have different brain wave patterns than the rest of us.

Perhaps the most remarkable findings in the Olympic level meditators has to do with what’s called a gamma wave. All of us get gamma for a very short period when we solve a problem we’ve been grappling with, even if it’s something that’s vexed us for months. We get about half second of gamma; it’s the strongest wave in the EEG spectrum. We get it when we bite into an apple or imagine biting into an apple, and for a brief period, a split-second, inputs from taste, sound, smell, vision, all of that come together in that imagined bite into the apple. But that lasts very short period in an ordinary EEG.

What was stunning was that the Olympic level meditators, these are people who have done up to 62,000 lifetime hours of meditation, their brainwave shows gamma very strong all the time as a lasting trait just no matter what they’re doing. It’s not a state effect, it’s not during their meditation alone, but it’s just their every day state of mind. We actually have no idea what that means experientially. Science has never seen it before.

Goleman and Davidson have written more about how meditation affects the mind and body in their book, Altered Traits.

Sweeping away common misconceptions and neuromythology to open readers’ eyes to the ways data has been distorted to sell mind-training methods, the authors demonstrate that beyond the pleasant states mental exercises can produce, the real payoffs are the lasting personality traits that can result. But short daily doses will not get us to the highest level of lasting positive change — even if we continue for years — without specific additions. More than sheer hours, we need smart practice, including crucial ingredients such as targeted feedback from a master teacher and a more spacious, less attached view of the self, all of which are missing in widespread versions of mind training.

There’s that pesky deliberate practice popping up again.


Stephen Hawking’s Brief Answers to the Big Questions

Stephen Hawking passed away back in March, but left us with a final book that just came out this week: Brief Answers to the Big Questions. There are 10 questions asked and answered in the book:

Is there a God?
How did it all begin?
Can we predict the future?
What is inside a black hole?
Is there other intelligent life in the universe?
Will artificial intelligence outsmart us?
How do we shape the future?
Will we survive on Earth?
Should we colonize space?
Is time travel possible?

Here are a couple of reviews from Physics World and NPR.

Take the chapter on “Can we predict the future?”. Starting with regular astronomical events, it swiftly moves on to scientific determinism, quantum physics, hidden variables and Heisenberg’s uncertainty principle. Under the guise of a simple question, Hawking has managed to take the reader on a whistle-stop tour of the quantum world (bottom line: no we can’t predict everything). It’s a clever ruse. Ask a simple question and you’ll draw in readers who might otherwise not know they’d be interested in complex science.

P.S. The UK cover of this book is so much better than the US cover. Why?? (via open culture)


Fly Me to the Moonmoon

Moonmoon

In a paper called “Can Moons Have Moons?”, a pair of astronomers says that some of the solar system’s moons, including ours, are large enough and far enough away from their host planets to have their own sizable moons.

We find that 10 km-scale submoons can only survive around large (1000 km-scale) moons on wide-separation orbits. Tidal dissipation destabilizes the orbits of submoons around moons that are small or too close to their host planet; this is the case for most of the Solar System’s moons. A handful of known moons are, however, capable of hosting long-lived submoons: Saturn’s moons Titan and Iapetus, Jupiter’s moon Callisto, and Earth’s Moon.

Throughout the paper, the authors refer to these possible moons of moons as “submoons” but a much more compelling name has been put forward: “moonmoons”.

Moonmoon is an example of the linguistic process of reduplication, which is often deployed in English to make things more cute and whimsical. In the pure form of reduplication, you get words like bonbon, choo-choo, bye-bye, there there, and moonmoon but relaxing the rules a little to incorporate rhymes and near-rhymes yields hip-hop, zig-zag, fancy-shmancy, super-duper, pitter-patter, and okey-dokey. And with contrastive reduplication, in which a word repeats as a modifier to itself:

“It’s tuna salad, not salad-salad.”
“Does she like me or like-like me?”
“The party is fancy but not fancy-fancy.”
“The car isn’t mine-mine, it’s my mom’s.”

Fun! And astronomy should be fun too. Let’s definitely call them moonmoons.


Earth-Sized Telescope Aims to Snap a Photo of Our Galactic Black Hole

Astronomers behind the Event Horizon Telescope are building a virtual telescope with a diameter of the Earth to photograph the supermassive black hole at the center of our galaxy. The idea is that different observatories from all over the surface of the Earth all look at the black hole at the same time and the resulting data is stitched together by a supercomputer into a coherent picture. Seth Fletcher wrote a great piece about the effort for the NY Times Magazine (it’s an excerpt from his new book, Einstein’s Shadow: A Black Hole, a Band of Astronomers, and the Quest to See the Unseeable):

Astronomical images have a way of putting terrestrial concerns in perspective. Headlines may portend the collapse of Western civilization, but the black hole doesn’t care. It has been there for most of cosmic history; it will witness the death of the universe. In a time of lies, a picture of our own private black hole would be something true. The effort to get that picture speaks well of our species: a bunch of people around the world defying international discord and general ascendant stupidity in unified pursuit of a gloriously esoteric goal. And in these dark days, it’s only fitting that the object of this pursuit is the darkest thing imaginable.

Avery Broderick, a theoretical astrophysicist who works with the Event Horizon Telescope, said in 2014 that the first picture of a black hole could be just as important as “Pale Blue Dot,” the 1990 photo of Earth that the space probe Voyager took from the rings of Saturn, in which our planet is an insignificant speck in a vast vacuum. A new picture, Avery thought, of one of nature’s purest embodiments of chaos and existential unease would have a different message: It would say, There are monsters out there.

A video by the EHT team says that imaging the black hole is like trying to count the dimples on a golf ball located in LA while standing in NYC.

EHT team member Katie Bouman also did a TEDx talk on the project.

P.S. There’s a cloud near the center of the galaxy that tastes like raspberries and smells like rum.


Climate Scientists: Humans Have Only 12 Years to Limit Devastating Climate Changes

In a 700-page report detailing the latest research on climate change, a UN panel of scientists strongly warns that unless we make “massive and unprecedented changes to global energy infrastructure to limit global warming to moderate levels” to limit the world’s warming to 1.5 degrees Celsius, there will be widespread coastal flooding, food shortages, wildfires, and other issues related to climate change. If you are 60 or under, these changes will occur in your lifetime. From the NY Times:

A landmark report from the United Nations’ scientific panel on climate change paints a far more dire picture of the immediate consequences of climate change than previously thought and says that avoiding the damage requires transforming the world economy at a speed and scale that has “no documented historic precedent.”

The report, issued on Monday by the Intergovernmental Panel on Climate Change, a group of scientists convened by the United Nations to guide world leaders, describes a world of worsening food shortages and wildfires, and a mass die-off of coral reefs as soon as 2040 — a period well within the lifetime of much of the global population.

The report “is quite a shock, and quite concerning,” said Bill Hare, an author of previous I.P.C.C. reports and a physicist with Climate Analytics, a nonprofit organization. “We were not aware of this just a few years ago.” The report was the first to be commissioned by world leaders under the Paris agreement, the 2015 pact by nations to fight global warming.

And from the Washington Post:

The transformation described in the document is breathtaking, and the speed of change required raises inevitable questions about its feasibility.

Most strikingly, the document says the world’s annual carbon dioxide emissions, which amount to more than 40 billion tons per year, would have to be on an extremely steep downward path by 2030 to either hold the world entirely below 1.5 degrees Celsius, or allow only a brief “overshoot” in temperatures. As of 2018, emissions appeared to be still rising, not yet showing the clear peak that would need to occur before any decline.

Overall reductions in emissions in the next decade would probably need to be more than 1 billion tons per year, larger than the current emissions of all but a few of the very largest emitting countries. By 2050, the report calls for a total or near-total phaseout of the burning of coal.

If you’d like to dive into the report itself, two good places to start are the headline statements and the summary for policymakers.


How We Could Build a Moon Base Today

This video explores how humans could begin to colonize the Moon today, using currently available technology.

We actually do have the technology and current estimates from NASA and the private sector say it could be done for $20-40 billion spread out over about a decade. The price is comparable to the International Space Station or the budget surplus of Germany in 2017.

That’s also only 12-25% of the net worth of Jeff Bezos. I don’t know whether that’s more an illustration of the relative affordability of building a Moon base or of Bezos’ wealth, but either way it’s a little bit crazy that the world’s richest man can easily afford to fund the building of a Moon base and somehow it’s not happening (or even close to happening).


Dark Matter: Looking for Whispers in the Cosmic Silence

For Motherboard’s The Most Unknown series, physicist Davide D’Angelo and geomicrobiologist Jennifer Macalady travel to Laboratori Nazionali del Gran Sasso to see one of the latest efforts to detect dark matter, the SABRE detector.

As with the search for neutrinos, looking for dark matter needs to happen under conditions of “cosmic silence” — in this case, beneath a mountain in Italy. D’Angelo, who is a collaborator on the project, likens the search to “hunting ghosts”.


How Do We Know Recent Climate Changes Are Caused By Humans?

One of the ways that climatologists know that the dramatically increasing amount of atmospheric carbon dioxide (and corresponding temperature increase) is caused by human activity is by measuring changing land use and how much fossil fuel has been burned over the last few hundred years. From a 2004 RealClimate article:

One way that we know that human activities are responsible for the increased CO2 is simply by looking at historical records of human activities. Since the industrial revolution, we have been burning fossil fuels and clearing and burning forested land at an unprecedented rate, and these processes convert organic carbon into CO2. Careful accounting of the amount of fossil fuel that has been extracted and combusted, and how much land clearing has occurred, shows that we have produced far more CO2 than now remains in the atmosphere. The roughly 500 billion metric tons of carbon we have produced is enough to have raised the atmospheric concentration of CO2 to nearly 500 ppm. The concentrations have not reached that level because the ocean and the terrestrial biosphere have the capacity to absorb some of the CO2 we produce. However, it is the fact that we produce CO2 faster than the ocean and biosphere can absorb it that explains the observed increase.

That was back when the CO2 concentration was ~380 parts per million…it’s now ~407 ppm. That is pretty convincing evidence all by itself…the inputs match the outputs.

But there is also extremely compelling corroborating evidence that has to do with what kind of carbon is being released into the atmosphere — the smoking gun of anthropogenic climate change, if you will. For several hundred years before the start of the 19th century, the CO2 in the atmosphere contained a more-or-less consistent ratio of two carbon isotopes: carbon-12 and carbon-13 (which contains one more neutron than carbon-12 and is therefore heavier). Plants prefer consuming the lighter carbon-12 over carbon-13 and since fossil fuels are ultimately made from decayed plants, when you burn them, they disproportionately produce carbon-12 (when compared to atmospheric CO2).

So if you’re burning a bunch of oil and coal, you’d expect to see carbon-12 levels in the atmosphere go up…and that’s exactly what scientists have found. If you graph the amount of carbon-12 present in the atmosphere over time, you can see very clearly that it begins rising in lockstep with CO2 concentration right around when people began burning a lot of fossil fuels circa 1800.

Light Carbon Graph

You can read more about how scientists took these measurements in the 2004 RealClimate article I mentioned above. Meteorologist Eric Holthaus says learning about these measurements “propelled me to a career in climate” and I can totally see why — this is really persuasive.


Sea Slugs Can Arm Themselves with Venom from Other Animals?!

These nudibranchs (sea slugs) are lit up like the midway at a county fair because they’re warning predators that they use stinging cells called nematocysts to defend themselves when attacked. But the nematocysts are not native to nudibranch physiology — they hoover them up from hydroids, a jellyfish relative, and distribute them around their bodies.

The nudibranch’s gut has fingerlike branches that extend up into the long cerata on its back. The unfired stingers travel up into the cerata and concentrate in little sacs at the tips, where they continue to develop.

If a fish or crab tries to bite the nudibranch, it squeezes those sacs and shoots out the stingers, which immediately pop in the predator’s mouth. It doesn’t take long for predators to avoid the brightly colored nudibranchs.

What a wild adaptation! (via the kid should see this)


Werner’s Nomenclature of Colours

While Isaac Newton and the 17th century were more decisive for understanding the physics of color, you can’t beat the late 18th and early 19th century for a broader, subtler, more humanistic sense of the science of colors. The playwright and polymath J.W. von Goethe built up his Theory of Colours by collecting almost 18,000 meteorological and mineralogical specimens, with an emphasis on subtle distinctions between colors and their psychological perception in nature, rather than wavelengths of light.

Another phenomenal collection of naturalist examples is Abraham Gottlob Werner’s Nomenclature of Colours, first published in 1814. An 1821 edition recommends it for “zoology, botany, chemistry, mineralogy, and morbid anatomy.” At My Modern Met, Kelly Richman-Abdou writes:

Nomenclature of Colours served as a must-have reference for artists, scientists, naturalists, and anthropologists alike. The exquisitely rendered guide showcases the earth’s rich range of color by separating it into specific tones. Illustrated only by a small swatch, each handwritten entry is accompanied by a flowery name (like “Arterial Blood Red” and “Velvet Black”) as well as an identifying number. What the book is truly known for, however, is its poetic descriptions of where each tone can be found in nature.

Werner was a German mineralogist who created the system of color classification in the book to help distinguish between his own samples. His Scottish collaborators Patrick Syme and Robert Jameson were a painter and naturalist, respectively, who adapted the system into the book format in which it exists today. As you might guess, each color in the book includes a name, a swatch, and examples from the animal, vegetable, and mineral world showing where each color is found in nature.

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Probably the most famous user of Werner’s book was Charles Darwin, who used it to help describe animals and other bits of the natural world in his books and journals. But if you think about it, before photography, anything that let naturalists describe what they were seeing in something resembling a universal vocabulary had to be essential. Essential enough that they were willing to produce the book by hand, with no real way to print in color.

Amazon sells a pocket-sized facsimile edition of the book. It may not be as handy as a color wheel for painting a room, but might be handier if you’re identifying bird eggs or a rare bit of stone.


Stunning high-res photo of a stellar nursery

Carina Nebula

Astronomers using an infrared telescope at the European Southern Observatory in Chile recently released an infrared photo of the Carina Nebula that shows the inner workings of the star factory “as never before”.

This spectacular image of the Carina nebula reveals the dynamic cloud of interstellar matter and thinly spread gas and dust as never before. The massive stars in the interior of this cosmic bubble emit intense radiation that causes the surrounding gas to glow. By contrast, other regions of the nebula contain dark pillars of dust cloaking newborn stars.

This is a massive image…the original is 140 megapixels (<- that’s a 344MB download). Phil Plait notes that it may contain about 1 million stars and gives a bit of background on what we’re looking at here:

The colors you see here are not what you’d see with your eye, since it’s all infrared. What’s shown as blue is actually 0.88 microns, or a wavelength just outside what your eye can see. Green is really 1.25 microns and red is 2.15, so both are well into the near-infrared.

Even in the infrared, a lot of gas and dust still are visible. That’s because there’s a whole bunch of it here. And it’s not just randomly strewn around; patterns are there when you look for them.

For example, in this subimage you can see long, skinny triangles of dust. These are formed when very thick clots of dust are near very luminous stars. The wind and fierce blast of ultraviolet light from the stars erode away at the clump and also flow around it. They’re like sandbars in a stream! This is the same mechanism that made the Pillars of Creation in the Eagle nebula, and they’re common in star-forming nebulae.


Ancient Denisovan/Neanderthal human-hybrid discovered

Wow! Genetic analysis of a human bone fragment found in Siberia reveals that her parents belonged to two different groups of humans: her father was Denisovan and her mother Neanderthal.

A female who died around 90,000 years ago was half Neanderthal and half Denisovan, according to genome analysis of a bone discovered in a Siberian cave. This is the first time scientists have identified an ancient individual whose parents belonged to distinct human groups. The findings were published on 22 August in Nature1.

“To find a first-generation person of mixed ancestry from these groups is absolutely extraordinary,” says population geneticist Pontus Skoglund at the Francis Crick Institute in London. “It’s really great science coupled with a little bit of luck.”

Luck is right…what a needle in a haystack.


Using a crane and concrete blocks to store energy for later retrieval

A Swiss company has designed a system for storing energy in concrete blocks. The blocks are lifted by a crane when surplus energy is available (say, when the Sun is shining or the wind blowing) and then, when energy is needed later, allowed to fall, turning turbines to generate electricity.

The innovation in Energy Vault’s plant is not the hardware. Cranes and motors have been around for decades, and companies like ABB and Siemens have optimized them for maximum efficiency. The round-trip efficiency of the system, which is the amount of energy recovered for every unit of energy used to lift the blocks, is about 85% — comparable to lithium-ion batteries which offer up to 90%.

Pedretti’s main work as the chief technology officer has been figuring out how to design software to automate contextually relevant operations, like hooking and unhooking concrete blocks, and to counteract pendulum-like movements during the lifting and lowering of those blocks.

The storage of energy in this way isn’t new…the ARES project uses hills and heavy trains to accomplish the same thing.

It’s a wonderfully simple idea, a 19th century solution for a 21st century problem, with some help from the abundant natural resource that is gravity. When the local utility’s got surplus electricity, it powers up the electric motors that drag 9,600 tons of rock- and concrete-filled railcars up a 2,000-foot hill. When it’s got a deficit, 9,600 tons of railcar rumble down, and those motors generate electricity via regenerative braking — the same way your Prius does. Effectively, all the energy used to move the train up the hill is stored, and recouped when it comes back down.

There’s something really interesting about big kinetic machines operating as though they were computers, autonomous black boxes where data flows in and out that can operate anywhere with a bit of flat ground.


On the nature of wormholes

Are wormholes science or just science fiction? As this video by Kurzgesagt shows, they’re actually a little bit of both. Einstein and string theory both posit that these “short cuts” through spacetime could exist, but finding or building a stable wormhole, a la Star Trek, is another matter altogether.

In the description of the video, they link to a pair of papers published by Michael Morris and Kip Thorne in the late 80s: Wormholes, Time Machines, and the Weak Energy Condition and Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity. For a high school physics class, I gave a presentation on wormholes & time travel and I’m pretty sure I used at least one of those papers as a reference. The presentation also included a clip of Bill & Ted’s Excellent Adventure. The teacher gave me a B+ — he felt the presentation was excellent (*guitar riff*) but that I had, in spite of the movie clip, “lost most of the other students” and should have chosen a more suitable topic.


A 20-year time lapse of stars orbiting a massive black hole

The European Southern Observatory’s Very Large Telescope in Chile has been watching the supermassive black hole in the center of our galaxy and the stars that orbit it. Using observations from the past 20 years, the ESO made this time lapse video of the stars orbiting the black hole, which has the mass of four million suns. I’ve watched this video like 20 times today, my mind blown at being able to observe the motion of these massive objects from such a distance.

The VLT was also able to track the motion of one of these stars and confirm for the first time a prediction made by Einstein’s theory of general relativity.

New infrared observations from the exquisitely sensitive GRAVITY, SINFONI and NACO instruments on ESO’s Very Large Telescope (VLT) have now allowed astronomers to follow one of these stars, called S2, as it passed very close to the black hole during May 2018. At the closest point this star was at a distance of less than 20 billion kilometres from the black hole and moving at a speed in excess of 25 million kilometres per hour — almost three percent of the speed of light.

S2 has the mass of about 15 suns. That’s 6.6 × 10^31 pounds moving at 3% of the speed of light. Wowowow.