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Ask a NASA astronomer! Is there proof that the Earth is round?
We've known for 2,000 years that the Earth is round. Here are three observable proofs that can instantly debunk flat-Earth theory.
Dr. Michelle Thaller is an astronomer who studies binary stars and the life cycles of stars. She is Assistant Director of Science Communication at NASA. She went to college at Harvard University, completed a post-doctoral research fellowship at the California Institute of Technology (Caltech) in Pasadena, Calif. then started working for the Jet Propulsion Laboratory's (JPL) Spitzer Space Telescope. After a hugely successful mission, she moved on to NASA's Goddard Space Flight Center (GSFC), in the Washington D.C. area. In her off-hours often puts on about 30lbs of Elizabethan garb and performs intricate Renaissance dances. For more information, visit NASA.
Michelle Thaller: So, Oscar, you asked the question, “What are some of the easiest ways that you can prove that the Earth is round?” Because apparently, this is something that we’re debating—I have no idea why.
That’s a hard thing for me to even start talking about because there are so many proofs that the Earth is round, it’s difficult to know where to start. And it’s not okay to think that the Earth is flat. This is not a viable argument.
I have friends who have been on the International Space Station, they have orbited the Earth once every 90 minutes; I've had personal experience with people who have been up in space and can see with their own eyes that the Earth is round. And of course, we‘ve taken all of these amazing pictures from space; they’re so beautiful, all those pictures of the Earth.
So I don’t really know what’s going on right now with this 'Earth is flat' thing, but I will tell you that this is one of the things I really enjoyed teaching my own astronomy class about because there are proofs all around you. It is not difficult to know that the Earth is round. In fact, people have known of this for way more than 2,000 years. The ancient Greeks actually had a number of really elegant, wonderful proofs that the earth was a sphere.
So let’s start from the simple to the slightly more complicated. One of the things you can see yourself, with a pair of binoculars, is if you actually go out to a lake and there are boats on that lake, the farther away a boat is the more the bottom of the boat will disappear, and you’ll basically just see the mast of the boat. And as a boat goes farther and farther away the last thing you will see is the very top of the mast of that boat, and that’s because the boat is actually going over the horizon that’s curved—and that means that as it goes farther and farther away you see less and less of the bottom of it, and more of the top of that. You can see that with binoculars by an ocean, by a lake, it’s really easy. That wouldn’t happen if the Earth were flat—you would simply see the boat getting smaller and smaller and smaller as it went farther away, but you’d be able to see the whole thing with the same proportions.
Now, another way that you can tell that we’re on a sphere is to think about how there’s something called the tropics on the Earth, and the tropics are places near the equator of the earth were sometimes the sun is overhead in the sky. This was actually something that the Greeks used, not only to prove that the Earth was round about 2000 years ago, but they actually measured the circumference of the Earth, accurate to within just a couple percent. 2,000 years ago we’ve known that the Earth was round.
There was a really brilliant Greek scientist called Eratosthenes, and Eratosthenes noticed that there was a town called Syene, and on a certain date the sun would actually shine straight down to the bottom of a well. That meant the sun was directly overhead; you could look down a well and see the sun shining back at you.
And on the very same date, farther away in the city of Alexandria, that didn’t happen. The sun was not directly overhead, it was a slight angle, and all that Eratosthenes did was he measured the difference in the angle of the sun. It was straight overhead in Syene; in Alexandria it was a little bit less than overhead, and he rationed that that change in angle from one city to another was probably indicative of us being on a curved surface, and you could make all kinds of measurements even between those two cities and see that the angles were different—the sun was at a different place in the sky. Using this, he actually measured the circumference of the Earth, and he got it right 2,000 years ago.
So another really simple proof is that on any given date, at different cities and different places around the world, the sun is at different angles in the sky. That wouldn’t happen if the Earth wasn’t round.
Then there are some other proofs that are a little more obscure, but they’re actually really lovely. One is to observe what happens during a lunar eclipse. Now, a lunar eclipse happens when the Earth casts a shadow on the moon. The moon actually goes dark, in fact, if you’ve seen one you can actually see the Earth’s shadow go across the moon, and when the moon is entirely in the Earth’s shadow the moon looks kind of dark and even kind of red-colored; it’s really, really beautiful.
What’s happening, in that case, is that the sun is on one side of the Earth—the Earth is in the middle—and the Earth is casting a shadow on the moon, and as the shadow moves across the moon you’ll notice that the shadow is curved, it’s round.
And so something like the sun that’s bigger than the Earth and is able to cast a shadow of the Earth on the moon can actually show you the shape of the Earth. “Ah-ha!” you might say, “but could the Earth to be a disk? Could it be flat but it’s actually still shaped like a disk, not like a sphere?”
There was a Greek scientist called Aristarchus and what he noticed was that you can get a lunar eclipse at many different angles where the sun is; sometimes the shadow goes straight across the moon, sometimes it just kind of glances the moon—just a little bit is in shadow just on the top or on the bottom. From every different vantage point, every different angle the sun is casting a shadow, you always get a perfectly curved shadow. The only shape that can cast a shadow that’s curved from any direction you put the light is a sphere.
So people have known that the Earth is spherical for thousands of years. It’s not okay to say that the Earth is flat. This is some sort of strange denial, I don’t know where it comes from, and it’s something where I keep getting this question. We really need to put this question to bed because we’ve known the Earth is a sphere for a long time.
There’s even some well-meaning people who say, “I don’t really believe the Earth is flat, but I’m not really sure what to think about it.” And they’ve asked me some interesting questions, like they’ve heard that space is a very hot, that when you go up above the atmosphere the temperature of space is millions of degrees, which is true. The problem is there’s basically no air at all. So the gas right around the Earth is actually millions of degrees hot. That’s actually true, but there’s almost none of it, there’s almost nothing. Like one single proton whizzes by you at a temperature of a million degrees, it’s not the same as temperature in the air, it’s not the same thing at all. So that's one that I get sometimes.
And the other one is—I actually said this to somebody, and I couldn’t believe they had never thought of it—that with binoculars you can see planets, you can see Saturn and Jupiter, you can see Mars with a telescope, the sun and the moon, everything else you see in the solar system is a sphere. So we’re the one thing that is different? And that actually made somebody who was more interested in actually hearing information, that actually got them to think. They were like, “You’re right… everything else we take a picture of is a sphere!”
Hey flat Earthers, it's time to put your theory to bed once and for all! A curious stargazer by the name of Oscar has submitted a question to Big Think's 'Ask an astronomer' series with NASA's Michelle Thaller. Oscar wants to know: "What would be the easiest proof that the Earth isn’t flat, that I could come back with whenever I get challenged on this issue?" Thaller sets the record straight. "There are so many proofs that the Earth is round, it’s difficult to know where to start. And it’s not okay to think that the Earth is flat; this is not a viable argument," she says. The ancient Greeks figured out we were living on a sphere over 2,000 years ago, and there are things you can do to prove that the Earth is indeed round—just go to a body of water and look at ships or boats on the horizon with binoculars. Thaller explains three observable proofs that instantly debunk flat-Earth theory with irrefutable evidence of the Earth's round, curvaceous, gloriously spherical shape. You can follow Michelle Thaller on Twitter at @mlthaller.
Ready to see the future? Nanotronics CEO Matthew Putman talks innovation and the solutions that are right under our noses.
Innovation in manufacturing has crawled since the 1950s. That's about to speed up.
A clever new study definitively measures how long it takes for quantum particles to pass through a barrier.
- Quantum particles can tunnel through seemingly impassable barriers, popping up on the other side.
- Quantum tunneling is not a new discovery, but there's a lot that's unknown about it.
- By super-cooling rubidium particles, researchers use their spinning as a magnetic timer.
When it comes to weird behavior, there's nothing quite like the quantum world. On top of that world-class head scratcher entanglement, there's also quantum tunneling — the mysterious process in which particles somehow find their way through what should be impenetrable barriers.
Exactly why or even how quantum tunneling happens is unknown: Do particles just pop over to the other side instantaneously in the same way entangled particles interact? Or do they progressively tunnel through? Previous research has been conflicting.
That quantum tunneling occurs has not been a matter of debate since it was discovered in the 1920s. When IBM famously wrote their name on a nickel substrate using 35 xenon atoms, they used a scanning tunneling microscope to see what they were doing. And tunnel diodes are fast-switching semiconductors that derive their negative resistance from quantum tunneling.
Nonetheless, "Quantum tunneling is one of the most puzzling of quantum phenomena," says Aephraim Steinberg of the Quantum Information Science Program at Canadian Institute for Advanced Research in Toronto to Live Science. Speaking with Scientific American he explains, "It's as though the particle dug a tunnel under the hill and appeared on the other."
Steinberg is a co-author of a study just published in the journal Nature that presents a series of clever experiments that allowed researchers to measure the amount of time it takes tunneling particles to find their way through a barrier. "And it is fantastic that we're now able to actually study it in this way."
Frozen rubidium atoms
Image source: Viktoriia Debopre/Shutterstock/Big Think
One of the difficulties in ascertaining the time it takes for tunneling to occur is knowing precisely when it's begun and when it's finished. The authors of the new study solved this by devising a system based on particles' precession.
Subatomic particles all have magnetic qualities, and they spin, or "precess," like a top when they encounter an external magnetic field. With this in mind, the authors of the study decided to construct a barrier with a magnetic field, causing any particles passing through it to precess as they did so. They wouldn't precess before entering the field or after, so by observing and timing the duration of the particles' precession, the researchers could definitively identify the length of time it took them to tunnel through the barrier.
To construct their barrier, the scientists cooled about 8,000 rubidium atoms to a billionth of a degree above absolute zero. In this state, they form a Bose-Einstein condensate, AKA the fifth-known form of matter. When in this state, atoms slow down and can be clumped together rather than flying around independently at high speeds. (We've written before about a Bose-Einstein experiment in space.)
Using a laser, the researchers pusehd about 2,000 rubidium atoms together in a barrier about 1.3 micrometers thick, endowing it with a pseudo-magnetic field. Compared to a single rubidium atom, this is a very thick wall, comparable to a half a mile deep if you yourself were a foot thick.
With the wall prepared, a second laser nudged individual rubidium atoms toward it. Most of the atoms simply bounced off the barrier, but about 3% of them went right through as hoped. Precise measurement of their precession produced the result: It took them 0.61 milliseconds to get through.
Reactions to the study
Scientists not involved in the research find its results compelling.
"This is a beautiful experiment," according to Igor Litvinyuk of Griffith University in Australia. "Just to do it is a heroic effort." Drew Alton of Augustana University, in South Dakota tells Live Science, "The experiment is a breathtaking technical achievement."
What makes the researchers' results so exceptional is their unambiguity. Says Chad Orzel at Union College in New York, "Their experiment is ingeniously constructed to make it difficult to interpret as anything other than what they say." He calls the research, "one of the best examples you'll see of a thought experiment made real." Litvinyuk agrees: "I see no holes in this."
As for the researchers themselves, enhancements to their experimental apparatus are underway to help them learn more. "We're working on a new measurement where we make the barrier thicker," Steinberg said. In addition, there's also the interesting question of whether or not that 0.61-millisecond trip occurs at a steady rate: "It will be very interesting to see if the atoms' speed is constant or not."
So far, 30 student teams have entered the Indy Autonomous Challenge, scheduled for October 2021.
- The Indy Autonomous Challenge will task student teams with developing self-driving software for race cars.
- The competition requires cars to complete 20 laps within 25 minutes, meaning cars would need to average about 110 mph.
- The organizers say they hope to advance the field of driverless cars and "inspire the next generation of STEM talent."
Indy Autonomous Challenge<p>Completing the race in 25 minutes means the cars will need to average about 110 miles per hour. So, while the race may end up being a bit slower than a typical Indy 500 competition, in which winners average speeds of over 160 mph, it's still set to be the fastest autonomous race featuring full-size cars.</p><p style="margin-left: 20px;">"There is no human redundancy there," Matt Peak, managing director for Energy Systems Network, a nonprofit that develops technology for the automation and energy sectors, told the <a href="https://www.post-gazette.com/business/tech-news/2020/06/01/Indy-Autonomous-Challenge-Indy-500-Indianapolis-Motor-Speedway-Ansys-Aptiv-self-driving-cars/stories/202005280137" target="_blank">Pittsburgh Post-Gazette</a>. "Either your car makes this happen or smash into the wall you go."</p>
Illustration of the Indy Autonomous Challenge
Indy Autonomous Challenge<p>The Indy Autonomous Challenge <a href="https://www.indyautonomouschallenge.com/rules" target="_blank">describes</a> itself as a "past-the-post" competition, which "refers to a binary, objective, measurable performance rather than a subjective evaluation, judgement, or recognition."</p><p>This competition design was inspired by the 2004 DARPA Grand Challenge, which tasked teams with developing driverless cars and sending them along a 150-mile route in Southern California for a chance to win $1 million. But that prize went unclaimed, because within a few hours after starting, all the vehicles had suffered some kind of critical failure.</p>
Indianapolis Motor Speedway
Indy Autonomous Challenge<p>One factor that could prevent a similar outcome in the upcoming race is the ability to test-run cars on a virtual racetrack. The simulation software company Ansys Inc. has already developed a model of the Indianapolis Motor Speedway on which teams will test their algorithms as part of a series of qualifying rounds.</p><p style="margin-left: 20px;">"We can create, with physics, multiple real-life scenarios that are reflective of the real world," Ansys President Ajei Gopal told <a href="https://www.wsj.com/articles/autonomous-vehicles-to-race-at-indianapolis-motor-speedway-11595237401?mod=e2tw" target="_blank">The Wall Street Journal</a>. "We can use that to train the AI, so it starts to come up to speed."</p><p>Still, the race could reveal that self-driving cars aren't quite ready to race at speeds of over 110 mph. After all, regular self-driving cars already face enough logistical and technical roadblocks, including <a href="https://www.bbc.com/news/technology-53349313#:~:text=Tesla%20will%20be%20able%20to,no%20driver%20input%2C%20he%20said." target="_blank">crumbling infrastructure, communication issues</a> and the <a href="https://bigthink.com/paul-ratner/would-you-ride-in-a-car-thats-programmed-to-kill-you" target="_self">fateful moral decisions driverless cars will have to make in split seconds</a>.</p>But the Indy Autonomous Challenge <a href="https://static1.squarespace.com/static/5da73021d0636f4ec706fa0a/t/5dc0680c41954d4ef41ec2b2/1572890638793/Indy+Autonomous+Challenge+Ruleset+-+v5NOV2019+%282%29.pdf" target="_blank">says</a> its main goal is to advance the industry, by challenging "students around the world to imagine, invent, and prove a new generation of automated vehicle (AV) software and inspire the next generation of STEM talent."
Health officials in China reported that a man was infected with bubonic plague, the infectious disease that caused the Black Death.
- The case was reported in the city of Bayannur, which has issued a level-three plague prevention warning.
- Modern antibiotics can effectively treat bubonic plague, which spreads mainly by fleas.
- Chinese health officials are also monitoring a newly discovered type of swine flu that has the potential to develop into a pandemic virus.
Bacteria under microscope
needpix.com<p>Today, bubonic plague can be treated effectively with antibiotics.</p><p style="margin-left: 20px;">"Unlike in the 14th century, we now have an understanding of how this disease is transmitted," Dr. Shanthi Kappagoda, an infectious disease physician at Stanford Health Care, told <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">Healthline</a>. "We know how to prevent it — avoid handling sick or dead animals in areas where there is transmission. We are also able to treat patients who are infected with effective antibiotics, and can give antibiotics to people who may have been exposed to the bacteria [and] prevent them [from] getting sick."</p>
This plague patient is displaying a swollen, ruptured inguinal lymph node, or buboe.
Centers for Disease Control and Prevention<p>Still, hundreds of people develop bubonic plague every year. In the U.S., a handful of cases occur annually, particularly in New Mexico, Arizona and Colorado, <a href="https://www.cdc.gov/plague/faq/index.html" target="_blank">where habitats allow the bacteria to spread more easily among wild rodent populations</a>. But these cases are very rare, mainly because you need to be in close contact with rodents in order to get infected. And though plague can spread from human to human, this <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">only occurs with pneumonic plague</a>, and transmission is also rare.</p>
A new swine flu in China<p>Last week, researchers in China also reported another public health concern: a new virus that has "all the essential hallmarks" of a pandemic virus.<br></p><p>In a paper published in the <a href="https://www.pnas.org/content/early/2020/06/23/1921186117" target="_blank">Proceedings of the National Academy of Sciences</a>, researchers say the virus was discovered in pigs in China, and it descended from the H1N1 virus, commonly called "swine flu." That virus was able to transmit from human to human, and it killed an estimated 151,700 to 575,400 people worldwide from 2009 to 2010, according to the Centers for Disease Control and Prevention.</p>There's no evidence showing that the new virus can spread from person to person. But the researchers did find that 10 percent of swine workers had been infected by the virus, called G4 reassortant EA H1N1. This level of infectivity raises concerns, because it "greatly enhances the opportunity for virus adaptation in humans and raises concerns for the possible generation of pandemic viruses," the researchers wrote.
A new Harvard study finds that the language you use affects patient outcome.
- A study at Harvard's McLean Hospital claims that using the language of chemical imbalances worsens patient outcomes.
- Though psychiatry has largely abandoned DSM categories, professor Joseph E Davis writes that the field continues to strive for a "brain-based diagnostic system."
- Chemical explanations of mental health appear to benefit pharmaceutical companies far more than patients.
Challenging the Chemical Imbalance Theory of Mental Disorders: Robert Whitaker, Journalist<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="41699c8c2cb2aee9271a36646e0bee7d"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/-8BDC7i8Yyw?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>This is a far cry from Howard Rusk's 1947 NY Times editorial calling for mental healt</p><p>h disorders to be treated similarly to physical disease (such as diabetes and cancer). This mindset—not attributable to Rusk alone; he was merely relaying the psychiatric currency of the time—has dominated the field for decades: mental anguish is a genetic and/or chemical-deficiency disorder that must be treated pharmacologically.</p><p>Even as psychiatry untethered from DSM categories, the field still used chemistry to validate its existence. Psychotherapy, arguably the most efficient means for managing much of our anxiety and depression, is time- and labor-intensive. Counseling requires an empathetic and wizened ear to guide the patient to do the work. Ingesting a pill to do that work for you is more seductive, and easier. As Davis writes, even though the industry abandoned the DSM, it continues to strive for a "brain-based diagnostic system." </p><p>That language has infiltrated public consciousness. The team at McLean surveyed 279 patients seeking acute treatment for depression. As they note, the causes of psychological distress have constantly shifted over the millennia: humoral imbalance in the ancient world; spiritual possession in medieval times; early childhood experiences around the time of Freud; maladaptive thought patterns dominant in the latter half of last century. While the team found that psychosocial explanations remain popular, biogenetic explanations (such as the chemical imbalance theory) are becoming more prominent. </p><p>Interestingly, the 80 people Davis interviewed for his book predominantly relied on biogenetic explanations. Instead of doctors diagnosing patients, as you might expect, they increasingly serve to confirm what patients come in suspecting. Patients arrive at medical offices confident in their self-diagnoses. They believe a pill is the best course of treatment, largely because they saw an advertisement or listened to a friend. Doctors too often oblige without further curiosity as to the reasons for their distress. </p>
Image: Illustration Forest / Shutterstock<p>While medicalizing mental health softens the stigma of depression—if a disorder is inheritable, it was never really your fault—it also disempowers the patient. The team at McLean writes,</p><p style="margin-left: 20px;">"More recent studies indicate that participants who are told that their depression is caused by a chemical imbalance or genetic abnormality expect to have depression for a longer period, report more depressive symptoms, and feel they have less control over their negative emotions."</p><p>Davis points out the language used by direct-to-consumer advertising prevalent in America. Doctors, media, and advertising agencies converge around common messages, such as everyday blues is a "real medical condition," everyone is susceptible to clinical depression, and drugs correct underlying somatic conditions that you never consciously control. He continues,</p><p style="margin-left: 20px;">"Your inner life and evaluative stance are of marginal, if any, relevance; counseling or psychotherapy aimed at self-insight would serve little purpose." </p><p>The McLean team discovered a similar phenomenon: patients expect little from psychotherapy and a lot from pills. When depression is treated as the result of an internal and immutable essence instead of environmental conditions, behavioral changes are not expected to make much difference. Chemistry rules the popular imagination.</p>