|Sun and Earth
Title text: But we don't need to worry about the boiling masses sandwiching the thin layer in which we live, since we're so fragile and short-lived that it's unlikely to kill us before something else does! Wait, why doesn't that sound reassuring?
This is one of a number of comics which describe everyday events in unusual terms, making them sound really weird. In this case, both the Sun and the Earth are "massive convective systems [blasting] huge plumes of heat", which contrasts sharply with the daily idea of the Sun being a ball in the sky and the Earth the thing under our feet.
Free convection is based on an difference in density. What is colder is typically denser, so gravity forces it downwards, displacing what is hotter (and less dense) upward (This should not be confused with forced convection, which uses fans or other devices that are not practical to build on the scale of a planet). In the sun, most of the energy to drive this process comes from nuclear fusion, specifically the fusion of hydrogen into helium. We cannot directly see inside of the earth, but its core is known to be much hotter than its surface.
The magnitude of these systems gives you an idea of the size of the fluctuations you can expect. The sun is very massive, meaning the fluctuations in its convective or heat-dissipating behavior are very large. This is an instance of the Fluctuation-Dissipation theorem. These fluctuations take the form of a solar flare, as explained below. For a more thorough (but non-technical) explanation of the role of gravity and entropy in such systems, see this.
The Sun produces great amounts of light and heat and blasts it towards us, which is why we can live on Earth. Since Ludwig Boltzmann pointed out the fact in 1875, people have been working on establishing exactly how such far from equilibrium systems as life might depend upon, or be formed by (like this article), such massive entropy gradients as between the sun and earth (or rather the sun and empty space). Main sequence stars like the sun transport energy by radiation and by convective currents of plasma, bringing the heat generated in the core of the sun to its surface. These quickly moving charged particles create a massive magnetic field, which occasionally gets concentrated into a solar prominence which can snap, causing a large amount of charged particles to get shot into space as a solar flare. If the Earth happens to be in the direction of the solar flare, we can notice all sorts of interesting and often damaging effects. Thankfully, there are lots of other directions for the sun to shoot solar flares, so they don't come by the Earth that often.
The Earth's interior is also very hot. Mantle convection causes plate tectonics which is the main cause of volcanic activity (next to mantle plumes), which essentially also consists of huge blasts of heat.
This could sound like a very bad scenario, but the title text reminds us that the real scenario we live in is far worse, as we are not likely to die from a Sun blast or volcano eruption. In doing this, he indirectly points out the hard truth about our lives: that they're limited and they're short, and it is far easier to die of because of other things. In this way Randall attempts to give the reader an existential crisis; he concludes that his statement did not help to reassure himself.
This comic was likely inspired by the recent eruptions of the Kīlauea and Volcán de Fuego. In contrast, solar activity is currently low, because the sunspot solar cycle is in the low end of the 11-year cycle.
- [The entire comic is within a panel. At the bottom of the image a curved shape depicting a small part of the Earth's surface and labeled as "Earth" is shown. At the top a similar sized shape but opposite curve is labeled as "Sun". The surface of the Sun is seething while on Earth's surface a few plants, two birds, and Cueball together with Megan are visible.]
- [Two arrows pointing to the Sun and the Earth with a caption applying to both of them:]
- Massive convective systems which occasionally blast huge plumes of heat at us without warning through mechanisms we can't directly observe and don't really understand.
- Cueball: What a nice day!
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There seems to be a glitch with the bar at the top (the one with the previous comic button and so on), it displays in a messed up way. Is this just something with my browser, or have other people been seeing this too? VannaWho (talk)
- I'm using K-Meleon76 in Win7x64 (in a non-Admin account), it looks good to me. It does help to sign with 4 tildes, it does this for you: 18.104.22.168 11:31, 8 June 2018 (UTC)
- Thanks IP, by using the 4 tildes OR the sign button at the top also a timestamp will be shown.
- VannaWho: What is messed up? What happens? And what browser do you use? I also can't see any problems. --Dgbrt (talk) 12:19, 8 June 2018 (UTC)
- I'm on Google Chrome from my phone, and the bar has a little extra bit above it. It's hard to explain, is there a way to attach a screenshot? --VannaWho (talk) 06:31, 10 June 2018 (UTC)
- Thanks for your complaint. I can see it now and it also happens by using Google Chrome on a desktop when reducing the size of the browser window. Firefox doesn't look better. It's now on my ToDo list and I'm looking forward to implement a mobile version in the future. Stay tuned... --Dgbrt (talk) 18:11, 10 June 2018 (UTC)
- Probably the only effective way to share a screenshot is to sign up for an image sharing site like Imgur, Flikr or Photobucket, put it there, then include a link to the image here. NiceGuy1 (talk) 06:07, 12 June 2018 (UTC)
- It looks fine now. VannaWho (talk) 06:55, 13 June 2018 (UTC)
The current explanation suggests that solar flares and volcanic eruptions are always quite benign. My interpretation of this comic, when I read it, was that volcanic eruptions can indeed be very deadly and potentially kill most humans (supervolcano, mini ice age... etc). But they are indeed rare enough that all humans currently alive and many generations to come are pretty safe from that risk.
Not sure if a solar eruption could actually threaten humanity, beyond damaging our satellites. 22.214.171.124 (talk) (please sign your comments with ~~~~)
- A huge Coronal mass ejection, like the Solar storm of 1859 that took down parts of the recently created US telegraph network, if occurring today would cause widespread disruptions and damage to a modern and technology-dependent society. It could simply melt down the transformers that distribute all electricity on Earth, potentially leaving us without electricity... Like no one has electricity. This would not be something we could fix, since the transformers are melted down. So yes mass starvation could occur when all refrigerators stop working. So potentially as lethal as a super volcano on the short term... Of course we can do absolutely nothing about this. Just like with super volcanoes. Only thing we are sure of is that both events will happen again sometime. Have a nice day ;-)  --Kynde (talk) 13:10, 8 June 2018 (UTC)
- The problems with the burgeoning North American telegraph network were because the wires covered such a great distances. In forthcoming geomagnetic events it will be similar processes causing problems. I'm curious though, we have lightning arresters on transmission lines for literally breaking the circuit when the voltage is too high, is there nothing similar that would prevent damage from a solar storm? 126.96.36.199 14:33, 8 June 2018 (UTC)
- Important to point out that only connected components are damaged in such an event (likewise with EMPs); Spare parts sitting insulated in boxes are unaffected. Also, yes, there are a lot more safeties in place now. Nothing short of our practical extinction will leave all technology inoperable, much less irreparable. It is urban legend that an EMP or solar flare of anything less than "burn everything within 100ft of the surface" would do more than temporary damage, & if that happened we'd have much bigger concerns, like our own biological nervous systems failing, & most of the biosphere dying immediately. Things far underground, airgapped from any long conductors near the surface would be fine. ProphetZarquon (talk) 19:40, 8 June 2018 (UTC)
After the major blackout of the Eastern US Coast, the connections between electrical stations were redesigned so that overloads would not cascade. A similar change was made to long distance land telephone centers when an incorrect update brought down telephone service. The Dining Logician (talk) 15:13, 8 June 2018 (UTC)
I feel like the fact that without Earth's own magnetic field, which is generated by processes related to Earth being massive convecting system, protecting us from solar flares, the damage from them would be much worse, should be noted. Wait. Once again: I feel that following fact should be noted: The damage from solar flares would be much worse if we wouldn't be protected by Earth's own magnetic field, which is generated by processes related to Earth being massive convecting system. -- Hkmaly (talk) 05:04, 9 June 2018 (UTC)
And so Randall's solution is to extinguish the sun... thus creating a safer world free from the threat of solar flares! Herobrine (talk) 03:12, 10 June 2018 (UTC)
- New Misc Points (3 of them)
1) We should not, as the current explanation does, say that the particles gain energy. The Law of Conservation of Energy strictly demands that we say, instead, that they convert gravitational potential energy into kinetic energy, but only as much as the resulting pressure, resisting gravitational collapse, allows.
2) I know that the Sun, as a star, is powered by gravitational collapse. (Massy bodies, really? Why not "Huge, and therefore heavy, cloud of gas"?) I have never heard of the Earth's core being powered by gravitational collapse, obvious on hindsight as it may appear. It would also imply that Earth's radius is decreasing (measurable/measured?). Some citation to geophysical articles saying the same would be very much appreciated.
3) I thought that a different enjoyment of the jokes in this comic, should be mentioned. It looks very much, in the comic, like the Sun and the Earth are heating elements sandwiching humans and the Earth's atmosphere within. Global warming aside, this is funny because it feels like we are in an oven of sorts, though we actually are not being cooked. For food, for one non-reason. 188.8.131.52 (talk) (please sign your comments with ~~~~)
- Yes that was my thought, that the drawing is suggestive of a hamburger inside a toasted bun viewed from the side. Rtanenbaum (talk) 13:39, 11 June 2018 (UTC)
- To say that particles "gain energy" is not incorrect. It is verbal shorthand for "gain kinetic energy". Everyone knows what you mean. The sun is not powered by gravitational collapse. As the article says, it's powered by nuclear fusion. The energy to trigger the fusion came from gravitational potential being converted to thermal, but the actual radiated energy comes from fusion. Nitpicking (talk) 11:50, 15 July 2022 (UTC)
The second and third paragraphs as written are completely wrong.
It take much more than a energy gradient to result in convection - both gravity and different density regions in the medium must be present - generally convective system are in media that become less dense at higher temperatures, and are heated in the region of lower gravitational potential. The media expands as it heats becoming less dense then rises against gravity as cooler higher density media flows to replace it. Since the two flows can not occur simultaneously in the same location, generally the flow self organizes into cells or adjacent regions of counter flow.
Neither the sun which is a main sequence star in its stable Hydrogen burning phase nor the Earth are appreciably heated by gravitational collapse. For the sun gravity does provide the pressures needed for, and contains, the resulting fusion processes that do provide the energy released by the sun. The Earth core is heated by the decay of radioactive elements and the energy released is in very near equilibrium with the energy lost to the surface and ultimately radiated away along with the energy received from external sources (overwhelmingly from the sun). This has resulted in a stable internal temperature profile and surprisingly stable surface temperatures with in a very few degrees (<15C) for billions of years.184.108.40.206 17:17, 9 June 2018 (UTC)
- Someone ought to do a 'citation needed' joke about the Earth being hot --220.127.116.11 01:30, 11 June 2018 (UTC)