ASM122 A Total Eclipse of the Sun

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we interrupt your regularly scheduled podcast for a total eclipse of the sun [Music] welcome to ask science mike the once again weekly podcast where i answer your questions about science faith in life this week is all about the total solar eclipse happening in the united states august 21st 2017 because you've asked me so many questions about it so what do you say let's get eclipsey and get it started okay two super cool announcements right at the top the first one is uh you know just the normal one i do every show reminding you of events uh the liturgist gathering is happening in los angeles september 15th october 6th in boston and october 27th in seattle washington and uh seattle is just about sold out so you should go ahead and get tickets if you're thinking about it boston looks like it's probably going to sell out la is is lagging behind pretty significantly which is funny to me since la is our biggest download market by far but you know in la people they'll buy tickets and not show up because they found a great taco stand and everybody's kind of commit phobic so they're not sure if they want to book tickets this far out so i'm hoping we'll get more la ticket sales as the event gets closer to happening uh but anyway the largest gathering it's an amazing experience we're going to get together we can do a podcast live we're going to do some weird strange innovative compelling worship experiences we're going to talk you're going to meet other listeners the liturgist podcast tons of fun love to see you there for my friends in the united kingdom and the republic of ireland i'll be headed your way in october for an ask science mike live tour happening in london and birmingham and edinburgh so i'll also be at the rubicon conference in dublin ireland so you can learn more about all those events at asksciencemike.com just click on the events tab to learn more the second and genuinely super cool announcement this week is i get a lot of bible questions on the show and i don't always feel qualified to answer them quite frankly because you ask me really difficult questions about historical interpretations about archaeological evidence all kinds of things that i can look up and i read a lot about but i don't know nearly as well as i know just general sciency stuff and so recently we did a show called ask biologos where some scientists from biologos came on the show and answer your questions about evolution and i wanted to do something like that again only this time the dr peter inns is going to answer your bible questions on this show so if you have a question about the bible you'd like pete ends to address just use hashtag ask bible pete on twitter or when you send in a recorded question or a written question on asksciencemike.com just include ask bible pete in your question and we'll consider it for that episode when will that episode be when you send in enough questions for me to send uh some to the patrons for selection and then on to pete himself for the show so again ask bible pete i wonder if i can convince jeb to record an ask bible pete version of the theme song that would be super fun uh that's all the announcements i've got so let's go to our special edition eclipse show okay so there's quite a backlog of questions on the program since i've been moving across the country and doing these kind of weird episodes and i had planned to just do a normal show this week with a poll and everything but uh then i noticed that my social media timeline and the ask science mic inbox is just clogged with questions about eclipses and specifically the solar eclipse that's happening across the continental united states august 21st 2017 so i thought it would be fun to do a show just about eclipses and the most logical question to start with so that we understand clearly is like what is an eclipse well the sun is the origin of light in our solar system by far the most powerful source of illumination and things that have light cast on them cast shadows behind them and so an eclipse is when because of their alignment one celestial body falls into the shadow of another okay when we have eclipses they can be different kinds of eclipses you can have a lunar eclipse or you can have a solar eclipse now those are kind of strange names they both involve the sun and the moon it's a matter of who is being shadowed so in a lunar eclipse the moon passes into the earth's shadow and when we have a solar eclipse the earth passes into the moon's shadow okay that may not make a lot of sense on a podcast but the internet will have lots of pictures if you google that you'll understand it pretty much instantly obviously lunar eclipses make a lot of sense because we have this big giant planet and a smaller moon and so sometimes the moon goes behind our planet and it goes dark and sometimes turns red because our atmosphere is great at scattering blue light but red light passes through our atmosphere pretty easily and so uh the sun's light as it bends around the earth makes it to the moon and the moon turns red in the most dramatic lunar eclipses and we have those quite often actually but solar eclipses are more rare and we'll talk about why in just a minute but first let's talk about why they work at all because an odd thing is that a solar eclipse happens all the moon is so much smaller than the sun about 400 times smaller than the sun so if you would imagine you know taking a let's say a grape and holding it in front of a bowling ball it's ridiculous like a grape wouldn't block out a bowling ball unless the grape was very close to your eye where the bowling bar was very far away and that's exactly what happens here even though the sun is like 400 times bigger than the moon it's also about 400 times farther away so by total coincidence the sun and the moon appear about the same size in the night sky there's basically four types of solar eclipses when you have a total solar eclipse this is when the sun gets blocked out completely by the moon but you can also have an annular eclipse and this is when the moon goes in front of the sun but you can still see the sun around it and this happens because the moon's orbit is ecliptical it's not a circle it's a it's more of an oval so its distance from the earth changes and that's enough to change the apparent size of the moon compared to the sun so when you have an annular eclipse you don't get a total eclipse you don't for example see the corona of the sun in a dramatic fashion okay you can have a hybrid eclipse which is a mix of an annular and total eclipse and they are comparatively rare and then you have a partial eclipse and that's just where the moon passes before the sun but you still see a lot of the sun and depending on where you are in the united states you will either see a total eclipse of the sun a total eclipse of the heart anyway uh or you will see a partial eclipse and we'll talk a little bit more about that in a second and why so obviously total solar eclipses are the most dramatic and also some of the most rare you know we have solar and lunar eclipses every year so why is this a big deal uh well first of all you're way more likely to see a lunar eclipse because they're visible everywhere it's night during the eclipse and the totality the period where the earth is completely or the moon is completely in the earth's shadow lasts hours but solar eclipses are only visible on small paths across the earth's surface and the totality of those events only lasts a few minutes and that's why people are so excited about the eclipse happening on august 21st because this path of totality just tracks across the entire continental united states and in fact some degree of solar eclipse will be visible everywhere in the united states assuming you don't have cloud cover and that's a real bummer some people are going to miss this event because of clouds now you may you may ask the moon orbits the earth every single month so why don't we have an eclipse every month wouldn't wouldn't the the moon pass into the earth's shadow like every 29 and a half days and wouldn't the sun fall into the moon's shadow every 29 and a half days well you would think that except for one little tweak the moon's orbit is tilted right about five degrees when compared to the earth okay so that that tilt's not much but it's enough that most of the time things don't line up well enough to cause an eclipse now because of that tilt there's you've got two intersecting planes basically um and with a with a an ellipse circumscribing one of the planes uh so that means there's two nodes there's two points where the moon's orbit lines up with the earth orbit around the sun and that means we have a handful of lunar and solar eclipses every year but the total eclipses are more rare especially total solar eclipses and solar eclipses as i've said because of the orbital mechanics they don't last very long and they're not visible um broadly um it's it's quite rare that something like a big populous nation like north america all gets to see an eclipse at the same time kind of a once in a lifetime thing and so that's why this is so exciting now you might ask like what will i see and what you see depends on where you are in the united states now i'll have a link to a map on ask sciencemike.com provided by nasa that will help you understand what the eclipse will be like in your area if you're in most of the united states you'll see a partial solar eclipse you'll see a dark disc obscure part of the sun and it will be cool it will be cool a partial solar eclipse is cool but if you uh are in the path of the total solar eclipse and this is a path that begins in oregon and it's a line that kind of comes across the entire united states diagonally from oregon to south carolina a 70 mile wide path of totality you'll see a total solar eclipse so it'll begin as a partial solar eclipse like everyone else sees but then there will be a moment and last depending on where you are from you know maybe a minute 45 to maybe two and a half minutes where uh the sun is completely blocked by the moon and you'll see the sun's corona appear around the moon i've never seen this i've seen video of it but i've never seen it myself i've heard this is a quite dramatic sight in fact one of the most beautiful and dramatic things you can see in astronomy so this would be worth traveling to if you're somewhere near this line i personally i'm going to travel to portland and uh hook up with some friends and we're going to drive south into the line of totality to experience the eclipse and we'll record our reactions and share them with you on a show following august 21st that's gonna be really exciting but a few things you need to know if you're going to watch the eclipse that day one we're talking about the sun here staring at the sun is bad for your eyes so you need special glasses to view the eclipse so i'll have a link to some glasses on amazon they're out of stock right now they're supposed to be in stock soon after this episode airs and so you could go place an order for some eclipse glasses that are very very very very dark lenses that allow you to safely observe the sun but it's not just your eyes that can be at risk you really don't want to point your camera or your smartphone at the eclipse because you could damage your equipment you definitely don't want to use binoculars or a telescope to view this event because you'll damage your equipment and permanently blind yourself if you have a solar telescope that's one thing but most telescopes are not designed to observe the sun and and this is really important if you're going to make a road trip out of this to see the eclipse understand that a lot of people are going to make road trips that day as well roads could be extremely congested travel could be slow and parts of the country food and fuel could become scarce so you want to be prepared basically to camp and backpack if necessary so you want to have some food supplies on you you want some fresh water and just just be safe be safe if you're going to travel into the line of totality experts are saying that some parts of the country could experience anywhere from 10 to 25 times their normal population during this event so be safe out there i will tell you from everything i've read and studied and everyone i've talked to a partial eclipse is cool but a total eclipse is raptuous it is stunning so it might if you're in good health if you can afford the time off work this this is really kind of a bucket list moment for people who are interested in the sky and astronomy and even people who aren't um i saw some footage of people watching the eclipse a few years ago in europe and you could hear people cheering and exclaiming uh you know just joy at what they saw so i'm gonna go see it if you're thinking about doing the same just be prepared and that means having a travel plan having supplies and definitely having glasses with which to observe the eclipse now an interesting thing about the glasses and we'll end the episode here if you're in the path of the total eclipse you want to keep your glasses on as you view the eclipse but once the total eclipse starts you actually want to lift your glasses and look at the sun with the naked eye and then just as soon as totality overs you want to drop the glasses back down on your eyes to protect your sight but i'm told i understand that totality is actually so dark and you'll feel you'll feel the day get cooler when totality begins it'll be quite dramatic but totality is is dim enough that you won't pick up all the details through solar glasses you'll actually need to look with the naked eye and just be careful right you don't you don't stare at the sun let your eyes be your guide um and like i say totality doesn't last very long so you want those glasses handy to pop right back down on your eyes and i think it's gonna be really cool and i'm so excited that many of you so many of you are excited as well excited enough to send in questions and i hope i've gotten all uh everything you wanted to know about the eclipse covered in the show if not uh just go ahead and tweet me or leave a comment on my facebook page and i'll try to patrol that more closely for eclipse questions in the next couple of weeks happy hunting everyone i hope no matter where you are you take some time to be outside with special glasses or a pinhole camera to view the eclipse on august 21st 2017. [Music] i want to thank my patrons on patreon for making this show possible and for frankly being so lenient as i've moved my family across the country and thanks for still helping me survive during that period we're returning the show to a normal schedule now so if you'd like to join my patrons the folks who make this show possible just go to asksciencemike.com click on the patreon button and you can learn about what the options are and how you can throw a dollar five dollars a month my way and keep this show going i deeply appreciate it i will thank andrew golucky for all of his uh pre-production work i want to of course thank greg nordin for producing mike the theme song for this show was written recorded and performed by jeb botiford thanks for listening everyone and i will talk to you next [Music] [Applause] [Music] week