Eclipse Across North America 2024

01Houston, we have a podcast.

02Welcome to the official podcast of the NASA Johnson Space Center, Episode 330, Eclipse Across North America 2024.

03I'm Gary Jordan, and I'll be introducing a new host today.

04On this podcast, we bring in the experts, scientists, engineers, and astronauts, all to let you know what's going on in the world of human spaceflight and more.

05And for this episode, I'm very excited to welcome a new voice of the podcast, Kenna Pell.

06Kenna, welcome.

07Hey, Gary.

08Thank you so much for having me.

09More than, what, 300 episodes?

10It's quite an honor to be here and to learn from you.

11Yeah, but you, I mean, you auditioned, and it was super clear that you would be an awesome voice for this.

12But you were not always at JSC, not always around here, but it was great to have you around here.

13You originally, your last job you had was over at the Kennedy Space Center.

14No, I was not always at JSC, and I absolutely love it here.

15I love Houston, but I also love where it came from, like you said, at KSC.

16They're so different, but so also the same in many ways, the NASA family, right?

17So transitioning from Kennedy Space Center over here to Johnson has been so much fun, and I'm really happy to be here.

18So in terms of your role, you work very closely with the International Space Station Program.

19Is that right?

20I do, and I love my role.

21I am, I work strategic and internal comms for the program, which is based here at Johnson Space Center, and I absolutely love it.

22Everyone knows that I love ISS.

23Yeah, and you're going to be doing some of the episodes coming up you're going to be doing have to do with ISS, so it'll be great to have you as a recurring voice on this podcast.

24Well, thanks, Gary.

25It is really cool to learn from you.

26Well, you're going to take it away for the great North American eclipse.

27Are you ready?

28Let's do it.

29All right, take it away.

30On April 8th, 2024, a total solar eclipse will cross North America, passing over Mexico, the United States, and Canada.

31This kind of eclipse is an awe-inspiring event that drastically changes how we see the two biggest objects in our sky, the sun and moon.

32While the path of totality over the United States begins here in Texas and crosses all the way up to Maine, the great news is that during this eclipse, all of the contiguous U.S.

33will be able to see at least a partial eclipse.

34We have Matt Wilkinson, a flight controller here at Johnson Space Center, joining us today to talk all things eclipse.

35Now, Matt's primary role is orbital mechanics on various consoles supporting ISS and Artemis in mission control.

36But we will get to his connection to eclipses at the beginning of the conversation.

37And here's everything you need to know about this phenomenon, how to best witness it, and the safety precautions that come with it.

38And find out why you don't want to miss out on this rare celestial event.

39Because the next time a total solar eclipse is visible from the contiguous U.S., well, let's just say it'll be a few decades.

40Let's get started.

41Matt, thanks for joining us today.

42Yeah, happy to be here.

43So one thing I love about working for the agency is there is a multitude of different jobs that everyone across, you know, the center or just the agency as a whole has.

44And I'm wondering from you, what do you do for NASA?

45But could you give us the high-level family and friends description?

46Sure thing.

47So I'm a flight controller.

48I work in mission control.

49And my area of focus is orbital mechanics and rendezvous.

50And now what is the more descriptive?

51What do you do on the day-to-day?

52Yeah.

53So we work with various partners, so SpaceX, Boeing, JAXA, and others, to make sure that their vehicles get to the ISS safely for the ISS program, and that we can safely have two vehicles meet up in lunar orbit for the Artemis missions.

54So you work both ISS and Artemis.

55I do, yeah.

56That's really exciting to see both of those.

57And what was your path to NASA?

58So when I was a kid, my family visited Johnson Space Center on a family vacation, and I was just hooked from the moment we stepped on site.

59Getting to see the Saturn V out at Rocket Park and taking the tour of mission control on the tram was really, really cool.

60So from that point, you know, I devoured everything I could find, movies, books, television.

61In high school, I did high school aerospace scholars.

62And then I did aerospace engineering in college.

63Did some internships and then got a job here.

64So orbital mechanics, working in mission control, you work ISS and Artemis.

65How does your day-to-day job apply to your understanding of solar eclipses?

66So I'm not a planetary scientist.

67Okay.

68My primary concern is where the moon is in terms of interference with our sensors.

69So my job involves a lot of orbital mechanics, and we also use a lot of vision-based sensors to track where the target vehicle that we're trying to get the chaser vehicle to meet.

70One of those sensors is called a star tracker.

71And the way it works is it looks out from the vehicle, and it sees the path of all the stars as it's flying.

72And it has a known map of the stars, and so it can go, okay, I look out, I see this pattern of stars, these constellations and things, and they match this map that I was given.

73So I know that I'm here.

74It's very similar to what sailors would do during the age of exploration.

75But the problem is the moon is super bright, and it can fool the star trackers or block out some of the light.

76So when we're planning our missions, we have to make sure that as the vehicle is flying that it's not going to be fooled by the moon passing through its field of view.

77We've seen it on console where where the moon is can trick the sensors into thinking it's the ISS because it's looking for a big shiny thing.

78We've actually seen, you know, it's tracking this thing, and then we look in our graphics, and you see the moon moving, and you're like, nope, it's tracking the moon.

79So that's primarily where my interest in, you know, lunar orbits comes from is making sure that we plan our mission so that we don't have to worry about lunar interference.

80And then, yeah, with the Artemis stuff, we really do have to make sure that we have a lit landing site.

81Thanks, Matt.

82So before we dive into some general total solar eclipse questions, I want to say for the ease of our listeners and for their sanity so they don't keep hearing me stumble over this, can we say eclipse as sort of synonymous to just saying total solar eclipse in this sense?

83Absolutely.

84Okay.

85So everyone, all our listeners, we're going to say eclipse so you don't have to hear us, or not you, Matt, me, at least stumble over saying it a couple times here.

86So first and foremost, where were you for the last solar eclipse over in America in 2017?

87So that was a work day.

88So I was actually here on site.

89And when it came time for the eclipse, several of us went outside of the mission control building and watched the eclipse there.

90Several of the folks had special telescopes with protective lenses, and so we were able to watch it that way.

91And then we also were able to see some really cool shadowing of indirect viewing by watching the light through the leaves on the trees as they cast shadows on the sidewalk.

92Where are you going to be for this year's eclipse?

93So several of us are planning a trip out to the hill country to go watch it.

94We do have a mission coming up later in April, so I may not be able to go, but I'm really hoping to get out for the totality to the hill country.

95And so for our listeners that might not be from Texas, where, what city is the hill country by?

96More towards San Antonio maybe?

97Yeah, it's a little west of Austin, San Antonio.

98Okay.

99I know we have a viewing host site at Kerrville.

100Is that near Kerrville?

101Yes.

102No.

103Okay.

104So let's dive into everything you need to know about the upcoming solar eclipse.

105Let's start with the basics.

106Can you tell us what a total solar eclipse is?

107Sure thing.

108So eclipses in general are when the dance of the orbits of the Earth, the Sun, and the Moon all line up.

109And so the Earth is going around the Sun, and the Moon is going around the Earth.

110But the Moon is actually tilted as it goes around the Earth about 23 degrees.

111So sometimes it's above where the Earth and the Sun are, and sometimes it's below.

112An eclipse is when the Moon is going from either below to above or from above to below as it's passing through the line between the Sun and the Earth.

113So you get all three bodies lined up together.

114And you have the Moon blocking the light from the Sun as it lands on the Earth.

115A total solar eclipse is one of those special times when not only are the three lined up, but the Moon is at the right distance such that its size matches the apparent size of the Sun as seen from people on Earth.

116Got it.

117Now what about a partial eclipse?

118So a partial eclipse would be either when the Moon just skirts the edge of how we can see the Sun, or during a total or annular solar eclipse for those not directly in the line of totality.

119They would be seeing a partial solar eclipse.

120So I like how you described it.

121It's a dance of orbits.

122And it's really for the total solar eclipse about the Moon's position, right?

123Yes.

124Now while it seems like just yesterday, recent, right, we had the last total solar eclipse over America, that was 2017.

125And before that, it was 1991.

126These are quite rare when it comes to seeing here in North America or America.

127How rare really are they?

128So total eclipses can happen pretty frequently.

129But in terms of eclipses over the same area, you may go decades or centuries between having total solar eclipses over the same area.

130Now when's the next one?

131So there will be a total solar eclipse over a small part of the U.S.

132in 2044.

133The next big one that covers most of the U.S.

134won't be until 2045.

135Now what area, do you know exactly where it'll cross in 2044?

136So it'll cover the area just around maybe Montana and that part of the U.S.

137So kind of that very northwestern part.

138Which is interesting because the path of totality in 2017 and the one we have this year wasn't over on the West Coast.

139So that'll be new for them.

140That's exciting.

141Okay.

142And the one in 2045 will start in Northern California and do a big swath across most of the U.S.

143and end in Central Florida.

144So a big chunk of the U.S.

145will get to see the path of totality.

146And that itself is new too.

147I know you can go to our different various resources to see the actual path and compare it to the one in 2017.

148And so that's going to be a really cool one in just a different area.

149So now I want to talk about viewing the solar eclipse and some safety precautions that come with it.

150And how long for this eclipse does it last?

151Or how long can you see it or view it?

152So the total period of the eclipse in general will be about three and a half hours.

153But any one area will only see it for about four minutes total.

154And so can you explain the difference in percentages, right?

155So there's a path of totality.

156And for example, here in Houston, I think we're in the 94th percentile or 94%.

157What does that mean?

158That's describing just how much the moon is actually blocking of the sun's photosphere, which is really the part of the sun that we care about because that's the part that can really damage your eyes.

159And so unless you're in really that 100% area, you have to be very careful and take precautions when looking at the sun.

160And speaking of being careful, how do you safely view the total solar eclipse?

161So if you are in the path of totality and you are absolutely sure that you are there in that area, during those few minutes of totality, you can take off the solar eclipse glasses and look at the sun.

162If you are not in that total path of blockage or you're concerned about it, you should always use solar eclipse glasses to make sure that you protect your eyes from damage.

163That's interesting that you say that.

164And when I was researching questions to ask, I had no idea actually that if you were in the path of totality, there's a certain part where you can take off the glasses and actually.

165And so you shouldn't view through, say, your camera on your phone.

166In that sense, in that time frame, sure, fine, if you're in the path of totality.

167But if you're not, what are some other precautions?

168Sure.

169So if you're using solar eclipse glasses, which you should, make sure not to mix different devices with your glasses because telescopes, your phone, binoculars, things like that can change the intensity and magnification of the sun and can change part of the wavelength that you see, which can then interfere with the protection provided by the eclipse glasses.

170If you're going to use some kind of additional device, binoculars, telescope, phone, things like that, they sell dedicated protective lenses that you need to put on your device that would replicate the protection provided by those eclipse glasses.

171So make sure to not mix your devices, but use the appropriate lenses based on how you're looking at the eclipse.

172Now, if you don't have eclipse glasses or a handheld solar viewer, you can use other indirect viewing methods.

173What are those?

174So there's several, and they're actually really cool with what they do.

175So, for example, what we did in 2017 is we watched the eclipse as the light was filtered through leaves.

176So as you look at that, the light through the leaves on, you know, a sidewalk or something, you will actually see thousands of little mini eclipses, and you can actually see the crescent of the sun.

177You can get a similar effect with a colander or a strainer, take it out and hold it up above a sidewalk, a similar effect.

178Or you can use what's called a pinhole projector or pinhole camera.

179And it's a similar theory where you cut a small hole in a piece of paper or a box, and you have it shining on a piece of cardboard or another piece of paper or something.

180And the light will be redirected, and you will see sort of the shadow of the eclipse on that other surface.

181And you will then see the moon pass in front of the sun and carve out the eclipse shape on the screen.

182And so can you walk us through what all you will see in the three and a half, four minutes or so, say if you're in the path of totality?

183Sure thing.

184So initially, it'll stay just a normal bright day, and then the moon will begin to move into the path of the sun.

185And so what you'll start to see is a little bit of a crescent part being eaten out of the sun.

186It'll look a little bit like a Pac-Man.

187And then as the moon continues to move further and further, the day will get a little bit darker.

188It might look a little bit like a light, cloudy day.

189As the moon is starting to get into that point of totality, you'll start to see some little interesting wavy lines on the sun or in your indirect viewing.

190These kind of shadowy waves are a really cool feature.

191They probably are due to some sort of atmospheric refraction as the light is being wrapped around the moon.

192But exactly how it works is still an area of active research.

193Then as the moon moves into its position of totality, what you'll start to see is the coronal area around the sun, because the moon will have blocked the entire photosphere.

194And so you'll get to see some really cool effects around the edge.

195Now, one of the things to be careful even during totality is the moon is not a perfect sphere.

196And so there are mountains and craters and valleys and rough patches.

197And some of those patches can actually allow a little bit of the sun's photosphere to pass through.

198That's called Bailey's beads or sometimes a diamond.

199You can sometimes get a double diamond effect as well.

200You have to be careful because that is part of the sun's photosphere and it can damage your eyes.

201So again, be careful even in the path of totality.

202You'll start to see as you look further away from the sun, the light get very, very dim, much like a dusk view.

203And you'll be able to see some very bright stars that you normally would not be able to see during the day.

204And so that's very cool to be able to see stars during midday.

205Then as the moon continues on its path, you'll see those wavy lines again as it's moving out of totality.

206And then you'll see the reverse Pac-Man as the moon continues to move out of the path of the sun.

207As you're explaining that, I'm thinking of those long exposure photos that you see.

208And that's where I'm thinking of the Pac-Man shape.

209I like how you mentioned research.

210And so we'll get to that a little bit later about the different types of NASA research that take place during eclipses.

211But so you slightly touched on this.

212How much will daylight change?

213And will the temperature fall?

214Yep.

215So as the moon moves into the path of totality, it will look a lot like dusk.

216Not quite night because you've still got a little bit of the sun's light on the atmosphere.

217But it will get fairly dark and you will have a temperature drop.

218It'll feel a little bit like late dusk as well.

219The big thing is that it'll happen over the course of a couple minutes as opposed to over the course of hours.

220So you'll definitely notice a temperature drop.

221So you might want to bring a light windbreaker or something.

222Now weather constraints.

223So if it's a cloudy day, how does that affect seeing the eclipse?

224Sure.

225Yeah.

226So if it's super cloudy, that's obviously going to really impact your ability to see the eclipse.

227If it's just light clouds, you can normally still see through it.

228One of the things that might happen is with some light clouds, you might actually see the coronal light from the sun kind of diffuse out like you normally would see the clouds blocking the sun.

229So it can actually provide a bit of a different view of the eclipse.

230But obviously, if you can find a clear area, that's going to be your best bet.

231Now you work both console for the International Space Station and future Artemis missions.

232And so how can the astronauts observe or can they observe the solar eclipse on board the space station, the crew right now?

233So the ISS is orbiting around the Earth and it's constantly moving.

234So its ability to line up with the eclipse is very difficult.

235So a lot of times they're not even in the path of totality when it's happening.

236Additionally, we don't have a lot of windows facing directly up towards the sun.

237There are some windows on some of their Dragon and Soyuz vehicles that they can see.

238But they do have to be careful because they're out in space without some of the protection that the atmosphere can provide.

239So we make sure that they don't look directly at the sun and just use it through indirect means and photographs that we provide to them.

240And so what about future NASA Artemis crewed missions to the moon?

241And do you have to plan to avoid eclipses?

242We do, actually.

243So when we have our astronauts land on the surface of the moon, we have a couple constraints we need to ensure.

244One is that they have calm with the Earth.

245And so that means that where they land needs to be looking towards the Earth.

246Additionally, we would need them to be in a lit area because they need light so that they can get to the surface, walk around, avoid craters and rocks.

247So in order for there to be both light where they're landing and it to be facing the Earth, we can't have the sun behind the moon.

248So we have to watch out for solar eclipse times to make sure that we have a lit landing area and a landing area facing the Earth.

249So it is something that we watch out for when we're planning our missions.

250These are things you just do not think about that go into the mission planning, right?

251And again, that's just one of the things I love about working here and meeting different people, all different walks of life and then different things you just have to think about on the day to day, right?

252So a short history lesson here to round out the conversation.

253Eclipses have been part of human history as far back as we can record or we've recorded.

254Can you tell us anything about the history of solar eclipses?

255Sure.

256So there's some really interesting solar eclipses that have occurred throughout history that have been recorded in the annals.

257So in ancient Chinese empires, the eclipses were seen as a dragon eating the sun.

258And it was an important part of the court astronomers to predict when these would happen because it was seen as a major negative event.

259Two astronomers failed to predict it around the time of a battle.

260And so they were actually beheaded for their failure.

261They were punished very harshly for not predicting that eclipse.

262Later on, Herodotus records that the Lydians and Medes actually stopped fighting because an eclipse occurred during the middle of the battle.

263And they took that to mean that the gods were angry with them for fighting.

264We're also able to pinpoint exactly when a civil rebellion occurred in the city of Asher because it corresponded to an eclipse that we know about.

265So there have been really interesting periods where we've been able to pinpoint exactly when things happen because they line up with these eclipses that we can predict very well.

266So from dragons to scientific discoveries now, what are some of the discoveries that have come out of these eclipses?

267Sure.

268So one of the really, really important ones of the 20th century is proving Einstein's theory of relativity.

269So he predicted that gravitational bodies like the sun would cause light from other stars to bend or it's called gravitational lensing.

270So in the early 1900s, during an eclipse, they were able to go, several scientists, and observe light from stars behind the sun that we normally cannot see because the sun is blocking it, curve from where they should have been observed on the ground because the moon was blocking the light of the sun.

271And that proved that gravitational lensing occurred and therefore proved Einstein's theory of relativity was correct.

272So what different types of NASA research is involved in this event?

273So you might see things like chasing the eclipse with high altitude planes.

274So one of the things that we still don't understand super well is the effect of altitude on the atmosphere and how solar radiation pressure can change that.

275It's a huge area of research both in aeronautics and in rocketry.

276So we have our WB-57 planes that are going to be chasing the eclipse and observing how the effect of the blockage of the sun affects changes in the atmospheric pressure.

277We also have some sounding rockets that will be launched and some balloons that will be launched.

278And they'll have tons of sensors and measuring equipment on board that they will use to measure how the atmosphere changes over a certain area before the eclipse and then during the eclipse and then during the eclipse at different points.

279So we can cross-check, you know, how does the eclipse change over different areas and how does the same area change before and after an eclipse and really get some good insight into how the sun affects our atmosphere.

280To be a passenger on one of those planes would be awesome.

281Now, how can general citizens contribute to NASA's research?

282So there's different ways.

283I think I read on the website, you know, seeing what critters are doing or animals, how they might react or if you see anything change in that realm.

284Sure.

285Yeah.

286So animals, just like we do, you know, react to the sun.

287So it's very interesting to see how, you know, daytime and nocturnal animals will react to that.

288So there's a lot of research here.

289People can also get involved in some of those balloon experiments.

290And if folks want to learn more, they can go to science.nasa.gov slash eclipses.

291And not only can they find out a lot about the research that's being done both through NASA and with public involvement, but we also have some really, really cool maps of the path of totality for those who want to maybe plan a trip for this eclipse.

292Well, we hope this podcast has helped you not only prepare for this exciting event, but you can help share in the excitement, right, of this eclipse that millions are going to be able to see.

293Be sure to tune in from 12 to 3 p.m.

294Central on April 8th for NASA's eclipse broadcast that will be streaming on all of NASA's platforms.

295Matt, thank you so much for joining us.

296Did you have any last words on the eclipse?

297No, thanks for being here.

298Yeah, just one last time.

299People, be careful with your eyes.

300Make sure you're using proper protection and know where you are and get your eclipse glasses ready.

301Thanks, Matt.

302And you stay good.

303Stop of the space shuttle.

304Roger.

305Zero.

306T.

307And I feel...

308Subtle has cleared the time.

309Became a date for all mankind.

310Actually, a huge honor to break a record like this.

311Not because they are easy, but because they are hard.

312Never used to.

313Welcome to space.

314Thanks for sticking around.

315I hope you learned something today.

316Check out NASA.gov for the latest.

317NASA.gov forward slash podcasts.

318And for more information on this year's eclipse, head to go.nasa.gov forward slash eclipse 2024, as well as NASA Sun on X and NASA Sun Science on Facebook.

319On social media, we're at NASA Johnson on Facebook, X, and Instagram.

320Use hashtag AskNASA on your favorite platform to submit your idea and make sure to mention it's for Houston We Have a Podcast.

321This episode was recorded on March 1st, 2024.

322Thanks to Will Flato, Dane Turner, Abby Grapp, Sarah Frazier, Jaden Jennings, Dominique Crespo, and of course, Gary Jordan.

323And of course, thank you to Matt Wilkinson for taking time to come on the show.

324Give us a rating and feedback on whatever platform you're listening to us on.

325And tell us what you think of our podcast.

326We'll be back next week.

327Thank you.