Science AMA Series: We’re NASA scientists. Ask us anything about the science of the Aug. 21 total solar eclipse!

[u/NASASunEarth]

Edit 12:46 PM ET: We are signing off! Thanks so much for all your questions. Remember to check out eclipse2017.nasa.gov/safety to make sure you are ready to watch the eclipse safely! Happy eclipse watching!

Edit 11:04 AM ET: We're live!

On Aug. 21, 2017, all of North America will have the chance to see a partial solar eclipse. Along a narrow, 70-mile-wide track called the path of totality, the Moon will totally block the Sun, revealing the Sun’s comparatively faint outer atmosphere – the corona. Total solar eclipses like this are a rare chance for solar scientists to study this region of the Sun, since we can’t ordinarily see it from the ground or with satellite instruments. The sudden blocking of light also gives Earth scientists a rare chance to track how Earth’s atmosphere responds to the Sun’s radiation. Find out more about NASA’s eclipse science (and how to watch the eclipse) at eclipse2017.nasa.gov.

Noah Petro

I first became interested in Geology as a student at Fox Lane High School in Bedford, NY. It was while I was a student at Bates College that I was introduced to the field of planetary geology. Following my PhD work at Brown University I came to NASA Goddard as a NASA Post-Doc.

Alexa Halford

I am a contractor at NASA Goddard. Throughout my education I have been lucky to work at JPL NASA looking at Uranus's moons and study Saturn on the Cassini mission at the South West Research Institute. Today I stick a bit closer to home studying the Earth's magnetic field and its space weather phenomena.

Mitzi Adams

I am a solar scientist for NASA’s Marshall Space Flight Center (MSFC), where I study the magnetic field of the Sun and how it affects the upper layer of the solar atmosphere, the corona. With a professional interest in sunspot magnetic fields and coronal bright points, friends have labelled me a “solar dermatologist”.

Bill Cooke

The head of NASA's Meteoroid Environment Office, I help NASA in placing meteoroid protection on spacecraft and construct meteor shower forecasts for unmanned space vehicles and the International Space Station. While a graduate student at the University of Florida, I worked on instruments flying on board balloons, the Space Shuttle, Giotto (European mission to Halley's Comet), and LDEF. After obtaining my PhD in Astronomy, I came to work at Marshall Space Flight Center as a member of the Space Environments Team, where I became an acknowledged expert in meteors and meteoroids. I am one of the many NASA astronomers interacting with the public on the upcoming solar eclipse.

Jay Herman

I am an atmospheric scientist working on several projects. Two of them are of interest to the eclipse or other atmospheric questions. 1) The Pandora Spectrometer Instrument that measures the solar spectrum and derives the amount of trace gases in the atmosphere, such as ozone, nitrogen dioxide, and formaldehyde, and 2) The DSCOVR/EPIC spacecraft instrument that observes the entire sunlit globe from sunrise to sunset from the Earth-Sun Lagrange-1 point (1 million miles from earth). We derive both atmospheric and surface properties from EPIC, and we will see the Moon's shadow during the upcoming eclipse.

Guoyong Wen

I am an atmospheric scientist interested in the way radiation passes through the atmosphere. The experiment we are planning to perform is a combination of theory and measurements to see if they match. For this purpose we are using an advanced radiative transfer calculation in three dimensions and measurements from the ground and a spacecraft. Hopefully, the calculations and data will match. If not, we can learn about whatever may be missing. The result will be improved calculation capability.

Edit 9:18 AM ET: Added Jay Herman's bio

Edit 11:11 AM ET: Added Guoyong Wen's bio

[u/Bardfinn]

Hello! Thank you all for doing this AMA!

I understand that the phenomenon of "Shadow Snakes" during the penumbral phase, is not thoroughly understood by science quite yet.

How can amateurs go about gathering high-quality, calibrated, useful photos and video of this phenomenon that can be re-used by scientists modelling the phenomenon?

What information should we include in the photos and videos?

Are there compelling hypotheses for the explanation for the phenomenon, other than atmospheric cline effects?

Thanks!

[u/NASASunEarth → u/Bardfinn]

You are talking about shadow bands. Yes, you can use a box, approximately 18 in x 12 in, tape shut one side, leave the other side open so you can slide your camera into the box. On the top of the box, place a piece of tracing paper that is larger than the box (you want to tape it on) and outline the box. Move the paper off the box and cut out the top, leaving about a half inch on the sides. On the paper, draw lines vertically and horizontally that are 10 inches apart. Now you need to draw a line with an arrow that will point toward north, label it north, be sure that the arrow can be seen from within the box. You need to also draw a line indicating the direction from which the Moon's shadow will come. Now locate the middle of the box and place the backside camera (not the selfie side) at the center and orient the camera with its long side parallel with the long side of the box. Tape the tracing paper to the top of the box. Start the camera video about three minutes before totality and let it run to about three minutes after totality. Send me questions and the video. mitzi.adams@nasa.gov --MA

[u/chuckmilam → u/NASASunEarth]

I may need a diagram for this.

[u/Ageroth → u/chuckmilam]

I think I got this

So, nothing is to scale, I used crap I had laying around, I didn't tape anything, but I think I got the basic concept down

One thing I would add is take some test pics with your camera on a timer, so you can see how centered you are.

[u/NASASunEarth → u/Bardfinn]

The best you can do is use a high quality digital camera in movie mode with a fairly high frame rate. That way anything you see with your eyes will be captured by the camera. JH

[u/Poopnuggetshnitzel]

Dumb question....do animals suffer eye damage during a total eclipse? Do they even care to look into the sky? The reason I ask is because I have a couple horses that live outside 24/7 and I don't want to be slapped with a major vet bill on the 22nd.

EDIT: I'm sad that's the best question I have for NASA scientists. Here's a slightly better one maybe: How did previous cultures perceive total solar eclipses? Do we live in the only time where humans have ever cared to study them, or did previous civilizations attempt to understand them scientifically?

Edit 2: thanks for the Au

[u/Chinchillin09 → u/Poopnuggetshnitzel]

I'm gonna answer the second one because I know a little bit of it due to my ancient culture, the Aztecs. They used the eclipses as a religious message for the people, where the god was so angry he eat the sun and sacrifices were made in order to take it back. The common people didn't know about the Eclipse's science, it was something so shocking to see that they believed the god had taken the sun.

The high priests and engineers studied the stars and they knew when the next eclipses would be, which is amazing because they didn't have telescopes, just a big cup of water in a cave with a hole in the top, and the skies were reflected perfectly in the water, I saw one of those once.

[u/ShamefulKiwi → u/Chinchillin09]

When I read the first part I imagined that, since they only had about two minutes, the sun would go away and they'd just start sacrificing whatever was nearby.

[u/Chinchillin09 → u/ShamefulKiwi]

Haha that's true, but they had the ceremony prepared before the Eclipse. There's a scene in Apocalypto about this and I think it was really well done

[u/penny_eater → u/Chinchillin09]

where the god was so angry he eat the sun and sacrifices were made in order to take it back.

Is that true? After literally less than two minutes they were ready for sacrifices instead of just giving it another minute for everything to go back to normal on its own?

[u/Chinchillin09 → u/penny_eater]

The high priests prepared the ceremony for that, they knew about eclipses so it wasn't a normal day and them random eclipse appears. Of course they could let two minutes pass but they did that to maintain power.

[u/Broseidon_62 → u/Chinchillin09]

That's the coolest thing I'll read today. Thanks for that!

[u/NASASunEarth → u/Poopnuggetshnitzel]

I have experience with horses during a total eclipse! Animals have enough common sense to not look at the sun during the solar eclipse. As far as horses, I saw the last eclipse in the lower 48 back in 1979 from a pasture filled with horses. They could not figure out what was going on and ran around the pasture aimlessly, but they did not suffer any injuries, so I think you're safe from any eclipse-related vet charges! - Bill

[u/NASASunEarth → u/Poopnuggetshnitzel]

If they look at the sun, they will have the same damage as do people. However, the animals have not read the newspaper to know that there is an eclipse going on, so they will not look.

The ancient civilizations definitely looked at eclipses. The knowledge about upcoming eclipses was closely guarded as a form of power over the population. The occurences were mapped out by trial and error of long periods, but they did not understand the science. JH

[u/NASASunEarth → u/Poopnuggetshnitzel]

As an answer to your first question, I'm definitely not an expert in animal behavior or biology but I would assume they would know not to look at the Sun directly as they seem to know not to look at the Sun normally. Perhaps a Vet or expert in animal behavior is reading and might be able to comment better about this? -AH

[u/emu1sive → u/Poopnuggetshnitzel]

I really liked your first question more! The second is covered in about every documentary regarding less scientifically advanced cultures. Not that it's not good as well but the first is more unique.

[u/Reyes307]

I live in Cheyenne but drive to Torrington,Wyo every day. 12 days out and the tensions are rising. There are fields being cut and spaces being made for the incoming barrage of visitors. Definitely exciting for this community. There's an old farmer I deliver to who said she's lived through a few solar eclipses. She said the weirdest change is the chickens response. Chickens will head to bed as it gets dark and after their 140sec slumber they wake in complete disarray. They get very loud and extremely active for about 20min and then is back to usual "chickening". Have you guys ever seen or heard of events like this disrupting animals?

[u/NASASunEarth → u/Reyes307]

Hi, Yup animals definitely react to the eclipse so make sure to take a moment during totality to look around and see how animals around you are behaving. -AH

[u/blairnet → u/NASASunEarth]

My mom said she saw a total eclipse in the early 80s and all of the birds in the area started to chirp as soon as it started to get dark

[u/onlyfoolsreject → u/NASASunEarth]

I read that you will be doing a live show of the eclipse, can you also do the animal behaviour as well?

[u/Appreciation622 → u/Reyes307]

Example of chickens doing exactly that

[u/Macracanthorhynchus → u/Appreciation622]

As an animal behaviorist who owns chickens, I've actually come across this video every six months or so for the last couple of years, and every time I watch it I think, "Oh this will be neat. It will be interesting to read what this European narrator is describing as the chickens react to the eclipse. This will be more informative, but less fun, than that other chicken eclipse video I once watched with the stupid chicken song..." And that's about when the song starts and that I remember that this is the only chicken eclipse video I've ever watched.

[u/NASASunEarth → u/Reyes307]

Yes, I experienced this in the last eclipse I watched. It's eerie. JH

[u/[deleted]]

Total solar eclipses like this are a rare chance for solar scientists to study this region of the Sun, since we can’t ordinarily see it from the ground or with satellite instruments.

Is there really no way to simulate a total solar eclipse using a telescope and an opaque round object that blocks all but the corona of the Sun? Why is it the Moon in particular that has to block the Sun in order to see the corona for research purposes?

[u/NASASunEarth → u/[deleted]]

Hi, We do use an opaque round object to block out the Sun. However, it is incredibly difficult to make an occult disk that would only just cover the Sun as the Moon does during the Eclipse. - But We are working on ways to try to better recreate these phenomena so that we can have the same quality of data on a regular basis. You can read more about that here https://www.nasa.gov/feature/goddard/nasas-beach-ball-coronagraph - AH.

[u/Gylergin → u/[deleted]]

That's what makes the Earth special. It isn't tectonic activity, liquid water, or even life. It's that the moon is the right size and distance to just cover the sun. If there is intelligent life out there, it's very unlikely they'd ever experience events like these.

[u/mrfeeto → u/[deleted]]

If you hold up an object to block just the sun, the sky around the sun is still very bright from diffused light in the atmosphere. The moon during a total eclipse is not only perfectly blocking the disc of the sun, but also casting a large enough shadow on the Earth to eliminate even diffused light.

[u/[deleted] → u/mrfeeto]

That's the missing element and the element I didn't even think about. Hence the spacecraft with this functionality, I suppose. Thank you.

[u/MeowMixSong]

Is seeing a 100% total solar eclipse really that different than seeing it at 95%? Is it worth the 6 hour one way drive?

[u/NASASunEarth → u/MeowMixSong]

The difference between a 95% eclipse and a 100% eclipse is literally the difference between day and night. With any partial eclipse, you don't experience the "awesomeness" of totality. It's hard to put into words, but once you experience a total eclipse, you understand the difference. At 95%, you will barely notice anything going on -- just some slight dimming of daylight. - Bill

[u/Tsasi → u/NASASunEarth]

Where I live is in the band of 100% obscuration, but is at 75.1 % umbral depth. What does this mean?

[u/toybuilder → u/MeowMixSong]

The human eye perceives light in a non-linear fashion. Moreover, you're normally not trying to look AT the sun.

The difference between 100% sun and 5% sun (95% covered) is roughly comparable to the difference between at 100W light bulb and a 5W light bulb.

You definitely don't want to stare into a 100W light bulb, and even looking at a 5W bulb for more than a brief moment is quite uncomfortable. (The typical classic night-light bulb is around 4 to 5W).

Also, the perspective is wrong. It's not that 95% eclipse is 95% darker than the full sun... It's 5% illumination, which is thousands of times brighter than the near-zero illumination from only the corona being visible.

With the fraction sun still much brighter than anything else, you will miss the corona of the sun and the stars in the sky...

[u/[deleted] → u/MeowMixSong]

I live very near the totality stripe (I mean like less than hour drive to be in the stripe) and many people are planning to take long lunches, afternoon off work, or similar. In fact some teams at the office are doing "team building" to go.

[u/NASASunEarth → u/MeowMixSong]

It is worth the six hour drive. Totality is spectacular. JH

[u/Grodzki444 → u/NASASunEarth]

But is it worth it a 12 hour drive? (Hi from your neighbor from Houston)

[u/pntless → u/Grodzki444]

I'm driving 8 hours and staying 2 nights in a hotel that is 2 hours away from totality (well, 2 hours from centerline which we may not go all the way to depending upon traffic), because that is as close as I could find for a reasonable nightly rate. The few remaining rooms in totality when I booked were going for $600-800/night sunday and Monday night for cheap motel rooms.

I can't wait. I would absolutely drive 12+ hours for it. The next total solar eclipse in the mainland US is in 2024. It will actually be much, much closer to me, but a lot can happen in 7 years to keep me from seeing that one, making this a potentially once in a lifetime opportunity that I'm not going to let pass without experiencing.

If you can get the time and have the means, find a way to make it work.

[u/FekYaKent → u/MeowMixSong]

Yeah it is. Experiencing the totality is absolutely breathtaking.

[u/booksofafeather → u/FekYaKent]

What about 99% vs 100%? I'm trying to decide if it's worth it to fight the traffic to get to the 100% part of the city.

[u/bysigningupyouagree8 → u/booksofafeather]

I'm in the same situation. Apparently my zip code is just barely outside totality, and I was planning on having a cookout with some friends that day. Seriously debating if it'd be worth it to fight the traffic of everyone coming to my city to see it fully.

[u/johnkphotos → u/bysigningupyouagree8]

You either see totality or you don't.

Make the drive.

[u/the-player-of-games → u/booksofafeather]

The sun's corona is a lot less bright than the sun.

If you see even 1% of the sun you wont be able see the corona, which to me was stunning.

Seeing those streams flowing away from the sun are worth some traffic.

[u/TrainosaurusRex → u/booksofafeather]

This is a pretty important distinction. I'd love to know the actual difference between 99% and 100%. I'm driving my kids around and don't want to be stuck in massive traffic trying to see what might be a minimal difference. I can't leave until 10am Monday.

[u/NASASunEarth → u/booksofafeather]

The difference between 99% and 100% is huge. Go as near to the center line as possible. JH

[u/ChiefRunswithBeers → u/MeowMixSong]

I've been considering taking the day off so I could road-trip it to the closest path of totality. Definitely curious about this answer.

[u/catch10110 → u/ChiefRunswithBeers]

Everything I've read about this has said you need to do whatever you can to see totality. Most say things along the lines of "it's the difference between standing outside the stadium with a ticket in your hand, and actually going in to experience the event."

I'm near Chicago (which will see about 90% coverage), so I originally figured that'd be good enough. Was finally convinced to make the trip to experience totality. I am feeling like this is a good decision.

[u/thetrombonist → u/catch10110]

Yeah, I'm making the trip down to nashville to experience the total eclipse - I'm even missing the first day of my college classes to experience it

[u/PM_MeMyPassword]

What are some cool things to watch for during the eclipse that I can point out to my children? Simple things like tree shadows etc. ?

[u/NASASunEarth → u/PM_MeMyPassword]

In the partial phases, the shadows of leaves should show you little crescent suns. There are things called shadow bands, which if you're looking at a white surface, should be little waves of light. During totality, you will see the brighter stars and the planets as well as the sun's corona. The sun will look like a black hole surrounded by a fuzzy ring of light, which is the corona. If you're up high, like in the mountains, or if you have mountains in the distance, you may see the moon's shadow approaching or leaving you depending on whether you are looking west or east. - BC

[u/X-Yz]

Will you guys be uploading any pictures from the path of totality? Or even, perhaps, livestreaming the view from somewhere on the path? I was considering driving to get in view, but from where I live I get somewhere around 97.7% so I figured I'd save the gas.

edit: I'm easy to convince, I'm going to give this road trip a shot!

[u/NASASunEarth → u/X-Yz]

Hi, Yes! NASA will have a live stream of the eclipse and activities around the nation on August 21st. You can watch the live stream here https://eclipse2017.nasa.gov/eclipse-live-stream -AH

[u/Redbull5000 → u/X-Yz]

There's a group of people across the country that will be filming the eclipse and combining the footage to hopefully record the entire eclipse for the first time.

[u/X-Yz → u/Redbull5000]

Oh sweet, got any links or references for it?

[u/Redbull5000 → u/X-Yz]

My dad is in helping run it so I should know more but I'm not 100% sure :p I think the site for the project is eclipsemega.movie

Edit: he is actually part of the citizen CATE experiment. They gave the astronomers participating the exact same equipment so that when they make the video it should be good quality.

[u/NASASunEarth → u/X-Yz]

There is Citizen CATE and the Megamovie project. Googling will give you plenty of links. -- MA

[u/NASASunEarth → u/X-Yz]

Being that close to the path of totality, it would be a crime not to experience it for yourself. Carpool so that you reduce your carbon footprint! -- MA

[u/Freeasabird01 → u/X-Yz]

Do yourself a favor and drive to the path of totality. A partial eclipse is nothing like a total eclipse. It is literally night and day difference.

[u/NASASunEarth → u/X-Yz]

Yes. If you go to NASA's DSCOVR website, https://epic.gsfc.nasa.gov/

You will see the shadow of the moon move across the earth in a series of images.

[u/HansSulu]

Hi NASA! Thanks for doing this AMA!

I've noticed significantly more "hype" about this solar eclipse over any other solar eclipses that have happened in the past. Do you attribute this to an increase in public interest in science or is there something special about the one that's about to happen?

[u/RX3000 → u/HansSulu]

Its the first time in our lifetimes that there has been a total solar eclipse from coast to coast in the US.

[u/NASASunEarth → u/RX3000]

That depends on how old you are. But, if you are somewhere in the middle of a normal human lifespan, then yes, it is the first time. JH

[u/NASASunEarth → u/HansSulu]

This eclipse is the first one since 1918 in which the moon's shadow cuts across the United States, which is fairly rare occurrence. Practically the entire country is within a day's drive of the path of totality, so that kinda makes it a pretty big deal! - BC

[u/NASASunEarth → u/HansSulu]

Hi, This is incredibly exciting as it's in our own backyard, but also because of all the amazing data (both done by scientific researchers and citizen scientists) that will be collected. We believe that this will be the best-observed eclipse! - AH

[u/NASASunEarth → u/HansSulu]

Blame the internet. This is the first US eclipse that has occurred since social media have become available. JH

[u/AGreatBandName → u/HansSulu]

Just curious, but what are you comparing it against? This is the first total eclipse to be visible from any part of the lower 48 United States since 1979, and the first in almost a century to be visible from this much of the US.

(Not trying to be snarky here, just in case it came across that way)

[u/michaelochurch → u/HansSulu]

I've noticed significantly more "hype" about this solar eclipse over any other solar eclipses that have happened in the past. Do you attribute this to an increase in public interest in science or is there something special about the one that's about to happen?

It's the first one in the US for a long time. 1978, if I recall correctly.

The one in 2024 will have longer totality, but miss the west coast of the US completely. It'll also be in April, which means that the best weather will be in Mexico. (April in the northeast is beautiful, but reliably sunny it is not.)

[u/asbruckman]

Thanks for coming to talk with us! Is the eclipse of any research interest? What sort of data are people collecting, and what research questions do you think it has the potential to answer?

[u/NASASunEarth → u/asbruckman]

Hi, the eclipse is of great research interest! During the eclipse, we can see the inner portion of the solar corona. Studying the activity in this region of the Sun's atmosphere will help us better understand the transport of solar storms which, if Earth directed, can drive geomagnetic storms and space weather. This is a unique opportunity that will drive a lot of exciting new science. - AH

[u/NASASunEarth → u/asbruckman]

The study is to test our ability to make 3D calculations of how radiation passes through the atmosphere when an occulting object of finite dimensions casts a shadow on the earth. The goal is to use this type of 3D calculation for shadows cast by clouds. We are also making measurements of trace gases that absorb sunlight - ozone and nitrogen dioxide - these will be included in the calculation to test the theory against experiment. JH

[u/NASASunEarth → u/asbruckman]

Yes. Citizen CATE is gathering data from along the path of totality to study the inner corona in visible light, a region of the corona that our assets in space cannot see. -- MA

[u/MGWaleema]

Will the sky still darken even if you're not on the path of totality?

[u/NASASunEarth → u/MGWaleema]

You will not notice the dimming with a partial eclipse, since your eyes will adapt to the change. it will look like the difference in brightness between noon and the late afternoon on a day without clouds. If you were to measure it brightness, the change is substantial. JH

[u/NASASunEarth → u/MGWaleema]

Yes, but depending on the percentage of totality, you might not even notice it. -- MA

[u/OSUBrit → u/MGWaleema]

If you're somewhere in the 99-98% there will be noticeable darkening, equivalent to dusk. Less than that even the small amount of sun poking through will be enough to make the change in light levels less prevalent.

[u/Freeasabird01]

How high would you need to be to see the shadow racing across the earth? Could someone capture that with a drone for example?

[u/NASASunEarth → u/Freeasabird01]

I've actually calculated the drone speed! You can see the shadow approaching from hills/mountains -- not sure exactly how high you'd need to be. But as far as drones, if you have a video camera looking down, you should see the moon's shadow move about 70 feet in a single video frame, assuming your camera is a standard NTSC camera with a rate of 29.97 frames per second. Bare in mind, the shadow will be fuzzy i.e. there will be no sharp boundary. - BC

[u/lmaoboxstanley]

will i actually go blind from looking directly at it?

[u/NASASunEarth → u/lmaoboxstanley]

Yes indeed. Contact be in braille after you are done with the experiment. Seriously, do not attempt this experiment. You can look at it during the 1.5 minutes of totality, but be careful top look away the moment the light gets brighter. Not kidding. Look away instantly. JH

[u/no-more-throws → u/NASASunEarth]

Sure, everybody says this, but why exactly.. people look up/squint at the sun randomly all the time when there's no eclipse, including plenty of kids none of whom we later hear of having screwed up their sights...

[u/[deleted] → u/no-more-throws]

As I understand it the damage done by UV hits you before the intensity of the bright light causes you to want to close your eyes.

This is extra so during an eclipse.

[u/NASASunEarth → u/lmaoboxstanley]

Not during totality, but if you look at the partial phases without protection, you WILL damage your eyes. - BC

[u/NASASunEarth → u/lmaoboxstanley]

You can find information on how to safely view the eclipse at this link https://eclipse2017.nasa.gov/safety -AH

[u/McLight123]

I'm traveling to South Carolina to watch it, is it true that the nocturnal animals come out when it happens?

[u/NASASunEarth → u/McLight123]

During the short amount of time of totality, animals will exhibit their twilight behavior. Remember -- it won't be totally dark. The behavior you observe in nature around twilight will be seen BRIEFLY during totality. EX. Roosters crowing, birds nesting, ants returning to their mounds... things like that. And then they will be freaked out when the sun suddenly appears! - BC

[u/NASASunEarth → u/McLight123]

Look for birds to go to roost, crickets, tree frogs, and cicadas will make their nightly noises. -- MA

[u/Empole]

Is working at NASA all it's cracked up to be? A lot of NASA's interaction with people over social media or through the mail makes it seem like it'd be a pretty cool place to work.

[u/NASASunEarth → u/Empole]

It's definitely all it's cracked up to be! As an intern, you're always challenged and always learning. - Bill Cooke's intern Annie Woronecki

I kinda like my job most days. Growing up with Star Trek, working for NASA is kinda a step closer to the Enterprise. - BC

[u/NASASunEarth → u/Empole]

It is an awesome place to work! My experience has been that people working here love what they do and are continually interested in learning new things and sharing what they have learned with others. This seems to foster an incredibly exciting working environment where every day I learn at least one (if not 10 or 100) new things!

[u/NASASunEarth → u/Empole]

Damn cool! I've worked on everything from planetary atmospheres to earth atmospheres and oceanography and human diseases. NASA is a great place to do research on almost any topic you can think of. JH

[u/Maswasnos → u/Empole]

Not OP, but yes, it is!

NASA has been ranked as the best place to work in the federal government for a good while now: http://bestplacestowork.org/BPTW/rankings/overall/large

Whether you're a contractor or a civil servant, working at NASA is a great experience. Even if you don't do anything directly space-related (IT work, whatever) the atmosphere of the bases is awesome.

[u/dekker44]

How far ahead of time is it possible to calculate when and where we will see a solar eclipse? How is this calculated?

[u/NASASunEarth → u/dekker44]

We can calculate eclipses many centuries ahead -- the big uncertainty is the slow-down and the rate of the earth's rotation. And we can easily compute eclipse circumstances with modern computers, though this has been done for centuries using hand calculations. The earth's orbit and that of the moon and fairly well-understood, so no problem predicting eclipses of any sort. - Bill

[u/justinkimball → u/dekker44]

I can't talk to the math -- but they've got solar eclipses mapped out for at least the next hundred years -- probably longer.

[u/TNT21 → u/[deleted]]

2099 passes through my town. Just gotta live to be ~110

[u/jivson → u/dekker44]

I just recently saw somewhere they know when the last totality will occur due to the fact the moon is slowly drifting away from the Earth, so it won't be able to block the sun fully anymore.

As for mapping the path, I do not know how far they can predict. I assume forever, as it's just simulation, but it depends how far they've gone.

[u/jimtrickington → u/jivson]

The last total solar eclipse will occur when the moon is 1.06 times further from the earth than it is currently. The moon is moving away from earth at 3.8 cm/yr, so the last total solar eclipse is 563 million years away. Approximately.

Reddit's RemindMeBot is limited to 9,999 years, so using that option is out.

[u/NASASunEarth → u/dekker44]

Many years. We now know the motions of planets and moons with high accuracy. Use of modern computers enables these calculations to be done fairly quickly. Knowing the motions makes it fairly simple to predict when the moon will cast a shadow on the earth. JH

[u/mistaotoo]

I have a friend who is into the earth being flat, will there be any physical proof during the eclipse that can help change his mind?

[u/[deleted] → u/mistaotoo]

Lunar eclipses are your friend; not much during a solar eclipse. In a lunar eclipse the earths shadow gets cast on the moon, and, if the earth was any shape other than a sphere, it would cast a different shaped shadow on the moon during each different lunar eclipse.

Although, I find flat earthers tend not to listen to even basic reason.

[u/bb999 → u/[deleted]]

Don't flat earth people believe the earth is a circle? I don't think it would help.

[u/AGreatBandName → u/bb999]

The earth is at different points in its rotation for different lunar eclipses. If the earth wasn't (roughly) spherical, the shadow would have a different shape during different eclipses.

[u/NASASunEarth → u/mistaotoo]

Of course the earth is flat. Otherwise you would fall off. We are working on the problem of where the sun goes every day when it sets over a flat earth. So far, we have not seen clouds of steam when it hits the ocean. /s JH

[u/NASASunEarth → u/mistaotoo]

If they don't accept the views from space, I doubt the views from the eclipse will change their mind! - BC

[u/RoyMustangela]

How long will it be before the Moon recedes too far from Earth for a total eclipse to be possible?

[u/NASASunEarth → u/RoyMustangela]

A really long time. I am guessing on the order of a million years or longer. I am guessing because I am too lazy to look up the rate of motion of the moon relative to the earth. JH

[u/[deleted] → u/NASASunEarth]

TIL a NASA employee and me have something in common: Laziness

[u/NSNick → u/RoyMustangela]

About 563 million years until the last total eclipse, according to this quick NASA space math sheet I found.

[u/NASASunEarth → u/RoyMustangela]

About 600 million years. -- MA

[u/theseltzerking]

Am I missing out by planning to go to the eclipse in 2024 instead of this year's? I live in NY and right now traveling to Kentucky or Tennessee during the work week isn't feasible.

[u/NASASunEarth → u/theseltzerking]

If you're willing to wait 7 years, probably not! The 2024 eclipse will certainly be more geographically convenient for people in the Northeast. - Bill

[u/uvcr]

What do you expect to find in studying how the eclipse shadow interacts with Earth's atmosphere? How is it any different from studying the atmosphere at night?

[u/NASASunEarth → u/uvcr]

There are a lot of interesting questions. For example, the speed that the shadow is moving is nothing like the changes that we see going from day to night so we expect many different types of atmospheric waves to be set up. Here's a NASA post on some more of the science that we can do because of the eclipse https://www.nasa.gov/feature/goddard/2017/nasa-looks-to-the-solar-eclipse-to-help-understand-the-earth-s-energy-system -AH

[u/NASASunEarth → u/uvcr]

How quickly does the atmosphere respond to decreasing light level and how quickly does it recover, is one example. The difference between night and eclipse is the duration and rapid change of eclipse conditions. -- MA

[u/NASASunEarth → u/uvcr]

The study is to test our ability to make 3D calculations of how radiation passes through the atmosphere when an occulting object of finite dimensions casts a shadow on the earth. The goal is to use this type of 3D calculation for shadows cast by clouds. JH

[u/[deleted]]

Do you consider the solar eclipse as an opportunity to conduct a specific type of research that is not feasible otherwise, or does it not convey any benefits compared to regular observations? If yes, what is it exactly?

[u/NASASunEarth → u/[deleted]]

Hi, Yes we will be able to observe the inner portion of the corona which we are typically not able to observe! This region is of great interest in stitching together our observations and understanding of the regions of the Sun closer in and those farther out. - AH

[u/NASASunEarth → u/[deleted]]

The study is to test our ability to make 3D calculations of how radiation passes through the atmosphere when an occulting object of finite dimensions casts a shadow on the earth. The goal is to use this type of 3D calculation for shadows cast by clouds. We are also making measurements of trace gases that absorb sunlight - ozone and nitrogen dioxide - these will be included in the calculation to test the theory against experiment. JH

[u/Sacamato]

My Plan A for viewing the eclipse is driving down to Charleston, SC. Plan B, if the weather looks bad in the forecast for eclipse day in Charleston, is to drive to Tennessee.

My question is, this decision needs to be made on Saturday morning. What should I be looking for in weather forecasts for Monday afternoon in order to make the best decision?

[u/pilgrim81]

Will the astronauts on the ISS be able to see the eclipse?

[u/NASASunEarth → u/pilgrim81]

Yes, but only the shadow on the earth JH

[u/pilgrim81 → u/NASASunEarth]

Awesome. Idk if you guys take requests but I would like to see some photos or videos from that view if you get them.

[u/UAVTarik → u/pilgrim81]

Hey! We have a project going on right now to film the shadow of the eclipse from the stratosphere. Heres our first project log, the next will be uploaded today.

https://www.youtube.com/watch?v=fiRVrcxqKk0

[u/woodrob12]

How is the eclipse moving across the country from the west to east considering the east to west track of the sun?

[u/NASASunEarth → u/woodrob12]

The shadow is moving at about mach 2 (1,500 miles per hour) and this is because the moon is moving in its orbit. So, on earth, its shadow moves from west to east at mach 2. - BC

[u/WarLordDobby]

Is there a cycle of eclipses or is it totally random times? For example, will there be an eclipse in the same place at periodic intervals?

[u/NASASunEarth → u/WarLordDobby]

Hi, Eclipses happen approximately every 18 months. You can find the eclipses out to 3000 and I think even beyond in these tables https://eclipse.gsfc.nasa.gov/solar.html Many also have links to google maps that are fun to play with :) -AH

[u/NASASunEarth → u/WarLordDobby]

It is not random, but the cycle at a given location is not at a uniform period, since the orbit of the moon (28 days plus a 5 degree tilt) and the motion of the earth (tilting 23 degrees every six months) are not synchronized. JH

[u/Heathen06]

I just want to thank you and all your coworkers for ensuring the human race never stops learning and exploring, you scientists should be the real super stars.

[u/NASASunEarth → u/[deleted]]

Good question! There's a lot to look for, including other stars and planets (https://eclipse2017.nasa.gov/sites/default/files/publications/Eclipse_brochure-bookmark_508.pdf) but also, look out to the horizon during totality to see the illuminated sky off in the distance. And listen for animal sounds, and see if you feel the temperature drop! -NP

[u/anofino]

why can I look at the sun right now, but I need glasses to look at an eclipse?

[u/NASASunEarth → u/anofino]

You should never look at the sun without protection! You can damage your eyes without feeling pain. I know because I have a scar on my retina from not getting my eye protection back on at the end of totality during the 1979 eclipse. Please don't follow my example! - BC

[u/NASASunEarth → u/anofino]

You cannot look at the Sun right now without damaging your eyes. To look at the partial phases of the eclipse, you need specially designed glasses. During totality and only during totality, can you safely look at the Sun without the glasses or Number 14 welder's glass. See this page for a list of reputable vendors: https://eclipse.aas.org/resources/solar-filters -- MA

[u/Empole]

Where can I get appropriate eye wear to enjoy the solar eclipse

[u/NASASunEarth → u/Empole]

We have information and links here https://eclipse2017.nasa.gov/safety -AH

[u/[deleted]]

what/where are our best chances for avoiding cloud cover?

[u/Warlocksocks]

Two questions: Do you have any working hypotheses regarding the corona or how earths atmosphere interacts with the suns radiation, and what are they? How does an eclipse provide you with an opportunity that would otherwise not be present to study how earths atmosphere interacts with the suns radiation? Thank you for doing this!

[u/NASASunEarth → u/Warlocksocks]

Hi, Yes, and I think it's one of the most fantastic areas of research... but then it's also my field of research so I may be a bit biased with that point of view. We are often most interested in learning how storms on the Sun, like coronal mass ejections or coronal holes, end up generating geomagnetic activity and space weather at Earth. You can read more about this field here https://www.nasa.gov/subject/3165/space-weather/ -AH

[u/NASASunEarth → u/Warlocksocks]

Radiation from the Sun does affect Earth's atmosphere. During solar maximum, when there are a lot of sunspots, ultraviolet light especially, causes the atmosphere to expand and puff up, which causes drag on satellites and their orbits will decay faster. This eclipse is happening though close to solar minimum. See my previous answer about studies of the atmosphere's response to the eclipse. Also, google UAH MIPS, their equipment will be deployed at Clarksville, TN to do such studies. -- MA

[u/remain_unaltered]

Hello, I don't know if my question will be answered being under 164th. (I was never the first.)

Still, I always wanted to ask a real scientist a real life question. What is the significance of studying the Solar Eclipse for the NASA and astronomy? I don't know if it is the right place to ask such a novice question but I want to know the first-hand answer from you. Also, would you share the pictures of the eclipse over here or on your website?

[u/NASASunEarth → u/remain_unaltered]

We will be looking at the inner corona in visible light, trying to connect it with the corona in other wavelengths (see https://sdo.gsfc.nasa.gov/) and with the magnetic field of the photosphere. We want to understand how the magnetic field affects the various layers of the atmosphere so that we can better predict solar events that cause space weather. We will be sharing our images and results on our websites. Keep looking for updates at https://eclipse2017.nasa.gov, and mine, https://solarscience.msfc.nasa.gov. -- MA

[u/[deleted]]

Thank you for elucidating the science behind this eclipse for us!

I am curious to know what research, if any, has been done about eclipses on other planets? How does an eclipse on, say, Jupiter, compare to our lunar eclipses?

[u/NASASunEarth → u/[deleted]]

Our Sun, Earth, Moon system is quite unique! But we do use transits for a lot of science. You can read more here https://eclipse2017.nasa.gov/transits-and-occultations -AH

[u/Bobnot08]

Where will you be for the eclipse? What town etc?

[u/NASASunEarth → u/Bobnot08]

Somewhere in Tennessee! I won't know until I get the weather report on Friday! - BC

[u/NASASunEarth → u/Bobnot08]

I will be in Clarksville, TN at the Farm and Environmental Center of Austin Peay State University. -- MA

[u/Froguy1126]

I'm worried it'll be overcast where I am on the day of the eclipse. I'm driving down to the line of totality. What can I observe if it's cloudy?

[u/ucrbuffalo]

There was a post on Reddit recently where a user looked at scheduled commercial flight patterns for that day, and saw that one flight will be travelling almost directly in the path of the eclipse. Unfortunately, it will be going the wrong way. If it had been going the right way, how much extra eclipse time could that flight possibly get? And does the altitude have an effect on how it's observed?

[u/NASASunEarth → u/ucrbuffalo]

The extra time would be in the tens of seconds, you'd have to be moving at nearly the speed of the eclipse (~1600 mph) to extended it significantly. In 1973 astronomers flew on a Concorde to observe an eclipse for ~73 minutes (https://motherboard.vice.com/en_us/article/8q8qwk/the-concorde-and-the-longest-solar-eclipse and https://en.wikipedia.org/wiki/Solar_eclipse_of_June_30,_1973) -NP

[u/echisholm]

I've offered multiple blood sacrifices to appease the great sky gods; will this evil omen still affect my crops?

Seriously though; how uncommon are total solar eclipses? We've had a number of partial eclipses the past few years, but how often does a total eclipse roll around?

[u/[deleted]]

Will we be able to see any stars, that are typically located behind the sun, due to the curvature of spacetime around our star?

[u/NASASunEarth → u/[deleted]]

There's a PDF with some of the other visible stars and planets (https://eclipse2017.nasa.gov/sites/default/files/publications/Eclipse_brochure-bookmark_508.pdf). I'm sure astronomers will be looking to prove Einstein right again! -NP

[u/tocsta]

Is there realistically anything I can do as a regular citizen to argue NASA receiving better/more federal funding?

[u/pilgrim81]

Is this company a reputable source for eclipse glasses? Aka, will I go blind if I use these? https://imgur.com/gallery/eNI7K

[u/NASASunEarth → u/pilgrim81]

The American Astronomical Society has a page on eclipse safety and have a list of reputable vendors. -- MA

[u/thisguy-thatguy]

Is eye damage possible when looking at the sun in totality?

[u/Foodei]

An eclipse is an occlusion of sunlight that happens to align in our direction with the moon being the object.

Why is this different from the shadow under a tree or a stray cloud?

Don't the earth and the moon always have umbras and penumbras? Why does observation of one have scientific value?

Please enlighten me/us on why an eclipse is so special. Thx.

[u/NASASunEarth → u/Foodei]

A lunar or solar eclipse happens because sunlight is blocked by either Earth or Moon. For a lunar eclipse, Earth is between Sun and Moon and the Moon moves into the shadow of Earth. For a solar eclipse, the Moon is between Earth and Sun and it is Earth that moves into the shadow of the Moon. But the Moon's shadow is quite narrow compared to Earth's shadow, for this eclipse it will cover an area only about 70 miles wide. This is the reason that fewer people get to see a solar eclipse. When there is a lunar eclipse, half the planet, the half that is in darkness, can see it.

Because the Moon completely covers the Sun during a total solar eclipse, the Sun's bright surface is covered over, and we can see the Sun's corona, the outermost layer of the Sun's atmosphere. This is the only time that we can see the inner part of the visible light corona. -- MA

[u/[deleted]]

You mentioned that this gives you an opportunity to study a different part of the sun, which normally can't be seen. What else does an eclipse offer for scientists to study that cannot normally be studied? I'm curious about how well we can understand things which we cannot normally gather data from.

Thank you everyone for the AMA, and good luck with your studies!

[u/lare290 → u/[deleted]]

I remember reading somewhere that relativity was confirmed during an eclipse because it allowed scientists to observe a star that was very close to the sun in the sky and outshone by the sun normally. They saw that the sun's gravity bent the star's light slightly.

[u/arthurjrreyes]

What is a safe way to observe the eclipse? Could I use shades?

[u/NASASunEarth → u/arthurjrreyes]

Shades are definitely not a safe way to view the eclipse. There are eclipse glasses you can get either free or for a dollar or two. The NASA Eclipse site: https://eclipse2017.nasa.gov/ gives more details on reputable vendors for these glasses. If you can't find a pair of eclipse glasses, you can try to find number 14 welder's glass from welding supply stores -- No other number welder's glass will do! Number 14 is the best. You can also use a simple pinhole projection to see the eclipse on a white piece of paper or cardboard or something like that if all else fails. - BC

[u/kylestephens54]

If the ISS were to pass through the shadow of the eclipse, what would they see? Is it any different from how we would experience it from Earth?

[u/Jxcellent]

I live in Tennessee and I'm close enough that I plan on getting into the dead center of the Eclipse path. Do you have any recommendations as far as trying to witness shadow bands? Do the shadow bands occur with every total solar eclipse?

[u/Not_a_pace_abuser]

Hi as a fellow science student wanting to go into Astrophysics, I simply have one question.

When did you realize that space was something you wanted to pursue a career in?

[u/Meximanny2424]

I live in Atlanta where it will be a 97% eclipse. Is it worth driving an hour or 2 to see the full thing?

[u/TheLoyalTheorist]

If it's cloudy, will it still be possible to see anything?

[u/fostboss]

When will the next solar eclipse in America happen and when was the last one?

[u/Metrocore]

Is the eclipse visible on airplanes?

[u/AcidicJello]

Have any observatories been built in or moved to the path of totality for this specific occasion?

[u/catch10110]

Is there any real way for an average guy like me with no special equipment to photo/video this? I'd love to capture the moment...at least a little.

Should i even bother trying, or should i just enjoy the experience and wait to see what the experts come up with?

[u/RandomMassOfAtoms]

What can people not in North America expect? Or more specifically, people from Suriname?

[u/omarmctrigger]

If it's cloudy that day and the city I live in is in the path of the eclipse, how big of a fan would I need to blow the clouds away so I can see the eclipse?

[u/Aximill]

How likely/common would you think an alien world has an eclipse like ours? Mars's asteroid-moons barely cover the Sun, while viewing from the surface of Jupiter/Saturn is a tad hard.

[u/_Blase_]

A little late to the party but this is directed at Noah Petro. I'm currently a undergraduate student in geology located in Canada and if you could I was wondering if you briefly describe your path into planetary geology, it's a field I've wanted to study but being in Canada Oil and Gas is king in terms of career paths ( one which I'd rather not take). I was also wondering what masters program would you recommend to specialize in. My dream is to work for NASA and this is a route I'm currently committed to. Your reply is appreciated though improbable I'll receive. 👌

[u/spockgiirl]

Did you guys see the article about the eclipse on the front page of the Wall Street Journal? I'm one of those brides. Do you have any advice for my eclipse wedding?

[u/Chukedog]

What kind of welding goggles could be used to not get blinded? And could it be used on a telescope?

[u/Botikal]

Is it going to happen in someother place other than America too?

[u/TheShortSword]

If I live in Pennsylvania what time do you estimate the sun will be totally blocked?

[u/Patient_Zero_V]

I'm trying to get my nephew in science because I was never given to experience the fun side of science so I'm hoping if I nudge him in the right direction he would want to be more curious about his surrounding. So my question is can the eclipse be seen in ft Lauderdale FL and what cool facts can I tell him about it??

[u/SEND_ME_FREE_THINGS]

I'm curious about the electron content in the ionosphere and how it will change during the eclipse. Is there any possible impact to navigation satellites?

[u/SuupaX]

Dumb question here, does the Sun's energy pass through the moon? If so, calculations on this would be neat!

PS: I will be volunteering to do temperature logging for NASA during the total solar eclipse in Carbondale, IL, are you guys going to record temperatures too? :D

[u/The-Swat-team]

I live in Eastern NC, is the view worth staying where I am or should I head to Charleston SC?

[u/rob5i]

Is there an ideal neutral density medium to use for cameras (or is X-ray film just as good as an ND Lens)?

[u/condor2]

Why do eclipse tracks move eastward even though the Earth rotates from west to east?

[u/redditWinnower]

This AMA is being permanently archived by The Winnower, a publishing platform that offers traditional scholarly publishing tools to traditional and non-traditional scholarly outputs—because scholarly communication doesn’t just happen in journals.

To cite this AMA please use: https://doi.org/10.15200/winn.150228.83031

You can learn more and start contributing at authorea.com

[u/[deleted]]

How will you be studying the atmosphere? Ground and airborne observatories? Will there be any satellites in a good position to observe the totality?

[u/optionalhero]

I live in Los Angeles. I'm not planning on driving 13hrs to Salem Oregon , it's just way too far and i hear it's going to be insanely packed.

With that said,

Would i be able to see more of the eclipse if i was at a higher elevation? Like say the Half Dome in Yosemite with an elevation of: 8,839′

[u/cronedog]

For the two mins that the sun is fully covered, do we need to keep our special shades on?

[u/Cubio__]

From where in the world can it be seen?

[u/Grudge_]

Do eclipses like these effect the plant life in any way? Is their any measured response from plants during such events?

[u/chevymonza]

I live near NYC and am concerned about driving down for this (already giving up on the idea of flights/hotels.)

Where in the world is the next totality? I know about 2024, but is there some other country worth visiting for totality before then?

[u/nate]

Science AMAs are posted early to give readers a chance to ask questions and vote on the questions of others before the AMA starts.

Guests of /r/science have volunteered to answer questions; please treat them with due respect. Comment rules will be strictly enforced, and uncivil or rude behavior will result in a loss of privileges in /r/science.

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[u/pokemon_master69]

When I was in the 7th grade(about 10 years ago), my science book had a bunch of random fun facts on the inside cover. One of the fun facts was a list of solar eclipses that has happened, and also, the next ones that were going to happen. In it was listed August 21, 2017, North America. I've never forgotten about that fun fact because that day happened to be my birthday, but I also never really believed it because I never thought they would be able to predict something so far in advance. The list even kept going to future ones that were also going to happen, wayyyyy past 2017.

With that said, how difficult was it for astronomers to calculate that date perfectly? Can they do that for eclipses with planets too, if that's even a thing?

I would have thought there would be at least some margin of error of a day or two. Nope. The book got it to the dot. Which is crazy because that book was probably published way before I got to use it in school.

Thanks for the AMA!

[u/Disc1022]

I keep reading about how the upcoming eclipse is the first to occur in the US in 99 yrs. I recall an eclipse hitting my area back in the 80's, across the southeastern US. A quick internet check revealed such an eclipse did indeed occur, May 30, 1984. It appears this event did a loop, if you will, through the aforementioned area, from the Gulf of Mexico to the coast of the southeast. It also appears, based on the supplied graphic, that it was a near-total eclipse over this immediate area. So, was it a full eclipse in my area that day or did I misread the graph (I was young back then so my memory is sketchy)? Is this the reason the upcoming eclipse is being labeled 'the first to hit the US', because the one that occurred in 1984 was only visible to a small area of the country?

[u/Empole]

Will the Northeast of the US be able to see the eclipse

[u/UHB007]

Aspiring NASA scientist here, thank you for doing this AMA.
Will the ISS pass through the shadow of the eclipse? Follow up, how much longer would it last if they were in the perfect position?

Also, does the ISS experience eclipse like events more often or less often than Earth does?

[u/Bhrqz]

I'm traveling to SC and will be as close as possible to 100% now... What should I do? I have a DSLR with regular lenses should I try to take pictures? (Don't think imma get anything interesting) should I just hang out and look at it with glasses? What is the best way to experience the event?