The Makings of the Stars

I am working on illustrating the constellation art for the modern sky. In this blog is my process into creating art

[plotsjotsandespressoshots-deact]

Remember in 1993 when Jurassic Park was like…the end all, be all of special effects?

[suicunesrider]

not gonna lie that still looks intimately real

[drtanner-dickery]

I’m still somewhat convinced that someone sold their soul to create the special effects in Jurassic Park because that shit is over 20 years old and it still really, really holds up, better than the stuff in a lot of current movies, even.

Fucking witchcraft, man. 

[fanboyingoverdemigods]

fucking look at this shit though

[mauridianhallow]

Literally see this post flying around with a few different responses added to the bottom each time so I’ll say it for this one myself:

THEY ACTUALLY BUILT A GIANT MASSIVELY DETAILED FUCKING ANIMATRONIC T-REX FOR ALL OF THIS THAT’S WHY THE EFFECTS ARE SO GOOD. CAUSE IT AIN’T CGI. AND IT AIN’T GUY IN A COSTUME. IT’S A BIG FUCKING ROBOT DINOSAUR. AND EVERY PART IS DESIGNED TO MOVE. IT COST LIKE HALF THE BUDGET OF THE FILM.

[mizushimo]

amazing

[shadowthorne]

And they had the film it in small increments, especially in the outdoor scenes, because the rain fall kept soaking into the ‘skin’ of the rex and would slow down and mess up its movements. So they would stop filming and have a crew out there drying off this massive, fake dinosaur, and then they’d start filming again until it was too wet. Repeat until the end of the scene.

[mad-dyspunktional]

They used animatronics and detailed costumes for most if not all of the dinosaurs in the first movie.

The triceratops for instance, was also animatronic.

And the raptors were dudes in suits. I shit you not.

[datneeks]

One of my favorite anecdotes I’ve read on tumblr is how the t-rex robot from Jurassic park would malfunction while it was drying out. How did it malfunction, you might wonder?

Motherfucker randomly started moving.

So apparently if you were on the jp set you would sometimes hear people screaming bloody murder even though they were all well aware that it was a giant animatronic puppet and wouldn’t actually, you know, eat them.

[muck-raker-deactivated20181222]

(link to said post about malfunctioning t-rex)

[alessariel]

Did not know this, had to reblog for awesome movie history insights.

[brainsforbabyjesus]

So, I knew about the animatronics bit but I did not know the raptors were guys in suits and the malfunctioning t-rex sounds terrifying.

And i just googled malfunctioning t-rex and was not disappointed. Apparently in order to put the skin on over the steel frame a guy had to crawl inside the t-rex while it was turned on and glue the skin down. And if somebody turned the t-rex off or the power went out the guy in the t-rex stood a very real chance of getting mangled and killed by the hydraulics.

So of course, the power goes out.

And this guy is still in there gluing the skin down.

Apparently the way to survive getting sheered to death by huge sheets of metal while you’re inside a giant t-rex robot is to curl into a ball and hope for the best.

And this guy hoped for the best and got it.

Some other people on stage pried open the t-rex jaws and glue guy crawled out of its mouth and was totally okay.

[alessariel]

This is getting better and better.

[red-dirt-roads-deactivated20161]

I think they only had like 6 minutes of CGI

[teslasturtle-deactivated2023011]

I’m just waiting for the T-Rex to come to life and leave its stand.

[perspectivemax-deactivated20181]

@spinosaurus-the-fisher is this the kind of content you love?

[myloverhammurabi]

Realism comes at a cost, it seems.

[gorsime]

i mean ok but why has nobody posted this:

[myloverhammurabi]

It’s a three piece raptor suit.

[flamingbluepanda]

Old movies had the best special effects

[skafuller-deactivated20180122]

The thing about this that gets my special effects nerd going is the fact that EVERY single dinosaur was sculpted by artists based on the current existent archeological evidence of the time.

[witwitch-deactivated20160508]

@jurassicparkandrecreation

[senkirowolf]

@shepfax

[prettyarb]

Even better than that, this movie ADVANCED our best understanding of dinosaurs at the time.  They were blowing out a budget bigger than anything Hollywood had ever seen, and along with employing almost the last hurrah of incredible physical FX, they had a bank of those newfangled digital SFX computers.  Nobody’d ever really created convincing dinosaurs in a movie before.  It’d all been stop-motion animation, and even when the models were exquisitely crafted, you could just tell there was something OFF about them.  Spielberg wanted THE BEST DINOSAURS EVER, and he figured on using the cutting edge of digital modeling and animation technology to build them for him.

So they got hold of some of the best paleontologists they could find and said, “We want you guys to take this tech that your labs could pretty much never afford and use it to build us the most realistic, accurate dinosaur models the world has ever seen.”

The paleontologists knew an opportunity when it bit them in the ass.  They plugged in everything they knew about dinosaurs, all the skeletons and their best guesses about soft tissue and all that.  And when they’d created those dinosaur models, they had the computer start moving them as they realistically would with anatomy like that.  One guy took a look at those walking t-rexes and velociraptors (really utahraptors, but whatevs, fam), and he said, “Wait a minute, I’ve seen movement like that before.”

He called up film of a chicken walking.  Everyone in the room said, “Holy shit.”

Prior to 1989, the idea that birds were descended from dinosaurs existed–we knew about archaeopteryx, we knew there was some minor connection there–but the idea that DINOSAURS LIVE IN THE MODERN WORLD AND THEY ARE CALLED BIRDS was not pre-eminent.  Jurassic Park changed our scientific understanding of dinosaurs.

[bastlynn]

That paleontologists’d be Kevin Padian. Who is awesome.

https://en.wikipedia.org/wiki/Kevin_Padian

[thistherapylife]

This post just gets better and better with time

[evilsquirrel18]

Always reblog this and it hurts my soul when they say old movies because I was like ten when this came out and… THIS WAS MY CHILDHOOD.

[nasa]

Solar System: Things to Know This Week

From observing our moon to Saturn’s mini solar system …here are a few things you should know about our solar system this week:

1. What a Long, Strange—and Revealing—Trip It’s Been

As the Cassini mission builds toward its climactic “Grand Finale,” we’re taking a look back at the epic story of its journey among Saturn’s mini-solar system of rings and moons.

+ Traverse the timeline

2. Our Very Own Moon

Unlike Saturn, Earth has only one moon. Let’s celebrate it! International Observe the Moon Night (InOMN) is a worldwide, public celebration of lunar science and exploration held annually. On Oct. 8, everyone on Earth is invited to observe and learn about the moon together, and to celebrate the cultural and personal connections we all have with it. 

+ Join in

3. What’s Up, October?

Even more about Earth’s moon is the subject of this month’s video guide for sky watchers and includes a look at the moon’s phases and when to observe them. Also featured are a guide to upcoming meteor showers and tips on how to catch a glimpse of Saturn.

+ Take a look

4. Nine Lives

Dawn’s discoveries continue, even as the asteroid belt mission marks nine years in space. “For such an overachiever,” writes Dawn’s top scientist, “it’s fitting that now, on its ninth anniversary, the spacecraft is engaged in activities entirely unimagined on its eighth.”

+ Learn more

5. The Incredible Shrinking Mercury

It’s small, it’s hot, and it’s shrinking. Research funded by us suggests that Mercury is contracting even today. This means we now know that Mercury joins Earth as a tectonically active planet.

+ Get the small details

Discover the full list of 10 things to know about our solar system this week HERE.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

[nasa]

What’s Up for October 2016?

What’s Up for October? Moon phases, Astronomy Day, meteors and Saturn!

The new moon phase starts the month on October 1. Of course, the new moon isn’t visible, because it’s between Earth and the sun, and the unlit side is facing Earth. 

Night by night the slender crescent gets bigger and higher in the sky and easier to see just after sunset. On the 3rd and 4th, the moon will pass just above Venus!

A week later on the 9th the moon has traveled through one quarter of its 29-day orbit around Earth, and we see the first quarter phase. Also look for Mars just below the moon.

Join us in celebrating International Observe the Moon Night Saturday, October 8th, with your local astronomy club or science center. Conveniently, the 8th is also Fall Astronomy Day, celebrated internationally by astronomy clubs since 1973.

One week later on the 16th the moon reaches opposition, or the full moon phase, when the moon and the sun are on opposite sides of Earth. And the sun completely illuminates the moon as seen from Earth. 

During this phase, the moon rises in the east just as the sun is setting in the west. Overnight, the moon crosses the sky and sets at dawn.

A week later, on the 22nd of October, the last quarter moon rises at midnight. Later, the pretty and bright Beehive Cluster will be visible near the moon until dawn.

To wrap up the month, 29 days after the last new moon we start the lunar cycle all over again with another new moon phase on October 30th. Will you be able to spot the one-day old moon on Halloween? It will be a challenge!

There are three meteor showers in October–the Draconids, the Taurids and the Orionids. Try for the Draconids on October 8th.  

See the Taurids on October 10th. 

The Orionids will be marred by the full moon on the 21st, but all three meteor showers will offer some possible bright meteors.

Finally, you’ll have an especially pretty view of Saturn, when it forms a straight line with Venus and the red star Antares on the 27th.

You can catch up on NASA’s lunar mission, the Lunar Reconnaissance Orbiter, the Cassini Mission to Saturn and all of our missions at www.nasa.gov.

Watch the full October “What’s Up" video for more:

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

[nasa]

Constellations and the Calendar

Did you recently hear that NASA changed the zodiac signs? Nope, we definitely didn’t…

…Here at NASA, we study astronomy, not astrology. We didn’t change any zodiac signs, we just did the math. Here are the details:

First Things First: Astrology is NOT Astronomy…

Astronomy is the scientific study of everything in outer space. Astronomers and other scientists know that stars many light years away have no effect on the ordinary activities of humans on Earth.

Astrology is something else. It’s not science. No one has shown that astrology can be used to predict the future or describe what people are like based on their birth dates.

Some curious symbols ring the outside of the Star Finder. These symbols stand for some of the constellations in the zodiac. What is the zodiac and what is special about these constellations?

Imagine a straight line drawn from Earth though the sun and out into space way beyond our solar system where the stars are. Then, picture Earth following its orbit around the sun. This imaginary line would rotate, pointing to different stars throughout one complete trip around the sun – or, one year. All the stars that lie close to the imaginary flat disk swept out by this imaginary line are said to be in the zodiac.

The constellations in the zodiac are simply the constellations that this imaginary straight line points to in its year-long journey.

What are Constellations?

A constellation is group of stars like a dot-to-dot puzzle. If you join the dots—stars, that is—and use lots of imagination, the picture would look like an object, animal, or person. For example, Orion is a group of stars that the Greeks thought looked like a giant hunter with a sword attached to his belt. Other than making a pattern in Earth’s sky, these stars may not be related at all.

Even the closest star is almost unimaginably far away. Because they are so far away, the shapes and positions of the constellations in Earth’s sky change very, very slowly. During one human lifetime, they change hardly at all.

A Long History of Looking to the Stars

The Babylonians lived over 3,000 years ago. They divided the zodiac into 12 equal parts – like cutting a pizza into 12 equal slices. They picked 12 constellations in the zodiac, one for each of the 12 “slices.” So, as Earth orbits the sun, the sun would appear to pass through each of the 12 parts of the zodiac. Since the Babylonians already had a 12-month calendar (based on the phases of the moon), each month got a slice of the zodiac all to itself.

But even according to the Babylonians’ own ancient stories, there were 13 constellations in the zodiac. So they picked one, Ophiuchus, to leave out. Even then, some of the chosen 12 didn’t fit neatly into their assigned slice of the pie and crossed over into the next one.

When the Babylonians first invented the 12 signs of zodiac, a birthday between about July 23 and August 22 meant being born under the constellation Leo. Now, 3,000 years later, the sky has shifted because Earth’s axis (North Pole) doesn’t point in quite the same direction.

The constellations are different sizes and shapes, so the sun spends different lengths of time lined up with each one. The line from Earth through the sun points to Virgo for 45 days, but it points to Scorpius for only 7 days.  To make a tidy match with their 12-month calendar, the Babylonians ignored the fact that the sun actually moves through 13 constellations, not 12. Then they assigned each of those 12 constellations equal amounts of time.

So, we didn’t change any zodiac signs…we just did the math.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

[ramblingsoftheinsaneuniverse]

Pegasus

Alright so I haven’t posted anything here in 2 years. I was going to use this as a place to post my progress on each design. Well life got in the way and I halted progress on Ursa Major.

As you can tell, this post is titled “Pegasus” because I moved all my focus to a different part of the sky. I am part of the Great Lakes Planetarium Association (GLPA). At our most recent conference in October, a colleague of mine announced he registered a star for Indiana’s Bicentennial (Indiana is where I currently reside). This star is 200 light years away, so the light that is reaching earth now from that star will have left when Indiana became a state. This star is in the constellation of Pegasus.

He has set up a section on his website for Indiana’s Bicentennial star, which you can find here and here. 

This image shows the star and where it is in the constellation of Pegasus *credit Stellarium*

This gives better perspective on where on the “horse” the star is in relation to the other constellations *credit Stellarium*

The star’s name is Scheat and it is the second brightest star in the asterism of the Great Square of Pegasus. Below is a better explanation on the translation of the star’s name. 

Beta Pegasi (β Peg, β Pegasi) is a red giant star in the constellation Pegasus. The apparent visual magnitude of this star averages 2.42, making it the second brightest star in the constellation after Epsilon Pegasi. Its traditional name is Scheat,[11] a name that has also been used for Delta Aquarii. According to Richard H. Allen, this name comes from the Arabic Al Sā'id for "the upper arm", or from Sa'd. Arabian astronomers named it Mankib al Faras, meaning the "Horse's shoulder". It forms the upper right corner of the Great Square of Pegasus,[11] a prominent rectangular asterism. 

The two images above are screenshots from the program Stellarium. It is a very useful program and I especially use it when working on constellation illustrations. This constellation artwork styles itself after traditional constellation artwork, but it is more simplistic. I’ve never been too crazy about the constellation art from this program, but I figured out a long time ago I could switch out the artwork for my own. 

Source

Source

I don’t hate this art style, that would be like hating art from the Middle Ages because they didn’t understand anatomy. Its old traditional art and it is what it is. But it's not my art style so that’s one of the reason’s I want to make more updated art. I use these traditional constellation designs for inspiration for my own designs. I also look up the mythology behind these stories to discern any other symbolism that I could incorporate into the designs.

Problems I had with this design

I’ve drawn horses before. I did grow up as a girl (to rely heavily on stereotypes) I had have toy horses and even grew up near a horse farm. But for some reason the horse anatomy was eluding me. Thankfully, I was able to find a lot of tutorials for drawing horses. 

Horse Tutorial Part 1 (Anatomy) by Vanycat <3 this one

How To Draw Horses Tutorial

Horse Tutorial

The first initial sketch wasn’t terrible, but it was very crude. I needed to know what direction to take the design. 

I like how comparing these two it seems to get better and worse all at the same time. In order to accurately draw the horse I looked up lots of reference photos

Here are some that I used. I had wanted to make Pegasus look like he was running, but it became easier to make it look like he was leaping. 

white gray overo paint 1

chestnut tobiano stallion 2

Bay Horse Rearing Stock

Bay Horse Rearing Stock

This shows the completed drawing of the horse part. I couldn’t find many progress images with the wings. Drawing the wings was somehow more difficult. I couldn’t decide on how to position the wings, or figure out the perspective of them. I also had to keep in mind to not making the entire design too large, going beyond the constellation boundaries, especially if I wanted to show it in Stellarium accurately. 

These images are from when I was testing the design in Stellarium. I ended up needing to fade the left wing to make it fit in the constellation better. To do this I needed to make a compromise with the constellation outline. You’ll be able to see a better example of that in the final design at the bottom. I’ll go into more detail then. 

Tutorials and stock images that helped me

Wings Tutorial by Vanycat < only useful wing tutorial on the internet

.Macaw wings 5. 1134

Swan Wings 1 

The next challenge was the mane. (At least there isn’t too much more to talk about, just pictures to look at. Don’t worry, the end is near!)

I went through several different styles of the mane before I came up with one that didn’t look terrible. This is not the final version. 

A note about the coloring: I drew up the designs in neon colors because it's traditionally what I used when design the blacklight mural. I would use bright colors to draw out the designs and that habit carried over to these designs. I have different colored hair here so I can tell the difference between all the different lines. The wings were green when they were a work in progress. 

The next few images are work-in-progress of drawing out the final design of the mane.

This is a better example of why the colors needed to be different. You can see this by looking at the area by the ears and the line of the neck. 

The hair was a bit overwhelming. I had wanted it to be more simplistic, but I couldn’t manage to make it any more stylized without losing the motion and feel of the hair. The shape of this hair really shows movement with Pegasus and it really helps the viewer visualizes wind whipping through the mane. 

And here is the final design! When it's in Stellarium, the left wing will be faded. Everywhere else, it will look like this. The problem I had with the constellation outline placing is that the little section just about the left wing is supposed to be on the face because it represents the head. Even the star’s names indicate that. I had to place the constellation outline like this in order for it to fit in stellarium better. It was that or completely remove the left wing and I really didn’t want to do that after all of the work I put into it. Another option would have been making the left wing look more like the right and make it look more tucked in. But again, all the work I already put in. 

A final thing I was considering was adding fur around the hooves (think clydesdale horses) and making wings look a little more interesting. Pegasus is supposed to be the God of horses and I wanted him to be more than a horse with wings. I think now, the wings are fine. I’m not even sure how to make them look different and “functional looking” at the same time. I would like to research different shaped bird wings to see what purpose serve. Adding fur to the hooves would add more interesting features to the design, but at the same time it would add more balance to the design since the mane is pretty intense. 

[nasa]

Secrets lie deep within Jupiter, shrouded in the solar system’s strongest magnetic field and most lethal radiation belts. On July 4, 2016, our Juno spacecraft will plunge into uncharted territory, entering orbit around the gas giant and passing closer than any spacecraft before. Juno will see Jupiter for what it really is, but first it must pass the trial of orbit insertion. For more information: http://www.nasa.gov/juno and http://missionjuno.swri.edu.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

[staff]

Tumblr: @nasa’s Juno spacecraft is just 4.8 million miles (five days!) away from its new home circling Jupiter. You really want to start following their Tumblr.

They’re going to be posting stuff all weekend, including early approach photos. And: once Juno gets situated they’re going to let people vote where to point the camera.

Besides, look what it’s carrying—these adorable LEGO people: Jupiter (the Roman god), his wife Juno, and Galileo Galilei.

Image via NASA

[ramblingsoftheinsaneuniverse]

Aquarius process and thoughts

Today I’m going to explain the process I made when I started on the mural with my first design. In order for me to sell this work, I’m going to have to recreate the entire zodiac. This is going to be extremely easy for some designs and extremely hard for others.

Aquarius is going to be one of the easy ones. When I saw the original mural, I saw great potential, until I was told that I needed to recreate each design as they were originally made. This included line quality and anatomy, or lack thereof.

Each design started with a tracing that was then transferred with chalk. I had some initial confusion with the first three designs when it came to transferring with chalk because I did not make the original tracing. Some of the challenges I had was in interpreting the lines. This was a result of the original artists not having a clear understanding of anatomy.

Sorry for the poor quality images. Some of the early images were not taken by me/I wasn't completely skilled on how to take the images and reduce glare at this time. The walls of the planetarium are weird on how they absorb and reflect light. 

The first designs started off with minor changes. This included, but wasn't limited to thickening up the lines. I decided to do this because the line quality was inconsistent and wavy.

This is a black light mural. The black light shows details easier

I filled in the eyes because thats what the original had. It looks different from the original because I the eyes were too small in the original. In the final design, I changed it to an outline. 

Some other changes I made was to adjust minor anatomy issues, such as the placing of the shoulder and the sculpting of the hip and legs. A main issue that came up with every humanoid design was that the feet and sometimes hands were disproportionate.

In the image above, the foot does not have toes and the one hand is a hook. I didn't originally add toes to the design because I was asked to keep the designs as simple as possible.

As I worked on the other humanoid designs, I noticed that there were lines indicating there were supposed to be toes. I added those to the later designs and fixed this design. I originally made a hook because I wasn't sure how to interpret the lines. Afterward, when I saw the image of the original design, it made more sense that it was supposed to be a hand supporting a vessel. I decided not to go this way because the hand position didn't match the anatomy. I would have had to change more than just the hand to match the original position. 

 Later on when I remake this design for myself, I plan on adding a wrap around his waist. Aquarius is a male youth. He served water to the gods on Mount Olympus. I would probably not have him float. I have not looked at the constellation outline, but that would depend greatly on the what I would do with the design. The original artists didn't use completely accurate constellation outlines so I cannot depend on this design's outline. 

My thoughts are kinda scattered. If I was unclear anywhere, let me know and I'll try explaining. 

[ramblingsoftheinsaneuniverse]

ROBOTS OR DINOSAURS?

Robotic dinosaurs

[ramblingsoftheinsaneuniverse]

Ursa Major (gathering resources)

I have decided to model Ursa Major after cave bears. This would be great except that the best description I could find a about cave bears is that the most likely resembled modern brown bears and since I would want the design to be modeled after large bears, it means I need to use Grizzly and Kodiak references. I wanted to avoid animals not found in the Mediterranean area, but I guess I'm going to have to overlook that. I have gathered reference images for the project and saved them to my Google Drive but just realizing now that I only saved the links to the images. I'll fix that later, but in the meantime I'm going to link that folder if you wanted to look at what I've gathered so far. https://drive.google.com/folder/d/0Byks507srqR9d1IyMjhpUUtHaFk/edit Kinda thinking I want Ursa Major to be a big fluffy bear, because big and fluffy is beautiful and scrawny bears are depressing. Not sure what I want to do with the position of the head yet, but I'll decide that when I start drawing.

[ramblingsoftheinsaneuniverse]

Ursa Major

Not too long ago, I was commissioned for a project to redesign a zodiacal mural in a planetarium. Through most of that, I researched each constellation and each myth tied with the constellation in order to create the best representation for the constellation

I have decided to start with the bears, but in order for me to get anywhere I need to decide on what type of bear. Generally, I like to focus on themes related to areas near Greece since most of the constellations are Greek myths. 

The myth of Ursa Major centers around the story of Callisto. In the story it doesn't talk about a specific kind of bear or any real description of said bear. Because of that I need to find a bear that would make sense. Picking a Grizzly or a Kodiak would be too cliche and I would really like to avoid North American themes. I believe a large bear would work the best and it needs to be an impressive bear to represent Ursa Major. I do feel that the Etruscan Bear and the Cave Bear would fit very well, as well as the Atlas Bear.

Etruscan Bear is the main ancestor of current modern bears and the Cave Bear was a very large, impressive and intimidating bear. Both of which fit with the impressiveness that is Ursa Major. The Atlas Bear is not as large and impressive as the first two bears, but it was the only bear of Africa and that in itself is impressive. 

Just a side note, while looking for reasons why Ursa Major and Minor have long tails, I came across a reason. Raccoons and mainly Procyonidae the family that raccoons are included in are sometimes thought of as small bears. Now thinking of this and the region and time period that the Ancient Greeks thrived, it seems difficult to imagine how they would have seen a raccoon. The only thing that could have made sense would have been if someone from that time period came across a Red Panda, which looks similar but is not a bear or a raccoon. 

Below is some links to what I've researched so far. After this, I'm going to settle on a type of bear and start gathering reference pictures which I'll post next. If you have any information to add, let me know. 

http://en.m.wikipedia.org/wiki/Ursa_Major

http://en.wikipedia.org/wiki/Marsican_brown_bear

https://www.google.com/search?site=&source=hp&ei=vDKzU-eBNtWkyASs8oHIAg&q=Bears+from+Mediterranean+reagion&oq=Bears+from+Mediterranean+reagion&gs_l=mobile-gws-hp.3..30i10.9145.35733.0.36387.42.34.8.1.1.0.476.7641.0j16j11j5j1.33.0....0...1c.1.48.mobile-gws-hp..12.30.5628.0.lJxHHWqDxZM#q=Etruscan+Bear

https://www.google.com/search?site=&source=hp&ei=dYuzU5Jig5KqBuydgtAL&q=Cave+Bear&oq=Cave+Bear&gs_l=mobile-gws-hp.12..0i20l2j0l2j5.17410.17410.0.18878.3.2.1.0.0.0.176.176.0j1.1.0....0...1c.2.48.mobile-gws-hp..1.2.224.3.6zdjZxVCPI8

http://planetearthscienceart.blogspot.com/2010/07/africas-only-bear-brief-natural-history.html?m=1

http://adsabs.harvard.edu/full/1946PA.....54..111D