Science - Draft 2 — Harlow Shapley Project

SHAPLEY’S KEY CONTRIBUTIONS TO SCIENCE

CONTENTS Banner Credits Below

I The Cepheid Revolution

I a Shapley's Ladder Across the Galaxy

I b Hubble Climbs Out to the Universe

I c A Generation of Astronomical Measurement

II a-d More Discoveries not linked
III a-c Breakthrough Contributions not linked
IV a-d Missed Discoveries not linked

Shapley Quotes | About This List | Sources & Credits

A. What can we humans learn about the Universe by peering far as we can into the night sky? What exactly is the Universe? And what is the Milky Way, the awesome dense white band across the night sky? For eons people have wondered about humanity’s place in the universe as they understood it.

In the early twentieth century a series of revolutionary answers was offered by a new generation of astronomers, telescopes and hard-to-believe physical theories. Harlow Shapley brought on the first of these revolutions: he displaced the model of a sun-centered universe that (dominated? science and thought since 400 years before, when Copernicus displaced earth from the center. .

B. Between 1914 and 1918 Shapley found that our Milky Way galaxy is vastly bigger than most astronomers thought In a series of startling papers filled with tables and charts of observations, Shapley mapped a flat wide disk. He showed the galactic center is a thick, dense bulge in the vicinity of the constellation Sagittarius in the southern hemisphere. He placed our solar system - Sun, earth, and us - two-thirds of the way out from the center.

Our galaxy seen from afar looks like the Needle Galaxy, NGC 3545 shown above. VB from large font. The black-white image is from a 1935 lecture by J.S. Plaskett; it shows Shapley’s model after the diameter he proposed (300,000 light-years) was adjusted to 100,000 light-years, close to its present value. 233

C. Copernicus and Galileo had already displaced the earth to a planet revolving around the sun. Now Shapley removed us to the sidelines of a “galactocentric” one. Or, as he often said in his Ozark farmer’s voice, “Man is not such a big chicken.” (See Shapley Quotes)

A less known part of the story is how Shapley discovered the galaxy’s size and shape. His papers lay out interlocking steps for finding the distance to fainter objects based distances he found for nearer ones. Shapley was the first effectively apply Leavitt’s Law to measure the universe.

[why switch to hub now?] Edwin Hubble started [what?] in the wake of Shapley’s revelations and used a more powerful telescope on Mount Wilson. Shapley’s quarry had been jewel-like globular clusters, round, glistening formations; he created a ladder to locate even the farthest of the 69 known. Hubble relied on Shapley’s ladder to search for Cepheids in the fuzzy nebulae and proved they are outside our galaxy - island universes. Hubble went on to show the expansion of the universe, measured on Shapley’s accepted distance scale. no ref Cephs yet.

D. Shapley made many other contributions in his long and restless scientific career. In this list, mapping the galaxy and cosmic distance ladder are only Number I, The Cepheid Revolution. Four More Discoveries follow. Then three Breakthrough Contributions, assemblages of [cientific knowledge] with ?great impact. Finally any list of Shapley’s scientific work is incomplete without Missed Discoveries. The three here are often told by his critics; my review finds that failure in science can have surprising results.

The writeups are sketches by a non-science journalist and granddaughter who knew him well. The brief sketches are anything but comprehensive. It also avoid digs and snipes among the leading players (eg Hubble’s disdain for Shapley; Shapley’s boasting, and so on). Its theme Shapley’s effective scientific work, a fresh look which may spark a re look debate, and more expert discussion than I can provide. I owe thanks to experts who have helped. The errors are mine alone.

I Leavitt and THE Cepheid Revolution

E. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

But Shapley built a new ladder for measuring distances never attempted by astronomers. He based his ladder on some very bright Cepheid variable stars [that Henrietta Swan Leavitt discovered change] their apparent light periods according to distance: the period-luminosity or p-l Law.

F. But Shapley built a new ladder for measuring distances never attempted by astronomers. He based his ladder on some very bright Cepheid variable stars [that Henrietta Swan Leavitt discovered change] their apparent light periods according to distance: the period-luminosity or p-l Law.

Shapley made the first effective calibration of distance from earth to Leavitt’s Cepheids, which were in the Small Magellanic Cloud (SMC). Thus Shapley measured (and revised) this rung of his distance ladder.

His further work on Cepheids turned them into standard candles. Cepheids became rungs for probing more distant globular clusters. His 3-D map of 69 globular clusters, drawn in Fig 1, outlined a wide flat galaxy with a bulging center and the eccentric location of our Sun. 120 words

**Caption:** Define Cepheids. the longer the period the greater the luminosity. P-L Relation became PL Law in her honor (year)

Back to TOP ↑

I a SHAPLEY'S LADDER ACROSS THE GALAXY

e. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

I a-1 THE BASE - RUNGS 1 & 2

f. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

•       Horizontal axis shows each star’s period of light variation. On far left are the slowest-blinking ones; the faster ones are towards the right.
•       Vertical axis shows real brightness or absolute Magnitudes (M) of each. The brightest at top approach -7 M; the faintest at bottom approach 0 M.
•       Shapley computed each star’s absolute Magnitude (M) by taking its apparent brightness (m) and applying Leavitt’s p-l relation of 0.48 for each M.
•       Absolute Magnitude yields distance by applying the inverse square law. A star two times as bright as another is 4 times farther away from it.
•       Base distances to the closest Cepheids were found by the accepted method of parallax.
Mt Wilson Contributions…ciw …. 1918

A Rung 1 Cepheids
Placeholder Smith 70 & RA pp 4-5. Picked up HSL Law that observing the period in a Cepheid’s light variation he could determine it’s intrinsic brightness (luminosity) & hence it’s distance. Used Hz values for 11 close Cepheids to publish a distance to the Small Magellanic Cloud. (This is Paper II in 1915, recalib 1918 with a value …
This paper opened the door to detailed study and use of Cepheids as standard candles - which Shapley proceeded to do. (See I Ladder Across the Galaxy.) The 1914 paper opened the possibilities for Arthur S. Eddington, dean of British astronomers, to investigate how such pulsation occurs. Even Alan Sandage a later fierce critic of Shapley wrote that his “masterful” 1914 paper lon Cepheid pulsation ed to important work at Mount Wilson and a new field in astrophysics.

Back to TOP ↑

I a-2 RUNG 3 BRIGHTEST STARS

I a-3 RUNG 4 - DIAMETER BRIGHTNESS

I a-4 OUR GALAXY IS REALLY WIDE AND WE ARE OFF-CENTER

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

“I have always admired the way in which Shapley finished the whole problem in a very short time, ending up with a picture of the Galaxy that just about smashed up all the old school’s ideas about galactic dimensions.”
—Walter Baade, quoted in OG HS and MWO p.16

Keep this point here? Why many accounts focus on how he was wrong (too big?) no dust, etc. But it was accepted & corroborated (landmark & oort) even as crit of basing a rev’y model on 11 Cepheids seemed a reach.

TRANS SEE Science Page Hubble Text Final 1-16. Passage is now > 200 words. Great Debate, Appt to Hvd.

Continued to defend an ultimately wrong position that Big Galaxy holds spiral nebulae.

Back to TOP ↑

I B HUBBLE CLIMBS OUT TO THE UNIVERSE

A From Science Page Hubble text 1-10-2025 pink. um dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iac

SO Insert new A’ wide text block below this.

A’ Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus.

**Caption:** Text here Credit Harvard University Archives for the Image

B Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin

**Illus GG:** Hubble’s photo of NGC 6822 (Barnard’s) taken in July 1923 and published in his 1926 paper. The distance Hubble got was comparable to Shapley's; had written in 1923 it could be one million light years away. Image shows indistinct nebulosity and possible Cepheids. *Source: “NGC 6822 A Remote Stellar System,” E. Hubble, 1926.*

**Illus G:** Shapley found these 39 globular clusters grouped in 3 percent of the sky near Sagittarius and Scorpius, suggesting it is the Galactic Center. Today’s precise center SgrA* is located there. *Image: Shapley, H. (1969) and AIP/ESVA.*

I b-1 DISCOVERY MOMENT

C. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

D Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales

E Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet

**Illus J :** M 31 Andromeda taken by Hubble

**Illus K:** VAR! the observation plate that transformed astronomy. Also Oct 5, 1923. By then Shapley and Hubble were in a dialogue over NGC 6822.

BOX Blue Rim (Release of 1925 paper. The 6822 story showed Shapley/HCO Science Service press machine. Above says Shapley had switched. Text ends with the huge public impact of Hubble Jan 1, 1925 paper. In box quote Hubble this changes our place in the universe. MB Shapley became the new universe’s most boisterous promoter. Quote him in the news. And would study galaxies rest of his career.

I b-2 VELOCITY = DISTANCE / TIME

G Slipher + Speed Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

**Illus Eye-Eye ;-). Caption:** Text here Credit Harvard University Archives for the Image

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. .

I b-3 RUNGS 2 & 3 BRIGHTEST STARS AND DIAMETER

H Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

I Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. tincidunt auctor.

J Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

I b-4 Paradigm Shift In Our Relation to the Universe

K. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

L Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodale

M Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus,

O Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus,

**Galaxy distances and velocities.** **LEFT** From Hubble’s 1929 paper. It shows their speeds increase with distance out to 2 million parsecs. In this paper he computed the rate known as Hubble’s Constant. **RIGHT** Hubble and Humason in 1931 shows galaxy velocity keeps increasing at the same rate out to about 32 million parsecs. **Red dots** approximate Shapley zero points and distances to Large and Small Magellanic Clouds. *Graphic: Harlow Shapley Project*

P Closing text Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam.

Q Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Proin diam risus, iaculis sit amet arcu eget, aliquet convallis diam. Duis ac nulla justo. Etiam euismod tincidunt auctor.

“Hubble could not have achieved his breakthroughs of the 1920s without Shapley’s pioneering work on the distance scale. Leavitt and Shapley were both essential to Hubble’s success.”

— Horace H. Smith, Astronomer and Historian

Back to TOP ↑

I C A GENERATION OF ASTRONOMICAL MEASUREMENT

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum

Back to TOP ↑

ShaPley Quotes

Moment of Discovery of the galaxy’s true shape in 1918

”It was a shocking thought--this sudden realization that the center of the universe was not where we stood but far off in space, that our heliocentric picture of the universe must be replaced by a strange sort of eccentric universe.

“Gradually a reorienting view developed; “I have put it wrong end to. I should not say or think that the center of our universe is so remote and removed from us, so removed from the proud observers.

“No, I should say that the trivial observer is far from the magnificent, star-filled center! He is the peripheral, the ephemeral one. He is the incidental biological by-product of water, soil, air and sunlight. He is off in a cosmic corner, invisible from the central nucleus around which billions of stars revolve and to which we, like they, pay gravitational homage.”

— View from a Distant Star, 1964, p. 2 Q# 1 HS Quotes VDS started 12-7-24.docx

Back to TOP ↑

ABOUT THIS LIST

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus.

Back to TOP ↑

CREDITS & Sources

Main image: Needle Galaxy NGC 4565 looks as our Galaxy would if we viewed it edge-on. Inset: J.S. Plaskett’s 1935 image of Shapley’s watch-shaped Galaxy; dots are globular clusters.

orem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum justo purus, sodales quis tincidunt sed, tristique id purus.

Back to TOP ↑

Sophia’s Questions:Are the following images to be removed or do they stay?

Deborah 12: 40 on Jan 31. Look for my 12:45 email today. It explains the new content & images are for the blog post about my talk! The empty one where you started the ladders. Can you just import this all over to the blog post? Then restore the 520 PM Science page here? I know it’s odd but a lot of people won’t go to the science page. And my talk presentation makes a strong argument re Shapley and Hubble. The science page text is detached and brief with more images. I am here. Thank you.

SHAPLEY’S KEY CONTRIBUTIONS TO SCIENCE

I Leavitt and THE Cepheid Revolution

A beautiful example of Leavitt’s law in practice

ShaPley Quotes

ABOUT THIS LIST

CREDITS & Sources