Prefaceix

Over many millennia, civilizations have been curious about the Universe in which they fi nd themselves, so stories about origins were devised: how the Milky Way formed, why there are seasons, what causes the rising and the setting of the Sun and the stars. These stories were handed down throughout generations, and became an important part of science history. As tools and understanding progressed, questions were answered but new discoveries and new questions arose to take their places.

In recent times, the pace of science and technology has increased enormously. Before 1950 we lived in a Universe that we detected almost entirely with our eyes, or with substitute eyes, such as telescopes or cameras. These instruments were generally sensitive only to the wave-length region seen by the eye. But in the last fi fty years or so, the pace of new astronomical discoveries has been enormous. Every decade or so, a new discovery has forced scientists to revise their understanding of the history and evolution of the Universe. Some of these phenomena were surprises, enabled by new technologies. Some advances came from using known technology, some from using new ideas, some from both.

Consider this increase in our knowledge of astronomy in only 50 years:

1950s: New detectors sensitive in the radio region of the spectrum returned images of stars and galaxies as seen by their emission of radio waves. Astronomers discovered radio galaxies, galaxies that emit more of their radiation at radio wavelengths than at optical wavelengths. Within a few decades or so, astronomers could detect and study galaxies also by their ultra-violet, infrared, x-ray, and gamma ray radiation.

Preface:era Rubin

Prefacex

1960s: Quasars were discovered, now understood as energetic cores of galaxies, many enor-mously distant from our Galaxy. They are also called quasistellar objects, due to their point-like nature.

1970s: Studies of rotation velocities for stars and gas in galaxies, some acquired from optical, some from radio observations, indicate that most of the matter in the Universe is dark. Now called dark matter, radiation is not one of its attributes. Most of the dark matter cannot be composed of conventional matter.

1980s: Distant galaxies appear to be expanding at velocities faster than predicted from sim-ple cosmological models. Dark energy, an unknown energy, is invoked to explain the high velocities.

1990s: Astronomers increase the dust mass in spiral galaxies by ninety percent. The fi rst extrasolar planets are also detected, planets orbiting nearby stars. The number of known extrasolar planets now numbers almost 250.

What discoveries will the next 50 years bring astronomers and the interested public? We can only guess how our view of the Universe will be altered. Earlier science history suggests an accelerating rate of discoveries. The work of David Block and Kenneth Freeman already forms an important part of this accelerating knowledge. As they describe in this book, their discovery that cold cosmic dust pervades space makes it necessary for astronomers to rede-sign their classifi cation scheme for galaxies. They suggest that symmetry should be at the heart of a new classifi cation scheme in the near-infrared. One look at the stunning images produced by astrophotographer David Malin in Chapter 11 is suffi cient to convince any skeptic.

Along the way, this book takes the reader on a whirlwind tour of astronomical photo-graphic history beginning with the world’s fi rst heliographs (one of these newly unveiled by David Block) to the present day diffi culties of classifying galaxies. But the described route is not linear. Instead, the reader is exposed to nights at a telescope, travels to talk and to learn, biographies of early and recent scientists who have contributed to the path David and Ken follow. Their story is part of the history as they describe their work as

Preface xi

astronomers. And they write about their discoveries in a manner that makes it fun to read. David and Ken’s book is unconventional. It mixes history, geography, physics, geometry, biography, art, poetry, plants and religion, with ground based and space pho-tographs of galaxies. Some readers may question the discussion of religious beliefs, but this is their story.

Even to an astronomer who studies galaxies, the comparison of the early and even recent images with the newly processed ones can only be described as breathtaking. The authors correctly call these “the new view of galaxies.” But some of the knowledge is old, only uncovered by the authors. The book contains extended quotes from the scientists them-selves. Many of Sir John Herschel’s drawings from the Cape of Good Hope concern the Magellanic Clouds observed by eye, and their details are unforgettable.

I congratulate the authors. As a tribute to them, I add a quote from Marcel Proust:

The real voyage of discovery consists not in seeking new landscapes but in having new eyes.

Vera C. Rubin is an observational astronomer who has studied the motions of gas and stars in galaxies and motions of galaxies in the Universe for seventy-fi ve percent of her life. Her work was infl uential in discovering that most of the matter in the Universe is dark. She is a graduate of Vassar College, Cornell University, and Georgetown University; George Gamow (George Washington University) was her thesis professor. A staff member at the Depart-ment of Terrestrial Magnetism, Carnegie Institution of Washington since 1965, she is now a Senior Fellow. She is a member of the U.S. National Academy of Sciences and Pontifi -cal Academy of Sciences. President Clinton awarded her the National Medal of Science in 1993. She received the Gold Medal of the Royal Astronomical Society (London) in 1996. The previous woman to receive this medal was Caroline Herschel in 1828. She has numer-ous honorary degrees, including Harvard, Princeton, Yale and Smith College. In 1994 she delivered the Henry Norris Russell Lectureship; previous recipients of this esteemed Lec-tureship have included Nobel laureates Enrico Fermi and Charles Townes. Vera is active in

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encouraging and supporting women in science. Her husband (deceased January 2008) and their four children are Ph.D. scientists in physical chemistry, geophysics, astronomy, and mathematics.

Photograph by Philip Birmingham

Cosmic Masks5

C H A P T E R

2Cosmic Masks: Shrouds of the Night

ow beautiful is the rising of the full moon upon the Continent of Africa. Sounds in the bush by day are so vastly different to those at night. Ancient hunters have depended on the eerie light cast by the full moon, in guiding them to their prey.

Enter cosmic masks, or cosmic shrouds. The full moon itself is a mask, for it masks (or hides) myriads of fainter stars in our heavens above. In its brilliant light by which lions stalk their prey, only the very brightest of stars are seen.

In Roget’s Thesaurus, we encounter the following defi nition of a mask: [noun] screen, cloak, shroud [verb] to camoufl age, to make opaque, to disguise.

How vastly different do the skies appear in the absence of the full moon. When our mask of blazing refl ected sunlight is no longer present, the skies show a breathtaking splendour of countless myriads of suns.

As with masks covering a human face (Figures 2–4), our perception of the night sky is inex-tricably intertwined by the presence of masks, or shrouds. Remove the mask – penetrate the veil or shroud – and behold wondrous, hitherto unimaginable, insights!

Our thoughts go back to hunters and gatherers in epochs past. What a breathtaking sight it must have been, in the absence of light pollution, for men and women of old to actually see the Milky Way Galaxy in all its grandeur and splendour.

In a book entitled Bushman Folklore by the late W. Bleek and L. Lloyd, there is a moving account of “The Girl of the Early Race, who made the Stars.” We share a section of that story here:

Shrouds of the Night6 Figure 2 [405]

Cosmic Masks7Figure 3 [405]

Shrouds of the Night8 Figure 4 [405]

Cosmic Masks9

“My mother was the one who told me that the girl arose; she put her hands into the wood ashes; she threw up the wood ashes into the sky. She said to the wood ashes: ‘The wood ashes which are here, they must altogether become the Milky Way …’ Then, the people go by night; while they feel that the ground is made light. While they feel that the Stars shine a little. Darkness is upon the ground. The Milky Way gently glows; while it feels that it is wood ashes. Therefore, it gently glows. While it feels that the girl was the one who said that the Milky Way should give a little light for the people, that they may return home by night, in the middle of the night. For, the Earth would not have been a little light, had not the Milky Way been there. It and the Stars.”

“The girl thought that she would throw up (into the air) roots of the !hiun, in order that the !hiun roots should become Stars … She fi rst gently threw up wood ashes into the sky, that she might presently throw up !hiun roots …” Bleek and Lyold elaborate: “She threw up a scented root (eaten by some Bushmen) called !hiun, which became stars; the red (or old) !hiun making red stars, the white (or young) !hiun making white stars. This root is … eaten by baboons and also by the porcupine.”

One’s mind refl ects back to the Middle Ages. What a foreboding sight the dancing Northern Lights, the Aurora Borealis (Figures 5 and 6), must have been, in an era when no scientifi c explanation was known. In Middle-Age Europe, the Northern Lights were thought to be refl ections of heavenly warriors. As a sort of posthumous reward, the soldiers who gave their lives for their king and country were allowed to battle on the skies forever. The aurorae were believed by some to be the breath of these brave soldiers as they resumed their fi ght in the skies. The Old Norse word for the aurora borealis is norðrljós, “northern lights.” The fi rst occurrence of the term norðrljós is in the book Konungs Skuggsjá (The King’s Mirror, known in Latin as Speculum Regale), written in 1250 AD, after the end of the Viking Age (the Viking Age dates ca. 800–1100 AD). In The King’s Mirror, the narration (as translated by L.M. Larson in 1917) between a Father and Son concerning the Northern Lights as seen by settlers in Greenland reads as follows:

Shrouds of the Night10 Figure 5 [405]

Cosmic Masks11Figure 6 [405]

Shrouds of the Night12

Father. But as to that matter which you have often inquired about, what those lights can be which the Greenlanders call the northern lights, I have no clear knowledge. I have often met men who have spent a long time in Greenland, but they do not seem to know defi nitely what those lights are. However, it is true of that subject as of many others of which we have no sure knowledge, that thoughtful men will form opinions and conjectures about it and will make such guesses as seem reasonable and likely to be true. But these northern lights have this peculiar nature, that the darker the night is, the brighter they seem; and they always appear at night but never by day, most fre-quently in the densest darkness and rarely by moonlight. In appearance they resem-ble a vast fl ame of fi re viewed from a great distance. It also looks as if sharp points were shot from this fl ame up into the sky; these are of uneven height and in constant motion, now one, now another darting highest; and the light appears to blaze like a living fl ame. While these rays are at their highest and brightest, they give forth so much light that people out of doors can easily fi nd their way about and can even go hunting, if need be. Where people sit in houses that have windows, it is so light inside that all within the room can see each other’s faces. The light is very change-able. Sometimes it appears to grow dim, as if a black smoke or a dark fog were blown up among the rays; and then it looks very much as if the light were overcome by this smoke and about to be quenched. But as soon as the smoke begins to grow thinner, the light begins to brighten again; and it happens at times that people think they see large sparks shooting out of it as from glowing iron which has just been taken from the forge. But as night declines and day approaches, the light begins to fade; and when daylight appears, it seems to vanish entirely.

The men who have thought about and discussed these lights have guessed three sources, one of which, it seems, ought to be the true one. Some hold that fi re circles about the ocean and all the bodies of water that stream about on the outer sides of the globe; and since Greenland lies on the outermost edge of the earth to the north, they think it possible that these lights shine forth from the fi res that encircle the outer ocean.

Others have suggested that during the hours of night, when the Sun’s course is beneath the earth, an occasional gleam of its light may shoot up into the sky; for

Cosmic Masks13

they insist that Greenland lies so far out on the earth’s edge that the curved surface which shuts out the sunlight must be less prominent there. But there are still others who believe (and it seems to me not unlikely) that the frost and the glaciers have become so powerful there that they are able to radiate forth these fl ames. I know nothing further that has been conjectured on this subject, only these three theories that I have presented; as to their correctness I do not decide, though the last men-tioned looks quite plausible to me. I know of no other facts about Greenland that seem worth discussing or mentioning, only those that we have talked about and what we have noted as the opinions of well-informed men.

Son. Everything that you have told here seems wonderful to me, though also very instructive, and this fact most of all, that men, as you have pointed out, are able to leave the earth, as it were, and view for themselves the boundaries which God has drawn amid such great perils. Your last remark, however, suggests that there is yet a little matter to inquire about along this same line. In speaking of those three conjectures you said that you think it most likely that these lights have their origin in frost and ice; but just before in describing their appearance, you added that now and then fog and dark mist resembling smoke would mount up among these lights. But even if the cold should be so prevalent there as to give rise to these lights with their fi re-like rays, I cannot help wondering whence that smoke can come which sometimes appears to shade and becloud the light till it seems almost quenched; for to me it seems more likely that the smoke is due to heat than to frost. There is one more thing that looks strange to me which you mentioned earlier in your speech, namely that you consider Greenland as having a good climate, even though it is full of ice and glaciers. It is hard for me to understand how such a land can have a good climate.

Father. When you say, in asking about the smoke that sometimes appears to accompany the northern lights, that you think it more likely that the smoke comes from heat than from cold, I agree with you. But you must also know that wherever the earth is thawed under the ice, it always retains some heat down in the depths. In the same way the ocean under the ice retains some warmth in its depths. But if the earth were wholly without warmth or heat, it would be

Shrouds of the Night14

one mass of ice from the surface down to its lowest foundations. Likewise, if the ocean were without any heat, it would be solid ice from the surface to the bottom. Now large rifts may appear in the ice that covers the land as well as openings in the ice upon the sea. But wherever the earth thaws out and lies bare, whether in places where there is no ice or under the yawning rifts in the glacier, and wher-ever the sea lies bare in the openings that have formed in the ice, there steam is emitted from the lower depths; and it may be that this vapor collects and appears like smoke or dark fog; and that, whenever it looks as if the lights are about to be quenched by smoke or fog, it is this vapor that collects before them.

We now have fully scientifi c explanations for the aurorae; they are generated as streams of high energy particles from our closest star, the Sun, enter the ionosphere of the Earth. The magnetic fi eld of the Earth steers these particles toward the poles; hence the dancing cas-cades of lights in regions close to the poles, such as Greenland and Iceland. The brilliance of an aurora may be greatly enhanced when the Sun undergoes periods of increased sunspot activity. In earlier centuries, myths abounded as these foreboding aurorae displayed ever changing curtains of light and of glowing color.

So much in our heavens captures the imagination. From the aurorae dancing above the tun-dra, to our Galaxy – and to multitudes of galaxies beyond. Early drawings of the Night Sky show the arching Milky Way, with numerous cosmic veils or shrouds. While these were once believed to be vacant holes in the very fabric of space, we now understand that these veils contain matter, and are indeed enigmatic Shrouds of the Night.

Renowned Aboriginal artist Collette Archer (of the tribe Djunban in Far Northern Queens-land, Australia) shares her thoughts:

Our people (Aboriginals) always use the stars to fi nd their way on walkabouts during the nights. At the same time, this is also when all the bushtucker come out, Witchetty Grubs (high in protein), and honey ants (very sugary). Track-ing of animals also best looked for on a night like this. Our people celebrate the full moon and dance with happiness. They always admire the stars as do myself.

Cosmic Masks15

From within the hearts of royalty (The King’s Mirror) and shepherd alike, the canopy of the Milky Way has aroused the deepest of emotions.

One of South Africa’s most celebrated veteran poets, Winifred Dashwood, vividly describes righteous souls triumphantly marching across the starry vaults of the Via Lactea.

Dashwood aptly utilizes the imagery of the Archer drawing his Bow amidst the rich star fi elds of Sagittarius, where stars appear as innumerable as the sand and where Shrouds of the Night abound.

Her poem is entitled “My Universe, My Home!” and reads as follows:

Let no memory remainOf the loved and lately lost.Bury hope and joy and painIn the grave where roses, tossedFrom a tired and nerveless hand,Bruise their petals on the clods.Sullen clay or fi ckle sandHides the victim from the gods.

This is execution’s stay.Here must retribution end.Prisoners freed on judgement dayNeed no advocate nor friend.Past the swinging stars they go,Out of sight and out of mindPast the Archer’s blazing bow,Leaving Betelgeuse behind.

Traipsing up the Milky WaySwaying on oblivion’s brink,Dazzled by the rainbow dayWhere new planets dance and sink.

Shrouds of the Night16

Gliding down through fi elds of force,Latticed by sidereal light,Drink at Resurrection’s source!Burst the carapace of night!

— (WINIFRED DASHWOOD PRESENTED THIS POEM TO COAUTHOR DAVID, ABOUT ONE YEAR BEFORE HER DEATH, AT AGE 84. THIS IS THE FIRST TIME THAT DASHWOOD’S

POEM “MY UNIVERSE, MY HOME!” APPEARS IN A BOOK ON ASTRONOMY.)

Collette Archer’s exquisite work on canvas, showing the setting Milky Way, with fi ery mete-ors entering the Earth’s atmosphere above, and the tracks of small creatures in the sand below, is seen in Figure 7. Let us now focus our attention on those smoky, black, dusty laby-rinths permeating the space between those glowing heavenly jewels, the stars.

Cosmic Masks17Figure 7 [405]