Allan Sandage, Astronomer, Dies at 84; Charted Cosmos’s Age and Expansion

New York Times, November 17, 2010

By DENNIS OVERBYE

Allan R. Sandage, who spent his life measuring the universe, becoming the most influential astronomer of his generation, died Saturday at his home in San Gabriel, Calif. He was 84.

The cause was pancreatic cancer, according to an announcement by the Carnegie Observatories, where he had spent his whole professional career.

Over more than six decades, Dr. Sandage was like one of those giant galaxies that sit at the center of a cluster of galaxies, dominating cosmic weather. He wrote more than 500 papers, ranging across the cosmos, covering the evolution and behavior of stars, the birth of the Milky Way galaxy, the age of the universe and the discovery of the first quasar, not to mention the Hubble constant, a famously contested number that measures the rate of expansion of the universe. Dr. Sandage pursued the number with his longtime collaborator, Gustav Tammann of the University of Basel in Switzerland.

In 1949, Dr. Sandage was a young Caltech graduate student, a self-described “hick who fell off the turnip truck,” when he became the observing assistant for Edwin Hubble, the Mount Wilson astronomer who discovered the expansion of the universe.

Hubble had planned an observing campaign using a new 200-inch telescope on Palomar Mountain in California to explore the haunting questions raised by that mysterious expansion. If the universe was born in a Big Bang, for example, could it one day die in a Big Crunch? But Hubble died of a heart attack in 1953, just as the telescope was going into operation. So Dr. Sandage, a fresh Ph.D. at 27, inherited the job of limning the fate of the universe.

“It would be as if you were appointed to be copy editor to Dante,” Dr. Sandage said. “If you were the assistant to Dante, and then Dante died, and then you had in your possession the whole of ‘The Divine Comedy,’ what would you do?”

Dr. Sandage was a man of towering passions and many moods, and for years, you weren’t anybody in astronomy if he had not stopped speaking to you. In later years, beset by controversy, Dr. Sandage withdrew from public view. But even after retiring from the Carnegie Observatories and becoming ill, he never stopped working; he published a paper on variable stars only last June.

In 1991, Dr. Sandage was awarded the Crafoord Prize in astronomy, the closest thing to a Nobel for a stargazer, worth $2 million.

Wendy Freedman, his boss as director of Carnegie as well as a rival in the Hubble constant question, referred to him on Tuesday as the last giant of 20th-century observational cosmology. “Even when we had our scientific differences, I got a kick out of him,” she said. “His passion for his subject was immense.”

James Gunn, an astronomer at Princeton, said of Dr. Sandage in an e-mail message, “He was probably (rightly) the greatest and most influential observational astronomer of the last half-century.”

Allan Rex Sandage was born in Iowa City, Iowa, on June 18, 1926, the only child of an advertising professor, Charles Harold Sandage, and a homemaker, Dorothy Briggs Sandage. The stars were one of his first loves; his father bought him a commercial telescope.

After two years at the University of Miami, where his father taught, Allan was drafted into the Navy; he resumed his education at the University of Illinois, earning a degree in physics.

In 1948 he entered graduate school at the California Institute of Technology, where an astronomy program had been started in conjunction with the nearby Mount Wilson Observatory, home of Hubble, among others.

As a result, Dr. Sandage learned the nuts and bolts of observing with big telescopes from the founders of modern cosmology, Hubble; Walter Baade, who became his thesis adviser, and Milton Humason, a former mule driver who had become Hubble’s right-hand man.

In the years before World War II, there had been a revolution in the understanding of the nature and evolution of stars as thermonuclear furnaces burning hydrogen into helium and elements beyond. Astronomers could now read the ages of star clusters from the colors and brightness of the stars in them.

For his thesis, Dr. Sandage used this trick to date a so-called globular cluster, known as Messier 3, as being 3.2 billion years old, which meant that the universe itself could not be younger than that. In fact, Hubble’s own measurements of the cosmic expansion suggested an age of about four billion years — remarkably, even miraculously, consistent.

At the time, astronomers were also still debating whether the universe had had a Big Bang and a beginning at all, not to mention whether it would have an ending as well. An opposing view championed by the British cosmologist Fred Hoyle held that the universe was eternal and in a “steady state,” with new matter filling in the void as galaxies rushed away from one another. [See earlier post for another view]

Choosing between these models was to be the big task of 20th-century astronomy, and of Dr. Sandage. In 1961 he published a paper in The Astrophysical Journal showing how it could be done using the 200-inch telescope. He described cosmology as the search for two numbers: one was the cosmic expansion rate, known as the Hubble constant; the other, called the deceleration parameter, tells how fast the expansion is being braked by cosmic gravity.

That paper, “The Ability of the 200-inch Telescope to Discriminate Between Selected World Models,” may well have been “the most influential paper ever written in any field even close to cosmology,” Dr. Gunn said. It was to set the direction of observational cosmology for 40 years, ruling out the Steady State and the Big Crunch and culminating in the surprise discovery in 1998 that the expansion is not slowing down at all but speeding up.

Meanwhile, Dr. Sandage investigated the birth of the galaxy. By analyzing the motions of old stars in the Milky Way, he, Olin Eggen of Caltech and Donald Lynden-Bell of Cambridge showed in a 1962 paper that the Milky Way formed from the collapse of a primordial gas cloud probably some 10 billion years ago. That paper still forms the basis of science’s understanding of where the galaxy came from, astronomers say.

In 1959, Dr. Sandage married another astronomer, Mary Connelly, who was teaching at Mount Holyoke and had studied at the University of Indiana and Radcliffe, but did not pursue further research. He is survived by her and two sons, David and John.

It was measuring the cosmic expansion that was the most backbreaking part of fulfilling Hubble’s legacy. In an expanding universe, the speed with which a galaxy flies away from us is proportional to its distance. The constant of proportionality, the Hubble constant, is given in the mind-numbing terms of kilometers per second per megaparsec. Hubble’s original estimate of his constant of 530 meant that for every million parsecs (3.26 million light years) a galaxy was farther away from us, it was retreating 530 kilometers per second (around 300 miles per second) faster.

Hubble’s original estimate, however, corresponded to an age for the universe of only 1.8 billion years, at odds with both geological calculations of the Earth’s age and Dr. Sandage’s later estimate of the ages of star clusters.

But Hubble had made mistakes — he saw bright patches of gas as stars, for example — and as Dr. Sandage and Dr. Tammann delved into the subject in a series of papers, the problematic constant came down and the imputed age of the universe rose.

In 1956, Dr. Sandage suggested that the Hubble constant could be as low as 75 kilometers per second per megaparsec. By 1975 the value, they said, was all the way down to 50, corresponding to an age of as much as 20 billion years, comfortably larger than the ages of galaxies and globular clusters.

This allowed them to conclude that the universe was not slowing down enough for gravity to reverse the expansion into a Big Crunch. That was in happy agreement with astronomers who had found that there was not enough matter in the universe to generate the necessary gravity.

As Dr. Sandage wrote in The Astrophysical Journal in March 1975, “(b) the Universe has happened only once, and (c) the expansion will never stop.”

“So the universe will continue to expand forever,” Dr. Sandage said in an interview, “and the galaxies will get farther and farther apart, and things will just die. That’s the way it is. It doesn’t matter whether I feel lonely about it or not.”

Shortly thereafter, however, their results on the Hubble constant came under attack by rival astronomers, who said that Dr. Sandage and Dr. Tammann had overestimated the distances to galaxies — a crucial part of the equation for the constant — making the universe appear bigger and older than it really was. The universe, they said, was really about 10 billion years old.

Stung by the criticisms, Dr. Sandage retreated from public view, even while he and Dr. Tammann redoubled their efforts to measure the troublesome constant, always getting a low value. As the groups shot back and forth at each other, the universe, as reflected in newspaper headlines, boomeranged back and forth from 10 billion to 20 billion years.

In 2001, a team led by Dr. Freedman, using the Hubble Space Telescope, reported a value of 72 kilometers per second per megaparsec, in good agreement with measurements of relic radiation from the Big Bang that give an age of 13.7 billion years for the cosmos full of dark energy and dark matter, and a Hubble constant of 71, which most astronomers now accept.

To the frustration of colleagues, Dr. Sandage, also using Hubble, kept getting a lower value.

We may never know the fate of the universe or the Hubble constant, he once said, but the quest and discoveries made along the way were more important and rewarding than the answer anyway.

“It’s got to be fun,” Dr. Sandage told an interviewer. “I don’t think anybody should tell you that he’s slogged his way through 25 years on a problem and there’s only one reward at the end, and that’s the value of the Hubble constant. That’s a bunch of hooey. The reward is learning all the wonderful properties of the things that don’t work.”

God, the Universe, Extraterrestrial Intelligence, and all that stuff

A Hubble Space Telescope Photo of the Planetary Nebula NGC 2818

A few days after my birthday in 2009 in a post titled, "The Search for Extraterrestrial Life," I promised to revisit in a future post the subject of extraterrestrial intelligence. Well, the future is here -- whoops! it's gone; we're in the present, or were...

Anyway, if you'll allow me, I'd like to ramble a bit in an effort to describe (explain would be too ambitious) my idea (theory would be presumptuous) about extraterrestrial intelligence. In doing so, I will necessarily touch on the concept of god (lack of capitalization is intended), the Universe, the Big Bang Theory, and stuff like that.

Big Bang Model, NASA/WMAP Science Team

Let me start with the Big Bang Theory, because it's so popular and many of the world's major religions assert that it supports their view of their God and His creation. So here's my take -- I don't buy it. I believe the Big Bang Theory is popular because it conforms with our experiential basis for understanding our own existence. After all, in our world, things have beginnings and endings, including us (our pets, too, which is really sad).

The idea that our universe had no beginning and will have no ending comes and goes in cosmology (kind of like our universe, as you'll see). In fact, no less a light than Albert Einstein initially believed the universe was closed and steady state. But his own General Theory of Relativity required that the universe be either expanding or contracting, so Einstein created a "cosmological constant" to insert in his equations in order to make them conform to his belief in a steady state universe. He later came to see this as a mistake. Well, anyone could have told Albert that, don't you think?

Anyway, where the hell am I going with this. Let me think... Oh yeah, there were other respected astrophysicists/cosmologists who believed in an essentially eternal universe, but the discovery by Edwin Hubble that the universe appeared to be expanding and the further discovery of microwave background radiation predicted by the Big Bang Theory seemed to seal the deal -- Big Bang was king.

Not so fast (although the "singularity" that composed all that existed before anything existed and became The Universe did it in ten to the minus four seconds and that's damned fast). There are other theories of cosmological reality and they are pretty cool, e.g., parallel universes anyone?

Mathematical physicist Neil Turok theorizes that the universe cycles through expansions and contractions (the "Cyclic Universe" theory), and neither time nor the universe has a beginning or end. Google Turok and you can read all you want about "string theory" and "M-theory," and branes, and black holes, and try to figure it all out -- good luck with that.



My own "theory" is that the universe is and has always been, but it's nature changes because it's being pulled in and out of an infinite number of black holes (thus the appearance of expansion and contraction); think about pulling your socks inside out before you throw them in the wash and then pulling them back right side out when you pull them out of the dryer. If you don't wash your socks and want a different example, forget about it you stinker!

I posit this theory because I want you to expand your ability to conceptualize possibilities that are outside the realm of your physical being and your experience as such. Consider this for example, mathematical physicists like Neil Turok deal with many more than 3 dimensions (10 or more sometimes) when they cogitate on the nature of our universe. Imagine how many pairs of special glasses you'd have to wear to watch a movie in 10-D.

Now that your mind has expanded, consider your place in a universe that is infinite and eternal. You may see yourself as floating on an air mattress in a pool, in your backyard, in your neighborhood, in, say, Washington State, in the USA. So, on the North American continent, on the earth, which you may think of as floating around the sun with a bunch of other planets that form our Solar System.

Well fine, but keep going. Okay, so you know about the Milky Way Galaxy. Do you know that the only stars we see with the naked eye are all part of our Galaxy? And that there are an unknown number of galaxies (some say billions) in the universe? That seems really big, doesn't it. Maybe not. Maybe all this is just a gas bubble in the lower intestine of a super being that ate too much dark matter for dinner, and you're a microbe sitting on a piece of undigested fruit, say a blueberry -- our earth -- working with all the other microbes on the partially digested blueberry to turn it into fecal matter (you have to admit, we're doing a pretty good job).

The point is, that in a universe of essentially unknown size, we have no real point of reference for the size of our Galaxy, Solar System, planet, or ourselves. I will tell you this. We are larger than some of the things on this planet that we know about, like bacteria. We're a lot larger than those little buggers.

Again, in an earlier post I wrote about something called Cyanobacteria. This microbe is largely responsible for creating the earth as we know it. An interesting question is, how did it get here? Furthermore, we might ask if it exists only here, or has this particular bacterium migrated elsewhere? Do the bacteria we encounter exist because we exist, or do we exist because they exist?

There is some evidence that suggests certain bacteria were carried to earth on meteorites. The possibility that life first came to earth and indeed, was distributed throughout the universe by ejecta blasted from planets bombarded by huge meteors has spawned a theory of interstellar life called "panspermia" (or "transpermia"). The prospect was first proposed in the 1870s by physicists Lord Kelvin (British) and Hermann von Helmholtz (German).

A hundred years later, British astronomers Fred Hoyle and Chandra Wickramasinghe found new evidence for panspermia, traces of life in the dust of space. They also proposed that comets carry bacterial life across galaxies and protect it from radiation damage along the way because comets are largely made of water-ice.

James Lovelock's Gaia theory of the earth can be seen as complementary to the theory of panspermia, or vice versa, I don't know. In any case, it's intriguing to think of the earth as a living being in its own right, and more so if we accept that it's "life" was seeded from space.

Let's summarize. We have an eternal, infinite universe that contains the building blocks of life. Life on earth was seeded from somewhere in that infinite, eternal universe. Given this, there's no reason not to believe that many other life forms exist in many other parts of the universe. But are they "intelligent?"

The very question is posed in such a way that it once again anthropomorphizes our consideration of possibilities. Why? Because it's altogether possible that we humans are an integral part of a pervasive, self-perpetuating, cosmic intelligence, i.e., Cosmic Gaia, in which elemental life is transported via comets throughout the universe, making course corrections as the universe expands and contracts and planetary bodies form and are destroyed.

The universe exists in a state of homeostasis, forever and always. The intelligence necessary for that to happen has existed and will exist forever and ever. Right now, we are part of it. Some day, we'll be replaced. Our replacements will be wearing their socks wrong side out.

Reborn Hubble and Stellar Blast

The repaired and improved Hubble Space Telescope is sending back some spectacular images, including dazzling pictures of galaxies headed for a pile-up, a star throwing off its outer layers, dense clouds of gas and dust, and a new pin-sharp look at the planet Jupiter.

In another remarkable development, two teams of astronomers reported their observations of a gamma-ray burst from a star that died 13.1 billion light-years away. The massive star died about 630 million years after the Big Bang. UK astronomer Nial Tanvir described the observation as "a step back in cosmic time". Professor Tanvir led an international team studying the afterglow of the explosion, using the United Kingdom Infrared Telescope (UKIRT) in Hawaii.

The Universe and all that Stuff

Hubble Photo: Giant Disk of Cold Gas and Dust Fuels Possible Black Hole at the Core of NGC 4261

In proposing an alternative to the conventional "Big Bang" theory of cosmology, Paul Steinhardt and Neil Turok point out that "the standard model does not explain the beginning of time, the initial conditions of the universe, or what will happen in the long-term future." For me, these are reason enough to consider other explanations for the nature of the reality we refer to as our universe.

For as long as I can remember pondering the imponderables -- when did the universe come about, when will it end, how big is it, and what is my place in the nature of its reality? -- I have been uncomfortable with the idea that all existence came about suddenly in a massive explosion spewing matter into the void -- the so-called cosmic singularity. What exploded? Where did it come from? Now what?

Steinhardt and Turok propose a cosmological model with an "endless sequence of cycles of expansion and contraction." In their scheme of things, there is, by definition, neither a beginning nor end of time, nor is there a need to define initial conditions. This appeals to me, because I've always felt that my views of reality are inextricably entangled with my experience. That's how I came to understand that touching the glowing red spiral on the stove top would cause pain, but it's also why I am predisposed towards believing that, like me, things are finite, have beginnings and endings, and exist in three dimensions. Truth is, it ain't necessarily so.

Steinhardt and Turok's description of their cosmic model involves black holes, dark matter, string theory, M-theory, quantum theory, branes (short for membranes), gravitational and microwaves, and other challenges for the lay person, like myself. But their cyclic model deals directly with the cosmic singularity, explaining it as a transition from a contracting to an expanding phase.

Of course physicists argue with each other about whose theory best represents "truth." Their arguments are based on evidence already assembled, testable theories/hypotheses, and mathematical proofs. And then there are religious proponents who by and large favor the Big Bang theory because it's a "creation event" -- presumably the big bang happened in the first nano second of the first day and a week later we had physicists arguing about dark energy -- and they weren't referring to Lucifer.

In any case, we have at least two distinct theories of our universe, one in which the universe has a definite beginning, and one in which the universe is made and remade forever. For me, based on nothing more than aesthetics, I believe in an infinite number of parallel universes passing into and through each other -- maybe through black holes -- in an unending blending of energy, dark energy, matter, and anti-matter, all of which looks very nice on God's flat-panel display.

Hubble Photo: Orion Nebula