December 4, 2004

The Search for Ourselves in the Cosmos

Our senses alone offer only a narrow window on the physical universe, as Neil deGrasse Tyson writes in his four-part NOVA/PBS series, "Origins". The tour de force looks at how we measure our place in the universe based on the part of the universe we sense around us.

Astrobiology Magazine -- Neil De Grasse Tyson is Frederick P. Rose Director, Hayden Planetarium, American Museum of Natural History (since 1996); Visiting Research Scientist, Department of Astrophysics, Princeton University (since 1994). He writes a monthly column called "Universe" for Natural History magazine and is the author of several books, including "One Universe: At Home in the Cosmos" (2000) and "The Sky is Not the Limit: Adventures in an Urban Environment" (2000).

His most recent work is the book (published by W.W. Norton & Co.) and NOVA PBS four-part series, "Origins". The chapter entitled "The Search for Ourselves in the Cosmos " is excerpted here with publisher permission.


Human senses display an astonishing acuity and range of sensitivity. Our ears can record the thunderous launch of the space shuttle, yet they can also hear a male mosquito buzzing in the corner of a room. Our sense of touch allows us to feel the crush of a bowling ball dropped on our big toe, or to tell when a one-milligram bug crawls along our arm.

Some people enjoy munching on habanero peppers, while sensitive tongues can identify the presence of food flavors at a few parts per million. And our eyes can register the bright sandy terrain on a sunny beach, yet have no trouble spotting a lone match, freshly lit hundreds of feet away, across a darkened auditorium. Our eyes also allow us to see across the room and across the universe. Without our vision, the science of astronomy would never have been born and our capacity to measure our place in the universe would have remained hopelessly stunted.

In combination, these senses allow us to decode the basics of our immediate environment, such as whether it's day or night, or when a creature is about to eat you. But little did anybody know, until the last few centuries, that our senses alone offer only a narrow window on the physical universe.

Some people boast of a sixth sense, professing to know or see things others cannot. Fortunetellers, mind readers, and mystics top the list of those who claim mysterious powers. In doing so, they instill widespread fascination in others. The questionable field of parapsychology rests on the expectation that at least some people actually harbor this talent.

In contrast, modern science wields dozens of senses. But scientists do not claim that these are the expression of special powers, just special hardware that converts the information gleaned by these extra senses into simple tables, charts, diagrams, or images that our five inborn senses can interpret.

Think of how much richer the world would appear to us, and how much sooner we would have discovered the fundamental nature of the universe, if we were born with high-precision, tunable eyeballs. Dial up the radio-wave part of the spectrum and the daytime sky turns as dark as night, except for some choice directions.

Our galaxy's center appears as one of the brightest spots on the sky, shining brightly behind some of the principal stars of the constellation Sagittarius. Tune into microwaves and the entire universe glows with a remnant from the early universe, a wall of light that set forth on its journey to us 380,000 years after the big bang.

Tune into X rays and you will immediately spot the location of black holes with matter spiraling into them. Tune into gamma rays and see titanic explosions bursting forth from random directions once a day throughout the universe. Watch the effect of these explosions on the surrounding material as it heats up to produce X rays, infrared, and visible light.

If we were born with magnetic detectors, the compass would never have been invented because no one would ever need one. Just tune into the Earth's magnetic field lines and the direction of magnetic North looms like Oz beyond the horizon.

If we had spectrum analyzers within our retinas, we would not have to wonder what the atmosphere is made of. Simply by looking at it we would know whether or not it contains sufficient oxygen to sustain human life. And we would have learned thousands of years ago that the stars and nebulae in our galaxy contain the same chemical elements as those found here on Earth.

And if we were born with big, sensitive eyes and built-in Doppler motion detectors, we would have seen immediately, even as grunting troglodytes, that the entire universe is expanding - that all our distant galaxies are receding from us.

If our eyes had the resolution of high-performance microscopes, nobody would ever have blamed the plague and other sicknesses on divine wrath. The bacteria and viruses that made you sick would have been in plain view as they crawled on your food or slid through open wounds in your skin. With ample experiments, you could easily tell which of these bugs were bad and which were good. And the carriers of postoperative infection problems would have been identified and solved hundreds of years earlier.

If we could detect high-energy particles, we would spot radioactive substances from great distances. No Geiger counters necessary. You could even watch radon gas seep through the basement floor of your home and not have to pay somebody to tell you about it.

The honing of our five senses from birth through childhood allows us as adults to pass judgment on events and phenomena in our lives, declaring whether or not they "makes sense." Problem is, hardly any scientific discoveries of the past century have flowed from the direct application of our senses. They came instead from the direct application of sense-transcendent mathematics and hardware.

This simple fact explains why, to the average person, relativity, particle physics, and even eleven-dimensional string theory make no sense. Add to this list black holes, wormholes, and the big bang. Actually, these concepts don't make much sense to scientists, either, until we have explored the universe for a long time with all senses that are technologically available. W

hat eventually emerges is a newer and higher level of "uncommon sense" that enables scientists to think creatively and to pass judgment in the unfamiliar underworld of the atom or in the mind-bending domain of higher dimensional space. The twentieth-century German physicist Max Planck about the discovery of quantum mechanics: "Modern physics impresses us particularly with the truth of the old doctrine which teaches that there are realities existing apart from our sense-perceptions, and there are problems and conflicts where these realities are of greater value for us than the richest treasures of the world of experience."

Each new way of knowing heralds a new window on the universe - a new detector to add to our growing list of nonbiological senses. Whenever this happens, we achieve a new level of cosmic enlightenment, as though we were evolving into supersentient beings. Who could have imagined that our quest to decode the mysteries of the universe, armed with a myriad of artificial senses, would grant us insight into ourselves? We embark on this quest not from a simple desire but from a mandate of our species to search for our place in the cosmos. The quest is old, not new, and has garnered the attention of thinkers great and small, across time and across culture. What we have discovered, the poets have known all along:

We shall not cease from exploration
And the end of all our exploring
Will be to arrive where we started
And know the place for the first time.
-T.S. Eliot, 1942


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