The Arizona Museum of Natural History presents an exhibition called Origins. The first image in the exhibition is labeled Cosmic Microwave Background, 13 billion years ago. There is no further information. Most visitors are not going to recognize immediately that cosmic microwave background radiation is the thermal energy informally filling the space of the universe and expanding since shortly after the “Big Bang,” of which cosmic microwave background radiation is evidence. Curators of the exhibition do not expect the average viewer to know this, but rather they wish to encourage the curious to seek out the answer on smart phones or other electronic devices.
We now have theoretical frameworks and observational data that greatly enhance our understanding of the universe. If Einstein’s Theory of Relativity provides one of the theoretical pillars to understand the cosmos, devices like the Hubble Space Telescope give us the tools to see and measure the universe. The Hubble Ultra Deep Field project allows us to peer through the slimmest sliver of space and see light that has been traveling from celestial entities towards Earth since as early as 400 million years after the origin of the universe, or Big Bang, about 13.76 billion years ago. Put another way, light traveling at 186,282 miles per second has taken over 13 thousand million years to reach Earth from its place of origin.
As we know, Earth is in a solar system, planets orbiting around a star, the Sun, towards the edge of the Milky Way Galaxy. The Milky Way is 100,000 or more light years across and may have 200-400 million stars and an equal number of planets. Andromeda, our nearest neighbor spiral galaxy, is 2.5 million light years away and contains about a trillion stars (1012). For some perspective, it
takes light from the Sun about 8 minutes and 19 seconds to travel the 93 million miles to reach the Earth. The universe may be about 93 billion light years in diameter, and the observable universe may contain as many as 100 billion galaxies. These galaxies may contain as many as 300 sextillion (3×1023) stars. That is a lot of stars, with presumably a lot of planets. I don’t pretend to know the underlying physics or mathematics, but multiple life forms elsewhere in the universe seem a good bet. Almost certainly, we are not alone. We just haven’t yet met our neighbors. This possibility might warrant rethinking the place of humans in the cosmos, and among other life forms here on Earth.
These are aspects of our state of knowledge about the universe today. Yet for the great swath of human history, we knew none of this. Humans have a deep interest in observing and understanding their surroundings, and these characteristics of the species hold considerable adaptive value. We have applied this interest to the heavens from our earliest days. Many cultures developed strong interests in astronomy, such as the ancient Egyptians, Maya, ancestral Pueblo peoples, Arabs and others who developed deep knowledge of the heavens based upon decades of systematic observation of the skies.
Before the advent of optical instruments in the early 17th century, celestial observations were essentially by naked eye. In the western tradition, ancient Greek astronomers grappled with evidence and logic whether the Earth revolves around the Sun (heliocentrism) or the Sun around the Earth (geocentrism). It is plausible, although erroneous, based upon daily observation, to conclude that the Sun circles the Earth. Every day we observe the Sun “come up” in the East and “set” in the West. This comforting view placed our world at the center of everything.
No less authorities than Aristotle (384-322 BC) and Ptolemy (c. AD 90-168) promoted versions of the geocentric model, not without considerable, if flawed, underlying logic, thus laying the groundwork for Earth- and human-centered philosophical and religious systems that have endured for hundreds of years.
There were contrary opinions. Aristarchus of Samos (c. 310-230 BC) articulated a heliocentric theory in classical Greece, and he had a few followers. Not until eighteen centuries later did Copernicus (AD 1473-1543) publish his monumental work on the Sun and planetary movements that established the heliocentric model and began the scientific revolution named after him. Nevertheless, Aristotelian and Ptolemaic ideas still dominated European thinking, and the Copernican Revolution was slow to take off.
By the early 17th century the Catholic Church banned Copernicus’ monograph and proclaimed his heliocentric hypothesis “false” and “contrary to Holy Scripture.” Galileo (AD 1564-1642), the great mathematician, astronomer and physicist, tried to forestall this result. For his support of the Copernican view that the Earth orbited the Sun, Galileo was tried by the Inquisition in 1633, threatened with torture, found “vehemently suspect of heresy,” required to “abjure, curse and detest” those opinions, sentenced to house arrest for life, and forbidden publication of his works. Thus was the Church’s response to freedom of inquiry, and in this case, broad truth.That the Earth orbits the Sun is today settled science. The larger issue, the place of humans in the cosmos, is much contested, indirectly if not directly. The origin stories of some religious systems promote humans as the spiritually superior life form and the Earth as the human domain and spiritual if not physical center of the universe. We may reject the geocentric view of the solar system in favor of heliocentric actuality, but we have not rejected the systems of belief that place humans at the pinnacle of life and center of everything. The geocentric view lives on in spirit.
The order of scientific discovery is crucial to the way we view and interpret phenomena. If Greek and Middle Eastern astronomers, philosophers and religious leaders of 2,500 years ago had knowledge of the universe as we do today, we would doubtless be operating under different religious and philosophical systems. These early ways of thinking reflected the observers’ efforts, sometimes quite creative and logical, to explain the world around them. Through time, we have been able to tweak, correct or reverse errors and misconceptions of scientifically testable phenomena. Systems based upon belief, often pre-scientific, may or may not be susceptible to similar adjustment.
A problem of the modern age is when science clashes with faith, ignorance or anti-intellectualism. Fact is, in the ancient world, it did not matter much in practice whether the Earth orbited the Sun or vice versa. Today, it does matter whether climate change is occurring or not, and the degree to which humans play a role in this drama. Decision-making based upon understanding of the scientific method, of replicative testing of hypotheses, versus acting on positions unsupported by scientific conclusion, now has the potential to cause grievous, perhaps fatal, harm to us and to the planet.
Certainly, we need better science education, in this country and abroad. In the United States, there seems to be a growing consensus that better science education is necessary for our economic future. A scientifically literate populace is also necessary for the great debates upon which the future of the Earth depends. Science education is only part of the solution. We also need better capacity for dialogue and problem-solving. The humanities can play a crucial role in establishing the systems and structures to assist us civilly to confront the crucial issues of our day. Disciplines dedicated to understanding what makes us human, like philosophy, literature, rhetoric, comparative religions, history, archaeology and elements of the social sciences applying philosophical or historical approaches provide ways to bridge gaps between science, public discourse and policy. The humanities offer perspectives and contexts to frame the discussions as we decide our collective future.
When an individual looks out from a mountaintop or flies across the ocean, the world looks almost infinite. It is hard to imagine that we can seriously damage the planet, or if we do, the Earth seems big enough to sustain and recover from our depredations. Now, we can measure the effects of our actions on the planet, calculate consequences, and suggest solutions. We are responsible for our own future. For the first time ever, we can look at the Earth from space. Suddenly, our home looks exposed. From the perspective of Voyager 1, as the spacecraft left the solar system, approaching four billion miles from Earth, the Pale Blue Dot looks a little lonely, a little fragile, a little more vulnerable. We should use all our considerable resources in the sciences and humanities to save it.