Introduction

ABSTRACT: This introductory talk at the Cosmic Questions conference (presented by Joel Primack) summarized some earlier pictures of the universe and some pictures based on modern physics and cosmology.

Today cosmologists are telling each other at every conference that this is the golden age - or at least a golden age - of cosmology. It is a tremendously successful period because we are seeing the death of so many theories! Back in 1984 George Blumenthal, Sandra Faber, Martin Rees, and I published a paperin which we described the theory of “cold dark matter” and worked out two versions of it in some detail. A couple of years later Jon Holtzman, a student with Sandra Faber and me, worked out 96 different variants of the cold dark matter scenario. Now, I am proud to say, all but one of them are pretty convincingly ruled out. But the one that is left (which is closely related to one of the two in our original paper) may actually be right. That is fantastic progress! 

Now as we are trying to put together a picture of the whole universe, its origin, evolution, structure, and future - that is what cosmology is all about - the question arises whether this has any broader implications. Does it matter to people as people, and not just as cosmologists (or other kinds of scientists)? I think it does, but that is for you to decide. I hope this Cosmic Questions volume helps.

What I am going to do in the rest of this paper is to try to explain cosmology, not in a technical way, but rather through stories and pictures, especially pictures. That is the way most people throughout history have experienced cosmology. Not as a series of scientific theories that are put forward as hopeful explanations to be tested against data - which is what we do as professional cosmologists - but rather as an understanding that one can grasp and visualize: a picture.

The joke about cosmology used to be that it was the only field of science in which the ratio of theory to data was infinite. But now the situation is reversed, and the ratio has gone to almost zero. Today data is flowing in so fast from new instruments that the question is whether a single one of the current theories can survive. If one theory survives the present onslaught of data, it will be revolutionary.

The advent of a new cosmology can radically change the culture of its time. In particular, the scientific revolution of the 16^th and 17^th centuries helped end the Middle Ages and bring about the European Enlightenment. But it also split scientific knowledge from human meaning, which was at the time largely determined by religion. How will a new picture of the universe at the turn of the 21^st century affect global culture? That is one of the questions explored in this Cosmic Questions volume.

Contributed by: Joel Primack and Nancy Abrams