Abstract

Two years ago, astrophysicists studying Type Ia supernovas discovered that our universe is a much stranger place than we had imagined, with invisible vacuum energy accelerating its expansion. (See my column about this in the May-1999 Analog.) However, new astrophysical observations from the BOOMERanG experiment (Balloon Observations Of Millimetric Extragalactic Radiation and Geomagnetics), a balloon-borne cryogenic microwave telescope measurement that flew at an altitude of about 24 miles over the Antarctic, indicate that our universe is also rather ordinary, in that its space is maximally flat. The term “flat” as used here means that the space of our universe is neither positively curved like a ball or negatively curved like a potato chip. It appears that in our universe, the tendencies of space toward positive curvature from gravitational attraction and towards negative curvature from expansion kinetic energy are precisely in balance, leaving space on the average completely free of curvature.