Cosmologists Enter Exciting New Era of Galaxy Exploration
AN astronomical satellite that senses radiation left over from the universe's birth has given cosmologists a major finding.
It has revealed the earliest traces of the underlying structure that produced the distribution of matter in the universe that is seen today.
Now those scientists look forward to the satellite's next expected discovery - the primordial glow of the very first galaxies and other luminous objects that formed along the lines of that structure.
The satellite is the Cosmic Background Explorer (COBE). Since its Nov. 18, 1989, launch by the National Aeronautics and Space Administration, it has opened an exciting new era of exploration for cosmologists who previously had little opportunity to test their theories.
Astrophysicist Stephen Maran of the Goddard Space Flight Center in Greenbelt, Md., explains that, before COBE, cosmologists had only three observational facts to work with:
1. The universe is expanding. This is consistent with theories that the universe originated 10 billion to 20 billion years ago in the "Big Bang" explosion of a super-dense primodial mass that was smaller than the period at the end of this sentence.
2. A weak radiation of microwave and infrared energy permeates all space. Theorists consider such radiation to be the Big Bang's afterglow.
3. A measured relative abundances of light elements conform to what cosmologists expect the Big Bang would have created.
"Up to now, everything we knew about the Big Bang could be written on the head of a pin. Now we're moving beyond that," Dr. Maran observes.
COBE is equipped specifically to study key aspects of the fossil radiation.