Imagine the Universe!
Imagine Home  |   Ask an Astrophysicist  |  
Ask an Astrophysicist

The Question

(Submitted March 01, 1998)

If it is possible to have hundreds of thousands of solar systems, is it possible to have hundreds of thousands of universes?

The Answer

People can, and are, going about extensive observing programs looking for planets around other stars, with a good deal of success recently. So not only can they exist, but we now know a few that actually do.

On the other hand, there is no way to observe any universe other than our own. This is not a practical issue (like there not being good enough telescopes), but rather a fundamental theoretical issue. By definition, our universe is self-contained. No other universe can affect anything in our universe, so we cannot gather evidence about its existence.

Applying Einstein's laws of general relativity, it is possible to come up with solutions that connect one universe to another via a spinning black hole. However even if we were to observe such a thing, it would still not tell us if there was another universe on the other side or if the other side was part of our own universe.

So, from a scientific standpoint the question is moot, but from a philosophical standpoint, it is fascinating.

Jonathan Keohane
for Ask an Astrophysicist

Previous question
Main topic
Next question

Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

The Imagine Team
Acting Project Leader: Dr. Barbara Mattson
All material on this site has been created and updated between 1997-2012.

DVD Table of Contents
Educator's Index