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

The Question

(Submitted May 16, 1997)

How serious is the hypothesis about anti-stars? (Are there some experiments, theories, etc.?)

I study physics and a year ago I did a kind of homework concerning CAPRICE experiment (balloon flight) who's aim is to measure the flux of positrons, antiprotons and possibly, search for lighter anti-nuclei. As far as I understood, one of the reasons for this kind of experiments is the fact that previous data of the flux of antiparticles showed higher flux than predicted from several models. There was a hint, that antistars may exist which emit anti-protons and positrons as Sun emits solar wind. Well, when I mentioned this to my professor, he smiled and acted as it was an astrology I was talking about, not astrophysics.

Are the results of CAPRICE experiments already known?

The Answer

We don't know for sure that we live in a matter Universe, only that individual superclusters of galaxies are each made of either matter or antimatter. (Otherwise anti-matter atoms in the gas that pervades a supercluster would interact with the matter parts of it, or vice-versa, giving an easily identifiable energy emission).

We may live in a matter supercluster within a segregated matter-antimatter Universe. (Most people don't think that it's likely, but we don't have enough data to rule it out. That's why people are still looking.) If we find any anti-atoms, they must come from anti-stars from a antimatter supercluster a long way away.

Your can find information and results from CAPRICE on a number of web sites:
- has references to papers
- describes the next generation CAPRICE

David Palmer, Jim Lochner, and Karen Smale
for the 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