Theoretical Considerations
Theoretical work simultaneously also showed that ancient MACHOs are not likely to account for the large amounts of dark matter now thought to be present in the universe. The Big Bang as it is currently understood could not have produced enough baryons and still be consistent with the observed elemental abundances, including the abundance of deuterium. Furthermore, separate observations of baryon acoustic oscillations, both in the cosmic microwave background and large-scale structure of galaxies, set limits on the ratio of baryons to the total amount of matter. These observations show that a large fraction of non-baryonic matter is necessary regardless of the presence or absence of MACHOs.
Read more about this topic: Massive Compact Halo Object
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