The idea that dark matter could be attributed to the combined mass of supermassive black holes in the universe is an interesting hypothesis. However, it is important to note that this is purely speculative and not currently supported by scientific evidence.
Dark matter is a theoretical form of matter that does not interact with light or other electromagnetic radiation, making it invisible to direct detection. Its existence is inferred from its gravitational effects on visible matter and the large-scale structure of the universe. While there are various theories and hypotheses regarding the nature of dark matter, none have been definitively proven at this time.
Supermassive black holes are extremely massive objects found at the centers of galaxies. They are known to have significant gravitational influence, but their mass alone is not sufficient to explain the observed effects of dark matter. The gravitational effects of supermassive black holes are localized to the regions immediately surrounding them, while dark matter is believed to be distributed throughout the entire universe.
Scientists have extensively studied the distribution of dark matter using various methods, such as gravitational lensing, galactic rotation curves, and the cosmic microwave background radiation. These observations indicate that dark matter is more uniformly distributed on large scales, rather than being concentrated around supermassive black holes.
While it is always valuable to explore new ideas and hypotheses in science, any proposal suggesting that supermassive black holes alone can account for the entirety of dark matter would need to provide strong evidence and be consistent with the extensive observations and measurements conducted by astronomers.