The nature of dark matter is still an open question in physics, and there are various hypotheses and theories attempting to explain its existence. One possibility is that dark matter could be composed of particles that exist in additional dimensions beyond the three spatial dimensions we are familiar with.
This idea is motivated by theories such as string theory, which suggests the existence of extra dimensions. According to some models, particles associated with dark matter could reside in these extra dimensions and only interact with ordinary matter through gravitational forces. This would explain why dark matter is difficult to detect using traditional observational methods, as it would interact very weakly with electromagnetic radiation.
However, it's important to note that this is just one speculative hypothesis among many. There are numerous other proposals for the nature of dark matter, including the existence of new types of particles that exist within our three spatial dimensions.
The search for dark matter and its fundamental properties is an active area of research. Scientists are conducting experiments using a variety of approaches, including particle accelerators, underground detectors, and astrophysical observations, to try to understand the nature of dark matter and its potential connection to other dimensions or fundamental physics.