**3. Possible solutions and even more problems**

#### **3.1 Wimps**

Hypothetical particles that constitute the dark matter are called WIMPs which stands for weakly interacting massive particles. All the matter that we know (and us) is made of baryonic matter, i.e., the matter is made of baryons. WIMPS would be a new type of particles beyond the standard model. Those should be massive, subject to the gravitational force, and possibly other forces that are comparable to the weak force. One such candidate for WIMP could be a stable supersymmetric particle. Supersymmetric model has a particle of this property which was even called a "Wimp Miracle," but we have not yet observed any trace of supersymmetry, moreover, Wimp Miracle in any of the particle colliders. WIMPs also should not interact via electromagnetism; hence the DM is not visible in any wavelength. We only can "see" the DM due to its gravitational interactions, which are strong enough to cause a phenomenon known as gravitational lensing.

### *3.1.1 Gravitational lensing*

This phenomenon is observed when the light rays passing near a very massive object are deflected (due to the curvature of space–time produced by this object) in such a way that a distant observer observes it lensed. **Figure 3** illustrates gravitational lensing: the stretched structures are distant galaxies, whose light was bent by the DM between them and the observer. This allows to calculate the mass required to cause such phenomenon [6]. Large aggregations of massive DM particles are able to produce such image letting us to know it's out there*.*
