The rotation curves of spiral galaxies show that the orbital velocities of stars do not decrease as far as expected based on the visible mass of the galaxy. This suggests that there is a large amount of unseen mass, or dark matter, haloing the galaxy.

Dark matter halos typically have masses of around 10^12 Msun, which is about the mass of a trillion Suns.

The density profile of a dark matter halo is typically described by the Navarro-Frenk-White (NFW) profile, which has a steep inner slope and a shallower outer slope.

Dark energy is causing the expansion of the universe to accelerate, which is evident from the observed redshift-magnitude relation of distant supernovae.

The energy density of dark energy is very low, around 10^-27 g/cm^3.

The equation of state of dark energy is typically assumed to be w = -1, which corresponds to a cosmological constant.

If dark energy continues to dominate, the expansion of the universe will continue to accelerate and the universe will eventually reach a state of eternal expansion.

There are many proposed candidates for dark matter, including weakly interacting massive particles (WIMPs), axions, sterile neutrinos, and primordial black holes.

There are many proposed candidates for dark energy, including a cosmological constant, modified gravity theories, quintessence, and phantom energy.

Studying dark matter and dark energy is challenging because they are difficult to detect directly, they are difficult to model theoretically, and they are difficult to distinguish from other phenomena.

Future research in dark matter and dark energy will involve a combination of direct detection experiments, indirect detection experiments, cosmological observations, and theoretical studies.

Dark matter and dark energy challenge our understanding of gravity, require us to modify our cosmological models, and provide new insights into the early universe.

Dark matter and dark energy play a crucial role in the formation of galaxies and large-scale structures, affect the dynamics and evolution of galaxies and large-scale structures, and determine the properties of galaxies and large-scale structures.

Some of the open questions about dark matter and dark energy include: What is the nature of dark matter? What is the nature of dark energy? How do dark matter and dark energy interact with each other?

Some of the potential implications of dark matter and dark energy for the future of the universe include: The universe could continue to expand forever, the universe could eventually stop expanding and collapse, the universe could eventually reach a state of equilibrium, or the universe could eventually rip apart.