Final answer:
Dark matter contributes to gravitational forces that could decelerate the universe's expansion, while dark energy causes an acceleration in this expansion, impacting the universe's ultimate fate. The tug of war between these forces predicts the future structure of the cosmos.
Step-by-step explanation:
The abundance of dark matter and dark energy in the universe greatly influences its ultimate fate. Dark matter adds to the gravitational pull that could slow down the expansion of the universe, while dark energy, which seems to become more dominant as the universe expands, has a repulsive effect that accelerates the universe's expansion. This acceleration has become more pronounced since the universe reached about half its current age. The balance between these two enigmatic forces will determine whether the universe will keep expanding indefinitely, slow down, or even collapse back on itself—a cosmic tug of war with immense ramifications for the cosmos.
Scientists continue to analyze the effects of dark matter in galaxy formation and evolution. The gravitational lensing reveals the presence of dark matter by the bending of light from distant galaxies, hinting at the massive influence unseen matter has in the cosmos. Moreover, measurements of the cosmic microwave background radiation provide further constraints on the role of dark matter in the early stages of the universe.