Inflation itself proceeds at a speed faster than the measured speed of light. - John Moffat

To physicists such as myself, the huge amount of invisible dark matter needed to make Einstein's theory fit the astrophysical data is reason enough for exploring modified gravity theories.

In estimating the amount of dark matter, cosmologists developing the standard model have to make some rather strong assumptions about their observations.

Almost 30 percent of the total matter-energy budget is said to be composed of so-called cold dark matter and almost 70 percent of "dark energy," leaving only about 4 percent as visible matter in the form of the atoms that make up the stars, planets, interstellar dust, and ourselves. Such is the degree of discrepancy between theory and observations today.