If, as we now believe, the rate of expansion of the universe was slower in the past than at present, then in the past the value of the Hubble ratio, H = v/d, was: (See Figure 25-16 of Universe, 11th ed.) A)negative. B)its present value, H₀. C)smaller than its present value. D)larger than its present value.

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Quizplus · Accepted Answer

The Hubble ratio, H = v/d, is the ratio of the recession velocity of galaxies to their distance from us. As the universe expands, galaxies move away from each other, and the recession velocity increases. Therefore, if the rate of expansion of the universe was slower in the past, the recession velocity of galaxies was also slower, while their distance from us remained the same. This means that the value of the Hubble ratio, H = v/d, was smaller in the past than at present.

If, as We Now Believe, the Rate of Expansion of the Universe