Some socalled creation scientists claim that the universe ca

Some so-called \"creation scientists\" claim that the universe came into being 6000 years ago. Find the value of the Hubble constant for such a universe (in km/s/Mpc). 2.72 Times 10^4 4.38 Times 10^5 1.63 Times 10^8 You can estimate the size of the observable universe by substituting v = c into the Hubble law and calculating d. What is d (in light years) when the Hubble constant is H = 73 km/s/Mpc? 1.34 Times 10^10 3.09 Times 10^6 4.11 Times 10^9 Repeat this calculation using your value of H from part 6000 2.72 Times 10^4 2.23 Times 10^6

Solution

[a]

1929, Edwin Hubble announced that almost all galaxies appeared to be moving away from us.

H= V/d,where v is the galaxy\'s radial outward velocity, d is the galaxy\'s distance from earth, and H is the current value of the Hubble constant.

Thus, the Hubble time T is just the inverse of the Hubble Constant:

T = 1/H

T=600years = 1.89 *10¹⁰ s

H= 5.29*10^-11 s^-1

1 km/s/Mpc= 0.324*10^-19 s^-1

1s^-1= 3.09*10¹⁹ km/s/Mpc

H= 5.29*10^-11 s^-1=1.63*10⁸ km/s/Mpc

[b]

H= V/d= c/d

H= 73km/s/Mpc= 23.652*10^-19 s^-1

d= c/H= 3*10⁸ m/s/ 23.652*10^-19 s^-1 = 0.127*10 ²⁷ m

1 light year= 9.5*10 ¹⁵ m

1m= 0.105*10^-15 light year

d= 0.127*10 ²⁷ m=0.0133*10 ¹² light year= 1.33*10¹⁰ light year

[c]

H= 5.29*10^-11 s^-1 [from part (a) ]

d= c/H= 3*10⁸ m/s/ 5.29*10^-11 s^-1 = 0.56*10 ¹⁹ m=0.059*10 ⁴ light year =590 light year

d~ 600 lightyear