Using our example from the previous unit, let's try to determine the Hubble time for this example universe. You were given that a good representative galaxy receded at a speed of 4000 km/s and was found to be 20 Mpc away. With that in mind, what would the age of that universe be in years (aka what is that universe's Hubble time)? Go ahead and take the number of kilometers per Mpc to be approximately 3.1*10^19 km/Mpc. While this problem may look scary at first, this is really just bringing you full circle to one of the unit conversion problems you encountered at the beginning of this course.

Using our example from the previous unit, let's try to determine the Hubble time for this example universe. You were given that a good representative galaxy receded at a speed of 4000 km/s and was found to be 20 Mpc away. With that in mind, what would the age of that universe be in years (aka what is that universe's Hubble time)? Go ahead and take the number of kilometers per Mpc to be approximately 3.1*10^19 km/Mpc. While this problem may look scary at first, this is really just bringing you full circle to one of the unit conversion problems you encountered at the beginning of this course.

Similar questions

In the reading, you were told that there were roughly 10,000 galaxies in the image of the Hubble Ultra Deep Field alone. The image is roughly 10 square arcminutes and there are roughly 1.5*10^8 square arcminutes composing the entire sky. With that in mind and assuming that the Hubble Ultra Deep Field represents an average part of the sky, roughly how many galaxies may exist in the observable universe? (Please include commas for every factor of 1,000; for example 2,343,567,890)
Calculate the age of the universe for the following Hubble's constant, (a) 30 km/s/Mpc
Suppose a hypothetical universe is expanding (at some moment in time) at a rate of H. What would the density of this universe need to be (at this same moment in time) in order for it to be spatially flat? Value: H = 80 km s-1 Mpc-1 Give your answer in units of (kg m-3), in scientific notation with one decimal place (two sig figs). Please show work because I have trouble following along
Your friends are talking about Olber's Paradox: Friend 1: When the universe was quite young, it was also quite small, and therefore light was trapped inside the universe. This is why we don't see light from the edge of the universe in every direction. Friend 2: No, Olber's Paradox describes only light from stars, not from galaxies, and why you can't use light from distant stars to see at night. Friend 3: You're both right and you're both wrong. The paradox concerns itself with the expansion of the universe, and explains why light from the early universe was able to be released. Are any of them right, in part or in whole?
Suppose you have obtained spectra of several galaxies and have measuerd the observed wavelength of the H-Alpha line (rest wavelength = 656.3 nm) to be Galaxy 1: 658.1 nm. Galaxy 2: 667.1 nm. Galaxy 3: 677.6 nm. Assuming a Hubble Constant of 72.5 km/s/Mpc, calculate the distance to each of these galaxies (answer in Mpc)
For the graph shown above, a) what quantity would you label the y-axis with if the distance is between galaxies and the Earth? Explain your answer. Think through what we know is happening, motion-wise, out there in the galaxy. b) Also explain why you think there are dots and a solid line, on the graph.
A new astronomical measurement suggests that the Hubble constant is 51 kilometers per second per Megaparsec. If this measurement is correct, what would the Hubble time be in units of years? Is this a plausible value based on other astronomical evidence? Why or why not?
Briefly explain what is meant by “particle horizon” and “event horizon” in cosmology. Calculate the physical particle horizon, RH(t), at time t. Assume a flat FRW universe whichis dominated by a fluid that gives rise to scale factor evolution where n is a constant with 0 < n < 1, and a(t0) = a0.
What was the typical density of the universe, when the microwave background radiation was last scattered (redshift around 1000)? Enter your answer in kilograms per cubic metres.
What is the estimated age of the Universe (in years) if the Hubble constant is 60 km/s/Mpc?
If you observe light emitted from a distance object when the cosmic background temperature was Tz=54K, what is the redshift z of that light? At that redshift, what was the diameter Dz of the universe at that time compared to the diameter of today's universe D0?