tudying for test: A new astronomical measurement suggests that the Hubble constant is 1112 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?

Mehul

In a globular cluster, astronomers (someday) discover a star with the same mass as our Sun, but consisting entirely of hydrogen and helium. Is this star a good place to point our SETI antennas and search for radio signals from an advanced civilization? Group of answer choices   No, because such a star (and any planets around it) would not have the heavier elements (carbon, nitrogen, oxygen, etc.) that we believe are necessary to start life as we know it.   Yes, because globular clusters are among the closest star clusters to us, so that they would be easy to search for radio signals.   Yes, because we have already found radio signals from another civilization living near a star in a globular cluster.   No, because such a star would most likely not have a stable (main-sequence) stage that is long enough for a technological civilization to develop.   Yes, because such a star is probably old and a technological civilization will have had a long time to evolve and develop there.

Planetary Nebula Age. Suppose a planetary nebula is 1 pc in radius. If the Doppler shifts in its spectrum show it is expanding at 20 km/s, how old is it? (Note that 1 pc equals 3.1x1013 km, and 1 year equals 3.2x107 seconds, to two significant figures.) Please round your answer to two significant digits. At = years

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?

Another explanation for the Universe is the Steady State Hypothesis. The Steady State Hypothesis says that the Universe has always existed and is infinite in extent. Which of the following supports the Big Bang Theory and which supports the Steady State Model. (Select B-Big Bang Theory, S-Steady State Model, If the first is B and the rest S, enter BSSSSS). A) An observation that some globular clusters show M-type stars that have evolved off the main sequence.   B) The measurement of redshifts that show galaxies appear to be moving away from each other and the Universe is expanding.   C) A measurement that shows the density of the Universe is close to the critical density.   D) The measurement of the microwave background radiation.   E) Observing that galaxies at very large distances look identical to those in the nearby universe.

There is only one part to this question and I need to know the particles per second. Thank you!!

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.

If the speed of light is given as  299,792,458 meters per second and the wavelength is 560 nm.  what is the frequency of this light?  Give your answer in THz!

T/ F  The distance unit best for interstellar distances is the light-year. ___   The distance unit best for intergalactic distances is the mega-parsec. ___