Why does the cosmic microwave background (CMB) shine in low-energy microwave wavelengths? The trapped photons within the plasma of the earliest universe originally had wavelengths in the microwave band due to rapid inflation The CMB was originally emitted as high-energy gamma rays and x-rays, but the light has redshifted downward to lower-energy microwaves through time

Calculate the Hubble constant for a universe that is 20 billion years old.

TRUE OR FALSE: In an unbounded universe, all hydrogen will be used up in about a trillion years

Explain the expanding Universe theory and its relationship to the Big Bang theory?

What is the CMB? Group of answer choices A dense region of 4.5 million stars. A large star of 4.5 million solar masses. The cosmic microwave background of photons left over and cooled down from when the universe became transparent 300,000 years after the Big Bang. The space curvature of the universe

The Milky Way grew through merging with many smaller galaxies. What are the observational signatures of this process? O The motion of old stars in the bulge and halo of our galaxy are randomly orientated, meaning they were formed from collisions of small, accreted, galaxies all on different paths. O The ordered motion of the bulge / halo stars means that they came from many objects. The random motions of stars in the disk means it was formed from collisions of small, accreted, galaxies. O The motion of young stars in the disk are all in the same direction, meaning they came in as seperate objects.

Why is dark energy required to explain the universe as we see it today according to the Big Bang model of the universe?  9

If the universe had a Hubble Constant (Ho) of 100km/s/Mpc and a critical density of 1. The universe will collapse on itself and come to an end collapse on itself but regenerate with a bounce expand and the speed of expansion will increase with time expand and the speed of expansion will decrease with time

To what does cold refer to the term "cold dark matter"? Why do models of large-scale structure agree best with the dark matter being "cold"?