Question

Place the following in the correct order in which they formed in the universe, and explain your ordering: hydrogen nuclei, helium nuclei, dust, our Sun, our Milky Way galaxy, CMB photons, big bang.

Answer 1

They were formed in this order:

Big Bang > CMB photons > Hydrogen nuclei > Helium Nuclei > Dust > Milky way galaxy > Our Sun.

Step-by-step explanation:

CMB photons are leftover radiation from the beginning of the universe, they are remnants of the extreme heat that took place during the universe first and violent expansion.

Then, when the universe was cool enough, only the lightest elements were formed, hydrogen and helium, which still today are the most present elements in the universe. The Hydrogen was placed firsts because its lighter than Helium. The rest of the elements were formed later via nuclear fusion.

Stellar dust was formed over the course of 380.000 years and then, gravity helped galaxies and stars to form. The milky way was formed around 13 billion years ago, and our sun was formed around 4.6 billion years ago.