Why Does an Atom Experience Red and Blue Shifts During Its Journey?

[cks]

Imagine an atom traveling to the right.

There's an EM radiation traveling to the right also.

From the atom's frame, it'll see a red shifted frequency on its left and a blue shifted frequency on its right??

 

[Meir Achuz]

The atom will "see" nothing on its right.

 

[LURCH]

Imagine an atom traveling to the right.

There's an EM radiation traveling to the right also.

From the atom's frame, it'll see a red shifted frequency on its left and a blue shifted frequency on its right??

Yes, bearing in mind that the term "shifted is relative. If the atom can "see," what it sees will be red or blue shifted compared to what you see.