Is energy always conserved?

this sounds a bit weird.

here's a hypothesis: 

1- lets say a stars sends a laser-precision pulse of blue light with a total of 1000 energy units (e.u. henceforth) towards earth over a period of one year.

2- that light travels for a billion years, and get stretched into the red light spectrum

3- the pulse hits earth, and after 1 year being irradiated, a total of only 600 e.u. hit earth.

4- BUT the pulse doesn't stop. it keeps hitting earth for another 8 months, with an extra 400 e.u., bringing the total energy to hit earth to 1000 e.u.

5- profit?


isn't that what happens? the energy isn't lost, just spread out into a longer span of time and space.