and on this fine evening i will once again be thinking abt *spins wheel* the cosmic microwave background 🥰🥰🥰
LIKE. it’s actual relic radiation from just after the Big Bang. it’s electromagnetic waves that have travelled for 13.8 BILLION YEARS from when the universe was a dense, uniform hot mass of plasma and they’re only now reaching us. like it was emitted 13.8 fucking billion years ago. and we’re observing it in the microwave band of the electromagnetic spectrum instead of visible light/UV that it was originally bc it got redshifted into a lower frequency BY THE EXPANSION OF THE UNIVERSE ITSELF??? it was visible and now it’s not bc during its journey the very expansion of the universe stretched the wavelengths so much they’re microwaves now. oh my god. cosmological redshift literally drives me crazy. the CMB radiation is a faint but ever-present remnant of the Actual Big Bang. i think abt it so much
