system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 how does radiation work?

I've been reading a lot about Chernobyl recently. And Google gives quite complex answers, so I thought I'd try here. So I have a few questions:-

What is radiation?

How do very high doses, like the ones workers and emergency workers experienced during the disaster, effect the human body?
gpt
It may help if we start with 'what radioactive decay is'. Radeoactive decay is when a large unstable element (like uranium) splits into two smaller elements. For seemingly most elements, this decay sends off subatomic particles and photons, often referred to as radiation. 

Those particles and photons from radioactive decay are very good at fucking up cells. They break down molecules, key among them DNA and RNA. So in addition to damaging the normal molecules of a cell, it damages the instructions used to fix the cells. So someone exposed to radiation might come out with a burn (sunburn is a mild, shallow version of a radiation burn from UV radiation), but the real danger is the cells' DNA/RNA basically making it so that the cell can't continue to function. Our body can handle some radiation, though it does increase your risk of cancer. The deadly non-cancerous issue is when you get too much at once. In the case of nuclear radiation victims, they get hit with such high doses that on a cellular level, too many cells stop functioning because of DNA damage.