Explain Like I'm Five

Yes - it's been the job of the DRAM controller for almost the entire history of computing. But that's still a part of the computer and if it stops working then your RAM will go blank in a fraction of a second

If you ever have the chance to use an old Apple II computer, run a text mode program, wait til the owner is looking in the other direction and turn the power off and back on quickly.

For about a second, before you hear the loud BOOP and the screen clears, you'll see whatever was on the screen just before you powered it off. But a few characters will be corrupted. Try it again, and wait a half a second longer than before. More characters will be corrupted.

For that brief second you're looking at the contents of the video RAM, then the ROM (Apple called what we call BIOS now "ROM") clears the contents and puts up the familiar text banner. The longer the power stays off, the more the contents of those flash cells decay and flip the bits that determine what character shows up in a location on the screen.

Dynamic RAM tracks bits by using a capacitor for each bit. Caps' charge bleeds out so you have to top it off again every so often. The way you do that is to just write the same data back again. So it reads and writes the same data to itself every refresh. The opposition to this is static RAM which does not use a capacitor and is just a clever arrangement of transistors. No refresh needed. It's not typically used commercially except under special requirements, though as transisters are significantly more expensive. So the refresh strategy is the better choice for consumer hardware. DRAM has been dominant for decades.

srsly... https://en.wikipedia.org/wiki/Memory_refresh

Some very early systems did do it at kernel level, but yeah you are correct. Though I'd also consider the dram chips to be part of the computer and DRAM refresh makes up a good part of your phones battery consumption at standby.

It's possible, and can be done at home. You need to literally freeze the RAM very quickly (typically with CO2) and transfer it to the new system. Then you dump the contents of the stick and hopefully find an encryption key.

From what i've read it's temperature dependent, and at room temp some dram cells might take as long as 10 seconds to decay. The 64mS refresh is a super conservative call because it's really bad when random bits go missing out of memory. The decay is faster at high temperatures, but some dram controllers might actually adjust based on temperature.