This is off topic, but I'm not sure wherre else to ask!

Can Blue Ray disks be played on a standard DVD player?

I've never owned a blue ray disk, or blue ray player, but if I was to
get a Blue Ray disk, will it play on a player made for regular DVDs?
I really dont have a need for blue ray, since my tv is just a plain old
CRT set, and as far as I know, Blye Ray only applies to HDTV sets.
Besides that, DVD is plenty fine for me.

And while I'm asking this, does this work in reverse, meaning does a
Blue Ray player also play regular DVDs?