Any question answered...

From my physics I know that a charger with the same voltage but higher current will mean a lower resistance. So I can safely replace one charger with another if the only difference is a higher current. Am I right? Will my laptop blow up, my house catch fire and my family all die?

Increased charging current -> increased heating in battery -> generally viewed as a bad thing unless using a peak detection charger (unlikely with a laptop)

http://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_problems suggests yes, your laptop may blow up, house catch fire etc.