Hi folks!
This is a schematic of the Arduino ProMini that I found on sparkfun.

Can someone please tell me the reason what the purpose is of the 2 capacitors marked in red circles? What electrical significance is there for them to be placed where they are?
Thank you

 

The capacitor between VCC and GND is to smooth any ripple that might be found in the power supply feeding the chip. I am not for sure, but I am guessing the capacitor between AREF and GND is the same idea, only to smooth out any ripple in the AD reference. Perhaps someone else can chime in and confirm.