expression
out of sight, out of mind; with time we forget those who have died
Proverb meaning that people gradually forget those who are no longer present, whether through death or distance. Often used to express the transience of human relationships.
See also: 去る者は日々に疎し
去る者日々に疎しというが、遠くに引っ越した友達のことを最近あまり考えなくなった。
They say 'out of sight, out of mind,' and I've recently stopped thinking much about my friend who moved far away.
expression
friendships fade with distance
Specifically refers to friendships or relationships weakening when people are separated by distance. Overlaps with sense 1 but emphasizes physical separation rather than death.
海外に留学したら、地元の友達と疎遠になった。去る者日々に疎しだね。
After studying abroad, I grew apart from my local friends. Friendships really do fade with distance.
Variant with the particle は, making it slightly more formal or emphatic. Meaning is identical.
A classical Japanese proverb. The exact origin is uncertain, but it reflects a common sentiment found in many cultures.