Abstract

Despite their rarity, (ultra-) wide binaries command considerable interest, both in terms of their origin and survival and on account of what they tell us about gravity in the ultra-low field limit. In addition, through assuming that their components are coeval and chemically homogeneous at birth, chemical anomalies can be used to probe differential accretion of planetary material.  Here I will discuss the main theories for wide binary formation (whether they form through orbital reconfiguration within small N clusters or whether they result from capture in the context of large N dissolving clusters), emphasising what observations can potentially constrain the dominant formation channel. Finally I describe the recent rise and fall of the idea that wide binaries prove the correctness of MOND .