The Opposite of Infinity - Numberphile (youtube.com)
Continuing to talk Infinitesimals, this time with Dr James Grime.- Abraham Robinson (Wikipedia)
Abraham Robinson (born Robinsohn; October 6, 1918 – April 11, 1974) was a mathematician who is most widely known for development of nonstandard analysis, a mathematically rigorous system whereby infinitesimal and infinite numbers were reincorporated into modern mathematics. Nearly half of Robinson’s papers were in applied mathematics rather than in pure mathematics.