Regarding Meltdown and Spectre

What are Meltdown and Spectre, and what is the difference between the two? From¬†meltdownattack.com: “Meltdown and Spectre exploit critical vulnerabilities in modern processors.¬†These hardware vulnerabilities allow programs to steal data which is currently processed on the computer. While programs are typically not permitted to read data from other programs, a malicious program can exploit Meltdown…