Why are the wings on supersonic aircraft swept back?

Answer 1

Supersonic aircraft are typically delta-winged rather than sweptback. (see f-16, f-15, mig-29, concorde, etc)

A sweptback wing allows airflow to move over it in a diagonal, increasing its effective width without adding extra weight to the aircraft. However the stall characteristics of a sweptback wing are very bad. They tend to stal at the tip first, meaning you lose airleron control immediately. This is a bad thing in the region of flight leading up to exceeding the speed of sound as the shock wave (sonic boom) that develops over the wing tends to move the center of pressure forward, accelerating the aircraft, and deepening the shock wave. As sweptback wings approach their critical mach number, they become very unstable. For this reason, most jet aircraft that have sweptback wings are limited to a speed well below their critical mach number.

Answer 2

It helps ease the transition from subsonic to supersonic by reducing the maximum cross-section area for a given wing surface area and allows the shift in center of lift to move less abruptly.

Answer 3

there is less drag this way and the entire plane then becomes a wing

Answer 4

the high speed bent them back