diff --git a/circleshape.py b/circleshape.py
index eb08882..e438e08 100644
--- a/circleshape.py
+++ b/circleshape.py
@@ -20,3 +20,6 @@ class CircleShape(pygame.sprite.Sprite):
     def update(self, dt):
         # sub-classes must override
         pass
+
+    def is_colliding(self, circle):
+        return (self.radius + circle.radius) > self.position.distance_to(circle.position)
diff --git a/main.py b/main.py
index 22ac5b1..fa4651b 100644
--- a/main.py
+++ b/main.py
@@ -42,6 +42,11 @@ def main():
 
         updatable.update(dt)
 
+        for asteroid in asteroids:
+            if asteroid.is_colliding(player):
+                print("Game Over")
+                sys.exit(0)
+
         for drawing in drawable:
             drawing.draw(screen)