diff --git a/src/main.cpp b/src/main.cpp
index 63e17fc..8ffc6bb 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -5,16 +5,53 @@
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
+#include <cmath>
+
+// Constants for unit conversion
+const double AU = 1.496e11;  // 1 AU in meters
+const double KM = 1000.0;     // 1 km in meters
+
+// Helper functions for human-readable output
+void print_position_readable(const char* name, Vec3 pos) {
+    double dist_au = vec3_magnitude(pos) / AU;
+    double x_au = pos.x / AU;
+    double y_au = pos.y / AU;
+    double z_au = pos.z / AU;
+
+    // Calculate polar coordinates (angle in XY plane)
+    double angle_rad = atan2(pos.y, pos.x);
+    double angle_deg = angle_rad * 180.0 / M_PI;
+    if (angle_deg < 0.0) angle_deg += 360.0;  // Convert to 0-360 range
+
+    printf("%s:\n", name);
+    printf("  Position: (%.6f, %.6f, %.6f) AU\n", x_au, y_au, z_au);
+    printf("  Polar (XY plane): r=%.6f AU, θ=%.2f°\n", dist_au, angle_deg);
+}
+
+void print_velocity_readable(const char* name, Vec3 vel) {
+    double speed_km_s = vec3_magnitude(vel) / KM;
+    printf("  Velocity magnitude: %.3f km/s\n", speed_km_s);
+    printf("  Velocity: (%.3f, %.3f, %.3f) km/s\n",
+           vel.x / KM, vel.y / KM, vel.z / KM);
+}
+
+void print_body_readable(CelestialBody* body) {
+    print_position_readable(body->name, body->position);
+    print_velocity_readable(body->name, body->velocity);
+}
 
 int main(int argc, char** argv) {
     // Parse command line arguments
     const char* config_file = "configs/solar_system.txt";
     bool headless = false;
+    bool readable = false;  // Human-readable output (AU, km, etc.)
     int sim_duration_days = 365;  // Default: 1 year for headless mode
 
     for (int i = 1; i < argc; i++) {
         if (strcmp(argv[i], "--headless") == 0 || strcmp(argv[i], "-h") == 0) {
             headless = true;
+        } else if (strcmp(argv[i], "--readable") == 0 || strcmp(argv[i], "-r") == 0) {
+            readable = true;
         } else if (strcmp(argv[i], "--days") == 0 && i + 1 < argc) {
             sim_duration_days = atoi(argv[++i]);
         } else if (argv[i][0] != '-') {
@@ -27,6 +64,9 @@ int main(int argc, char** argv) {
     if (headless) {
         printf("Mode: Headless (terminal output only)\n");
         printf("Duration: %d days\n", sim_duration_days);
+        if (readable) {
+            printf("Output: Human-readable units (AU, km/s)\n");
+        }
     }
 
     // Create simulation with time step of 60 seconds
@@ -51,11 +91,15 @@ int main(int argc, char** argv) {
         printf("\n=== Initial State ===\n");
         for (int i = 0; i < sim->body_count; i++) {
             CelestialBody* body = &sim->bodies[i];
-            printf("%s:\n", body->name);
-            printf("  Position: (%.3e, %.3e, %.3e) m\n",
-                   body->position.x, body->position.y, body->position.z);
-            printf("  Velocity: (%.3e, %.3e, %.3e) m/s\n",
-                   body->velocity.x, body->velocity.y, body->velocity.z);
+            if (readable) {
+                print_body_readable(body);
+            } else {
+                printf("%s:\n", body->name);
+                printf("  Position: (%.3e, %.3e, %.3e) m\n",
+                       body->position.x, body->position.y, body->position.z);
+                printf("  Velocity: (%.3e, %.3e, %.3e) m/s\n",
+                       body->velocity.x, body->velocity.y, body->velocity.z);
+            }
         }
 
         printf("\n=== Running Simulation ===\n");
@@ -66,8 +110,16 @@ int main(int argc, char** argv) {
             if (sim->time >= next_output_time) {
                 printf("Day %.1f: ", sim->time / SECONDS_PER_DAY);
                 for (int i = 0; i < sim->body_count && i < 3; i++) {
-                    double dist = vec3_magnitude(sim->bodies[i].position);
-                    printf("%s=%.3e m  ", sim->bodies[i].name, dist);
+                    Vec3 pos = sim->bodies[i].position;
+                    double dist = vec3_magnitude(pos);
+                    if (readable) {
+                        double angle_rad = atan2(pos.y, pos.x);
+                        double angle_deg = angle_rad * 180.0 / M_PI;
+                        if (angle_deg < 0.0) angle_deg += 360.0;
+                        printf("%s(r=%.4f AU, θ=%.1f°)  ", sim->bodies[i].name, dist / AU, angle_deg);
+                    } else {
+                        printf("%s=%.3e m  ", sim->bodies[i].name, dist);
+                    }
                 }
                 printf("\n");
                 next_output_time += output_interval;
@@ -77,11 +129,15 @@ int main(int argc, char** argv) {
         printf("\n=== Final State (Day %.1f) ===\n", sim->time / SECONDS_PER_DAY);
         for (int i = 0; i < sim->body_count; i++) {
             CelestialBody* body = &sim->bodies[i];
-            printf("%s:\n", body->name);
-            printf("  Position: (%.3e, %.3e, %.3e) m\n",
-                   body->position.x, body->position.y, body->position.z);
-            printf("  Velocity: (%.3e, %.3e, %.3e) m/s\n",
-                   body->velocity.x, body->velocity.y, body->velocity.z);
+            if (readable) {
+                print_body_readable(body);
+            } else {
+                printf("%s:\n", body->name);
+                printf("  Position: (%.3e, %.3e, %.3e) m\n",
+                       body->position.x, body->position.y, body->position.z);
+                printf("  Velocity: (%.3e, %.3e, %.3e) m/s\n",
+                       body->velocity.x, body->velocity.y, body->velocity.z);
+            }
         }
 
         destroy_simulation(sim);