Physics.gravity

static var gravity : Vector3

Description

The gravity applied to all rigid bodies in the scene.

Gravity can be turned off for an individual rigidbody using its useGravity property.

JavaScript

Physics.gravity = Vector3(0, -1.0, 0);

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void Example() {
        Physics.gravity = new Vector3(0, -1.0F, 0);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Example():
        Physics.gravity = Vector3(0, -1.0F, 0)