//Called when the game ends i.e the player loses all their lives
    public void GameOver()
    {
        HighscoresContainer highscoresContainer = FindObjectOfType <HighscoresContainer>();
        BlockOfAliens       blockOfAliens       = FindObjectOfType <BlockOfAliens>();
        FlyingSaucer        flyingSaucer        = FindObjectOfType <FlyingSaucer>();
        int numHighscores = highscoresContainer.GetNumberOfHighScores();
        int lowestScore   = highscoresContainer.GetLowestScore();

        //If there are less than 10 highscores or the player got a score greater than the lowest high score
        //Then the player has just got a highscore so...
        if (numHighscores < 10 || score > lowestScore)
        {
            //Stop the aliens and flying saucer from moving
            blockOfAliens.SetPaused(true);
            flyingSaucer.gameObject.SetActive(false);
            //Make the add score panel active and give the add score script the new score
            addScore.gameObject.SetActive(true);
            addScore.SetScore(score);
        }
        //Else the player didnt get a high score so...
        else
        {
            //Stop the aliens and flying saucer from moving
            blockOfAliens.SetPaused(true);
            flyingSaucer.gameObject.SetActive(false);
            //Display the game over panel
            gameOver.SetActive(true);
        }
        //Pause the game
        Time.timeScale = 0f;
    }