function updateImage() {
    if (pic == 1) {
        caption = "GO BEYOND EARTH";
    }
    else if (pic == 2) {
        caption = "EXPLORE NEW WORLDS";
    }
    else if (pic == 3) {
        caption = "EXPERIENCE DEEP SPACE";
    }

    $('.pic-titles').text(caption);
    $('.center').css('background-image', 'url(img/space' + pic + '.jpg');
    pic++;

    if (pic > 3) {
        pic = 1;
    }
  }
});