public ArrayList<Projectile> handleCollisions(List<Projectile> projectiles)
	{
		
		ArrayList<Projectile> collided = new ArrayList<Projectile>();
		boolean sort = false;
		
	
		
		for(Projectile p : projectiles )
		{
			if(p.getDirection() == Direction.UP)
			{
				boolean collision = false;
				for (Iterator<Alien> ia = _aliens.iterator(); !collision && ia.hasNext();)
				{
					Alien a = ia.next();
					
					if(a.contains(p.getCollisionPoint()))
					{
						sort = (a.equals(leftAlien) || a.equals(rightAlien)) ? true : false;
						ia.remove();
						
						SpaceInvaders.playAudioFileOnce("Explosion1.wav");
						collided.add(p);
						collision = true;
					}
				}
			}
		}
		
		if(sort)
		{
			computeBoundsAliens();
		}
		return collided;
	}