I hear astro-physicists constantly repeating when u look at the sky and the stars, it's all in the PAST and doesn't really exist. This concept baffles me, maybe it's due to my ignorance of the cosmos. But I literally 'see' those stars in the sky at night in the present moment. Do they mean by the time 'we' as humans with our primitive technology 'reach' those stars they won't exist? or do they mean even if we could travel millions of kilometers per second we would arrive at those stars not existing?