Sorry i put this in the wrong forum so reposted it here: [Mentor's note: Please don't do this. We end up with responses in both threads and straightening out the resulting mess is a tedious and error-prone task. Next time, just report your own misplaced post and any of us mentors will be happy to move it for you] Hi everyone, just joined simply to ask these following questions but before I do, just want to make a few things clear: - I have read numerous topics/pages/articles/forums on this subject, and i'm still unclear about things. - I am useless at maths, i can't even do the most basic of equations so please try not to answer using equations So here are the things i'm really struggling to comprehend in my head, and i've not found anything that gives me the answers: 1. I know time slows down as you move faster, but I don't understand this. I've read that if my same age friend (say we're both 25) hypothetically went into space at 99% speed of light, came back 30 yrs later when i'm 55, he'd only be 35? Would he look 35? Or something along those lines. How can this possibly be? Surely no matter where he is in the universe, 30 earth years have still passed for me, he is alive during those 30 years, so surely he would have aged 30 years as well? Are we saying that while i'd look like an old man he will still look young - even though we were both the same age before he went? 2. I know light has no concept of time, but surely it's still travelling through time as opposed to getting from a to b in a instant? If we were able to observe the universe from afar in space, we would see light leaving a star millions of miles away and travelling towards earth. Obviously it doesn't get to earth instantly as some light can take thousands/millions of years. IF we could observe this, it means light is still travelling and taking x amount of time to get there - regardless of whether the light particles themselves realise this or not. I don't understand how time could be 0 for light, even when it's travelling millions of miles and taking years to get there. 3. If you were travelling in a car at the speed of light in space, turn on your headlights, the light will move forward from you at the speed of light. This is what i've read, but if the car is already going at light speed or say 99% of it for arguments sake, wouldn't that make the light go faster then light speed? Sorry for these questions which might be basic to you, i have a genuine real fascination with this stuff but unfortunately not the mind to go with it to be able to work it out or understand some of the stuff i've read!