I was watching a science fiction movie last night about time travel. Scientists and the military had made a huge expensive machine that smashed sub-atomic particles together at incredible speeds and energy. In the zone of collision an ‘exotic’ window opened up to the past. The scientists were completely amazed as they gazed back at scenes 10, 20 and hundreds of years ago. I got thinking about that and realized – big deal! It happens all the time!
Have you ever looked up the beautiful night sky and wondered what’s out there right now! It’s too bad you will never know and can’t ever know because you’re not looking at the sky as is is right now. You’re looking at the night sky as it was thousands of years ago! If you could locate our closest star neighbors – the Alpha Centauri System – you would be seeing them as they were a little over four years ago. That’s how long it takes the light to get from there to here.
A lot of us have looked up at the night sky at the North Star. It is a little over 300 light-years from us. A light year is the distance light can travel in one year. So if you’re navigating with the North Star you are using information that is a little over 3oo years old. The oldest object visible to the naked eye in the night sky is the Andromeda Galaxy which if you can find it is 2.25 million-years in your past.
You might say; ‘So what! I’m not a star gazer – I’m a practical person! I deal with what’s real in the here and now’!’ No you don’t and that’s the point. You can never deal with the ‘hear and now’ because all you can ever see has already happened. Would you put up with a watch that ran five minutes behind without you knowing it? I don’t think so but in reality if you’ve ever checked the time by looking up at sun – say at noon when it is the highest in the sky – you’re automatically eight minutes behind. It takes about eight minutes for the light from the sun to arrive at earth. The sun could disappear and we wouldn’t know it for eight minutes.
‘So what!’ you retort, ‘I have a good watch and when I want to know the exact time, this very instant, I’ll just check it!’
Sorry to say this but that’s impossible! You’ll never see the right time ‘this instance’. If your watch is about 1 meter from your eye then it will take light 3.3 nano-seconds to get to your eye. From there, it will take about 50 more milliseconds for your brain to register the information. What difference does 50 milliseconds make? Well if you were a passenger in a car on the freeway cruising at 100 km per hour and you checked the time ‘this instant’ you would ‘know’ the time as it was 1.4 meters behind you! That is not ‘this exact instance!’ As a matter of fact because of our physical bodies we actually ‘live in the past’; “. . . about 80 milliseconds in the past, to be precise. Use one hand to touch your nose, and the other to touch one of your feet, at exactly the same time. You will experience them as simultaneous acts. But that’s mysterious — clearly it takes more time for the signal to travel up your nerves from your feet to your brain than from your nose. The reconciliation is simple: our conscious experience takes time to assemble, and your brain waits for all the relevant input before it experiences the ‘now.’ Experiments have shown that the lag between things happening and us experiencing them is about 80 milliseconds.” (Discover Magazine)
So looking into the past isn’t a big deal. It happens all the time and we don’t need a Billion dollar particle accelerator to do it. We’re born with that ability and many don’t even know it! Because the ‘lag of our flesh’ automatically puts our consciousness 80 milliseconds in the past in a real sense we live in the past. But what about time travel further back into the past? Is that possible? Do we have to step through the portal like the scientists did in the movie? And suffer all kinds of ‘time travel’ motion sickness?
No, transporting things into the past is a snap! It’s as easy as throwing a baseball! Think about it. When you’re holding the baseball it is right there with you. Setting aside the time for the nerve impulses to get to your brain and just looking at the instant you throw the ball into the air. If you throw the ball with a horizontal velocity of 20 meters per second, after 0.5 seconds, the ball is 10 meters away from you and it takes the light from the ball 3 microseconds to get to you. Essentially, you are seeing the ball as it was 3 microseconds ago. The ball exists for you in the past but it has no meaningful existence in the present. At 100 meters distance you have projected the ball a full 33.3 microseconds into the past. As a matter of fact the further you throw the ball from you the further back you are projecting it into the past. That’s time travel.
What about the future? The ball moves at 20 meters per second so after 5 seconds it is 100 meters away from you. Surely you must be able to perceive it as it exists. No, it’s gone – all you’ve got is an image that is 33.3 microseconds old. I don’t think we can time travel into the future faster than we already are but that is for a later reflection.
What do you think?