A light pulse came out of a caesium chamber 62 nanoseconds before entering it...

I heard this on the radio just when I was about to have a shower. I stared at the mirror, and I was already naked and wet. I wondered if this had to do with this amazing discovery or with the terrible hangover I had this morning.
Are we starting to enter a world full of FTL paradoxes?
The most popular FTL paradox is the grandfather paradox: an astronaut leaves Earth in a spaceship than can travel faster than light (if such thing ever exists, we’re not massless photons, you know), and when he returns, he finds that he has travelled back in time, and he is living in a time where his grandparents are yet to give birth to his father (or mother). So he could kill them and enter the realm of FTL paradoxes…

This astonishingly finding was announced yesterday in the Nature magazine by Lijun J. Wang and his team from the NEC Research Institute at Pricenton (New Jersey). Wang warns that Einstein’s special relativity theory and the principle of causality aren’t being infringed:

“you can make light pulses travel faster than c. This is a special property of light, which is different from a known object like a brick, as light is a wave without mass”.
According to his reasoning, faster than light pulses are the result of the classical mechanisms of interference, caused by the wavy nature of light, and they don’t allow any kind of FTL information transmission.
So...what happened this morning was caused by the hangover, uff!!

There's an explanation, but it's kinda complicated. Everyone knows that light travels as both a wave and a particle, right? The wave part allows for funky things to happen.

When two waves overlap they create an interference pattern. To help visualize an interference pattern, take two similar hair combs and overlap them (really, this will help). Note the dark and light bands caused by tines and spaces overlaping; these bands are an interference pattern. Now move one horizontally with respect to the other and watch the bands of light and dark move. You should observe that these bands move faster then either comb.

The combs have mass, and thus cannot move at speeds greater then that of light is a vacuum. The bands, however, do not. By moving the combs fast enough you could make the pattern move faster then c. You'd have hard time using them to carry a message from one end of the comb to the other, however.

Because photons travel as a wave, they have crests and troughs (much like the combs have tines and spaces between the tines), so they too create an interference pattern. This pattern (called a wave group) can also move at a different speed (called the group speed then the photons composing the light.

It is this pattern, rather then the photons themselves, that scientists have made move at speeds far greater then that of light. Certainly an impressive feat, but does not violate the known laws of physics.

Astronomers say there is an Earth-like planet orbiting the star Gliese 876, fifteen light-years away. The day I woke up faster than light, I walked outside and jumped over to it.

That morning was strange for a number of reasons. There was the light-speed thing, yes, that was certainly odd. But I could also see as far as I wanted. It took a few minutes of searching, standing on my porch on Earth, but I found the planet I wanted eventually, and then it was just a matter of aiming myself.

When I landed, I looked back behind me at Earth. Fifteen light-years from where I stood, my home planet was circling the Sun, much the same as it was when I left. The whole trip had taken a few seconds for me. A few seconds earlier I had been standing on my porch with the Sun shining in my eyes. That sunlight had bounced off the Earth and back into space, but it would not reach me again for fifteen more years. Me being fifteen light-years from the Earth, the reflected light that had left Earth fifteen years ago was reaching me at that very moment.

I didn't need to go home. I began to realize that I didn't need food or oxygen for some reason, and that the extreme temperature of Gliese 876d did not bother me. There was a thin atmosphere, but I have no idea if it could supporte human life.

Fifteen years ago, I had been in kindergarten. I sat in the hot, silvery dirt of this foreign planet, breathing foreign gases, and watching the Earth revolve 1.45x1015 kilometers above me. In a few hours (give or take fifteen years), North America was illuminated by the Sun, and I could see the school I went to when I was five years old. I saw myself playing in the schoolyard. For a long time I stood there and examined myself closely, smiling at the awkward gestures and motions that would develop into the mannerisms I have now. It was not like watching a home movie; it was more like time travel.

I hopped Earthwards a bit. The reflected light from my childhood bombarded my eyes and effectively fast-forwarded my life in front of me. At interesting parts, I would stop on a moon or asteroid to watch in real time, and then continue along.

I chuckled at the mistakes I made in my youth. I watched my friends and family to see how they acted when I had not been around. Seeing behind the scenes, I learned so much about my own life and how it affected other lives.

______________________

For five whole years, I drifted along in outer space, slowly approaching my home planet. I was on a small planet the size of Mercury, five light-years away from home, when the length of my voyage matched my distance from the Earth. I saw myself jump from my house into the sky, towards me. Since I had been moving faster than light, my eyes failed to capture myself approaching, but I knew that if I looked behind me at Gliese 876d and waited ten years, I would see myself standing there. I had to remind myself that the me on Gliese 876d would not be able to see the me on this Mercury-sized planet, and that there was no other me. It was leftover light, and that was all.

I turned back to face the Earth, and jumped towards it. I watched my family question my disappearance, and mourn me. My mother and father died within a week of each other, presumably of grief. It was awful. I kept moving forward, lamenting the irreparable damage my absence had caused. It just got worse as I got closer. I watched a year of the Earth that did not have me on it.

The world turned and forgot me.

______________________

I turned around and flew to Gliese 876d and watched my eleventh birthday. It had taken me five years to travel ten light-years on the way home, and then I had spent a year mostly still, just observing. Now I was back here, six years older than I had started out.

I did some mental calculations. I could see my eleven-year-old self on Earth, fifteen light-years away. I had nine years to wait to see myself take off, but if I watched the small planet that was only ten light-years away, I would be able to see myself reacting to that very takeoff. That reaction happened a year ago for me, but from where I stood I would not be seeing it for nine more years, being ten light-years away from the event.

Wait, what? I would see both events happening at the same time? Well I suppose that makes sense. I had, after all, watched it happen on that small planet five years after it really happened. The light of those two events (the takeoff and the reaction to it) were bunched together in a big wave headed straight for me.

I didn't want to wait nine years though. Instead, I hopped forward nine light-years and let the light wash over me. Sure enough, I saw myself standing on the planet, one light-year away, watching the Earth five light-years farther, as I jumped up off the porch into the sky. But now there was another me in the picture: the one I had just made. It was like looking at a hall of mirrors. Me watching me watching me.

______________________

I couldn't go back home; there was no point in trying. Most of the people who knew me assumed I was dead, and I would never be able to explain why I had been missing for so long. "I've been in space watching myself grow up." So I retreated further and further back, watching the famous historical events that were out of reach for every other living person. I couldn't get a good angle on Hiroshima (a star was in the way), but Nagasaki was terrifying and beautiful, even from 69 light-years away. I saw... well, everything. I spent a thousand years, my time, watching humankind flourish in reverse. One day there was nothing left of us. We had been reduced to a planet of apes.

I had little way of knowing exactly how long I had been away. I did not age. However, once I had reached the beginning of human history, I started to feel a tightening in my lungs. It had been a millenium since I had felt anything in any of my organs. The sensation startled me. I felt more and more uncomfortable, and found that when I moved closer to the Earth, the sensation faded. I was faced with the decision of suicide. Can it rightly be called suicide, having lived a hundred lifespans longer than I should have?

In the end, I chose life. I was not afraid of death, and I felt like I deserved it, but I was curious about the Earth. I jumped home across 150,000 light-years of space in one instant, but what I found was not home. It was indistinguishable from the hundreds of barren planets I had visited, watching the Great Fire of Rome or the burial of Tutankhamun. There were no people or animals here. No plant life. I was surrounded by the empty shells of highrises. I tried to jump back into space to see what had happened, but I couldn't even stand. The tight feeling in my lungs returned.

My vision swam. A duststorm swept over me and I closed my eyes.

Disclaimer: I don't know much physics. I'm pretty sure that some of the
science here is good enough and some is way off. We're talking faster-than-
light travel, so things are expected to be iffy. I know this is ScifiQuest 9999
and not FantasyQuest 1255, but if you notice something a little off, that means
a wizard did it.

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