How fast we go affects how we perceive time. That lesson was implicit in the mathematics of Special Relativity, but at the speed most of us live our lives, easily describable in Newtonian terms, we could hardly recognize it. Get going at a substantial percentage of the speed of light, though, and everything changes. The occupants of a starship moving at close to 90 percent of the speed of light age at half the rate of their counterparts back on Earth. Push them up to 99.999 percent of c and 223 years go by on Earth for every year they experience.
Thus the ‘twin paradox,’ where the starfaring member of the family returns considerably younger than the sibling left behind. Carl Sagan played around with the numbers in the 1960s to show that a spacecraft moving at an acceleration of one g would be able to reach the center of the galaxy in 21 years (ship-time), while tens of thousands of years passed on Earth. Indeed, keep the acceleration constant and our crew can reach the Andromeda galaxy in 28 years, a notion Poul Anderson dealt with memorably in the novel Tau Zero.
Image: A Bussard ramjet in flight, as imagined for ESA’s Innovative Technologies from Science Fiction project. Credit: ESA/Manchu.
Not long after Monday’s post on fast spacecraft I received an email from a young reader who wanted to know a bit more about humans and speed. He had been interested to learn that the fastest man-made object thus far was the Helios II solar probe, while Voyager I’s 17 kilometers per second make it the fastest probe now leaving the system, well above New Horizons’ anticipated 14 kilometers per second at Pluto/Charon. But that being the case for automated probes, what was the fastest speed ever attained by a human being?
Speeds like this are well below those that cause noticeable relativistic effects, of course, but it’s an interesting question because of how much it changed at the beginning of the 20th Century, so let’s talk about it. Lee Billings recently looked into speed in a fine essay called Incredible Journey: Can We Reach the Stars Without Breaking the Bank? and found that in 1906, a man named Fred Marriott managed to surpass 200 kilometers per hour in (the mind boggles) a steam-powered car at Daytona Beach, Florida. This is worth thinking about because Lee points out that before this time, the fastest anyone could have traveled was 200 kilometers per hour, which happens to be the terminal velocity of the human body as it is slowed by air resistance.
So the advent of fast machines finally changed the speed record in 1906, and it would be a scant forty years later that Chuck Yeager pushed the X-1 up past 1000 kilometers per hour, faster than the speed of sound. I can remember checking out a library book back in the 1950s called The Fastest Man Alive. Before I re-checked the reference so I could write this post, I was assuming that the book had been about X-15 pilot Scott Crossfield, but I discovered that this 1958 title was actually the story of Frank Kendall Everest, Jr., known as ‘Pete’ to his buddies.
Everest flew in North Africa, Sicily and Italy and went on to complete 67 combat missions in the Pacific theater, including a stint as a prisoner of war of the Japanese in 1945. If there was an experimental aircraft he didn’t fly in the subsequent decade, I don’t know what it was, but if memory serves, the bulk of The Fastest Man Alive was about his work with the X-2, in which he reached Mach 2.9 in 1954. Everest was one of the foremost of that remarkable breed of test pilots who pushed winged craft close to space in the era before Gagarin.
But to get back to my friend’s question. Lee Billings identifies the fastest humans alive today as ‘three elderly Americans, all of whom Usain Bolt could demolish in a footrace.’ These are the Apollo 10 astronauts, whose fiery re-entry into the Earth’s atmosphere began at 39,897 kilometers per hour, a speed that would take you from New York to Los Angeles in less than six minutes. No one involved with the mission would have experienced relativistic effects that were noticeable, but in the tiniest way the three could be said to be slightly younger than the rest of us thanks to the workings of Special Relativity.
Sometimes time slows in the way we consider our relation to it. I noticed an interesting piece called Time and the End of History Illusion, written for the Long Now Foundation. The essay focuses on a paper recently published in Science that asked participants to evaluate how their lives — their values, ideas, personality traits — had changed over the past decade, and how much they expected to see them change in the next. Out of a statistical analysis of the findings came what the researchers are calling an ‘End of History Illusion.’
The illusion works like this: We tend to look back at our early lives and marvel at our naïveté. How could we not, seeing with a certain embarrassment all the mistakes we made, and knowing how much we have changed, and grown, over the years. One of the study authors, Daniel Gilbert, tells The New York Times, “What we never seem to realize is that our future selves will look back and think the very same thing about us. At every age we think we’re having the last laugh, and at every age we’re wrong.”
The older we get, in other words, the wiser we think we are in relation to our younger selves. We always think that we have finally arrived, that now we see what we couldn’t see before, and assume that we can announce our final judgment about various aspects of our lives. The process seems to be at work not only in our personal lives but in how we evaluate the world around us. How else to explain the certitude behind some of the great gaffes of intellectual history? Think of US patent commissioner Charles Duell, who said in 1899: “Everything that can be invented has been invented.” Or the blunt words of Harry Warner: “Who the hell wants to hear actors talk?”
The Long Now essay quotes Francis Fukuyama, who wrote memorably about the ‘end of history’ and French philosopher Jean Beaudrillard, who sees such ideas as nothing more than an illusion, one made possible by what he called ‘the acceleration of modernity.’ Long Now adds:
Illusion or not, the Harvard study shows that a sense of being at the end of history has real-world consequences: underestimating how differently we’ll feel about things in the future, we sometimes make decisions we later come to regret. In other words, the end of history illusion could be thought of as a lack of long-term thinking. It’s when we fail to consider the future impact of our choices (and imagine alternatives) that we lose all sense of meaning, and perhaps even lose touch with time itself.
We’ve come a long way from my reader’s innocent question about the fastest human being. But I think Long Now is on to something in talking about the dangers of misunderstanding how we may think, and act, in the future. By assuming we have reached some fixed goal of insight, we grant ourselves too many powers, thinking in our hubris that we are wiser than we really are. Time is elastic and can be bent around in interesting ways, as Einstein showed. Time is also deceptive and leads us as we age to become more doctrinaire than can be warranted.
Sometimes, of course, time and memory mingle inseparably. I’m remembering how my mother used to sit on the deck behind her house when I would go over there to make her coffee. We would look into the tangle of undergrowth and trees up the hill as the morning sun sent bright shafts through the foliage, and as Alzheimer’s gradually took her, she would often remark on how tangled the hillside had become. I always assumed she meant that it had become such because she was no longer maintaining it with the steady pruning of her more youthful years.
Then, not long before her death, I suddenly realized that she was not seeing the same hill that I was. At the end of her life, she was seeing the hill in front of her house in a small river town in Illinois. Like her current hill, it rose into the east so that while the house stood in shadow, sunlight would blaze across the Mississippi to paint the farmlands of Missouri on the bright mornings when she would get up to walk to school. When I went back there after her funeral, the hill was still open as she had remembered it, grassy, free of brush, though the house was gone. It was the hill she had returned to in her mind after 94 years, as vividly hers in 2011 as it had been in 1916. In such ways are we all time travelers, moving inexorably at the velocity of thought.
I really enjoy your posts Paul! Here’s a question I’ve been puzzling on: does travel at relativistic speeds actaully slow the biological processes? One might expect that these processes are driven at the molecular level by the speed of electrons in those atoms etc, so your body aging processes slow down as well?
Solar system is moving at 368±2 km/sec relative to the microwave background in the direction towards the constellation Leo.
So about 33 times faster than Frank, Jim and Bill.
And it’s interstellar flight too!
So we are aboard a star ship.
So Paul you and everyone is going licky split.
The glorius communication between humankind and the universe is made by way of our intelligence. Science has in fact made the hopes of the religious more possible instead of less.
It is the idea of progress- of perfecting existence. Using massive energies we can theoretically travel back in time. Even an atheist can imagine being resurrected with a time machine and being with their loved ones.
If an atheist can believe, how much more can those with faith?
A God would not care if we believe as long as we continue to learn.
I am just hoping we survive as a race long enough to get to other places so we do not go extinct. It would be nice to see it all happen but if not- as I wrote- there is always hope in the future.
What a moving essay, thank you.
Amazing how in so many ways we are taught from an early age to think about things in terms of goals, end-points, perfection. Do X and you will achieve the state called “success”. Do Y and you will arrive at the destination called “happiness”. Do Z and you will have access to an eternal, unchanging “after-life”. And yet we have such trouble considering our individual and collective actions in terms of wider and longer-term consequences.
A life, like the exploration of space, like the universe itself, is a process, a trajectory. There really is no static, perfect end-point to be reached. Even black holes evaporate, and when we die, every atom of the matter that comprised us continues to exist, in new patterns and combinations.
“-every atom of the matter that comprised us continues to exist, in new patterns and combinations-”
Which means that every atom can be recovered from any moment in history if you can go back in time. Consider a civilization that lasts millions of years! The velocity of thought is the speed at which our starship will take us into the future. A black hole starship can theoretically get into those fractions where travel millions of years into the future takes place. If we took off in our supership and took a million light year tour of the universe and came back here what would we find?
I think we would find beings figuring out how to escape the death of this universe but also taking all our past living creatures into this different plane with us. They might want us modify ourselves to a higher level of intelligence and perhaps bodily utility (disembodied brains?) that we might not want to participate in.
The future may be truly beautiful, or not so much, but we can get there simply by going fast. Maybe not as simple as that but what about going back in time?
The big If of the immediate future is in computers. If a machine can be built more intelligent than humans, what likelihood is there of it solving any of our problems?
If the machine could become more intelligent in scale then could we not potentially build a god like being the size of a small moon? I think then our questions might get answered about resurrection and the escape from this dying universe.
Paul, that was not only brilliant, it was very beautiful. What a bunch of important and slightly wistful thought you have gently proded out of the reader. It’s a gem! Thanks.
Thanks Paul for sharing that touching story about your mother. It reminds me that as we look to the future we might want to appreciate where we came from and what we have.
A.A et al…Bravo! how long before we reach Leo or the closest star in our path?
Nice piece. Once we have entanglment mastered we will accelerate a crack research team and lab to relativistic speeds and have then Q-radio their results to solve our toughest problems. Instant Karma.
First, a quote from a famous author, concerning an apropos altruism:
“Time is an illusion; lunchtime doubly so.”
(Douglas Adams, “The Hitchhiker’s Guide to the Galaxy”)
Now, to my comments. :)
I’ve been amazed by how many over the last 2+ centuries have remarked, even balked, at the ever-increasing speeds and modes of transportation, often in a disparaging manner, often saying it is an impossibilty (manned powered flight, vehicles powered by engines rather than beasts of burden), that such words still are uttered about spaceflight, and science in general- We know almost everything, and it’s impossible to travel the stars at a reasonably-timely speed. My own study of history is that we’ll probably have everything we know turned on its ear within a very few centuries! :) If even that long, I dare! (And just how long ago was it that our notion of what a galaxy and universe was was so radically changed? A century, now? That isn’t terribly long! Even less than two for discovering our world was greater than a billion years old- It was still considered to be in the thousands to a bare few million!)
Some humbling perspective from our past on our future,
d.m.falk
We may think we flow in time but it really is only one long NOW – it’s always now – it was now when I was born, the same now it is now, right now – no, right now – no, right now and so on. I think time is the way our brain makes sense of the world. With the million and million of conscious and unconscious stimuli we are exposed to every second of every day, our brains equipped with but the most rudimentary of senses, has to have a format or a template to imprint reality onto us. Time is that format.
Great post, Paul.
Yeah! The time is ripe for rocket travel. No more sitting in a cramped seat for many hours. The jet age is over, let us welcome the rocket age!
Paul, we lost my father,a WWII vet, to Alzheimer’s, last summer. An awful disease. When he could still communicate, he often said things and talked of events from as much as eighty years earlier as if they had just happened. It was both extremely frightening and extremely interesting at the same time. I learned tales from his childhood on a Florida ranch and stories of friends long gone. Toward the end, he decided my wife was actually my mother,( his wife) and loved to hold her hand and ‘talk’ with her. We took it all in stride, and he seemed mostly happy. We were the ones who were sad. Now I pray that I and my children did not get the gene passed to us. I wish the same for you also and that a cure can be found soon. A very good article.
Graham: “…does travel at relativistic speeds actaully slow the biological processes?”
No. I think this common misconception comes about because the traveler is so often described as having their clock slow down. It doesn’t.
What happens is that the stationary twin who, by some suitable apparatus, measures the traveling twin’s clock to be running at a slower rate. The traveling twin notices no such thing. He simply measures the trip as taking less time than the time measured by the stationary twin.
For all those looking to the future for the solutions to all our problems, I would say not to bother. The reason is that for so many of these so-called problems the solutions are already known. It is that we do not like the solutions and therefore deny them or refuse to implement them. Current technical impossibilities, like rapid interstellar travel are to me matters of a different sort: desires, not problems.
Something strange is going on from 90%-99% of the speed of light, something even stranger from 99%-99.9999%. Why the precipitous skew at these levels? Light, an almost mass-less bradyon, has no problem attaining C; in fact, outside of a black hole it seems unable to travel at any other velocity. And yet light does have some mass (m = 4.417 x 10-36 kg). Do tachyons have somewhat less mass than light, allowing them in some “imaginary” universe to exceed the speed of light?
Of course, thought is “thought” to be mass-less, but is it really? Does the fact that thought springs from a very massive brain allow for it to have no mass? What the hell is a thought, anyway, really? Since (mass-less?) thoughts do appear to exist in the universe, can its reach extend beyond it? If a thought has less mass than either bradyons or tachyons, or no mass at all, can it travel faster than light and therefore super-extend itself anywhere in the universe instantaneously? Quantum mechanics suggests the answer is yes, since one thought event is “thought” to influence the entire universe, among other reasons.
So if a not-so-massive object like a nanochip-clock (if such a thing were built), could be accelerated to 95% of C, and somehow made to return to Earth, what time would it show? What if a bunch of thoughts were contained in a nanochip and sent into space on a photon of light, would it be possible to make those thoughts perform something? I wish I knew.
Thanks to the many of you who’ve written to me about this post via email or comments here. And a quick note to Daniel Suggs, who wrote this about his father’s Alzheimer’s:
I had much the same experience of finding some of the Alzheimer’s symptoms both frightening and wondrous at the same time. Like your father, my mother stayed more or less happy to the end, and we wound up exploring much of her early life in ways I would never have dreamed. It was a poignant time but as you say, we take these things in stride, one day at a time.
A moving and beautiful post. I wish all the people in the public who look on scientists as amoral thinking machines could read this. They might begin to understand what we are trying to do. The passion to understand burns, but I have never met a single scientist who wouldn’t rather spend another day with their family than in the lab.
Merci pour ce magnifique et poétique essai sur la vitesse, le temps, la vie, la mémoire et la mort ! I shall forward it to a few people over here. Etienne
“How fast we go affects how we perceive time.”
The perception of the passage of time of the 0.99c-travelling astronaut and his earthbound twin are the same, are they not? In other words, the swiftly moving astronaut measures 1 second as taking exactly 1 second to transpire. Ditto for the grounded twin. It’s when you compare them upon the astronaut’s return that you notice the paradox. It’s not perception at all. Upon return, when you stand them next to each other, one is in fact a wrinkled old man, the other still youthful. This difference is not an illusion.
On Christmas Day, I was briefly visited by an elderly friend I hadn’t seen for some time (I’m disabled and don’t have a car, and her daughter drove her over to my apartment building). I was saddened to learn that she is going blind due to her Type II diabetes, but she was genuinely happy despite it, with her youngest daughter, her daughter’s husband, and their two children living with her in her home. I couldn’t shake my sadness until several days later, when another friend of mine said that if she doesn’t let her infirmity bother her, I shouldn’t let it bother me, but that I should rejoice in her happiness in the face of her infirmity. Also:
A childhood neighbor of mine learned–at his father’s doctor’s suggestion–to not fight his father’s Alzheimer’s, but to “work with it.” The doctor said, “There *is* a bright side to this. Your father is dying, but *he* doesn’t know that; he’s re-living his boyhood, and he is happy and doesn’t have a worry in the world. He thinks you’re one of his boyhood friends, so just play along with it.” My neighbor told me that by making that one change, he was able to share many genuinely happy times with his father before he died.
James Jason Wentworth writes:
Absolutely right. It worked for my mother’s situation, too.
“We always think that we have finally arrived, that now we see what we couldn’t see before, and assume that we can announce our final judgment about various aspects of our lives.”
I forgot to refill my meds and had to go to the hospital yesterday- and did not make it in time so they sent me to the emergency room. While waiting the 3 hours to be seen- first triaged, then doctor screened, and then finally talked to about what I needed- I witnessed an unhappy scene.
An old man close to 90 I think, wheelchair bound, was brought in by his son and verbally abused and left; the son almost threw something at him but threw it at the wall at the last moment. He stomped out and an hour or so later the old man was still there and the staff was talking about what to do with him when I left.
I communicated with the old man and while he was deaf he could speak; he said his son had to take off from work to bring him to the hospital and was putting his job at risk.
So I am not looking forward to getting really old. I would rather get frozen and revived at some point in the future where my condition can be reversed or I can at least live out my last days with some dignity.
I am one of the last of the baby boomers so those in my generation may get the worst ending.
Ron S January 25, 2013 at 0
“No. I think this common misconception comes about because the traveler is so often described as having their clock slow down. It doesn’t.
What happens is that the stationary twin who, by some suitable apparatus, measures the traveling twin’s clock to be running at a slower rate. The traveling twin notices no such thing. He simply measures the trip as taking less time than the time measured by the stationary twin.”
Not so.
The twin travels 4.5 LY to Alpha C at 99.9 % of light speed. The trip seems to take some number of weeks in his reference frame. He returns. Again more weeks. He meets his 9 years more aged twin. The traveller is only weeks older. Of course his bio processes which relate directly to the atoms, EM waves and everything that obey relativity slowed down. The distance to Alpha C and back also seemed shorter due to Lorentz contraction along his velocity axis.
A wonderful post. Regarding Sagan’s calculation that it would take 21 years to get to the center of the galaxy at 1 g of acceleration: to visit another star and land on a planet, the spacecraft would also have to decelerate. So the quickest way to visit another star would be by constant maximum acceleration (something more comfortable than what military fighter pilots endure), followed by continuous reverse thrust at the halfway point until arrival. Maybe this concept has already been discussed somewhere. This idea makes me think of the quickest way to travel between Los Angeles and New York if a straight tube could be forged through the hot deep of the Earth, bypassing the curved surface of the Earth. The train would accelerate at the limits of human comfort, then decelerate with the same g-forces. It’s all still relatively slow – when compared to instantaneous! Too many limitations in this universe. The stars are too damned far.
philw1776, um…did you really read that text you quoted from me? You say “not so” and then you proceed to agree with me. Regarding length contraction, I chose not to mention it since the question was about time interval and not other (of many) relativistic effects.
“The stars are too damned far.”
So is the finish line of a marathon. One trains, prepares then perseveres.
“Too many limitations in this universe. The stars are too damned far.”
Hi Nat,
Einstien talked about imagination being more important than knowledge; a hundred years ago they said the Moon was too far and nobody really had a clue about how to even start. In 1913 nobody was very open to the idea that in 30 years the first rocket would fly into space (V-2). Thirty years after that a Russian woman orbited world 48 times in 71 hours. Thirty years after that astronauts space walked around the hubble space telescope. And now thirty years after that we have a tremendous body of knowledge to support whatever schemes we can imagine.
A hundred years from now we will be talking about 2013. Well, maybe not the people commenting on this blog, but somebody will be.
I am hoping for a big comet show in 13. The Year of the Comet!
A hundred years from now they may say 13 was the year space exploration really began because of the impact threat. The public may finally demand that we stop building nuclear submarines and stealth fighters and start building atomic spaceships to intercept comets and asteroids.
What we’re describing here is nothing less than time travel. If even we humans can logically posit relativistic space travel and, theoretically, can go forward in time, what would it take to back in time?
@nat
The stars are at just the right distances, else wise the wheels on the universe would come off.
It’s us that don’t have the right stuff.
If we lived as long a stars do the universe would our stomping ground.
It’s always been my thought that the life sciences will some day , give us, what our physical sciences cannot, the stars.
“Some say, ‘time flies, alas, we go, time stays.'”
Thankyou for a lucid & thought-provoking piece. A really good way to start my week,& I hope it may even come to bear on some of the decisions I make this week. Then again, I doubt I’m famous for my forethought…
A very quick addition to my earlier comment (what was I saying about forethought?). My own Father, too, went through a decade-long descent into Alzheimer’s, & I was with him all the way. At times I was one of his brothers, his father even, & my partner became, occasionally, his mother, but as long as I was around, he was relatively comfortable, & yes, we did explore many parts & aspects of his life before me with a clarity not achievable in earlier years, pre-senility. Of course it was, or became, highly restrictive for me, in many ways, & for some years I had to give up an “outside” life, but looking back on it all now, with him (Bill was his name, William, & so I have now named my own son) over 14years dead, that time grants me many things, like patience, a certain inner peace, & the ability, now, to actually listen to what people are saying to me. Or so I hope. Oh, & I also like to think I’ve learnt to take the long view on my own life, though I hope with all my heart to never succumb to that same dread disease. Let my son learn his lessons himself. Thankyou for reading.
”The End of History” has an aditional meaning , which somwhat complements the one mentioned above . It also implies the naive notion that the darvinistic ”Realpolitik” has ended , and that it has been excanged with a new set of more moral-based rules , based on ” human rights” …
I have noted this too. I’ve called it temporalcentrism . We condescend toward the past and toward the future, both of which are greater than the present . Like ethnocentrism or geocentrism almost. We tend to detail everything out the present, but paint the future and past with broad brushstrokes.
Thanks Paul, what a great post. A nice combination of the sciences and the humanities is part of the reason why I like Centauri Dreams as much as I do.
A friend of mine and I were recently discussing this disease, as I was sharing with him some of my experiences as caretaker for an elderly gentleman who has Alzheimer’s. During the conversation he brought up an interesting point that’s somewhat related to this post: people often say that they would hate developing this scourge. Indeed, it is found that more people dread mental decline than physical decline. However, by and large we are thinking about it from our current temporal perspectives as younger people. From what I have observed of the man whose care I participate in, I am not sure he has been all that cognizant of what has happened to him over the past 5-10 years. Mental decline associated with this neurodegenerative illness is often a gradual process and, as we know, humans are not very good at noticing the gradual transformations as they are at sensing drastic fast-paced changes (e.g. 9-11 and terrorism vs. global climate change).
It’s been wonderful to see the responses to this post, and thanks to all who’ve weighed in with recollections and reflections on Alzheimer’s, the topic with which the post closed. One common thread is that Alzheimer’s decline can be gradual, so that the person involved is not suffering as much as one would think, and is often simply reliving older times. This is what I’ve seen in many cases, though I’ve also had contact with at least one person whose sharp mental decline didn’t fit this model. But it can be comforting to caregivers to realize that Alzheimer’s isn’t necessarily a nightmare for those experiencing it, but in some situations can be more like a quiet dream. It’s something to keep in mind as we mourn our loss and watch ‘the long goodbye’ happening.
Outstanding post Paul, but it also provokes a Physics question for anybody to answer. If somehow a way was found for an intelligence to travel at the speed of light (lets call it “intelligent light propelled” for the sake of argument) and not just slightly below C would that entity have any sense of time at all or would everything be happening at the same time? In essence, would the entity traveling at C perceive itself to be both Alpha and Omega and would they even see sequential cause and effect? What would they see according to our current knowledge of Physics? Please forgive the ignorance I simply do not know.
Thank You
Of course, Alzeimer’s disease, like most other diseases, has increased dramatically in the population because of the many slow poisons introduced in the body by “modern” life. These begin with the injections babies get, the vaccines people are encouraged by the manufacturers to get throughout their lives, and the numerous drugs promoted by the drug industry. Add to this the pollution sprayed into the atmosphere on tight schedules, introducing aluminum and barium compounds into the soil and air, the hair sprays, the food additives, etc. Of course, this is also why such things as cancer and autism are off the chart. It is why terms like “cure”, “natural remedy”, and “non-GMO” are dirty words. Drugs are not made to cure anything, but to elleviate symtoms and enrich investors. The same with vaccines.
Thomas Hackney: I am afraid you are completely wrong on almost all counts, there. Try reading the actual scientific literature for insights about the epidemiology of Alzheimer’s and some of the other subjects you mention.
Just to mention one obvious thing: People simply did not get old enough to have Alzheimer’s before we had all these modern “many slow poisons”.
Some of these “poisons” help us become 80 years old, when Alzheimer’s will take its toll on some. One of these days, so we can hope, an even more modern “poison” will be developed to banish Alzheimer’s to where it belongs, the rubbish heap of history. Together with its cousins polio, leprosy, small pox, the plague, and so many others.