Physicists have shown that simulating models of hypothetical time travel can solve experimental problems that appear impossible to solve using standard physics. Credit: Yaroslav Kushta via Getty Images
Time travel. We’ve all thought about it at one time or another, and the subject has been explored extensively in science fiction. Once in a while, it is even the subject of scientific research, typically involving quantum mechanics and how the Universe’s four fundamental forces (electromagnetism, weak and strong nuclear forces, and gravity) fit together. In a recent experiment, researchers at the University of Cambridge showed that by manipulating quantum entanglements, they could simulate what could happen if the flow of time were reversed.
A time machine connects to the past. Credit: David Revoy / Blender Foundation (CC BY 3.0)
Time travel is a staple of science fiction, and not without reason. Who wouldn’t want to go back in time to explore history, or save the world from catastrophe. Time travel has also been deeply studied within the context of theoretical physics because it tests the limits of our scientific theories. If time travel is possible, it has implications for everything from the origin of the universe to the existence of free will. One of the central problems of time travel theory is that it gives rise to logical paradoxes. But a couple of researchers think they have solved the pesky paradox problem.
The ESA's CHEOPS launching aboard a Soyuz-FG rocket from Kourou, French Guiana. Image Credit: ESA - S. Corvaja
Believe it or not, time travel is possible.
In fact, you’re doing it right now. Every single second of every single day you are advancing into your own future. You are literally moving through time, the same way you would move through space. It may seem pedantic, but it’s a very important point. Movement through time is still movement, and you are reaching your own future (whether you like it or not).
Artist illustration of a spacecraft passing through a wormhole to a distant galaxy. Image credit: NASA.
Time travel into the past is a tricky thing. We know of no single law of physics that absolutely forbids it, and yet we can’t find a way to do it, and if we could do it, the possibility opens up all sorts of uncomfortable paradoxes (like what would happen if you killed your own grandfather).
But there could be a way to do it. We just need to find a wormhole first.
Using a wormhole to travel through time? Credit: NASA.
“Tell me what time is it?” asked the stranger on the street.
A simple enough question that can be answered with a simple enough glance at the watch on your wrist. And so goes the appreciation of time for the average person. But is time simply a notation of events in our life? Or is it a truly robust dimensional attribute? For one answer read Paul Nahin’s book “Time Machine Tales” and you will soon discover that it is the latter. And that time may be much, much more.
If time is a dimension, then Nahin’s book has us believe that we can move along this dimension as easily as we move along a Euclidean spatial dimension. This means that time travel should be possible. Yet, as someone said, “If people can travel in time then why aren’t we seeing time travelers popping up all over?”
And in a sense, this conundrum shapes this book. From very many perspectives, Nahin explores and conjectures. From the viewpoint of ancient Greeks or Catholic scholars long since gone, the book gives rise to, what is time? does the past stop at the Big Bang? and is our future predefined?
This book presents philosophers’ quotes and their views from yesteryear and from today. Now philosophy is fascinating unto itself but throw in large quantiles of technical lore and this book’s perspective on time expands to a much larger knowledge base. That is, the book brings up exotics like Dirac radios, block universes, the bilking paradox, chronons and things smaller than the Planck length.
Intrigued by this? It gets better as the book takes the reader through the derivation of the Lorentz transformation and on to the backward and forward tilt of light cones. If this doesn’t get your interest up, then also consider that Nahin has liberally strewn quotes and references from science fiction throughout. This leaves the reader pondering if the fiction stories are forerunners to reality or merely offshoots of very active imaginations.
And a lasting question revolves around whether scientific discovery is attained through hard work, through thoughtful imagination or through provisions by a time traveler. That’s just one of the choices that you, as the reader, get to make. Just give yourself the time to decide.
Given the fascinating, current discussions on dimensionality, it’s not difficult to pique a science reader’s interest on time travel. And this book grabs and holds such a reader. However, abrupt swings like from the musings of H.G. Wells to the showcasing of the concerns of John Wheeler make for bumpy reading on occasion. Further, the introduction implies that teachers could use the book; implying that this book is a textbook. Yet where are the courses on time travel? Nevertheless, from the view of simply enjoying science, this book makes for enjoyable reading, homework assignments and all.
Will people travel in time? Will they only travel forward in time? Can they only travel between here and other universes? When will this take place? There are so many questions about time. If nothing else, use the time you have wisely.
Comet ISON was used in a search for time travelers. NASA’s Hubble Space Telescope provides a close-up look of Comet ISON (C/2012 S1), as photographed on April 10. Credit: NASA, ESA, J.-Y. Li (Planetary Science Institute), and the Hubble Comet ISON Imaging Science Team.
You can find anything on the internet, right? A new study reveals, however, that you can’t find evidence of time travelers on the internet. Credible time travelers, that is.
The study was conducted by astrophysicist Robert Nemiroff who is part of the Astronomy Picture of the Day (APOD) team, along with some of his students from Michigan Technological University.
They did three separate types of searches, and developed a search strategy based on what they call “prescient knowledge.” They looked for discussions on social media and various websites where there might be evidence of a mention of something or someone before people should have known about it. If they were able to find evidence of that, it could indicate that whoever wrote it had traveled from the future.
They selected search terms relating to two recent phenomena, Pope Francis and Comet ISON, and began looking for references to them before they were known to exist.
First, they looked for specific terms on Twitter, then secondly looked for “prescient” inquiries submitted to a search engine, and the third search involved a request for a direct Internet communication, either by email or tweet, pre-dating to the time of the inquiry.
The team used a variety of search engines, such as Google and Bing, and combed through Facebook and Twitter.
“In our limited search we turned up nothing,” Nemiroff said in a press release. “I didn’t really think we would. But I’m still not aware of anyone undertaking a search like this. The Internet is essentially a vast database, and I thought that if time travelers were here, their existence would have already come out in some other way, maybe by posting winning lottery numbers before they were selected.”
So far, no lottery winners have confessed to using time travel to make their winnings.
In the case of Comet ISON, there were no mentions before it was discovered in September 2012. They discovered only one blog post referencing a Pope Francis before Jorge Mario Bergoglio was elected head of the Catholic Church on March 16, but it seemed more accidental than prescient.
In the third part of their search, the researchers created a post in September 2013 asking readers to email or tweet one of two messages on or before August 2013: “#ICanChangeThePast2” or “#ICannotChangeThePast2.”
Nemiroff and physics graduate student Teresa Wilson will present their findings today, Monday, Jan. 6, at the American Astronomical Society meeting in Washington, DC.
Sergei Krikalev gives a thumbs up during suit check before the launch of STS-88 in 1998. Credit: NASA.
Is time travel a fact or is it just science fiction? Thanks to time dilation and Einstein’s theory of relativity, we know that time travel can and actually does happen, albeit only in extremely tiny increments at the speeds and distances we can travel in space. If you add up the accumulated speed cosmonaut Sergei Krivalev has traveled in space – the most of any human with a total time spent in orbit of 803 days 9 hours and 39 minutes – he has actually time-traveled into his own future by 0.02 seconds.
Time dilation is caused by differences in either gravity or relative velocity — each of which affects time in different ways. When astronauts and satellites orbit the Earth, they are slightly further away from the center of the planet –compared to people on the ground – and so they actually experience less gravitational time dilation. This means the astronauts’ time would run slightly faster, and when they return to Earth, they’d have to “come back” to the past compared to when they were in space.
But time dilation due to velocity means that clocks for astronauts in space run slightly slower relative to people who are on the ground. When you come back to Earth, you’d be have to go into the future slightly to catch up with clocks on the ground.
The effect of time dilation due to gravity, however, “is quite small because Earth’s gravity is quite weak,” says educator Colin Stuart in this great instructional video from TedEd, “and so the time dilation due to their speed wins out and astronauts really do travel a tiny amount into their futures.”
But, as stated earlier, with our current technology limiting the velocities of astronauts, these differences are minuscule: after 6 months on the ISS, an astronaut has aged less than those on Earth, but only by about 0.007 seconds. The effects would be greater if we could get the ISS to orbit Earth at near the speed of light (approximately 300,000 km/s), instead of the actual speed of about 7.7 km/s.
This effect has been proven by GPS satellites, which orbit Earth at about 14,000 km/h (9,000 mph) which cuts several microseconds off their clocks daily, relative to clocks on Earth.
Was the 44th President of the United States a time-traveling teenage Mars explorer?
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Forget 2012 prophecies, Mayan calendars and lurking planets that go only by the name “X”… there’s an even kookier conspiracy theory in town, and it has to do with our nation’s fearless leader and his teenage teleportation adventures on Mars.
Yes, you read that right.
It seems that two government employees and self-professed time-travelers – er, “chrononauts” – Andrew D. Basiago and William Stillings have come forth and named President Obama as one of their own, along with the current head of DARPA, Regina Dugan.
(DARPA, if you don’t know, is the agency responsible for keeping U.S. defense up-t0-date with advancements in technology. Begun as a response to the Sputnik program in the late 50s, DARPA finds ways to integrate cutting-edge tech developments into stuff the military might want.)
Basiago, a Washington state lawyer, says that he was part of a time travel program developed by DARPA in the 1970s code-named Project Pegasus. He and Stillings claim that both Obama and Dugan were in their “Mars training class” at California’s College of the Siskiyous in 1980, part of a group of 10 young adults chosen to travel to Mars via a top-secret teleportation “jump room”.
They also claim that the then-19-year-old Barack Obama went by the name “Barry Soetero”.
But wait, there’s more.
"I'll beam ya down Mister President but I'll have to see your birth certificate first." (Photo via startrek.com)
The two former chrononauts also said that they encountered the future president at secret U.S. bases on Mars, which he is said to have visited twice between the years 1981 and 1983. On one instance Basiago said he even exchanged words with Ob – uh, Soetero – en route to the “jump room” while on Mars.
“We’re here,” Basiago claims the young president-to-be said to him.
And the supposed reason for the secret teen task force’s Red Planet expedition? To “acclimate Martian humanoids and animals to their presence,” according to Basiago.
You know, to make good with the locals so there’d be no trouble when setting up camp.
White House officials have denied all allegations of the President’s Martian travels, or the existence of a Mars training class. But, of course, they would.
And you thought the whole birther thing was a bit extreme? Wake up sheeple, this is some real crazy here. Chrononaut style.
