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May 11, 2010

Geek Out!: Stephen Hawking and five ways to travel in time

Posted: 01:31 PM ET

Editor's note: Geek Out! posts feature the latest and most interesting in nerd-culture news. From scifi and fantasy to gadgets and science, if you can geek out over it you can find it on Geek Out! Look for Geek Out! posts on CNN's SciTech blog.

Stephen Hawking's new Discovery Channel series, "Into the Universe," aired again last night and continues into next week. In it, the famed cosmologist discusses the mathematical probability of aliens, the Big Bang and time travel. Hawking's theories on time travel in particular seem fairly optimistic - although "Back to the Future"-style DeLoreans are conspicuously absent. That will be the topic next week. Taking a cue from the show, here are five semi-practical models of time travel:

Barrel through a wormhole
If time itself is a dimension like length and height and width, then Hawking says the fabric of time contains imperfections we could take advantage of. A smooth billiards ball has microscopic crevices, and so does spacetime. We'd need to find a true "wormhole" and prop it open, and then head on through.

The caveat, of course, is that we'd be facing heavy radiation feedback concerns (a bit like the screeches you hear at rock concerts) and even without that problem, that we would create paradoxes by messing around with historical events in the past. For this reason, Hawking believes travel to the past may well be impossible.

Go near a black hole
It's simple: All we have to do is find a supermassive black hole and get into its orbit without being sucked into it. Hawking says time would slow down for the people in orbit relative to people elsewhere. Now to find a black hole ...

Go really, really fast
Hawking says if we can get close to the speed of light, a "cosmic speed limit" will kick in to prevent going any faster. Approaching roughly 186,000 miles per second, time will slow down for the traveler vs. the observer. When the traveler emerges, they will have jumped into the future. We just have to develop an engine that can go that fast. Don't try this on the Autobahn, folks.

Live on a space station
Turns out Cosmonaut Sergei Avdeyev is said to hold the record for the most time traveled into the future: about 20 milliseconds. His cumulative experience aboard Russian space station Mir gave him an edge over the competition. Hawking discusses in his documentary how orbiting global positioning satellites must have their timekeeping adjusted every so often because of the relative time slowdown.

Become a Retronaut
This one might be a cop-out, but many scientists (including Hawking) argue that time travel to the past is paradoxical and potentially impossible. In lieu of a Wayback machine, we can turn to the work of Chris Wilds, who created a website about his experiments with being a being a Retronaut. That is, a person who travels into the past by exploring perceptions of time. Whether by looking at old pictures juxtaposed with new ones (which we experimented with at CNN iReport a few weeks ago) or hunting anachronisms, Wilds' site hints that time travel may be all in your head.

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Filed under: Astronomy • Space • television • universe

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M. J. Fox   May 11th, 2010 2:11 pm ET

1.21 Gigawatts!

M. J. Fox   May 11th, 2010 2:12 pm ET

88 mph!

B. Tannen   May 11th, 2010 2:15 pm ET

Since you're new here, I-I'm gonna cut you a break... today. So, why don't you make like a tree and get outta here?

G. McFly   May 11th, 2010 2:19 pm ET

Who are you?

M. McFly   May 11th, 2010 2:20 pm ET

Silence Earthling! My name is Darth Vader. I am an extraterrestrial from the planet Vulcan!

M. McFly   May 11th, 2010 2:25 pm ET

Dear Doctor Brown, On the night I travel beck in time you will be shot by terrorists. Please do whatever is nessisary to prevent this terrible tragedy from occurring. Your friend, Marty.

Nommerz   May 11th, 2010 10:27 pm ET

"Manure...I HATE manure!"

peyote   May 12th, 2010 3:51 am ET

I hate these shows they take a complex theory and dumb it down for the masses. If you are challenged by making my pizza then astrophysics is not for you. I'm so tired of the media trying to make stupid people, feel not so stupid. Listen I'll make it simple the world needs ditch diggers and if your IQ is under a 100 guess what it's you

Bob   May 12th, 2010 9:41 am ET

Way to dumb down an article CNN! Comments from the author such as "Now to find a black hole ...", just prove how lacking science education is in this country.

Just so you can be educated a little more than you currently are Nicole, let me clarify something for you. Astronomers/physicists have located MANY black holes. They are fairly common in our universe, and are not nearly as rare as your flippant comment suggests. You could find this out for yourself even if you did nothing else but read the Wikipedia entry for Black Holes.

Please try not to dumb down science articles on CNN in the future. Doing this simply makes it seem as if science is some esoteric field of study, and is worthy only of ridicule, or pity.

No Knows the Nose   May 12th, 2010 11:08 am ET

@ Bob: After all, Wikipedia has all the right answers. Apparently naivety still exists out there. :(

James   May 12th, 2010 12:37 pm ET

Hey Bob;

Don't be such a Pi brain. I am sure the author is aware that black holes exist. I enjoyed the entire article and I ain't knott a dummee!

Learn to read sarcastic wit.

Please try not to completely “not get” articles posted on CNN in the future, doing this simply makes it seem as if using humor to make something interesting to a larger segment of people is some esoteric style of writing, and is worthy only of ridicule, or pity.

And hey Peyote;

Stop being such science elitist. Clearly you’re no rocket launcher yourself or you would be above making such comments. A truly intelligent person would simply not be reading articles meant for a more scientifically uncluttered mind. CNN is a business, and as such they must attend to the masses, or did your obviously superior intellect not think of that? You want hard core science go read the astronomical journal and leave me to enjoy CNN articles such as this without you harassing my enjoyment, or my intellect. Who are you to insult me because I enjoyed the article?

As CNN is one of the most successful news, information and entertainment networks around, I think they have a pretty good handle on the formula that works best for the “masses”. I’m betting they have a better education on the subject than you.

Finally, for M.J Fox, and G. McFly and B. Tannen, all I can say to you guys is;

“ the way I see it, if you're gonna build a time machine into a car, why not do it with some style?”

Clearly we are all geniuses in this comment thread. (Sarcastic wit)

Doc Brown   May 12th, 2010 12:55 pm ET

Roads? Where we're going, we don't need roads.

G. McFly   May 12th, 2010 12:56 pm ET

Last night, Darth Vader came down from planet Vulcan and told me that if I didn't take Lorraine out that he'd melt my brain.

Doc Brown   May 12th, 2010 12:58 pm ET

If my calculations are correct, when this baby hits 88're gonna see some serious --.

G. McFly   May 12th, 2010 12:59 pm ET

Loug. Give me a milk.......chocolate.

M. J. Fox   May 12th, 2010 12:59 pm ET

So you're my Uncle Joey. Better get used to these bars, kid.

JL Picard   May 12th, 2010 1:58 pm ET

there was a young lady from Bright
who could travel at the speed of light
she left home one day
in the usual way
and returned the previous night

Desmond Hume   May 12th, 2010 2:25 pm ET

Time travel is real Brotha!!!

Doctor Who   May 12th, 2010 2:32 pm ET

I'm with the idea of traveling back in time being impossible.
You simply cannot Create or Destroy matter or energy, it's a Universal law that cannot be broken.
To simplify, say you want to send a 1" square block of lead back in the past by 1 day.. and 1 day ago that block of lead already existed..
So now you have TWO identical blocks of lead.. you just Created a new block of lead in a point of time and space where there was only one..
Also, when you sent it back in time.. you Destroyed the existence of that block of lead from that point on..
Of course this can apply to anything.. including a human being.. who is made up of matter that already existed at any point in the past.. be it 5 seconds ago or 5 billion years ago..

I could be with the idea that if you did manage to go into the past, it would be an alternate universe.. one you will be stuck in and never able to return to your original timeline/universe.. but again you are breaking the law of not able to Create or Destroy matter/energy... and again it shouldn't be possible.
I think the alternate universe theories are based upon paradox issues.. but it seems to surprise me that there hardly ever is mention made about this simple fundamental, yet unbreakable law of existence of matter/energy.

ricstir   May 12th, 2010 2:43 pm ET

and not to long ago Good doctor, the world was flat and it was beleived that you would fall off if you sailed to far into the horizon.

Right now we dont have the technology , or the science to answer some of those questions, but just because we dont understand does not mean we should not try , that is how we invent and create things and learn so much valuable information, and in some cases, Prove theorys!!

I say it can be done, because we can think it, we just have to figure it out, may take some time, but we will get there.

Never know....

macuy   May 12th, 2010 3:28 pm ET

maximum warp...engage.

BackNTime   May 12th, 2010 3:46 pm ET

I love how in Back to the Future 2 Doc Brown has a whole spiel about why Marty went into an alternate reality since Biff was handed the almanac, yet the old Biff came back to his correct present reality at the beginning of the flick after going back to 1955 to hand himself the almanac. Kind of a big loophole fifteen minutes into the movie, no?

Nookleerman   May 12th, 2010 4:06 pm ET

To the Good Doctor:

While I make no claims toward expertise in this matter, it seems to me that you are leaving out yet another fundamental truth in your examination of this problem. Yes, matter can neither be created nor destroyed, but the block of lead from your example is not being created, nor is it being destroyed. It is simply being transported.

While that lead block exists today at this time, it also exists at that previous time. So when you transport it from one time to the other, it ceases to exist now and begins to exist in the past.

Simply put, all things that exist do so at every point in time that they exist. Using my own example, if you were to lay out a strip of tape, spanning 10 feet, and then cut out the section from the 8' mark to the 9' mark and move it on top of the piece of tape starting at the 4' mark, you wouldn't have created or destroyed anything.

And combining the examples, as time progresses forward or as you move along the tape when you get to that point where the cut was made or the lead block transported, they would both cease to exist.

Suffice to say, in the standard 3 dimensional view of existence, you are right in the idea that you would be adding mass from nothing. But when viewed in the fourth dimension it becomes clear that the mass already existed, it was simply outside our perceivable view.

Dave   May 12th, 2010 4:14 pm ET

"does anyone really know what time it is?" –Chicago

Nookleerman   May 12th, 2010 4:19 pm ET

I'm afraid I don't really care, Dave.

Sean   May 12th, 2010 4:23 pm ET

Makes me wish I hadn't cheaped out on my cable & could watch the Discovery Channel. :(

Also, does no one else find it painfully ironic that someone calling hirself "Doctor Who" is talking smack about time travel? :p

John   May 12th, 2010 4:36 pm ET

Honestly, wouldn't the Time Lords try to convince us it was impossible? That phonebooth drawn on cave paintings, thats just coincidence! I'm on to you, Doc...

bes   May 12th, 2010 5:29 pm ET

This is nonsense. Steven Hawking is just trying to sell something, or pay some alimony. It is not too difficult to travel forward in time, if we can just develop an engine that will provide 1G of gravitational force for a year of space travel and back. We can also look into the past. The processes cannot be reversed. But apart from dangerously warping space time with masses or velocities that may be harmful to the human DNA, it would seem wiser to direct intellect toward immediate liberation in this lifetime. Refute the self and time means nothing.

james   May 12th, 2010 5:52 pm ET

Interesting, one and all. I just took a look at another interesting feed you might all enjoy. Are tachyons impossible?? The mind simply JIGGLES at all the possibilities!!! :)

Because after all, we are ALL genius minds in this thread... ( again sarcastic wir BOB!) ;)

CJ Smith   May 12th, 2010 5:53 pm ET

"It is not too difficult to travel forward in time, if we can just develop an engine that will provide 1G of gravitational force for a year of space travel and back."

And developing an engine that can run continuously for a year, much less one that can generate 1G acceleration for a year, is not too difficult? LOL

james   May 12th, 2010 5:55 pm ET

Ok fine. I typed wir instead of wit, my sorrynesses to one and all. ;)

Ren   May 12th, 2010 5:59 pm ET

I did respond to this post tomorrow

Doctor Who   May 12th, 2010 6:15 pm ET

Nookleerman, your post got me pondering.. but the moment you suggested your "tape" theory, my mind went into paradox's.. and that in itself is very difficult to paint a picture of...
we go into variable mathematics where we have a variable on both ends and begin an infinate variable.. a paradox.. seemingly an open ended beginning and end.. sigh.. my brain fries at even a fraction of thought with the "tape" theory..
if you wish to further discuss.. e- m ai l me at bimmer fan 222 at y ah oo dawwwt cawm.. would love to further discuss it.

Time Travel has always been a fascination for me.. along with other technologies.

Sean... the Good Doctor NEVER EVER would travel back into his own timestream to redo his screwups... hey, fantasy stories are great! I'm probably the BIGGEST fan of Time Travel stories ever!
So no, it's not ironic I would choose this handle and yet come to the conclusion that you CAN NOT travel BACK in time.. but I'm ALL for leaping foward! ;)

Doctor Who   May 12th, 2010 6:22 pm ET

CJ Smith, the continuous 1G vehicle is called a Bussard Ramjet...

IA   May 12th, 2010 6:45 pm ET

I'm sure it feels like time travel to people in extended comas. To them they went to sleep and then woke up days, weeks or even years later. That has to seem like time travel. Time passed by and changes happened all while to them they simply went to sleep one day woke up the next to find the world different.

Keith   May 12th, 2010 6:49 pm ET

I was under the impression that recent experiements proved that the speed of light is not a "speed limit" as was once thought. That said, the unverisal "laws" that we have self established may not be universal at all. Current M-Theory suggests the exisistence of 11 parallel universes and the theory that Gravity, one of the "laws of nature" is actually based in another universe and is only "leaking" into ours. From what I've read, this was proven, mathetically by a professor at Harvard. The point is that we don't have all the answers and we shouldn't assume to believe we know everything. Science is evolving and our understanding of the know, and unknown universe evolves as well. The fun is being able to keep an open mind and enjoy the ride. At the end of the day the universe doesn't care if we're right or wrong or understand or even care about the true nature of things. "It" will be here long after we're gone. So, intellectual curiosity, reciting fun movie lines... just enjoy the concepts in any way you see fit and why not allow others to do the same?

A. Dilbert   May 12th, 2010 7:50 pm ET

Article's author is no geek. She actually thinks "Hawking's theories on time travel in particular seem fairly optimistic" even when "Hawking believes travel to the past may well be impossible". Her idea of traveling to the future by the way of a very fast spaceship is more similar to Austin Powers being frozen and then being revive in the future. That is not traveling to future, its more like time slowing due to your time clock running slow from the lightspeed travel while rest of the world runs at normal time. It's this misinterpretation that suggest time traveling to future or past is possible.

A way she can go to the future is to put herself in a coma then have someone wake her when she's an old lady. By then they may have technology to fix her cognitive deficiencies.

fireass   May 12th, 2010 11:06 pm ET

death is the answer to time travel....with no physical abilities, we could not wreak havoc on the past or the future, merely observe.

peyote   May 12th, 2010 11:36 pm ET

Hey James, stop with the posts I have ditches that need digging. lazy boy must be one of those free loading liberal types

jon   May 13th, 2010 12:09 am ET

he forgot to mention fly around our planet opposite way really fast and make our planet go that way, time will go back.

Oremus   May 13th, 2010 5:20 am ET

I'm already time traveling to the future. (at a rate of 3600 seconds/hour)

DC   May 13th, 2010 6:37 am ET

Maybe time travel to the past can be done without causing paradoxes.

Assume that every possible outcome (down to the quantum level) occurs and splits off into a seperate timeline. This means you could go back into the past and kill your father, but you could not return to the same future you came from because your actions created a new timeline as soon as you entered the past.

In the timeline you came from, your father lived and you were conceived. In the new timeline, you are never born, but you still exist because of your timeline of origin.

In a sense, time travel would be one way because you could never return to your point of origin.

CommanderBill   May 13th, 2010 7:12 am ET

This is heavy, Doc.

gizmokc   May 13th, 2010 7:12 am ET

why is my comment awaiting moderation?

gizmokc   May 13th, 2010 7:20 am ET

wow, all I can say is wow

billshut   May 13th, 2010 7:35 am ET

Cosmonaut Sergei Avdeyev missed a real opportunity! A few more years, and he might have been far enough ahead of the rest of us that he could have gotten the winning LOTTO numbers before the drawing happened!! ;)

Jim Hawk III   May 13th, 2010 7:49 am ET

Sergei Avdeyev didn't travel into the future. From his perspective, we simply lagged in experiencing the same interval. From the perspective of a hypothetical outside observer, he simply experienced 20ms less "time" than the rest of us in the gravity well during this hypothetical observation interval. Richard Gott made the mistake of assuming that there are privileged observers, which is directly contrary to relativity theory. Perhaps in the ensuing 9 years since that silly statement was published, he has recognized the mistake.

Joe P   May 13th, 2010 8:09 am ET

The world is full of STUPID people............and there sure are a lot of them on this blog. So much so, I had to dumb myself down just to post a comment.

DC   May 13th, 2010 8:49 am ET

@Joe P ... that was uncalled for.

People are just chit chatting among themselves. A lot of what is being said is in jest. A lot is also speculation, as was what I posted earlier. I see no harm in that.

Block of Lead   May 13th, 2010 8:53 am ET

For Dr Who,
I'm the block of lead. I've been stuck in a loop – I keep getting put in this machine for a few seconds, then time goes backwards a few seconds (and I unlearn the present so I'm not even able to type this), then they pick me up again, and put me in the machine and time goes backwards again for a few seconds, and I forget the present. This keeps happening (without me actually being able to remember it) until the machine breaks by random chance, which maybe will never happen. I'm not destroyed, I'm not recreated beside myself, I just get deja vu.

Or Plan B, I go heading towards a time machine, but meet myself coming towards me before I arrive. I get confident enough to go barrelling into the time machine, because heck, I already did it! Just hope I dont try to kill my old self after I come out! I can just check to see if I'm beat up to know whether I'll do that. Then, after I jump into the machine, my now self will continue on the path, and my past self will jump into a time machine and vanish. Sure, it took a lot of neat gadgetry to recreate me and place me on the surface of the planet where it was in the past.

Benjamin   May 13th, 2010 9:03 am ET

"Timeline, we don't have time to argue about time... What was I saying?..."

V   May 13th, 2010 9:53 am ET

Hawking forgot to mention the Hot Tub Time Machine- that one can only take you back to teh 80s though.

brent   May 13th, 2010 9:59 am ET

everyone knows time travel is only possilbe through parallel universes based on infinite time and infinite space equals infinite possilbilites. Yes my brothers and sisters you exist else where at this moment. but remeber you cannot go back in time, otherwise, we would hve recieved visitors from the future already.

Doc Brown   May 13th, 2010 10:41 am ET

We shall proceed as planned, and as soon as we return to 1985, we'll destroy this infernal machine. Traveling through time has become much too painful.

Martin McFly   May 13th, 2010 10:44 am ET

@BackNTime, 2 was filled with massive plot holes. Doc constantly talked about not altering the timeline, yet they stop Marty Jr. from going on the robbery with Grif, It had NOTHING to do with the time machine or events that time travel caused. So they essentially went ahead and altered future history simply because it was Marty's son. So Doc just thew all his ideology out the window. It was a really heavy handed attempt for the screenwriters to bridge the 2 movies. It was almost as if they really didn't care at all about the central plot of the series but were just hoping that the audience would not notice.

Doc Brown   May 13th, 2010 10:47 am ET

This reminds me of the time I attempted to reach the center of the earth. I'd be reading my favorite author, Jules Verne. I spent weeks preparing that expedition, I didn't even get this far. Of course, I was only 12 at the time. You know, it was the writings of Jules Verne that had a profound effect on my life. It was when I was 11 that I first read 20,000 Leagues Under the Sea. It was then that I realized that I must devote my life to science.

Mort Terra   May 13th, 2010 11:18 am ET

Go back to yesterday, oops killed myself. Go back to yesterday, oops killed myself.Go back to yesterday, oops killed myself. Go back to yesterday, oops killed myself.Go back to yesterday, oops killed myself. Go back to yesterday, oops killed myself.Go back to yesterday, oops killed myself. Go back to yesterday, oops killed myselfGo back to yesterday, oops killed myself. Go back to yesterday, oops killed myself.Go back to yesterday, oops killed myself. Go back to yesterday, oops killed myself.Go back to yesterday, oops killed myself. Go back to yesterday, oops killed myself.Go back to yesterday, oops killed myself. Go back to yesterday, oops killed myself......................................................................................................

Just2Reason   May 13th, 2010 1:36 pm ET

Time does not exist as a real dimension, as Hawking claims. The problem with mathematicians is that they can't see the big picture, and they try to make the "non-interesting" solutions to their equations interesting. Looking at the big picture, it doesn't seem rational to say there's an infinite number of copies of the universe that exist in both directions in time. Here's a possible alternate explanation for "traveling into the future" when you are near the speed of light. It's my own idea, although I would not be surprised at all if it's been thought of before. I got this idea years ago in Jr. High school. Suppose there's a vibration that drives matter changing, reacting, and existing. As you get near the speed of light, the vibration gets slower. Very simple. No infinite number of copies of the universe. (As an analogy – a computer is driven by a clock. Everything happens on a clock cycle, so all the interactions of the 0's and 1's are in sync. If you speed up the clock, the computer runs faster, but the computer would not be able to tell without some time reference outside of itself, or a way of telling what the clock speed is.) The present is what exists. The past and future do not exist, and cannot be traveled to. I do enjoy science fiction stories about time travel, however. Hawking's "traveling into the future" is simply a result of the vibration being slow (one possible explanation), and you experience less in the same time frame (age less, think less). Time is not a real dimension that can be traveled through.

Fatty McFat Jr.   May 13th, 2010 2:42 pm ET

I have already invented a time machine. In fact, I just used it to travel several seconds into the future as I was typing this message. Oh, there I go again. On the count of three I will be three seconds into the future. One... Two... Three... Wow, it really really works!

Fatty McFat Jr.   May 13th, 2010 2:44 pm ET

Hey, nobody better steal my 123 time machine before I can patent it. Have to figure out how to make it work as a 321 time machine so's I can go backards...

Fatty McFat Jr.   May 13th, 2010 2:45 pm ET

Oh, and be careful not to use the 123 time machine too much, on accounta it has the side effect of making you get older proportionately to the amount of time traveled forward! :o

Darren   May 13th, 2010 2:52 pm ET

I don't have a DeLorean but my chevy cobalt did come with a flux capacitor. It was an option.

Joe   May 13th, 2010 3:25 pm ET

Its HOWDY DooDY time!

ezra2009   May 13th, 2010 3:27 pm ET

If only we could send CNN into time travel. Either way as long as it billions and billiions and billions of light years away.

Mark in the Heartland   May 13th, 2010 4:40 pm ET

Time travel is quite possible, and done all the time (no pun intended). The problem is the travel is only one way and at one speed – all you have to do is sit still (preferably in front of your computer making posts on CNN) and you will travel forward in time. The rate is 1 sec = 1 sec.

Unreal   May 13th, 2010 4:53 pm ET

lol, nothing makes stupid people feel smarter than using pseudoscientific logic to explain time travel to other stupid people. Time is not a real dimension? Fail. If you're disagreeing with both Hawking and Einstein (as well as dozens of other theoretical physicists, mathemeticians, and cosmologists) it's a pretty good chance that what you're posting is going to make you look like an idiot.

Rose   May 13th, 2010 5:19 pm ET


I'm pregnant. There are two heartbeats, so either I have twins or you're the father. Pick up my pills and get them to me last Valentine's before "dessert," or you'll be paying child support!

John   May 13th, 2010 5:51 pm ET

I had a flight that departed from Taiwan on 1/1/2010 at 1AM and landed into San Francisco on 12/31/2009 at 2PM. Who said traveling in time wasn't possible!!??

The_Mick   May 13th, 2010 5:56 pm ET

As a chemistry major, in my last undergrad semester I decided to take an easy "Modern Physics" course where the course syllabus noted "no calculus required." All my prior physics classes had been calculus based and I wanted to cruise through my last semester. By the time I learned "no" calculus was a misprint, it was too late to add another class and I needed that course to graduate, so I couldn't drop it. A junior math major dropped the course because the multivariable calculus partial derivatives, flux calculations, etc. were too hard.

I struggled through with a "C" but I ended up with a much greater understanding of what time is. If you want a much clearer explanation, though, read Hawking's "A Brief History of Time". The only equation in the whole book is something like A = pi.r-squared and that's only used once without having to calculate anything!

davetharave   May 13th, 2010 6:56 pm ET

Time travel was already accomplished, he built a machine with a large rotating disk in the back. When it rotated clockwise he went into the future and the other way around went back in time. The people in the future scared him so he came back.

Unreal   May 13th, 2010 7:16 pm ET

Why is it that time travel machines in movies always involve some sort of large rotating disk? I think the Screen Actors' Guild is really a secret society of enlightened scholars who seek to cover the truth about time travel by hiding it in plain sight... excuse me while I go watch "Wheel of Fortune" to keep an eye out for temporal anomalies...

Hey!   May 13th, 2010 7:22 pm ET

So if you could travel faster than light speed and stopped to look back at earth, the light from the past would just be reaching you. And If you had a telescope strong enough, The Lucy Show would be on TV...

maze1gerald   May 13th, 2010 11:39 pm ET

No one can convince me time travel isn't possible.

Terry W. Brookman   May 14th, 2010 12:36 am ET

We are traveling in time. We just go to where we have not happened yet!

Nighthhaaawk   May 14th, 2010 7:01 am ET

The cleverest version of "Time Travel" I remeber is from Calvin and Hobbes, where Calvin sends snail-mail letters to his future self.

T   May 14th, 2010 8:51 am ET

Here's some fun Time Travel Flicks & TV shows to check out....
1. Timecop
2. Back to the Future I (the sequels stinks !)
3. Time Machine (1960 version)
4. Terminator 1 & 2
5. Voyagers !
6. Timecop (the short-lived 1990s tv series, anyone remember ?)
7. Time Machine (2001 version)
8. The Time Tunnel (1960s show)
9. Quantum Leap
10. Doctor Who
11. Star Trek: First Contact
12. Time Travelers (Irwin Allen pilot movie from 1974)

T   May 14th, 2010 8:58 am ET

Also...(sorry, I forgot these......)
1. Seven Days (another tv series, why isn't this on DVD ?)
2. Time Trax (Dale Midkiff)
3. Journeyman
4. Time after Time
5. Philadelphia Experiment
6. Austin Powers: Goldmember
7. Timecop 2: Berlin Decision (Direct to video flick)

Tony 2 Fingers   May 14th, 2010 10:18 am ET

May favorite movie about time is Time Bandits...

McFly Sr.   May 14th, 2010 10:31 am ET

Last night, Darth Vader came down from planet Vulcan and told me that if I didn't take Lorraine out that he'd melt my brain.

Dr. Brown   May 14th, 2010 10:33 am ET

Roads? Where we're going, we don't need roads.

blahmanb   May 14th, 2010 12:00 pm ET

Time paradoxes might not exist as, according to one theory, we are already living with the effects from time travelers actions,

So if I went back in time and killed a butterfly, according to the thoery, when i travel back to the present nothing will have changed as the world was already dealing with the effects of the dead butterfly before I traveld back in time.

HawaiiReside   May 14th, 2010 1:03 pm ET

Sometimes I wonder if the original Star Trek series could have just lasted a few more seasons.

Z   May 14th, 2010 3:01 pm ET

Maybe time should be looked at as a set of spacial coordinates, not a dimension, based on the expansion of the Universe. If you could, say create a worm hole to traverse space I imagine it would be harder to target the past at aspecific date than creating to worm hole itself.. If any feel that traveling to the past is even the slightest bit posible then every bit of the past would be everlasing like the frames of a movie. Then it would only require moving to that point in space. I guess it would be easier to shoot the eye out of a chipmunk sitting on the moon with a BB gun than finding that exact spot in space.

Buckaroo   May 14th, 2010 3:25 pm ET

Wherever you go, there you are.

Bonzai   May 14th, 2010 6:07 pm ET

About that small block of lead ...

Lead is found embedded in rock. To the guy who postulated that if you move a block of lead to the past, it simply has been transported, and it preserves matter and energy, well, I don't think so. If the lead had not yet been mined (which would be the case if you transported it far enough), then in fact, that block of lead would then exist twice in that time: once as a cube of lead, and also as unmined lead in rock.

Assume then that someone mines the lead, and forms a cube, and then repeats the previous action of transporting that block to the past, placing it next to the first block of lead. And then someone mines the lead, and forms a cube, and then ...

All I can say, is that done enough times, you could build a very heavy pyramid, and all of the material would be sourced from the same mine.

No ... time travel is not possible if conservation of matter and energy is an inviolable law.

capexcitemnt   May 14th, 2010 6:34 pm ET

i would like to travel back in time and watch the saints win the superbowl

Presto   May 14th, 2010 7:33 pm ET

Are we at the front edge of time or living in the past of some else's present? If time travel to the past is possible, then it's already been done by us in our own future, which exists at this time because theoretically we can travel to the future more easily than to the past. If we can travel to the future, we can inform our future selves how to do it so they can travel to the past and inform us in the present how to conquer time so we can travel to the past. But, all of that has already happened.

Jnan R. Saha   May 14th, 2010 11:01 pm ET

Stephen Hawkins is supposed to be a great Physicist. He writes about something no one knows about. He writes about Black Hole, Worm Hole, Big Bang etc. He also shoots his mouth off about Biology and Molecular Biology, he knows nothing about. But Reporters writes with great fanfare his saying about Advanced Civilization in the Universe that can pose a danger to Earthlings!
Now about Advanced Civilization if exists does not pose any danger to Earthlings. But some Microorganisms can arrive piggyback on Meteorites on Earth that can be an extreme danger to Earthlings, because there is no immunity to living organisms on Earth. If this happens it can be extremely rare event. The following is just an assumption of such an event. One meteorite with microorganism in freeze dried condition crashed on Earth 3.5 billion years ago and seeded life on Earth. Another meteorite crashed about 250 million years ago and probably made 99% life on Earth extinct, Permean Extingtion!
I am not a Physicist, yet I can say that Black Hole as theorized cannot exist. The reason is “INFINITY”. Infinity is an abstract concept not a reality. For this reason Big Bang could not happen either. But I cannot say how the Universe started. His Worm theory about Worm Hole is just a lot of baloney.
I do not believe in Black Hole but in dense objects with density of 10**17 grams per cc exist in every Galaxy are swallowing up Stars may be one in every minute. Some of them will be as massive as 100 billion Stars. The Galaxies are also moving away and toward other Galaxies (that’s what I read in Astronomical articles). At some point two such massive objects will collide and everything within a few million light years will broke into elementary particles and new Galaxies get started!! By the way I did not watch Hawkins program about Universe and time travel etc. If anyone wants to communicate with me will be very welcome.
Jnan R. Saha
9 Village Green
Wesley Hills. NY 10952

Jnan R. Saha   May 15th, 2010 11:26 am ET

I wonder why no one is responding to my post! And how long does it take to moderate a post?

Jnan R. Saha   May 15th, 2010 12:06 pm ET

Time travel is also a lot of Baloney. One cannot go to the past or future only stay at the Present. Yes one can see something happened in the past like a Supernova!

Doctor Who   May 15th, 2010 4:16 pm ET

Bonzai- Thank god someone understands my lead block example. Yes, in effect if time travel to the past were possible.. you could end up "cloning" matter over and over.. why stop with lead?
Get a gold bar, zap it in the past a few seconds.. now you have two... zap the two in the past.. now you have four.. then eight.. then 16....
You could become very rich in a matter of an hour's time!
But the conservation law of matter/energy appears to be inviolable, as you say, perhaps even more so than the speed of light barrier.

I think the problem with visualizing time travel is too many of us perceive it as motion... like walking from point A to point B. And it's not really like that at all.. but we DO perceive it that way because its the simplest way to comprehend it.. such as watching the hands on a clock move.. or the sun cross the sky.. or the movement of a car in MPH.. time always has a connection with movement to give us reference of it's presence.

As far as leaping ahead in time.. as shown in time dilation effects caused by fast moving objects such as satellites or spaceships.. I think thats more of a retardation of time on the moving object.. like a form of Stasis.
And that in itself brings on questions of just how old a photon really is that has travelled great distances to reach an observer.. since a photon is both a particle and a wave..

Apply the time dilation effect for a photon travelling one light year...
What was the scenario for a spaceship that travels 1 year at light speed? That the pilot would age 1 year, but people on earth would age 50 years??
So wouldnt a photon that travels 1 year at lightspeed seem to actually take 50 years? Thus what we see from a hundred light years away is from a time older than 100 years ago... it would actually be light from 5000 years ago.
Some rules simply have been put in place to not be broken.. and if you try.. there will be consequences in trying to do so.. humans cannot live forever.. we all DIE.. even when we have the technology to further our lives longer, new diseases and complications pop up to again stop us from living forever.
Sure, we are very crafty beings.. but we live in a universe created by something MUCH smarter than us.. and if It dont want a law broken.. it wont be. I'm sure It has its reasons.. reasons we may never know why they are there... for every action, there is a re-action.

Sency   May 15th, 2010 6:33 pm ET

I saw Stephen Hawking on Larry King – it was pretty interesting

Doctor Who   May 16th, 2010 12:01 am ET

Saha- you wrote, "Advanced Civilization if exists does not pose any danger to Earthlings"...

have you ever heard what happen to the Native Americans when the Advanced Europeans came to America??

Z   May 16th, 2010 8:00 am ET

Block of lead thought.
If I form a block of lead 1"x1"x1" today then wait till tomorrow and transport it back to today I would have 2 blocks of lead. One is an active participant in todays time the block from tomorrow is now a viewer participant in todays time. The two co-existing together each in its own space. I then stamp the letter "A" on the origional block of lead., and move the transported block from the exact spot it was tranported to and wait until tomorrow. The transpoted block of lead would not have the letter "A" on it because it was not an active participant of that time and not occupying the exact same space as the origional. You could not merge the two into 1 and still occupy the same space. So you are stuck with 2 blocks of lead one from the present and one from the future. Matter has not been created or distroyed only moved. Each governed by its own timeline. Unless you can merge a 1" cube of lead with another 1" cube of lead from the future and still have a1" cube of lead all occupying the exact same space you are stuck with two blocks of lead.

Jnan R. Saha   May 16th, 2010 8:24 am ET

Dear Dr. Who:
I am glad that you answered my post. Yes I am aware of what did the advanced White Civilization did to not so “Advanced” people all over the World. What they did to Native Americans, enslaved the Africans, Asians and looted their wealth. We were also the victims of the White oppressions. What we had seen in the last Bush Administration, Conservatives had design for the whole World.
But any advanced Civilization is so far from our Planet, it is impossible to have encounters like ET, or in Star Wars Sagas. We only have to fear the “lowest” organisms. It is also for the Earthlings, no matter how advanced we get, there is no way to get physical contact with other Civilizations. However the Probes we sent in the Seventies can crash to another World in many thousand years can cause destruction to that place if that probe has any Earthly Microorganism in suspended animation!

Jnan R. Saha   May 16th, 2010 8:30 am ET

Even somehow Advanced Civilization have Physical contact with us, those will be in greater danger than us. They will not have any immunity to Earthly Organisms. In other words the lowly microorganism will be our shield.

Jnan R. Saha   May 16th, 2010 10:27 am ET

I bet Dr. Stephen Hawkins has no understanding about basic Immunity and the lack of it is dangerous to other Living Beings. So he shoots off his mouth and reporters without this knowledge reports with much fanfare!

Jnan R. Saha   May 16th, 2010 10:32 am ET

Hey James Black Holes cannot exist as I posted my reasons before. But a Dense Object with enormous mass can exist. These are swallowing other stars and one day may be our sun will be swallowed. But don’t panic, we still have a few billion years to go.

Doctor Who   May 16th, 2010 6:26 pm ET

"Your comment is awaiting moderation."

come on CNN! just because I posted something lengthy, you wont EVER post it?
if anyone has interest in what I posted.. email me at

good day!

K. Newton   May 17th, 2010 1:37 pm ET

Someone posted this limerick but missed the point:

there was a young lady from Bright
who could travel at the speed of light
she left home one day
in the usual way
and returned the previous night

It should be:

There was a young lady from Bright
Who could travel at the speed of light
She left home one day
In a relative way
And returned the previous night



Josh J.   May 17th, 2010 1:51 pm ET

On a serious note. I contend that the abaility to travel back in time will never occur. The reasosn is that if that abaility was to ever exist, 'Wouldn't we already have seen evidence of it?'

Are you telling me that nobody from the future with the power to go back in time wouldn't have come back and stopped Hitler, the holocaust, the assassination of Martin Luther King or John F. Kennedy, or even prevented 911?

if traveling back in time would ever be possible in the future, then we would already know it!

O.K. Scholars, your retortes!

Roger   May 17th, 2010 1:53 pm ET

If I went back in time and killed my dad before I was born, then how can I ever be born? And if I can't be born, then how can I go back in time to kill my dad.

People, time travel is nothing more than fantasy. It's NOT possible. It's like the Special Olympics...if if you win (this argument), you're still a retard.

ubetya   May 17th, 2010 3:28 pm ET

The example of going back in time and killing your dad (mom, self...) is not proof you cannot go back in time. Its just proof that you cannot go back in time and kill your dad. You can go back in time, but be unsuccessful in the killing. Maybe you get hit by a bus or the gun misfires. Even for non-time travelers, killing someone is not a sure thing.

Two thoughts on the conservation law of matter/energy.

First, this is just a theory, not a “law”. The way you are looking at it may be too limited. If time and space are really connected, then maybe the conservation law of matter/energy involves all of time and space and not just this moment of time and space.

Second, it took energy to send the bar of lead into the past. Therefore, new matter was not created, just converted from energy to matter. The matter was just created in another time.

MakeUthink   May 17th, 2010 3:55 pm ET

Doctor Who got me thinking about his theory on time travel. The lead block idea of a piece of mass traveling back in time tho that piece would already be there. So what if Time travel would just be time viewing. What if you even did travel back in time it would just be the images not neccessarily the matter? What if?? What if??

Pilot to Navigator   May 17th, 2010 4:23 pm ET

I think the most challenging aspect of travelling to the future is a point of reference for locality. With the universe expanding, how do you plot your physical point of arrival? If you simply travel in time and not simultaneously in physical space, the location of your launch is not at the same physical spot at the time of your arrival. Wouldn't you have to first travel out into space, then travel in time, then determine your physical location of arrival, then travel to your desired location of arrival?

Pilot to Navigator   May 17th, 2010 4:35 pm ET

Maybe that was actually me who crashed in Roswell? My time machine worked, but my spacecraft didn't!

Z   May 18th, 2010 8:18 am ET

Who came up with the idea that time is a dimension? I remember HG Wells writing that in the Time Machine novel. If time and space are the same than time should be targeted by the space occupied at a certain time. The thought of moving to a certain point in space for a certain date of the past is an interesting thought but also rememder that the universe is also expanding at light speed or so they say. If I consider empty space as inert and the only mass within it is the universe then the only action taking place are the actions of other bodies within that inert nothing nott the actual space. All of those actions would cause various eddys and currents on the matter within that space making it extremely hard to plot a course to a specific set of corordinates

Doctor Who   May 18th, 2010 12:59 pm ET

I think the problem here is that we want to view Time like we do Space.. we can travel thru Space by movement.. we perceive objects moving in space and think we can do the same with Time... but Time is not Space.
Time is the name we give for something we cannot quite truly understand.. we see the effects of motion within it, but we dont really SEE it.
The only thing that exists in regards to Time is NOW.. there is nothing to go "back" to because it doesnt exist.. what was then exists only now..
The same goes for the Future.. it cant exist yet because it hasnt happened yet.. because what's to become is existing now.
And as far as time dilation effects of going fast in a spaceship.. that's more akin to a form of suspended animation.. ship time will slow down while the rest of the universe goes on as usual. It's more complicated than that, but the point is that the space traveller never leaps through time.. he still coexists with Time itself.

geekout   May 21st, 2010 8:47 pm ET

wormhole. like stargate. ahaa

Z   May 22nd, 2010 10:27 am ET

Let me break all the laws of physics to make a point!!!!

I construct a spacecraft capable of unlimited, multiple times speed of light speed. So now I travel to a spot 100 light years away at so at 10,000 times speed of light. I arrive in say after 3 days of travel. I then look back to where I started and the faint glow of our sun being viewed is from a hundred years ago, that is as long as it has be traveling. I return back to earth at 15,000 time light speed. I arrive back at real earth time no closer to the past or the future. Only the elapsed time I was physically gone. No matter how fast I travel I cannot go to any time earlier than the time I left plus any elapsed time . I am only changing the distance the light traveled. I can only move away to a point that allows me to view the past from a far distance. I can not take part in that past.. I can only move in present real time

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