So much for travelling back in time

[TKnHappyNess]

Idiot scientists.

http://news.yahoo.com/s/livescience/20070309/sc_livescience/youcanttravelbackintimescientistssay;_ylt=At0iDaiK C6d1pHcqoxT_e1vMWM0F

[mr_pikachu]

Space-time, Liu explains, can be thought of as a piece of spandex with four dimensions. “When something that has mass—you and I, an object, a planet, or any star—sits in that piece of four-dimensional spandex, it causes it to create a dimple,” he said.

“The gasoline necessary to energize a time machine is far beyond anything that we can assemble with today’s technology.”

Cosmic strings are either infinite or they’re in loops, with no ends, said J. Richard Gott, author of “Time Travel in Einstein's Universe” and an astrophysicist at Princeton University. “So they are either like spaghetti or SpaghettiO’s.”


So, is LiveScience supposed to be some sort of joke scientific website? If so, I've seen better. If not, then yes, they're idiots.

Incidentally, someone needs to create a band called Four-Dimensional Spandex.

[Asilynne]

lol Scientists have been deeming things as "impossible" for years, and this is no different. Key word was what it said in this article: "And almost all of them, if you look at them closely, brush up right at the edge of physics as we understand it." thats not to say they understand everything about the way things really work, or understand correctly. Itd be pretty close minded and arrogent to think that.
I think the real thing is not "can we go back in time" but "should we go back in time" Cause while I dont think its impossible, and yes it would be interesting to do so, I dont think it would be right to have this power. Too much could screw up that we cant even comprehend how to fix. Like the saying "A butterfly batting its wings in china could cause a hurricane in the pacific" or something, a seemingly small change could have massive outcomes.

[mr_pikachu]

I could think of plenty of ways where travelling into the past could avoid any possibility for paradoxes such as the grandfather paradox.

Let's look at the wormhole theory, for instance, and assume that for the number of years you travel back in time you must travel an equal distance away in lightyears. For instance, if you travelled back five years, you would end up five lightyears away. Therefore, none of your actions would have any direct repercussions on your own past events.

If, for the sake of argument, you travel to the earth at the speed of light (which is commonly believed to be the speed limit of the universe) to try to kill yourself before you can travel back in time in the first place, your attack will arrive just as your previous self makes the time-travelling trek, and your mission to create a paradox will therefore fail.

Any actions that you take while in the past would have no effect on you or the rest of earth until at least the moment at which you left; even the image of your form would only travel as fast as the speed of light. Thus, we can argue that any of the actions you will take in the past had already occurred before your voyage... you're not changing anything!

This theory isn't perfect, of course. Assume for a moment that you take two separate time-travelling ventures of one year each. Also assume that the first trip takes you one lightyear in some random direction while the second takes you an additional lightyear in the exact opposite direction - therefore placing you at the exact spot from which you left, but two years in the past. This would allow room for plenty of paradoxes. A further conflict could occur if there are other means of matter or energy spanning distances in less time that light (including travelling through space in negative time).

Yes, this is extremely complex, and I'm probably not explaining them very well. Then again, how the heck do you talk about these things in a way where people can actually understand them?

...I think about such issues far too much.

[RedStarWarrior]

Why the fuck would we be using gasoline anyway?

[Gavin Luper]

Then again, how the heck do you talk about these things in a way where people can actually understand them?

With spandex and SpagettiO's, evidently.

[Jeff]

Yeah, I wonder if these are the same scientists that proved that everyone is psychic through that phone study.

I'd go back in time and find that thread, but the way gas prices are these days...

[Dark Scizor]

Uh-oh, spaghetti-o's.

[Drago]

I go by the theory that it's like Back to the Future, they could have changed the past ninety-three times already, and we wouldn't know because the only reality we know is the one we're in right now. Yesterday I might have been a Norwegian ocelot, but someone messed with the past and now I'm me.

...Incidentally Brian, you post too smart. It hurts my brain. Butthead.

EDIT: No good Back to the Future post goes without calling someone a butthead. :yes:

[Asilynne]

Hello? Hello?? THINK MCFLY THINK!
That was the best f***ing movie ever :>

[Outlaw JT]

Don't forget that every single point in space is in constant motion. Where the Earth is right now is a more than considerable distance from where the Earth was even five years ago. To have a direct effect on the past of our own species one would not only have to manufacture a means to travel back in time but also across a vast distance in space in practically the blink of an eye. Even if time travel is possible it is far from practical. The speed at which one would have to travel to get to a familiar point in space more than a few days removed would be so excessive it could literally break matter down to the atomic level and disperse it.

Sorry to say that time travel as it is commonly perceived is completely and utterly bogus. To actually travel to a specific point in time one must also travel to a specific point in space, something that is astronomically difficult to calculate with no guarantee that such calculation is even possible as we can only use astrophysics to calculate movement within our own galaxy. As our own galaxy is also constantly at motion within the universe we quite possibly lack any means of truly calculating the specific spatial coordinates of any moment in time!

[mr_pikachu]

You are correct that such a calculation would be, as you said, astronomically difficult. However, I disagree that it is necessarily beyond possibility. While we certainly lack the ability to do such a thing in this day and age, who is to say what capabilities we will have a few millenia from now?

There's a quote I heard awhile back from some guy at the beginning of the 20th century... "All possible inventions have already been invented," or something like that. For reference, this was about a decade prior to the Wright brothers' work, and a heck of a long time before the TV, the computer, the internet... yup. While that's a bit of an extreme example, it does show that human ingenuity is not something to be underestimated, even if we can't see how such a thing would be possible nowadays.

You do make a good point about the constant movement of objects in space, however... I think I'll have to refine my "travelling through space and time" theory to account for that.

[Mikachu Yukitatsu]

The morning sun I feel
all pain and sorrow
the apparation of my words in these days
makes me feel I've told them before
all my plans will come true
I'll controll destiny
in the desert of my life
I've seen it again and again
(lead: André)

By my dreams I must find a way
to stop the raging war
I've to choose now
I will leave
my body and seek
and time will stand still
when I've to leave
my body and find
a way back to the world I love
when I'm a million miles from home

Ref.: Traveler in Time
knowing that there's no rhyme


(Blind Guardian: Traveler In Time)


Don't forget that every single point in space is in constant motion. Where the Earth is right now is a more than considerable distance from where the Earth was even five years ago. To have a direct effect on the past of our own species one would not only have to manufacture a means to travel back in time but also across a vast distance in space in practically the blink of an eye. Even if time travel is possible it is far from practical. The speed at which one would have to travel to get to a familiar point in space more than a few days removed would be so excessive it could literally break matter down to the atomic level and disperse it.

Sorry to say that time travel as it is commonly perceived is completely and utterly bogus. To actually travel to a specific point in time one must also travel to a specific point in space, something that is astronomically difficult to calculate with no guarantee that such calculation is even possible as we can only use astrophysics to calculate movement within our own galaxy. As our own galaxy is also constantly at motion within the universe we quite possibly lack any means of truly calculating the specific spatial coordinates of any moment in time!

Ahem...

http://img340.imageshack.us/img340/1443/img099einsteinxx2.jpg

OK, OK, I know, I know it isn't that simple.

If it's like in 'Back To The Future' then if you have a newspaper with you and change something in the past, the text changes, too.

But if you travel through a wormhole and change something, does that make a new universe? Then you are a god and have created a new universe where perhaps nobody knows about your time travel. And am I right in saying that black holes also function as wormholes, and then there's the white holes which, but this is a bit off topic.

I have two physics teachers at lukio (high school). Veikko Taipale and Pekka Vuolo. I think Veikko treated a certain magnitude in certain situation positive and Pekka negative in the very same situation. So why couldn't energy be negative?

[mr_pikachu]

"Negative energy," as you put it, is an idea that is at the forefront of high-level scientific research. Most of us probably know about electrons, neutrons, and protons (the subatomic particles that are widely believed to comprise the atom). But some scientists claim to have identified positrons and other subatomic particles that don't fit such a narrow definition.

A positron, if you didn't know, is essentially a positively-charged electron. If I remember correctly, this is a form of what is called "dark matter." I honestly don't remember the others, but it can be inferred that if there is a dark matter counterpart to the electron, one likely exists for the proton, as well. (Such a thing may not be necessary for the neutron, as it is lacks any charge whatsoever.)

This dark matter could be considered a form of "negative energy." The mass of a subatomic particle is negligible, but if World War II is any indication, a single one can pack an enormous amount of energy. If these subatomic particle have the opposite energy pole that would normally be expected, these may fall into such a classification.

Wouldn't it be ironic if the greatest mysteries of the universe could be unraveled through the smallest of all particles?

(Yes, I know I'm ignoring quarks. I'm trying to be poetic here!)

[Mikachu Yukitatsu]

Hm, what about gravitons? I don't see anyone mentioning them. Those particles are believed to travel faster than light since they can escape from black holes. I am not sure about the English term, but that means their speed is more than the escape velocity from black holes.

[mr_pikachu]

Hmm, that aspect of gravitons is new to me. I hadn't heard about such escape capabilities... an important question that needs to be asked is whether such instances are due to an inherent characteristic beyond that of light, or if there was simply a greater distance between the black hole and the gravitons than between the black hole and trapped light. This would explain how the gravitons escaped and the light did not, according to Newton's theory on gravitational force.

On a somewhat related note, I read an article yesterday about some new data from the Pioneer Anomaly that may suggest a flaw in Newton's description. It should be interesting to see what that yields, although the data may not be ready for a complete analysis for many years.