First Habitable Planet Confirmed.

I think we're arguing the same thing, just saying it differently. That may be my fault. I'll try again. =)

Time dilation for the people on the ship means that when they get off, more time will appear to have passed outside the ship than was measured inside. To those inside the ship, this appears as though the universe has aged around them.

On our clocks here on Earth, 20 years has passed and all is great. It doesn't particularly matter, as the effects of any actions they take, including a conformation broadcast of their arrival, wouldn't reach us at the 20 year mark anyway, but for all intents and purposes we can throw a party back home assuming they got there safely.

But let's say they got on a ship and traveled for 20 years their time. Now many thousands of years have passed back here on Earth, and we're screwed if we ever want to have a reasonable agreement on what happened when.

A light year is a measurement of distance, a certain number of miles/meters/au. A light year wouldn't be effected by which direction an object is traveling as it is simply a certain number of units of distance, not effected by time.

The reason we are at an impasse is because we're discussing speed of travel and the time a travel at a certain distance would require. When time plays into the problem, the relative position of the observer becomes important, because the position of the observer determines the speed of the observer, and therefore their perception of time.

My argument is that what we call the speed of light, the -time- it takes light to move a certain distance is a speed that was determined by observers on earth. That crucial component of time in speed is relative to earth observers.

So when are talking about a year, we are talking about a year that passes relative to earth observers, not a year that passes relative to observers moving at or near the speed of light. When we say a car is moving at 55 m/h we are saying a car on the planet earth is moving a distance of 55 miles in the course of one earth hour. I think the same thing when we're discussing the speed of light. An object moving at the speed of light moves a distance of 186,282 miles in one earth second. Not 186,282 miles in one second on the craft that they're traveling on.

I guess I could be wrong on that, but I've looked at a few pages and haven't found anything contradicting that.

This I completely agree with.

Correct. What I'm trying to say is that IF we had a ship capable of near-light speed travel, a group of people on said ship could reach a destination many many light years away in a seemingly short period of time, making colonization of a far-off world a real possibility. However, everything outside the ship will have aged accordingly to the actual distance traveled (20+ years for a 20 light-year voyage).


In this case the ship itself will have traveled "many thousands" of light-years.

so basically, to time travel forward, we have to travel at light speed forward

and to travel back in time, travel at light speed backwards ?
:P

Fight aliens for a couple hours near Jupiter, then come home to realize that 40 years have passed? What a bummer, huh?

no matter which direction you are moving, you will be "traveling forwards in time".

Okaerinasai. Welcome home.

What can screw with you is that you can actually in a way travel faster as you stay the same speed. Because distance is constant and time is relative, as you move faster through the universe time slows down. You end up moving the same distance in increasingly long seconds.

The speed of light of someone moving the speed of light is faster than the speed of light of someone on the earth.

do particles count as an object?

http://en.wikipedia.org/wiki/Large_Hadron_Collider

It's also worth mentioning that the force or "pressure" is only exerted as an object is accelerating. If a ship were to accelerate gradually at a rate like 1.5g or 2g, it could reach near-light speed without crushing a human.

Exactly, and that's what sucks about the whole thing.

"Colonizing the galaxy" in most people's minds implies that the various worlds, travelers, etc all basically tick at the same rate and thus have an agreement on time, events, communication, etc. Think Star Wars and Star Trek. But sadly, as soon as you start zipping around at high rates of speed, the whole thing blows apart.

If you're going to get on a ship for a few months and arrive at a potentially different destination than you thought when you departed, (because time will appear to have jumped forward), is there really any point in traveling at all? Why go visit a friend on another planet if they're going to be dead by the time you get there?

Talking about time space continuum...
/head explodes

Pretty nifty news though.
Hopefully we'll be able to put this information into tangible fruition someday.

So confusing though. I thought time was relative and was measured on terms of being human. Isn't this ultimately subject to perception, or are there mysteries of physics that are involved here?

Okay...So, another question popped into my mind in terms of colonization.

Twenty years is a significant chunk of time as far as the human life-span goes. If human females basically have only a twenty-five year span or so to produce healthy children, then what problems does that pose for when traveling within that time?

Just saying... (Yes, I know it's possible for women over forty to produce children without downs-sydrome, cerebral palsy, etc., and this just going off of current medical problems that we may or may not overcome by the time that space travel is even relevant.)

I love you.

Ranking in least scifi to most.
We'd likely have to develop simultaneous technology with cryogenics and slow or stop the aging of a human, find some way to extend the fertility cycle, or else find a way to shorten the trip. Keep in mind a trip like this would be shorter than 20 years for the people on the ship

Yeah, we're all earthlings and can't even get along.

I think there are some exceptions. But on a fundamental level, this is pretty true. Besides, exceptions would be a subjective and personalized, individualistic point of view that would clash with the nature of one's own purpose and species.



Example: Joshua Trees tend to grow in large groups, but every now and then you get one that sits by itself in a vastness of nothing.

Edit: Why the hell did I say examples? /tired

Ok, I barely made it out of highschool and that was in '99. All I want to know is: Jaerik, Eugene or Kirana, are any of your real names Will Hunting by any chance??

That is all....carry on making my head hurt!!

If I remember my physics classes correctly I seem to recall that at 99% the speed of light a 20 yr trip would (from the time reference of the people aboard the ship) would seem to only take about 3 years, while the full 20 years would have passed here on Earth.

Edit: Just remembered also that the number of decimals you go makes a difference in calculating time dilation. 0.999996 is different than 0.9999999999999.

2 Suit

You need gravity

Artificial Gravity

There is also cryogenics, however it is extremely unlikely the human body could ever sustain it.

A full stop or freeze of the the human body might be impossible, but there is already evidence that the human body can be slowed to extremely slow levels of functioning.

Certain medical procedures require dropping the core body temperature to incredibly low levels, and people have survived days buried under snow in avalanches because of the way the cold slowed the body's metabolism.

It just means that any trip to another star is likely going to involve several generations, one or more of which is born in space.

You will end up with more people arriving than originally departed, or you're going to be in trouble once you get there. =)

And for trips longer than a human lifespan, well... you have to set off knowing you're never going to get there, but your grandchildren might.

Nothing good ever happens on space ships. That ***is gonna show up at the new planet like the ship from dead space or Alien.

Im not... like i said, historical fact. Why are you even talking to me when you know I think you are worthless.... get off my nads. (I apologize for that earlier post moderator)

Or just make a ship that goes fast enough that there wont be a time issue for those on board! I love relativity.

this thing looks human to me. We're good

this thread is giving me mindgasms... i love this kind of stuff XD


...and random thought based on the idea of time dilation (didn't know much about it at all til reading this)...assuming we had ships that could travel 99.9% speed of light (or however close) wouldn't that, in a sense, be like time travel? i mean, say you take a round trip going in one of these ships to... any random spot far from earth, and then back. Say this trip lasts a week for the ship, when the people come out of the ship back on earth it will have been years.

a problem with this might be the thought of being able to curve accurately back to earth going this speed, cause going in a straight line, stopping, then going straight back may seem ridiculous... or maybe not XD i'm not sure, but it came to mind after reading some of the things here

Correct. It is essentially "time travel" into the future, for those on board the ship.