Reading some of this sci-fi stuff. Distances to other systems can be hundreds of thousands or even millions of light years away. Let's assume that we have ships that can travel those distances in reasonable time periods.

How does one navigate to them? If we look at the light from them and point the ship in that direction, that's where it was hundreds of thousands or millions of years ago. How do we know where to point the ship so that we arrive at the intended destination, not where it was a long long time ago?

It takes a lot of math....

Equally important how do you avoid every tiny particle of matter along the way which would destroy your vessel?

^^^ - Georgeair, you typed your response faster than me

Slight tangent on your premise - and I'm paraphrasing what the physicist I was watching said: Spacecraft that could travel those distances in a reasonable timeframe would have to be incredibly small. He posited that a toothpick size or smaller would be optimal due the amount of 'dust' in space. He equated impacting one particle when traveling even a fraction of light speed would be equivalent to being hit by a baseball x 19,000.

Wormholes.

Using a Mass Pointer, of course.

quote:

Equally important how do you avoid every tiny particle of matter along the way which would destroy your vessel?

That's what the shields are for

Derrrrrrrrrrrrrrrrrrr

The navigators would need to embrace their inner Wayne Gretsky and 'skate to where the star is going to be.'

Correct answer is: use your imagination. Otherwise where’s the fiction?

Years ago, playing World of Tanks online, far removed and with an awful ping, i would shoot into the future (leading the target) in order to match the arrival of the enemy tank and my round to the same location. I was a decent AT gunner

PS: I played with Joel ^^^^

0-0

I dunno, but always carry a towel.

"Traveling through hyperspace ain't like dusting crops, boy! Without precise calculations we could fly right through a star or bounce too close to a supernova and that'd end your trip real quick, wouldn't it?” — Han Solo

Really it's this:

quote:

Third Law: Any sufficiently advanced technology is indistinguishable from magic.

Astronomers use software that can predict the future position of stars, even over centuries.

quote:

Originally posted by BigSwede:

quote:

Equally important how do you avoid every tiny particle of matter along the way which would destroy your vessel?

That's what the shields are for

Derrrrrrrrrrrrrrrrrrr

Or in Star Trek, the navigational deflector.

Could go with a wave motion engine or Boson Jumping.

I knew you guys would know.

As mentioned, during high speed space travel you transfer all power to your forward deflector shields...

As an interstellar navigator, you don't travel any distance at all.  Your position is a constant in the Universe, and has always been.  The position of your target is a constant,  and has always been.  You simply converge the positions by combining them, similar to quantum entanglement.  Your "travel" time is - almost - zero. "Almost" because there are some complicating factors, the constant of Universal expansion being only one. 

The simplest explanation is that two separate ink dots on a balloon are "farther" apart when you blow up the balloon, but are in the same position they always were with reference to the surface of the balloon.  They haven't "moved" from where they were originally - the balloon has. 

Converging them is a little more complex - "folding" space is referenced in old Earth SciFi, or "wormholes," or "warp drives."  The reality is that interstellar travel involves overlapping the original positions by manipulating spacetime - both a mechanical and metaphysical process.  Not an exact overlap, so some actual continuation along the time axis is involved to prevent objects occupying the same space at the same time - a bad thing: i.e., a "trip" of 100 parsecs may take hours quantumly versus theoretical zero time, or 326 years at light speed, but not a linear relationship so a "trip" of 1,000 parsecs might also take hours, plus some minutes.  I'm not a nav tech, so that's my simple take. 

The speed of light in a (practical) vacuum is the absolute speed limit for physical travel in this part of the Universe.  Physically moving "stuff," including energy, is restricted by this limit, no exceptions. Plus a hydrogen atom along the route of whatever physical object you send at even a fraction of this speed will vaporize it.  So interstellar travel is a practical impossibility using this method - relativity will just insist.  Transposing spacetime coordinates however is a realistic method of traveling between stars, long proven and used. 

Traveling between galaxies is another problem entirely, not yet solved, largely because of the difference between interstellar and intergalactic space.  There shouldn't be and there isn't observationally, but there is, perhaps something along the lines of the ancient novella by Cordwainer Smith, "The Game of Rat and Dragon."  We haven't yet succeeded, because there is something there between the islands of stars that shouldn't be,  and that doesn't exist between stars warming themselves rotating around the glow of a galactic hub.  Spacetime cannot be manipulated between galactic halos.

The only possible way we ever travel to ANY other star system is if Einstein was right in his wormhole theory. The only way. And that only works if wherever the wormhole ends has planetary conditions similar to earth. I say this because we are not built for anywhere but the planet we evolved on. That includes travel through space.

While en route, we couldn’t approximate the conditions our bodies need to stay healthy humans. Our hearts would atrophy, our eyes lose shape and likely normal vision, bone density would deteriorate, declining immune systems, as well as a slew of other maladies. And that’s just during travel.

But to answer your original question, as has been stated, math as far as we are capable of applying it. But even if we could attain light speed travel (spoiler- not possible) it would take us longer than the number of light years of distance as we have to decelerate on the back half of the journey which would use time and a LOT of fuel.

According to UFO fanatics, you use zero-point energy and make space/time move while you remain stationary.
This allows for near instantaneous travel to anywhere in the universe and no G forces.