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14 4 days ago

When I try to explain to someone just how big and massive our universe is I usually fall back to the Voyager 1 satellite which was launched almost 50 years ago. I like to tell people that it is traveling at an amazing 17km per second! Even at such an amazing speed it has still only just traveled approx 1 light day. At such a speed it will travel about 1 light year every 18,000 years.

Then I like to say the nearest next start is roughly 4 light years away. So even at 17km per second, or about 10.5 miles per second, it will still take approx 72,000 years for it to reach the nearest star.

That star is 4 light years away and our galaxy is about 100,000 light years across. The next galaxy is about 2.5 million light years away!!! So at the incredible speeds of one of our fastest man made objects it would take something like 45 billion years to just get to the next galaxy!

Seeing how the known universe is estimated at over 46 billion light years in size and looking back on the other numbers I wrote it quickly becomes apparent that to travel across the galaxies one would need to be able to reach unbelievably unimaginable speeds. Even the speed of light as you mention would not be even close to fast enough to get anywhere significant.

On a side tangent I was always a trekie back in the day. I know their warp drive was faster then light but now I almost want to go back and look at the math of how fast they must have been going to be going the distances they were going.

watersb 4 days ago | parent | next [-]

> I almost want to go back and look at the math of how fast they must have been going

While there's a rough polynomial (v =~ c * w^3, I think) for post-TOS Star Trek warp factors, the only consistent rule: a starship travels at a velocity that helps tell a good story.

It's fun to try mapping Star Trek stories, anyway; it helps you ponder how much time they must have spent in transit. They have to find things to occupy their time.

14 4 days ago | parent [-]

Yes I think you are spot on, they move at the speed of how fast the plot needs them to move. After posting my comment and looking online at some suggested speeds for the various warps speeds it is very inconsistent and far from realistic given the size of the universe. One would need to be able to travel at something like 100,000 times the speed of light to realistically travel just around our galaxy. Probably would need to travel at about 1,000,000 times the speed of light wanting to make it to the next galaxy in a realistic time. Even at 1,000,000 times the speed of light it is going to take years to just reach the next galaxy so it is no where near fast enough to get around like they did in star trek.

But I absolutely loved the show growing up so not here to knock them. I am sure in hindsight they may have come up with a better definition of how warp speed works and how they can travel great distances. I won't think about it too much.

jl6 4 days ago | parent | prev | next [-]

It’s not that light speed is too slow, it’s that our lives are too short. If you can solve mortality, you just hop on board your 17km/s ship, turn YouTube on (all of it), and spend a relaxing 72,000 years getting to Alpha Centauri.

danielheath 4 days ago | parent | next [-]

If you accelerate at 1g half way there, then decelerate equally fast for the second half, you can reach almost any point in the galaxy in a single human lifespan - thanks to time dilation.

ozim 4 days ago | parent | next [-]

Obviously just don’t forget aiming for where we see it now is not where it is and not where it will be in 100 years.

I have never seen anyone writing about us having solid reference points to travel that far in case we can reach those speeds.

If you miss you end up in some empty space you won’t be able to mine anything for fuel to have more shots.

actionfromafar 3 days ago | parent [-]

Stuff keep moving predictably. Plus you can course correct during a fair bit of the acceleration / deceleration phase.

ben_w 4 days ago | parent | prev | next [-]

Just remember to account for blue-shifted CMB.

I'm not sure if the CMB itself will decay fast enough with the expansion of the universe to avoid 1g eventually getting you hull eroded by positron-electron pair production from photons blueshifted above 1022 keV, but that's in the set of things you need to think about.

Scarblac 4 days ago | parent | prev [-]

Is it possible to take enough fuel and mass with you to accelerate that long without turning into a black hole?

MichaelRo 4 days ago | parent | prev [-]

>> and spend a relaxing 72,000 years

This just shows a juvenile and naive level of thinking. You can't spend 72,000 years with our current brains in full conscience without going insane.

DonHopkins 4 days ago | parent | next [-]

I Hope I Shall Arrive Soon

https://en.wikipedia.org/wiki/I_Hope_I_Shall_Arrive_Soon

jl6 4 days ago | parent | prev | next [-]

> current brains

greenbit 4 days ago | parent | prev [-]

Are we nearly there yet?

MichaelRo 3 days ago | parent [-]

We live to 72 on average so only off by a factor of 1000x :)

Anarch157a 4 days ago | parent | prev [-]

That is assuming the objects will be at the same place relative to us, which is not true. Like reaching Andromeda. Voyager I will reach oyr neighbouring galaxy in roughly 4.5 billion years, not 45, that's because Androneda is moving in our direction. Reaching Proxima Centaury would take longer than your estimation because of it's orbit around Alpha Centauri A/B.

Estimating time-to-arrival when your destination is also moving at ludicrous speeds is incredibly difficult.