First images from Euclid are in

The actual problem is that we were made early enough to begin to understand the full scale of it, but we're still not mature enough to go out there and explore it. Therefore, you can reason that now is the right time to get behind anything that pushes us beyond the Earth.

These distances are well outside the scope of exploration. Getting to the next solar system is already a seemingly insurmountable challenge. Getting to the next galaxy? Forget it. Getting to these galaxies we see in the picture? Absolutely no way. I know people like to be optimistic about these things but it's honestly pure wishful thinking.

Once we have fusion reactors, it won't be.

Your fusion reactor will still take a while to travel 420 million light-years.

This is short-sighted. Maybe not in our lifetimes. If it were 1902, you'd probably be mocking the Wright brothers.

Fusion reactors won't really help. Sure, you can accelerate indefinitely - but only at maybe 1G or a bit more if you don't want to kill the occupants. Then you have to flip and decelerate. Unless we find a way to freeze/stasis people, the limits are still shockingly small.

We'd need to start cracking some kind of jumping/FTL/etc technology to have any hope of real exploration.

No, I wouldn't be. The speed of light is a much more fundamental limitation than anything we have ever seen before. It's probably the single most fundamental and most sure fact that we know of, besides perhaps the quantum nature of reality.

And I have heard it all before: worm holes, warp drive, etc pp. A fun exercise, but not rooted in reality at all.

All you can do is to appeal to completely unknown, unimaginable magical breakthroughs, which are inherently difficult to discuss, so I don't think this will be very fruitful.

There are three levels of difficulty in innovation: New Engineering, New Science, and New Fundamentals.

What the Wright Brothers did was the easiest of the three: New engineering. It didn't contradict anything then known in accepted science.

Fusion energy is being studied now, and it's substantially more difficult than what the Wright brothers did because it requires New Science. But it doesn't violate any of the accepted fundamentals of the universe, so it will probably happen eventually.

Now we come to the most difficult of the three: New Fundamentals. Traveling to other galaxies falls in this category. For it to work we would have to discover some brand new principle that makes the universe work, and that principle would need to be so radical that it makes what we now know about the laws of physics wrong.

That's not likely to happen. By comparison, the Wright brothers' invention was for all practical purposes inevitable; people had been flying heavier-than-air craft like gliders and kites for hundreds of years. All that was needed was an energy-dense power plant.

Well... you don't need to freeze people if you can travel at a substantial fraction of c, because of time dilation.

Caveats:

1. It's really, really hard to supply enough energy to go that fast, even with fusion power.

2. Your passengers won't be able to go home again, because by the time they get back everyone they've ever known will be long dead.

3. Even if you could go that fast, you'll eventually hit a speck of dust and disintegrate.

IF you believe the whistleblowers, all the tech already exists.

https://www.pbs.org/newshour/politics/watch-live-house-overs...

Since we don't observe any sign of anyone else explore it, or even broadcast themselves through it, it might be that it's not possible to explore it.

Well, fortunately, our rock-solid science has some major holes to be patched. There's no way to guess what consequences those will have to our understanding of what we're limited to exploring.

> 3. Even if you could go that fast, you'll eventually hit a speck of dust and disintegrate.

Can you elaborate on that? Do you mean if we clash with anything (even as small as a space dust) while traveling at a substantial fraction of c, it would disintegrate us?

Or maybe it's due to the Dark Forest theory (https://en.wikipedia.org/wiki/Dark_forest_hypothesis#:~:text....)

F=ma

At 1% the speed of light (approx 3000000 m/s) and a medium-mass dust (1x10-5 kg, stationary), not enough force or area to dent steel (350 N/mm^2), but over time, lots of dust could cause erosion (quick math/estimates).

It would cause damage. The faster you go, the worse is the damage. Even just the cosmic microwave background will eventually turn into dangerous gamma radiation, so you will need heavy lead shields in the front, which makes traveling even more expensive and difficult. At certain speeds, you should think of your spaceship as a drill penetrating the inter galactic medium. And even then the journey will take millions or billions of years (in the reference frame of those staying at home).

   There are three levels of difficulty in innovation: 
   New Engineering, New Science, and New Fundamentals.

Wow, I've never seen this put so succinctly before.

While the claims of the whistleblowers may or may not be true, your link is sworn Congressional testimony from credible sources.

So, despite the stigma attached to all things UAP/UFO, I think it should be upvoted and not downvoted.

The relevant equation is for kinetic energy, which is 0.5mv^2. Using your numbers that's about 4.5E+7 Joules, or the energy of about 10kG of TNT exploding. That will certainly make a dent, and your space ship won't survive many of those.

I was thinking v would be more like 10% of c, which would mean about 1000kG (1 kiloton) of TNT, or about 1/20 of the energy of the Hiroshima atomic bomb. From a particle of dust weighing 10mG. You'd be toast.

Accelerating indefinitely with reaction drive is impossible. You have to take fuel along, and then fuel to accelarate that fuel. The rocket equation means that get quickly get enormous numbers. Like you have to take Jupiter along for fuel.

"Completely unknown" is the main point here. I don't think categorical statements make sense when they are based only on what we know.

The Wright brothers seem like a poor example. But consider the slowing down of time near mass, the tunnel effect, superconductors, super fluids... There are many examples of things that make absolutely no sense in the context of older theories. I don't think our theories are the final ones just because we can explain most things that we have observed so far.

Sure I find it hard to imagine how individuals could travel to another galaxy, absent something like usable wormholes. But some kind of giant world moving through space over the span of millions of years, why not?

The point of these discussions is not to find the correct answer about what will happen. It's just fun to dream and imagine the possibilities, precisely because nobody has the answer (and certainly not those who pretend to know what's possible).