Right now, there are only three things limiting how far our spacecrafts can take us in the Universe: the resources we devote to it, the constraints of our existing technology, and the laws of physics. If we were willing to devote more resources to it as a society, we have the technological know-how right now to take human beings to any of the known planets or moons within the Solar System, but not to any objects in the Oort cloud or beyond. Crewed space travel to another star system, at least with the technology we have today, is still a dream for future generations.

But if we could develop superior technology — nuclear-powered rockets, fusion technology, matter-antimatter annihilation, or even dark matter-based fuel — the only limits would be the laws of physics. Sure, if physics works as we understand it today, traversable wormholes might not be in the cards. We might not be able to fold space or achieve warp drive. And the limitations of Einstein’s relativity, preventing us from teleporting or traveling faster than light, might not ever be overcome. Even without invoking any new physics, we’d be able to travel surprisingly far in the Universe, reaching any object presently less than 18 billion light-years away. Here’s how we’d get there.

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