sevenperforce

They won't accept it because they want the treadmill to accelerate to hundreds of gees.

All rocket failures (excluding sabotage) are due to poor design.

Perhaps a glider built around a Mk1 cockpit?

The Soviet moonshot failed because the N-1 failed, and the N-1 failed because the N-1's first stage failed, and the N-1's first stage failed (over and over and over again) because it was a rush job with untestable engines and a poor control computer.

You don't need a launch window if you can hang out waiting for an alignment indefinitely. Launch from Woomerang east-south-east, so that you'll reach the equator roughly as you reach initial apoapsis, then circularize until you get a nice high orbit. Wait there until you get a transfer window line up, then burn the rest of the way.

Let's see here. I fire the two decouplers to drop the command pod and free the axle, then start pushing W to rotate the whole assembly. The axle uses a triple-nested structural tube with matching caps for maintaining alignment. I get it going as fast as I can (it won't show surface-relative speed because the CoM isn't really moving)... ...then "Leave Seat". But drag is high. And I glide for a while: But not quite to the island. At all.

Good question. However, inclination change in cislunar space is really really cheap, dv-wise. So this probably wasn't the big deal.

Familiar: https://www.insidescience.org/news/every-black-hole-contains-new-universe

Using a rather large electromagnetic trebuchet I can get up to around 380 m, which is nowhere near high enough.

Presumably no.

I wonder if I could trebuchet a Kerbal high enough to chute himself to the island.

Also, is solid fuel allowed? Because if solid fuel is allowed then this becomes super easy.

I like it! Are there any rules limiting behemoths? Otherwise it just ends up being "biggest vehicle wins". What about multiple launches?

What about building a massive tomb/temple complex shaped like the waterman map projection, with reinforced foundations exactly tracing the shapes of the continents?

Both very good ideas. I think the major challenge to these ideas is that you do not necessarily know how you will die, and so you cannot guarantee the circumstances of your burial. Unless, of course, you commit suicide at the height of your power; that'll do it. Plus, it depends on the particular item not being looted, and on being found. Looters are no respecter of locale; even if you have no valuables stored around your sarcophagus, looters may still crack it open and look inside, just in case. You're also taking a large gamble on the idea that someone will actually eventually crack it open. Hence the general goal being more toward "what can I create that will last and carry my knowledge?" As I said before, though, if pi had been calculated to a high degree of certainty thousands of years ago, we could also suspect that the whole of mathematics would have charted a different path, and so the conclusion would be that such series were discovered in antiquity. Hah!!

You realize they didn't know about irrationals back then... Like, 1 million is really unneeded. Well, we know that, but the archaeologists of the alternate future (alternate present?) would simply conclude that irrationals were discovered much earlier.

Who made this?!

Circles on the left depict the relative masses of the 14 heaviest elementary particles. The three smallest particles (pulled out in the row on the upper right) are the electron, the up quark, and the down quark. Up quark and down quark combine on the second row to form a neutron and proton. Electrons, neutrons, and protons combine on the third row to form H1 and O16. Hydrogen and oxygen combine in the bottom right to form H2O. If someone recognized it, it would be far, far beyond any possibility of coincidence. I'd like to see that. Here: Bonus if you can actually carve out spheres depicting the general topography/appearance of the planets and their moons. Hard to be sure that will last, though. Let's say you can take back a Kindle with a solar panel attached to the back, carrying on it text-only versions of all the pages on Wikipedia. All you need to build an AC generator is a windmill, magnets, and copper wire. The former is simple enough; the latter two......not so much. That's why it has to be simple enough that everyone will see it and look at it and examine it. The other option is to give the ancients something they CAN understand, but in far greater detail than they would be able to know at the time. Like detailed topographical reliefs of portions of the globe. They'd recognize that it's a map, and preserve it for that use, but future archaeologists would see that it was something they couldn't have figured out on their own. You need signposts like a detailed map to get people thinking "how did they know that?" and subsequently looking more closely at some of your other inscriptions. If they recognize you're drawing Mars and not a fantasy world. Someone will steal it. And even if they don't, the conclusion will be "Wow, they must have figured out a way to calculate many digits of pi using some expansion we haven't yet discovered! Probably with a bunch of mathematicians working in parallel!"

Your envelope is correct. Although apparently I cannot spell schwarzschild.

One of my tattoos is a spiral galaxy wrapping around the schwarzschild radius of Earth with arcs representing the masses of the major elementary particles.

Foundations will remain. If the following inscription can be made a spear-length deep in granite, it ought to survive. And anyone who has any sort of knowledge of physics will pick up on it.

Yes, the point of the thread is to figure out how to pass a message on to the future. But apparently some people also thought the "how would one rise to power?" question was equally interesting, and the rest was history. More canister than grapeshot. You can pack it with stones, nails, whatever. Compound bows are challenging because they require carefully machined cams that must withstand tremendous forces. Machined pig iron might be good enough to build compound bow cams but I'm not sure. Anything weaker than pig iron is a complete non-starter. If you have sufficient historical knowledge, you don't even have to do the scouting. You should translate these magic terms to the archaeologists. Otherwise they, as usually, will explain to everybody that this is a magic inscription, and your lab is obviously a temple (because what else it could be?). If you do a big complex with the inscriptions in the center of the temple, then they will be studied and published and someone will realize it's unique. Especially if the rest of the monolith complex has obvious advanced knowledge encoded in it. Yeah, maps would be readily recognizable, and maps that show the whole globe would be obviously non-ancient.

"Technology is infrastructure" is the truest thing on this thread so far. That's why the actual Connecticut Yankee is so preposterous. There are a lot of advances to be had in the realm of agriculture. Irrigation (e.g. water screws) and planting cycles and crop density. You can't manage industrialized farming, of course, but you can move in that general direction. On the military side of things, you can readily build seige engines with exploding projectiles. A wagon-mounted trebuchet that can accurately lob grapeshot into tight enemy formations well behind the front line would turn the tide of literally any pitched battle before the 1500s. The biggest challenge, of course, is to not die before you learn the language. And on the subject of actually leaving something for the future..... All this depends on your inscriptions lasting, and not being looted/sacked/destroyed. What is the most advanced (and obviously non-coincidental) idea that could be expressed with something as simple as the stonehenge? Well, WW2 would never happen. Nuclear weapons and moon landings might, but the details would be different. Trying to think how I'd engrave that on a blank sheet without using an established language. Even a list of planets and moons within our solar system points beyond ancient tech.

Not to mention pumping fluid in microgravity.

The Rosetta Stone idea also runs into the question of legitimacy. Even if the stone survives, is found, and is decoded, how do future archaeologists know that it is truly the writing of a time traveler and not just a proto-science-fiction novel written by a particularly inventive pharaoh? This question was inspired by all the "ancient aliens" and "Golden ratio" nonsense out there...I started wondering what actually WOULD be considered valid evidence of advanced scientific knowledge in the ancient world.