32

Observe the star, particularly its spin. That will tell you where the debris disk (planets) are most likely to be. The star's equator is likely to be close to the plane of the debris disk. Jump to a spot well above/below the expected debris disk. Mask out the star's light. Take a 6-hour photographic exposure (or equivalent). The lines (not dots) on the ...


23

Frame Challenge It's not a ship that would find a planet, it's an observatory. Keep Watching the Skies Right now, we've found 4 341 planets outside our solar system, and we've only barely sent one space ship outside of same. Even with many space ships, people wouldn't be sending ships to go find planets. Even in Star Trek, stellar cartography is mostly ...


10

As mentioned by jdunlop, the question is not about detecting the planet. What follows from that is that a mapped but not yet visited planet is no better or worse for hiding than an unmapped planet. It fact, if there are a limited number of agencies doing most scouting (the Galactic Patrol or the Scout Service), a little insider info might yield a planet that ...


8

Per this source (https://phys.org/news/2019-09-fast-universe-mystery.html) the universe is expanding at between 70 and 90 km/s/megaparsec. With the middle value being 82. A rocket, even a perfect one, is limited by the rocket equation: dv = ve (mo/mf) Substitute c for ve, and dv of 0.3c has an mf / mo of 74%. Just on the acceleration. Squared to include ...


7

Doable yes. Practical? Probably not. Assuming you have a spherical propellant tank filled with a fluid type of fuel, you don't actually need to turn the whole contents of the fuel tank, just the fuel tank itself. So, if your main body is only ~5% of your mass and your tank is ~5% of your mass, and your fuel is ~90% of you mass, then on a rigid bodied ship, ...


5

We don't know, and probably wont till someone dies after returning... So there's two extremes to this, and I'm going to start by laying out the extremes: Extreme 1 - Worst case: They're unfit / unhealthy to begin with. They're diet is missing vitamins and minerals. They do no exercise the entire time they're away. They're not under any medical observation ...


5

There is plenty on this stack about space beasts. Maybe I will link up some of my favorites. But first - ideas about vacuum dwellers! Not boil. Liquids under vacuum boil away. These creatures must be able to close any aperture connecting any wet areas with the outside environment. They will have impermeable waxy exoskeletons covering everything. That is ...


4

Navigating around the star and planets could be done simply with optics. They would be able to compute their polar coordinates very accurately with respect to the local star by observing the star's new location relative to the background stars after each warp. They would also be able to easily use the inverse square law to compute their new relative ...


3

A meteorite impact broke the earth's magnetic field, and made space uninhabitable. Meteorite impacts can reverse the earth's magnetic field. A large collision could do this, and also leave enough debris in space that travel up was very complicated. In addition, the meteorite could have enough mass and enough oxidixable material that it notably depleted the ...


3

Part One of Four: Assuming relatively realistic and probable space travel. Assuming that humans will eventually be able to build spacecraft that can accelerate to speeds of 0.001 to 0.1 of the speed of light, and decelerate at the end of their voyages, it should take those spacecraft about 10 to 1,000 years to travel one light year. Assuming that humans can ...


3

Your aliens stumbled onto a cache left by someone else. They simply know how to use what they have but have no understanding of either how it works or how to replace what they have if something breaks.


3

Setting aside that different models have just different approximation level of reality and there is no totally wrong one or totally right one, it's perfectly that case already with the theories we have developed so far. Take the Copernican model of the Universe vs the Ptolemaic model. A civilization using the first one would have no practical advantage ...


2

Even if it is possible, it won't happen; since the astronaut was in a space pod, his or her suit probably wasn't designed for re-entry. A space suit strong enough to withstand re-entry would be so bulky and reinforced, it might as well be a small spaceship. Of course, the odds that this astronaut survived the pod explosion to begin with are, shall we say, ...


2

Adding to what M. A. Golding and GrumpyYoungMan said, there's reasonable reason to believe that we'll never even leave Earth, let alone colonize space. If you're talking about exploring the entire universe we could set up a sleeper ship with a theoretical total conversion rocket and just go in any one direction, but the thing about colonizing space (as well ...


2

If the ship is moving, then the fuel inside the tank is moving as well, with the same speed as the ship so you can't just change it's course without cost. You will probably save a bit of thrust as you will be able to precisely place the thruster on the best angle to achieve the best trajectory to a new course. But what you save is very small compared to the ...


2

It's an innate physical skill. Imagine that humans encountered a species without eyes. They had developed cameras and every manner of sophisticated AI pattern recognition. If we lost a crewman somewhere on the Moon, we could never look over photos of the entire surface fast enough to find her. But the aliens could run our satellite feed through their ...


2

I don't see what's the advantage of this design. For most of their travel spaceships simply coast without any propulsion, they don't really drive around like cars looking for a parking spot in downtown on a Friday evening. In those times crawling around would not help. And for those times when a maneuver is needed, the tank will need to be accelerated anyway,...


2

I remember a nice bit from the (marvellous) book Mining the Sky, by John S. Lewis. There were studies in how to reduce dependency on goods launched from Earth and closing as many resource cycles with in situ lunar resources. A significant part of lunar regolith is made of ilmenite, mainly containing, among other more minor (albeit valuable) things, titanium, ...


2

I see 4 ways this could happen: The inherited / found / trade their tech. They dont know how to build their own ships because they are not the builders. Perhaps the ships (and training) were delivered as part of a trade deal. This is totally plausible and has real world parallels; Australia cant build an F-35 fighter jet but we've arranged through diplomacy ...


2

Tether/Skyhook systems First, I advise you watch this video. A Skyhook or tether system is broadly what we describe as a "momentum exchange system" in space travel. The concept is simple: a spacecraft is sped up by slowing something else down, however, the thing being slowed down has orders of magnitude more mass than the spacecraft meaning that ...


1

Vacuumorph: This has already been done, in the book Man After Man. It has a protective shell, pressure-sealed eyes, and highly flexible limbs with a crazy grip. In this case, it is described as being a genetically-engineered and sterile (on it's own) species, but I don't see why it would have to be. While it would be extremely awkward in gravity, I don't see ...


1

If they must live long time in the void of space, they must be able to hybernate and have some kind of symbiosis with photosynthetic organisms It is safe to decide that a space dwelling humanoid should have no lungs and breathing system. They would be useless, plus would expose to the vacuum a lot of mucose and thin bllod vessels. Heat should not be a ...


1

I have a few comments. One) Rockets operate more efficiently in a vacuum than in an atmosphere. Two) Without a magnetnosphere the solar wind would strip away air particles from Earth's atmopshere. But very slowly, over millions and billions of years, a time span much longer than the time span of your story. The planet Venus has a very weak magnetosphere ...


1

You can only control what you can directly see. The simplest example is a stage director. The director calls start, stop, and the details in-between. He (or she) judges what the performers do or don’t do. And, if the actors are not providing what the director wants, he (or she) can call security to have them removed. This scales to star empires. If ...


1

One way to find out how habitable an exomoon might be is to look up scientific discussions of of hyopthetical exomoon habitability. I suggest that you read my answer to the question: https://worldbuilding.stackexchange.com/questions/199555/how-bright-is-night-on-a-moon-orbiting-a-gas-giant/199585#199585[1] It cites a number of scientific articles discussing ...


1

As @jdunlop and @Hobbamok noted, current telescopes can detect extrasolar planets quite well. I disagree with Hobbamok that having the planet's orbital axis be pole-on toward the observer would be enough to hide the planet. There's another way however. Dark nebulae Paraphrasing Wikipedia, a dark nebula is dense enough to absorb light from beyond it. So a ...


1

Flip it and make humans the ones who specialize in practical models Human understanding of physics is already geared far more around practicality than reality. The Scientific Method does not actually care about truth, it just cares about things being repeated often enough to get a less than random pattern. Therefore any theory derived from the Scientific ...


1

Go biology instead (with a nod to Harry Harrison's West of Eden) Have them selectively bred organisms (and even themselves) without understanding the micro science behind it. A bird doesn't know calculus or physics to do their intense aerodynamics. (at least we don't think so) Their abstract thinking could be more purposeful rather than explanatory. They ...


1

Stereoscopic view of the system, and triangulation. Arrive in the system. Take one high-resolution optical image of the system. Jump in any direction by a distance of a few AU, not directly towards or away from the sun(s). Take a second high-resolution optical image of the system. The difference between the two images are the suns, planets, moons, and larger ...


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