Questions tagged [hard-science]

Requires answers backed up by equations, empirical evidence, scientific papers, other citations, etc. Contrast with: science-based and reality-check tags. This tag should never be the only tag on a question because this tag frames how a question should be answered, not the topic. Review the tag info before using this tag, and flag your question for moderator attention once posted to have the hard-science notice added.

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60
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16answers
11k views

Stealth in Space: How realistic is it?

This has been considered other places on the net, but I thought it would be good for the hard-science challenge, since it is often an example of the subtle difference between soft and hard science. ...
2
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2answers
228 views

Pocket Clarketech

Background: In the year 2204, humans have colonized most of the inner solar system. During the first explorations of the vast outer system, a team of researchers uncovers a series of alien artifacts. ...
3
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1answer
97 views

Dystopian Future | Moon Destroyed What Would Our World Look Like in 500 years? [duplicate]

This question came to me after reading this question on the Astronomy Page, and having a length discussion with colleagues about the 2002 movie "The Time Machine". As a result I am looking for hard-...
3
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1answer
107 views

How do I determine whether hybridization would be possible between various creatures? [on hold]

I ask because the world I'm building has eight distinct races of humans on one planet, as well as various non-human animals that don't currently exist in the real world. I'd like for some forms of ...
-3
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1answer
101 views

How to calculate time to reach fractions of the speed of light when accelerating at 1g

Currently writing a scifi novel and am trying to do the math to establish time frame of the lore. The main points are that in 2068 CE Earth sent a generation ship to colonize Proxima Centauri. They ...
3
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3answers
392 views

Aliens blew up Pluto so we would stop debating whether or not to call it a planet, what happens to Earth? [closed]

It seems the Fraxians, an alien race from Alpha Centuri, have been secretly watching our television ever since we started broadcasting it (well technically I suppose 4.367 years after we started ...
26
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12answers
2k views

How can spacecraft manufactured on the moon be powered?

Background: The moon has been selected as the base for human space exploration. Rather than ship tonnes of material out of earth's gravity well, interplanetary spacecraft and space stations will be ...
10
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15answers
3k views

Natural Armour and Weapons

In my fantasy world, the magic system pretty much makes metal armour and weapons obsolete. The magic system's specifics aren't important, just note that the magic system allows the users to 'penetrate'...
4
votes
1answer
198 views

Steam-powered organ

Today I visited a two hours long organ concert (man, it was amazing) and weird idea have popped up in my head: organ powered by steam instead of pressurized air. This also made me thinking that it ...
8
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3answers
228 views

What gases could be present in a viable atmosphere for humans?

I'm working on a story involving humans looking for another habitable planet, and I have been scouring the net for days, finding lots of info on varying levels of oxygen and nitrogen, but none that ...
7
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4answers
208 views

Is this atmospheric composition breathable on a planet with 50% more surface pressure?

I've read all the related questions on here and as far as I can tell this should be breathable on my planet Liskuel, which has 1.5 bars of pressure. However, I'm really bad at maths and don't really ...
0
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0answers
64 views

If there's a human-level civilization in a nearby star system, would we detect it? [duplicate]

So, I'm not into writing or creating any new worlds, but this question (or a set of questions) was bothering me for a while and I thought it's a good place to ask. If there exists an alien ...
8
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5answers
340 views

Can early astronomers determine the gravity of their planet's “moon” without ever going there?

As I was thinking about space flight for my world, I thought about how they would need to know a planet's gravitational force before they could land, and found that humans figured out the moon's ...
4
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4answers
96 views

Requirements for melting snow from orbit using EM radiation

My (your) goal is to melt several tons of snow and ice in a small area using electromagnetic radiation beamed down from a spacecraft in orbit. The atmosphere that's in the way is vaguely Earth-like ...
4
votes
1answer
123 views

How much of our solar system can you change without breaking the science of life on earth? [closed]

I am making a near-future setting that takes place in an alternate solar system that's similar to ours (one planet with life, a moon, and other planets without life and their associated moons). And ...
6
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1answer
208 views

What are the effects of a nearby supernova on a young solar system?

I'm building a S-Type binary system where the primary star is a black hole. Yet the system formed as a O + K-Spectral class binary and the 20 solar-mass O giant went nova 2,7 myr after both the stars ...
11
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2answers
186 views

Rogue Planet Illuminated by Galactic Centre

The black hole question reminded me of an idea I wanted to implement at some point in a space campaign, but didn't go forward with because I was unsure whether it's merely statistically very ...
6
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6answers
727 views

How would the US re-conquer a Moon Base?

The year is 2030. The US has set up a moon base with about 2,000 people. The base can theoretically survive indefinitely, growing its own food and 3D-printing supplies, but in practice it needs ...
49
votes
7answers
10k views

Can I use a trebuchet to launch satellites into space from a lunar colony?

I've got a lunar colony that struggles to obtain resources, so they're looking for ways to launch satellites into orbit without using up a bunch of rocket fuel. One plucky engineer has suggested ...
8
votes
4answers
388 views

What's the largest an Earth-like planet can be and support Earth's biosphere?

For certain reasons I decided to not set my story on Earth. However, the planet is meant to host an Earth-like biosphere (including humans, most of Earth's species (perhaps some that didn't evolve ...
5
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0answers
58 views

Relationship between Ocean Gases and Atmospheric Gases [closed]

A version of this question is posted in Chemistry SE but doesn't seem to be getting traction there. Perhaps this SE is a bette place for this question? If you think it belongs on a different SE please ...
8
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2answers
306 views

How would a rail gun affect the trajectory of a spacecraft?

What sort of force would a railgun need to produce to have a measurable affect on the trajectory of a large spacecraft? In the scifi book I am working on the primary craft of the story is a military ...
9
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2answers
409 views

What is the theoretical maximum number of habitable planets in one solar system?

In the DC comic book universe, the Vega System is a solar system around the star Vega (Alpha Lyrae), which is depicted as having dozens of habitable planets. While it seems to be an implausibly large ...
102
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10answers
10k views

Would planets be cubic in my “cuboverse”?

Summary The main idea behind the "cuboverse" is that spacetime distances are measured by (something close to) the sup norm or infinity norm. Under this norm, spheres (the set of points at a fixed ...
11
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2answers
2k views

Could a planet have a naturally occuring moon at one of its Lagrange points?

Would it be possible for a planet to naturally have a moon or large natural satellite at one of its Lagrange points? If so would it then also be able to have a second moon that would be orbiting this ...
5
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2answers
306 views

A universe without light?

In the story Wang's Carpets (and part of the novel Diaspora), Greg Egan sketchily describes a high-dimensional universe which contains no analog for light, such that the aliens who inhabit this ...
13
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2answers
602 views

How Efficient Could Anaerobic Megafauna Be?

Obviously, if available, atmospheric oxygen is a great source of energy. However, I'm surely not the first worldbuilder who wants an alien species which doesn't depend on it (whether due to having ...
44
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0answers
1k views

How soon can the first stars form?

Introduction In our universe, the cosmic microwave background was formed approximately 400,000 years after the Big Bang. It was hot, but within a few million years after the Big Bang, it would no ...
1
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0answers
114 views

Can a system of 10 planets be stable if star is not on the main sequence?

My star is 2.17 Solar masses. For narrative purposes, I decided this so it will collapse in the theoretical Quark star. Could such a big star that isn't on the main sequence (Because its an A type, ...
0
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0answers
79 views

What is the largest amount of natural satellites (with a Hill sphere H1) that can be placed in orbit around a planet with a hill sphere H2? [on hold]

(If possible, please answer this as a function of the radii of both Hill spheres) Additional requirement: All celestial bodies in this scenario have to have a stable surface and the setup has to be ...
29
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7answers
2k views

How do ballistic trajectories work in a rotating cylinder world?

For the sake of fixing some image in your mind, imagine you want to practice some sport in a rotating cylinder world: whether it be launching a javelin, strike a tee at the golf club or scoring a 3 ...
10
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4answers
665 views

Life on the Broken Ring - an issue of size

One of my ongoing projects is what I think of as the "constructed worlds gallery", a series of Megastructures as settings for stories and games, including things like the "Flying Pie-plate" a world ...
5
votes
2answers
193 views

External ATP Synthesiser Plausibility

Assume a civilisation with futuristically advanced knowledge of biochemistry. Assume it wants to develop a cybernetic device meant to facilitate the organism's ability to perform high-power activities ...
11
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8answers
3k views

Low-tech inertial dampener options

As mentioned in this discussion: How to keep humans pilots instead of AI in sci-fi future? the ability to handle G forces is a limiting factor on what pilots can do. Some of my solutions to address ...
5
votes
1answer
229 views

Black hole stardrives/artificial gravity [closed]

I'm a sci-fi world builder, and I was recently reading Charles Stross's sci-fi/space opera novel Singularity Sky for inspiration, and I noticed some interesting but scientifically dubious ...
9
votes
7answers
995 views

What near-future propulsion system(s) could be employed by my spaceships?

In a near future setting I am working on, humans have built space-habitats and have established colonies on celestial objects such as Luna. Their spaceships cannot go faster-than-light and have their ...
9
votes
4answers
490 views

Crop production in mountains?

Would potato- or grain-like crops be able to flourish in northern alpine regions? There's a lot to be said about the Andeans, but the have the benefit of living near the equator that other ...
5
votes
1answer
147 views

How many terrestrial moons can my planet hold?

I have a Gas Giant with 13x the mass of Jupiter. How many satellites of Earth size and mass can it hold safely in its orbit? Edit: This gas giant lies smack dab in the middle of its parent star's (...
3
votes
3answers
2k views

If Mars contains coal, will it become a dominant source of energy?

In the year 2099 A.D, humans made a major discovery. There is a rich source of fossil fuel buried beneath layers of Martian soil. It is estimated that the coal deposit that was discovered could fill ...
31
votes
9answers
5k views

How useful would a hydroelectric power plant be in the post-apocalypse world?

The details don't matter, just that a large fraction of people have died (let's say 90%) and society has completely collapsed. It's only a year or two later, and people have started to gather ...
11
votes
2answers
471 views

Body plan of a 4D human-analog?

I am attempting to design aliens that live in a universe with a 4+1 space-time--i.e., a universe with four orthogonal spatial dimensions, rather than three, in addition to a fifth time dimension. In ...
7
votes
1answer
303 views

Brown Dwarf Star vs Gas Giant as parent for habitable moon

I seek to build a habitable moon of a giant planet, thus I looked at the Rouche Limit Equation to figure out how to get the biggest possible Hill Sphere for my moon to exist in. $r_H = a(1-e)\sqrt[3]{...
5
votes
3answers
345 views

Mega-human: What are the largest possible dimensions of a human? [duplicate]

How big can a person be while retaining all the functions of all their organs (including bones)? I am wondering if it is possible for large people to exist without compromising some part of their ...
13
votes
1answer
245 views

What would happen to air flow and fires in an O'Neill cylinder?

I was curious: Suppose we built an O'Neill cylinder with an air mixture similar to Earth's (not pure oxygen). Does the air also get "thrown" down towards the floor of an O'Neill cylinder? If I ...
37
votes
5answers
7k views

Can a planet survive a supernova?

The Sun has nowhere near enough mass to enter the branch of stellar evolution that would lead to a supernova, fortunately for us. However, there are planets that orbit stars that are destined to go ...
4
votes
4answers
280 views

How can I measure the distance between two stars? [closed]

So I am doing a write-up for a world setting set in our galaxy. I know the distance from Earth to the different stars in Light Years. However I am now trying to figure out how to measure the distance ...
82
votes
19answers
18k views

Would a 'World Tree' be feasible in real life?

A livescience.com article claims that trees can reach a theoretical height of 400 to 426 feet (122 to 130m). This is due to the tree being unable to carry water up to the top at that certain point due ...
14
votes
3answers
245 views

How to calculate the loss of primordial heat for a given age and mass of a planet?

I´m working on a computer program which generates realistic planets for worldbuilding purposes. I´ve run into an issue with calculating my planets heat loss. While radiogenic and tidal heat generation ...
63
votes
21answers
17k views

Is it possible to kill all life on Earth?

Edit: It has been suggested that my question is a duplicate of What could humans do to render the earth uninhabitable?. That question only asks what would be necessary to make human life ...
4
votes
2answers
220 views

A Dozen Cubic Miles of Volcanic Ash--How Big Would the Cloud Be?

On May 18, 1980, Mount Saint Helens made American history with an eruption that took 57 human lives and killed thousands of animals. It has released only a quarter of a cubic mile of ash, but it is ...