Questions tagged [astrophysics]

For questions regarding the application of the laws of physics to orbital mechanics, stellar evolution, and other astronomical processes and celestial bodies.

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3answers
171 views

Could the electrical charge of a black hole neutralize it's gravitational pull?

It's well-known that gravity is the weakest of the 4 fundamental forces. With this knowledge, would it be possible to cancel out the gravitational forces of a black hole with it's charge? Say a black ...
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62 views

Relative masses of Binary Systems

I'm writing a sci-fi novel and I have an some astrophysics questions. First, is it possible for a binary system to be made up of a large gaseous planet and a dwarf star? I know it's possible to have ...
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Where should I place my Earth-like planet within my binary system?

I am working on a RPG setting which requires my planet having a nearby flare star. I understand from reading through other, similar questions and from doing some research, that flare stars are ...
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2answers
118 views

Days with a torus shaped Sun

What would day and night look like on Earth (or any habitable planet), if the sun was torus shaped, with the same circumference? And moreover, how much the Earth will be affected, if the sun was ...
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1answer
88 views

Two celestial bodies tidal locked - not with the sun

I tried to do my homework and actually thanks to this question and answer, I found myself to this site. But I just found more questions :) Basically the setting would be close to what Earth - Moon is, ...
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178 views

Is delta v relevant for interstellar travel for generation ship?

Imagine I have a generation ship that is heading to a nearby star system say 10 light years away, the average lifespan for the crew is 150 years on Earth and is expected to increase by about 5 years ...
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1answer
91 views

How Far In Advance Could People See A 100-1500 Meter Earth Bound Impactor Before It Hit

How much advanced notice would we likely have in advance of an Earth bound impactor with a place of origin outside Earth's orbit (e.g. a meteor, asteroid, comet, space debris that doesn't rotate ...
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1answer
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What Size and Likelihood Of An ET Impact Would Destroy A Small County Sized Region But Not Our Species?

Motivation The question is inspired by the astronomy journal preprint released publicly today, entitled: From impact refugees to deterritorialized states: foresighting extreme legal-policy cases in ...
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348 views

Time scale and mechanism to “realistically” remove Sol from the Milky Way

What is the fastest rate a star could be flung out of our galaxy and by what mechanism(s)? (i.e. from a gravity kick by a hypothetical passing hypervelocity black hole) Secondary question: how far ...
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131 views

How could a human with infinite strength crash a planet into earth

A bad guy was kicked off earth and lands on another planet or dwarf planet. He has magical powers that let him have as much physical power as he needs to accomplish his goals. He is also extremely ...
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1answer
249 views

How big can a whirligig/planetcake get while still maintaining human-survivable gravity at its equator?

A whirligig/planetcake/whatever punny name you want for it is a super-sized planet (we're talking about Jupiter masses here, not Earth masses) that spins so quickly that it's shaped like a pancake (...
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324 views

What would the local effects/affects be of a ring spinning near luminal velocity?

To better solicit more inline with what I'm trying to imagine, I'm editing my question, the original question is left below and removing the hard science tag, as that just seemed to cause issues, ...
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Moon hit strong enough to put it in a slow spin?

I’m building a world nearly equal to earth; i need a catastrophic event that make the moon start spinning breaking the tidal lock, a really slow spin, like 500 years for a full spin. i thought about a ...
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Aliens pressure cook the Solar System, do we notice?

550 million years ago, aliens erected a spherical barrier 1/6th of a light-year (~10,000 AU) in radius around the solar system, centered on the solar barycenter. Things outside the barrier can enter, ...
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263 views

Enlightening Dark Matter?

As an ironic twist, I wanted a story in which dark matter is actually caused by light. Somehow, the physics of light cause it to create the appearance of the existence of dark matter. But I'm not a ...
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50 views

Would a gigantic meteor impact in the Strait of Gibraltar create a peak-ring crater, or at least a complex one?

Background: A peak-ring crater is a sub-type of complex crater (an impact crater in which the impact wave rebounded from the rim of the crater and pushed up a mountain in the middle) where, instead ...
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Would a meteor blowing up the Strait of Gibraltar 2 million years ago kill all of humanity's ancestor species?

Let's say that, 2 million years prior to the present day, a meteor impacts roughly in the middle of the Strait of Gibraltar. It is large enough and strikes at sufficient velocity to create an impact ...
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279 views

Effects of magic on stellar evolution

I believe it'd be foolish to assume that magic wouldn't affect astronomical phenomena like stellar evolution, But since I'm not smart enough to create the equations for a new fundamental force, I have ...
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1answer
155 views

What would happen if a planet gradually lost mass?

The idea I have is to have a planet that, at its core, has a being that gradually eats away at the planet's substance and converts it into massive amounts of energy (think matter-antimatter ...
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2answers
235 views

Estimating thrust and kg fuel for a generation ship's journey to Alpha Centauri

Premise: A generation spaceship leaves Earth around the year 2060 on a journey to colonize Alpha Centauri A (ACA). In this fiction, fusion power is achieved in 2040, improved over 20 years, and used ...
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448 views

What would be the structural impact of an oscillating orbit on a planet?

Notice : If you wish to know how to make an oscillating orbit with real-world physics, you can looky-look at this question which is following mine. My question focuses on the consequences of such ...
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1answer
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Could a planet about 30% larger than earth but only 80% as dense still support a strong magnetosphere?

I've been trying to work out a few calculations for a planet I am working on and hit a bit of a roadblock. The planet in it's current state is 1.35x the size of Earth, but in order to get a density ...
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107 views

Monoreactant pathway for electrical power and thrust using only hydrogen?

In Space Engineers, Hydrogen is employed as a fuel for both propulsion and for electrical power (via the Hydrogen Thruster and Hydrogen Engine, respectively). This feels unrealistic to me, and I am ...
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Seeking good physical candidates for total collapse of the universe we live in

Bringing this question over from Physics SE where it was closed: I'm looking for an 'as close to our understanding of current physics' doomsday scenario that results from something about the physics ...
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1answer
203 views

It would be possible to enter and exit a black hole using a Warp Drive? [closed]

Well, a Warp Drive expands and contracts space, passing it through you, technically allowing faster than light travel. And so, it would be possible to actually enter a black hole and thus, exit it? I ...
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115 views

How Much Solar Wind Does A Star Produce?

I need someone to give me a way to figure out how fast the solar wind from a star with a known mass travels, as well as how much solar wind the star releases in a given amount of time. I hope that it ...
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86 views

Predict The Orbital Eccentricity Of A Planet In A Circumbinary Orbit

Okay, I have a planet smaller than Earth that has a mean orbital radius of .9 AU, and it orbits twin suns. The larger sun has a mass of 1.15 solar masses, and the smaller sun has an mass of .45 solar ...
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How would the reflection of sunlight change the day / night cycle of a binary planet system?

I am thinking of setting a story in a binary planet system, but am unsure what mechanics would be at play in regards to the reflection of light off of one planet and the day/night cycle. In this story,...
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332 views

What would a neutron star look like up close to the human eye?

I suspect it would look something like the black hole Gargantua in Interstellar, but instead of a dark center, it would be glowing, like a star? It would still produce gravitational lensing and bend ...
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How much sugar and potassium nitrate I would need to make a rocket reach the moon? [closed]

I know the question itself is kinda crazy, but a rocket need a fuel and a oxidiser to work. And in this case, the oxidiser is potassium nitrate. Well, in this video, this guy makes a homemade rocket ...
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Could a ion thruster work in atmosphere with enough energy?

Well, some days ago I watched a video talking about the Halo transport ship "Pelican", which uses nuclear fusion turbines (don't worry, this question isn't about Halo). And technically, ...
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Influence of an inner gas giant over a solar system

I'm designing a solar system with three planets in its hot zone, two in its cold zone and three in its habitable zone. All of the planets are rocky worlds of various sizes, except for the middle world ...
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Which space bodies have helium-3 besides the moon? [closed]

There is a certain attention given to the moon in order to use its helium-3 to supply nuclear fusion on earth. But there is some problems involving energy there that concerns me. A day on the moon is ...
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Would it be possible to make a black hole using the Bose-Einstein condensate?

Well, my crazy question is whether it would be possible to make a "dyson sphere", but with the sonic black hole made with Bose-Einstein condensate (and whether it would be possible to create ...
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3answers
94 views

Can periodic gravitational tug and pull of binary star ensure that a planet stays extremely tectonically active?

There's a binary star system with a close pair of stars ( A1 V and G2 V), in which there's a rough analogue of our Mercury that orbits both of them - a planet that's supposed to be closest to the pair ...
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Would it be possible to mine the metallic hydrogen from jupiter with our current technology? [duplicate]

Simply put, metallic hydrogen is obtained at absurd atmospheric pressures, becoming a stable liquid with very interesting properties. As a super conductor or simply the most efficient fuel that ...
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1answer
92 views

Using the densest galactic superclusters motion to see a universal structure or motion

My alien species has their science and observation based on our current understandings and observations, they have an observabe universe of the same distance as ours they have noticed the structure ...
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313 views

Can a super-Earth of Approximately 1.5 Earth-Radius and 3.0 Earth-Mass Be Habitable?

Can a super-Earth of approximately 1.5 Earth-radius and 3.0 Earth-mass be habitable? By habitable, I mean terrestrial with liquid water on its surface, a rocky ocean floor, and no thick hydrogen/...
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What are reasonable densities for terrestrial planets?

Earth's density is about 5.51 g/cm^3 and it's the highest density in the Solar System of a terrestrial planet. I understand that planet density is partially determined by various factors, including ...
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2answers
739 views

Could a planet's tidal forces break an asteroid passing very close to it?

I want a certain asteroid of my system to break into pieces as it approaches a planet, having one fragment impact the planet itself, another fragment slingshot and impact the planet's moon and the ...
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Earth is accelerated out of the solar system - do we keep the Moon?

I've been reading about stellar engines. The Wikipedia article on them says this about the acceleration they could provide to a star: Such thrust and acceleration would be very slight, but such a ...
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1answer
98 views

Could a habitable gas giant with an electropshere exist?

So, there are several questions on this site about gas giants. In particular, I am mostly building off of this one: Could a gas giant with layer similar to Earth atmosphere exist? This question seems ...
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Detecting an escaping Earth

Suppose that, some day, for reasons, the Earth is mysteriously accelerated prograde until it reaches escape velocity. It then starts a trajectory that will take it off of the solar system. It might ...
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A 1 kilometre wide sphere of U-235 appears in an orbit around our planet. What happens?

Let's suppose that after seeing aliens get portrayed negatively in science fiction and wishing to end the discrimination, the ancient H'andh'wh'a'vians decide to destroy Earth and humanity. As they ...
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1answer
110 views

Could a "super-Enceladus" moon exist?

Firstly, let us define the term "Super-Enceladus". In the context of this question, a "Super-Enceladus" is a moon that has permanent or near-permanent polar jets spewing out matter ...
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What are realistic numbers for the engineering/physics for a mag-lev train which would circumnavigate the entire planet earth?

Suppose that you were writing a science-fiction novel (or movie script). In the story, a giant magnetic-levitation (mag-lev) train encircles the entire planet earth. The ring-shaped train track is ...
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4answers
384 views

What If A Positively-Charged and a Negatively-Charged Planet Collided?

Let's say we have two planets. Both are around the same mass and radius as Earth, and are 1 year away from colliding with each other, each traveling at 20 km/s. At first. Planet 1 has a sufficient ...
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Making A Geosynchronous Orbit Impossible

Here's the idea: A geosynchronous orbit is an orbit that makes sure that the orbiting satellite is always above the same spot on the planet, so its orbital period is equal to a local day there. I've ...
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The Orbit Of Cryomoreth

Cryomoreth is the homeworld of the Cryomonians. Its year lasts for about 273.15 Earth years, and it is inhabitable for carbon-based life. Its orbit is very eccentric, which results in its seasons. ...
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Sigelon's Terrible Neighborhood

Sigelon is a mountainous world that's volcanically-active due to pass-bys with an larger neighboring planet that has a more eccentric orbit. These volcanoes release enough soot and smog to ...