Questions tagged [gravity]

Questions regarding the attractive force which exists between any two bodies of matter.

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5
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1answer
44 views

How could a captured asteroid enter a circularized orbit?

Ok, the simple answer would be through gravity assists from moons, taking a ballistic capture orbit into a circular orbit. I am wondering the chances of a ballistic orbit becoming a stable (on the ...
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2answers
122 views

Is gravity affected by time dilation? [closed]

I just thought about what time realy is but I can't put my head around this so I was thinking that if time dilation happens at the edge of a black hole that just everything gets slower. But does ...
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1answer
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What is the best visual-aide model that most accurately depicts objects moving through warped spacetime?

so far, the best model I've seen, to help me visualize objects moving through a warped spacetime is this video... A new way to visualize General Relativity. Is there a better visual representation to ...
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Density and Velocity profiles of a self gravitating explosion

Suppose an asteroid explodes, into a spherically symmetrical cloud, of radius R, mass M, and surface receding velocity V (normal to the edge of the cloud), initially the density is radially uniform. ...
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How much mass to make a shperical object?

I was googling around for info for D&D campaign I am going to run. I was wondering about the mass required for a object to pull itself into a shperical shape and it seems that the answer varies ...
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1answer
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Is a black hole's gravity strongest at its event horizon or at least near it?

I know black holes are extraordinarily powerful when it comes to the gravitational pull. But I wanted to get something clarified - is the gravity stronger at the event horizon (like, on the very edge ...
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2answers
2k views

Is there a better formula for gravitation, besides Newton's?

Many experiments (e.g. changes in Mercury's orbit) show that Newton's Law of Gravity is not exact. According to the theory of relativity, what is the exact formula?
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1answer
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Gravitational influence of other planets?

I have a friend who believes in astrology and she insists that the gravitational influence of the planets has an effect on the child when it's born. The last time she was going on about this a thought ...
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2answers
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How slow would you age on a double gravity planet?

How slow would you age on a double gravity planet? Gravity of the planet A is 10 units. If you are taken from planet A to planet B where gravity is double that of A, i.e. 20 units. How slowly would ...
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1answer
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Does the Barycenter shift/combine when 2 planets line up with the sun?

On August 1st-2nd, Earth & Saturn lined up together in relation to the sun. Here is a website that discusses it: https://www.healththoroughfare.com/science/saturn-will-line-up-with-earth-and-the-...
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Why do gravitational waves travel "only" at the speed of light but the gravitational scalar potential is instantaneous?

To my old Space SE question Besides retarded gravitation, anything else to worry about when calculating MU69's orbit from scratch? @DavidHammen's excellent answer replies that one should not add a ...
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1answer
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Is it "nonsense to even talk about" objects outside the observable universe not having gravitational influence on us? (finite speed of gravity)

In this supplemental answer to Is the zero gravity experienced in ISS the “artificial” kind? in Space Exploration SE I said: Gravity moves at the speed of light so nothing outside out observable ...
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microwave background radiation and dark matter

Does the microwave background radiation predict the presence of a large proportion of dark matter over normal matter a few seconds after the Big Bang, or now? Is it possible that there isn't much dark ...
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2answers
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Is a Hertz ratio to 65M ☉ proof that Betelgeuse had a core collapse in 1491 from a gravitational wave on January 14, 2020? [closed]

By analysis of gravity waves GW150914 to S200114f when compared to a ratio from the Black Hole merger of 65 M ☉ at 260 Hz with Betelgeuse frequency of 64.698303 Hz the gravitational release on January ...
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2answers
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What if Earth gained 1 km/s orbital velocity?

How would Earth's orbit be affected if we (hypothetically) added $1 {\rm km/s}$ to its orbital velocity? Would Earth reach close to Mars' orbit? Could Earth get gravitational assist from Mars and go ...
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1answer
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Which A. M. Fridman is the author of this paper on gravitational stability?

Is this paper on globular cluster stability still up to date? links to The Stability of Globular Clusters and Spherical Galaxies. by A. M. Fridman of the: Institude of Nuclear Physics, Siberian ...
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Is this paper on globular cluster stability still up to date?

I'm looking to better understand the stability of globular clusters for an n-body dynamical simulation, specifically with respect to initial data conditions. I know that the total potential energy ...
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3answers
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What would I experience on a planet orbiting close to a black hole? [closed]

I can't get my head around it completely. I am standing on an Earth-sized planet circling a black hole. Let's assume the planet to be an incompressible one. It is observable that matter is sucked in ...
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4answers
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Why doesn't the Sun wobble towards Jupiter instead of away from Jupiter?

This is the page I am referring to. It seems counterintuitive to me that the Sun should be on the opposite side of the barycenter's wobble. I realize I am wrong, but I cannot see why I am wrong. Can ...
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3answers
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Gravitational time dilation

Did clocks run more slowly in the early universe due to gravitational time dilation? Or, alternatively, do they appear to be running more slowly when observed from today, if that is not the same thing?...
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3answers
1k views

Can a small black hole orbit a large star?

I recently read about the discovery of a tiny black hole (with only three times the mass of the sun) nicknamed ‘The unicorn’ about 1500 light years from earth. This got me thinking, can this black ...
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8answers
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Are there places in the Universe without gravity?

Not sure if that is possible as I couldn't find an answer about it. Are there places in the Universe where there are no gravitational forces?
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3answers
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Was there a formula-first hypothesis for gravity?

Being a mathematician I wonder, has there been an attempt to blindly approximate a formula for gravitational attraction that would match the data, based on "normal" matter we can see plus ...
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2answers
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Gravity of a gaseous planet without a core

Both Jupiter and Saturn have rocky cores. Is there such of a thing as a gaseous planet without a core? And would a planet without a core have gravity?
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1answer
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Can two neighboring galaxies move apart at steady speed?

While I was trying to understand the three models that obey Friedmann's two assumptions of a non-static universe, I came across a line that says and I quote "It (referring to Big Bang) starts at ...
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4answers
164 views

If a black hole has the same mass as me, then why dont i suck everything at my center of mass?

So, a black hole is very dense that you can get really close to its center of mass that it has a strong pull, well, if i have the mass of a black hole that has a really small event horizon, why doesnt ...
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4answers
191 views

Gravity inside a star?

Recently, I answered this question and need some clarification regarding the gravity when within the radius of a star. I thought that, when something is inside a star (ignoring drag), it will ...
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1answer
110 views

If a black hole has a mass similar to a star, why does it have a different gravitational pull?

Say there is a black hole with 1 solar mass, having the sun's mass, it would have the same gravity as the sun, right? But it still has an event horizon, so why does it have such a strong gravitational ...
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Accretion disk formation

Why a mass transfer in a binary star system, from the less dense star to the denser star forms an accretion disk? Why the material does not fall directly to the denserstar?
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Calculating the radial tidal amplitude on a planet from the fluid Love numbers

How do you calculate tidal amplitudes from the fluid Love numbers? In my course on planetary physics I saw an approximate expression for the displacement from equilibrium tide: $$\Big|\frac{V_T}{g}\...
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3answers
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Is there anything different about the gravitation around a non-spinning black hole and a neutron star of the same mass?

If we perform a simple experiment by orbiting identical spacecraft around a non-rotating black hole and a non-rotating neutron star of equal mass at a "safe" distance, and ignore differences ...
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4answers
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Can Newton's gravity equation explain why black holes are so strong?

I was just wondering why black hole's gravitational forces are so powerful. I know it's usually explained by Einstein's relativity which states that when an object becomes infinitely dense (a compact ...
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0answers
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Moon cycles used for gardening & harvesting

I appreciate that this question may deviate from the standard astronomy questions. I have recently read an article that suggest that gardeners, farmers & winemakers etc sometime use the moon's ...
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3answers
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Is the measurement of distance and position of remote celestial bodies accurate?

Considering that light is affected by gravity, how accurate are measurements of distant stars and galaxies? When light passes through objects with great mass, such as Jupiter size planets, stars, or ...
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0answers
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Is the measurement of distance and position of far away objects accurate? [duplicate]

Considering that light is affected by gravity, how accurate are our measurements of distant stars and galaxies? When light passes through objects with great mass, such as Jupiter size planets, or ...
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1answer
2k views

Does bending of light around the Sun depend on the wavelength?

If the energy of light is high, does its curvature differ from that of low-energy light around the Sun? In other words, if the wavelength of the light is shorter than another wavelength of light, then ...
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0answers
91 views

I have a scientific paper on gravity, how do I publish it, and will my research benefit me? [closed]

I read a lot about gravity and discovered a hole in it, and I want to publish that hole, but I am not good at mathematics. To show that gap, what should I do? Should I use Newton's equations which are ...
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1answer
40 views

Is there a way to estimate or calculate the tidal range induced on a water-bearing planet?

Consider a system in which a central star is orbited by a planet with liquid water oceans, which is itself orbited by a moon. Given the masses and distances between these three objects, is there some ...
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3answers
721 views

Computing the rate of orbital decay

We know that the estimated time until a binary system merges is given by: $$\dfrac{5c^5r^4}{256G^3(m_1m_2)(m_1+m_2)}$$ But what is the formula to determine rate of decay, in some sort of distance unit,...
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2answers
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A comet orbits the Sun in the same plane as Earth's orbit

If the Earth around the Sun follows a practically circular orbit of radius equal to one astronomical unit, determine its orbital speed in astronomical units per year. If the Earth around the Sun ...
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1answer
110 views

Can air/gas be slowed down by friction [closed]

Can wind/air that is moving at average speeds be slowed down by the cause of Friction? Also, Can Air bubbles in water be slowed down because of Friction? Please cite your sources.
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1answer
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This article says the moon may start moving closer to the Earth in the distant future; could this be true?

Bruce Dorminey wrote an article for Forbes with the title of "Earth And Moon May Be On Long-Term Collision Course". The article notes: "For now, our anomalously large Moon is spinning ...
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How spaghettification is possible at the Event Horizon of a supermassive black hole?

if gravity is too strong then it will break a object apart as gravity is strong enough to break the chemical composition of object why we consider "Spaghettification" relevant in this case ?
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If the Sun disappeared, could some planets form a new orbital system?

If the sun were to suddenly disappear, the planets would continue to travel tangentially to their former orbits. (This I know from this answer to a somewhat related question here.) In such a scenario, ...
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1answer
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Orbital decay via gravitational emission in a hypothetical, two-body universe

Assume we have a universe with nothing in it except for two objects. One of them is a stationary object that is perfectly spherical with the mass of the Moon (without any atmosphere, of course; also, ...
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1answer
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How do pressure, temperature, and gravity affect a smaller body than Earth with the same bulk composition?

Earth has a density of about ${\rm 5.513 ~g/cm^3}$ with one Earth radius and one $g$. Venus, a very similar planet to Earth and likely with about the same bulk composition, has a density of about ${\...
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2answers
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How much lighter would someone be on the Jupiter-facing side of Io?

Io is the Galilean moon closest to Jupiter. Its average surface gravity is 0.183g and it has a tidal lock with Jupiter. So if you stood on the near side of Io at the equator, how much lighter would ...
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1answer
60 views

In 'Modified gravity' theories like MOND, are galaxies and stars actually, slowly accelerating? In the normal sense?

In the Modified Theory of Newtonian Gravity or MOND, they say that massive objects, accelerating slowly, experience this modified gravity. But are they actually gaining in velocity, albeit very slowly?...
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1answer
140 views

Will there be any more planets come into our solar system and make it their "home"?

Could we have more planets come into our system and get trapped by our suns gravitational field and rotate?
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New evidence against the existence of dark matter?

I've just read and heard about an article which gives new evidence for MOND - Modified Newtonian Dynamics, which is an alternative to dark matter by proposing that our gravitational law should be ...

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