Questions tagged [mass]

Questions regarding the property of astronomical objects that determines their inertial resistance and gravitational interaction with other bodies.

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34
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2answers
4k views

How was the mass of Venus determined?

The mass of Venus seems rather complicated to determine to me: Venus doesn't have any satellites, so you can't just apply Kepler's third law (like you would with Jupiter or Saturn for instance) to ...
26
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3answers
4k views

Is the sun's volume shrinking currently?

The Sun loses about 5.5 million tonnes of mass every second, does this mean Sun's volume is also going down? If so can we tell by how much every year? E: "by how much" I mean can we tell if ...
25
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1answer
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Why don't (or can't) stars be more than 325 or so times the mass of the sun? What limits their size?

Is there a particular reason why stars cannot grow as massive as they want to? And why doesn't this limit apply to supermassive black holes?
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4answers
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Is Jupiter made entirely out of gas?

I heard that Jupiter is made out of gas. But in school I learned that Jupiter has gravity which is 2.5 times that of Earth (Gravity that can tear apart a comet) and gravity is proportional to mass. ...
20
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1answer
3k views

Why are most discovered exoplanets heavier than Earth?

Looking at all discovered exoplanets (4393 exoplanets), I found than only 17 of them (less than one percent!) have masses less or equal to Earth's mass. Why so? Is it because it is very difficult to ...
20
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4answers
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Does a planet's mass or gravity affect the height of it's mountains?

According to this Wikipedia page, the top five highest mountains on Mars (and the highest on Venus) are all taller than Mount Everest (and Mauna Kea as measured from the ocean floor). Does a planet's ...
18
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1answer
5k views

Moon's unusual gravity

We know that the Moon's gravity is about one-sixth that of Earth. Then I recently read that the mass of the Moon is about one-eightieth the mass of Earth. Since gravity depends on the mass of the 2 ...
18
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6answers
14k views

What is the minimum mass required so that objects become spherical due to its own gravity?

Is this minimum mass known? or maybe, is it given in terms of density? If so, how much density is the minimum to have an spherical object due to its own gravity?
14
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1answer
191 views

Mechanisms of binary/multiple star formation

What are mechanisms of binary/multiple star formation in different mass ranges (low, intermediate and high stellar masses)?
13
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2answers
1k views

Mass of black holes compared to parent star

What is the range of percentage mass of parent star left in a stellar black hole directly after its formation? What factors determine this number for a specific case?
12
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1answer
1k views

Can dark matter be found in the shape of planets, galaxies etc.?

If dark matter has gravity just like normal matter, does that mean it can also form planets, solar systems and so on? Any answer will be appreciated.
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4answers
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Does the mass of the observable universe ever change?

First do we have anyway to even estimate the mass of the entire observable universe? And then is there any data that shows mass being gained or lost? Would we ever know if someone was playing with ...
10
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3answers
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How do we get to know the total mass of an atmosphere?

Since atmospheres don't end abruptly but gradually get thinner the higher you go, I wonder how we can get the total mass of an atmosphere if we don't know where exactly it ends. E.g. the Earth's ...
9
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3answers
949 views

Is there a flaw with the newer purposes and correlations attributed to the HR diagram? (And would a third axis of mass correct the enclosed flaw?)

When I was younger, I was looking at HR diagrams, and began to experiment with the HR diagram. I was looking at plotting different groups of stars on the HR diagram when I found RV Tauri stars. ...
9
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1answer
4k views

Are planets moving away from the sun?

I saw on the tv show Through the Wormhole (hosted by Morgan Freeman) that the planets in our solar system have been continuously moving away from the sun for millions of years. however, when I try to ...
9
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1answer
607 views

How is the total mass of all the Solar System's small asteroids and meteoroids estimated?

This diagram from wikipedia (shown below) graphs asteroid Diameter against Number of asteroids, for the Solar System. (Graphic is courtesy of the Marco Colombo, DensityDesign Research Lab). ...
9
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1answer
343 views

How can I measure the mass of eclipsing binary stars?

Is there any method to measure the mass of eclipsing binaries without using Doppler shift effect?
9
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2answers
2k views

Are there upper or lower mass limits for black holes?

Natarajan & Treister (2008) describes a practical upper limit for black hole masses at $\sim 10^{10} M_\odot$. This is all due to the black hole's interactions with nearby matter. However, is ...
8
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1answer
3k views

Size and mass of comet ATLAS (C/2019 Y4)

I read some news about this new comet and some unreliable sources said it is twice as big as Jupiter. I tried to find a reliable estimation of its size or mass, but I couldn't find anything. Would you ...
8
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2answers
283 views

Can "rogue" supermassive black holes be made this way?

Could two galaxies (one big and one small)intersect at a velocity to allow the smaller black hole to escape but not the galaxy around it?
8
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1answer
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Is there an upper limit to the mass of terrestrial planets?

The exoplanet Kepler-10c has a mass between 15 and 19 times the mass of the Earth (making it comparable in mass to Neptune), and yet is thought to have a density of about 7g/cm3 and to be a ...
7
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1answer
846 views

How are the masses of celestial bodies determined?

I was scrolling through the list of moons of Jupiter and I wondered how astronomers where able to determine the masses of those objects. When I tried to google it I meanly found results of people ...
6
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2answers
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Relation between black hole mass and radius, and our universe's [duplicate]

Is there a graph of known black holes, with their estimated mass in the X axis and their estimated radius in the Y axis? If so, where can we find it? I would like to know if a black whole with the ...
6
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4answers
5k views

What is the exact mass of the Sun?

I am having trouble finding data on this. So far, I have found at least seven values: ...
6
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1answer
236 views

Would gravitational waves be subject to external gravitational perturbations?

Given that the gravitational wave detected by LIGO was a very weak echo of a very distant event, could it have been "deviated" and distorted on its way here by a sufficiently massive black hole in ...
6
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2answers
880 views

Why does the Chandrasekhar limit affect white dwarfs differently?

The Chandrasekhar limit is the maximum mass of a stable white dwarf star. Beyond this, a carbon-oxygen white dwarf will typically explode in a type 1a supernova, due to the nuclear reactions at those ...
6
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2answers
84 views

Is there a way to calculate the mass of of a stellar remnant given the initial mass of the star?

Assume there is a star in a completely empty region of space, away from any outside influence. Is there a way to calculate the mass of a resulting stellar remnant, a white dwarf, neutron star, or ...
6
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1answer
129 views

Unbelievably high masses/ densities in NASA website data

In May, I did my own amateur analysis of Kepler data that was supplied here. This was a table of all confirmed "Kepler planets" to date (April 1, 2015). This table had some unbelievably high masses/...
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2answers
537 views

Weight of a celestial body

How do astronomers find out the correct weight of a planet even though there isn't any direct means to weigh them? What technique do they use? Just curious!
5
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2answers
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Are red dwarfs really 30-100 times our Sun's density?

This article by K. E. Edgeworth claims red dwarfs tend to be around 30-100 times our Sun's density. However, this seems a bit high. With smaller stars, mass tends to be proportional to radius but ...
5
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2answers
977 views

Why do certain massive stars leave no remnants?

Mass and metallicity are the two main determinants for a star's fate. This is simple enough. What's more complicated is how exactly these determine the star's fate. For example, you can see in this ...
5
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2answers
501 views

GW190521 black hole merger total mass calculation and missing mass, how does this happen?

I have just read an article about that black hole merge event (it's in Italian): Sette miliardi di anni fa, due mostri si unirono What made me curious is that the article tell that a 66 solar mass ...
5
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2answers
1k views

What's the mass of the interstellar neighborhood of the Sun?

What's approximatively the mass of the interstellar neighborhood of the Sun ? (for example the neighborhood of radius 50 light-years). Remark: The mass of the observable matter should be completed ...
5
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2answers
118 views

What is the (overall) half-mass radius of Milky Way

I am doing some simulation and I need the half-mass radius of Milky Way (total mass: including all objects, dark matter, nebula...), but I cannot find the value and I don't know how to calculate it. I ...
5
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2answers
249 views

What type of star does theory predict should be the most massive?

The most massive known stars are Wolf-Rayet stars. However, as Wolf-Rayet stars do not appear to be the first stage of any star's lifecycle, I infer that whatever these Wolf-Rayet stars used to be ...
5
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1answer
745 views

Why is metallicity important in the death of stars?

I always thought that mass was the sole determinant of a star's fate. Then I saw the table here. So why does metallicity influence a star's ability to become a black hole or neutron star? Does it have ...
5
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1answer
528 views

From what distance can one object influence gravity of another object?

Each object in the universe has its own gravitational influence on all other objects in the universe. What distance do they have to be from each other to create only one gravitational influence? ...
5
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1answer
7k views

How do star densities work?

If we take a look at stars more massive than the Sun, their densities vary a lot. UY Scuti is an extremely low-density star that's only 8.5x more massive than the Sun, but is 1000-2000x its size. ...
4
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1answer
782 views

Stellar mass limits for Neutron Star and Black Holes

Don't hate on me if I am asking a very basic and straightforward thing. I have a few questions about black holes and neutron stars. What is the mass range (in terms of solar masses) for a main ...
4
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1answer
645 views

Why the Sun-Jupiter barycentre is outside Sun?

The Earth-Moon barycentre is said to be inside Earth. But Moon-Earth mass ratio (1.2%) is larger than Jupiter-Sun mass ratio (0.09%). Then how come the Jupiter-Sun barycentre is outside the surface of ...
4
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1answer
63 views

Relation between molecular cloud mass and galactic mass

Would it be true to assume that the mass of a galaxy is approximately the mass of all molecular clouds detected within it, let's say, through CO observations and then converted to H$_2$?
4
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1answer
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How do I create a galaxy stellar mass function?

Suppose that I have an array of stellar masses of tens of thousands of galaxies, and that I also already know what the total "survey volume" is (in Mpc^3) within which all of those galaxies are ...
4
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2answers
303 views

How much more massive would Pluto have to be to clear its neighborhood?

How much more massive would Pluto have to be to clear its neighborhood?
4
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1answer
523 views

What type of energy is escaping from black-hole's poles?

Following this article, it is stated that: As a star drifts too close to a supermassive black hole, intense tidal stresses rip the star to shreds. As this happens, the shredded material will ...
4
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1answer
1k views

Sum of the Masses of All Moons in the Solar System

I'm looking for the total mass of the moons in the solar system in Earth Mass this would be include the 67's moons of jupiter, the 62's of saturn, the 27's Uranus and the 14's for Neptune. it's a ...
4
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2answers
165 views

Galactic mass estimation from apparent magnitude and distance

Can we estimate the order of the total mass of any galaxy from the apparent magnitude and its distance to us? Just like \begin{equation} M_{galaxy}=c\times 10^{8}M_{\odot }, \end{equation} where $c$ ...
4
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2answers
118 views

Is it true that we can estimate the mass of a star more accurately if it has a companion star?

I remember I hear a theory that if a star has a companion star, we can know the mass of the star more easily, is that true? if it is true, while I understand that by measuring the period of the ...
4
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1answer
130 views

If we've only observed Oumuamua as a single pixel, how can we know its shape?

On a separate Oumuamua question (Oumuamua alien space junk?), I was confused how shape could be inferred from a single pixel, per another user's (@Uwe) comment. It was suggested I ask this question ...
4
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1answer
317 views

How would I define mass in a space

I always heard that mass is a measure of inertia during my school days. Is this applicable to bodies which are in space ? Suppose there is space craft in a space; how would I define mass ? I read ...
4
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1answer
88 views

How can I estimate the M/L ratio from a fitted SED on a galaxy?

This answer (here in the forum) provides background to my question: https://astronomy.stackexchange.com/a/5953 I am trying to understand the process in which a stellar population synthesis (SPS) is ...