Questions tagged [velocity]
Questions regarding the movement of an object at a given speed and direction, often related to the concepts of orbital velocity and escape velocity.
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Calculating obital velocity from radial velocity
I'm not really a physicist so I don't know if it's possible to get the real orbital velocity of a star from its radial velocity. I'm working on a paper for school and I want to get the mean velocity ...
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How is interstellar gas density mapped from GAIA data?
I found the image below in Space.com's article This 3D Color Map of 1.7 Billion Stars in the Milky Way Is the Best Ever Made.
The caption for this image reads:
The Gaia spacecraft gathered ...
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Is there a rough analytical expression for the Milky Way's radial mass distribution?
I found the image below in Space.com's article This 3D Color Map of 1.7 Billion Stars in the Milky Way Is the Best Ever Made, although it is not the map mentioned in the title.
The caption for this ...
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How do I determine the velocity of Pluto at aphelion and perihelion?
I am a college astronomy student and I have to find the velocity of Pluto at aphelion and perihelion. I have found the distance of perihelion to be $1.96\times10^9$ km. Aphelion has a distance of $3....
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Why most planets don't spin retrograde? [duplicate]
Edit: just found duplicate
Since orbital velocity is greater on small orbits, and smaller on large orbits, why don't planets spin retrograde around their own axis?
One portion of planet's mass is ...
user16500
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Circular velocity in axisymmetrici potential [duplicate]
If a matter distribution is spherically symmetric, the circular velocity is straightforwardly related to the mass via:
$v_{circ} = \sqrt{GM/r}$
In an axisymmetric potential, on the other hand hand, ...
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Does Absolute Velocity Exist?
It seems everyone is on the same page about there being no "absolute velocity" due to the fact that everything is relativistic. However, this leaves me confused. This seems to be disconnected with the ...
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Question about doppler effect
We know that we can use Doppler effect to determine equatorial velocity of a planet. We send a electromagnetic wave with wavelength $\lambda_0$ to an equatorial edge of planet and we get wavelength $\...
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If velocity is relative, why mass (inertia) is increasing absolutely? [closed]
Would inertia not grow if we took out the reference frame?
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Which celestial object in the solar system has the fastest tangential velocity at its surface?
Consider all of the naturally-occurring objects in the solar system : in the reference frame of the object's center (ie, ignoring the orbital velocity around the sun or, in the case of satellites, ...
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What does the velocity dispersion of a galaxy mean?
Also, what is the advantage of getting information about the velocity dispersion of a galaxy?
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Why does the neutral hydrogen velocity have this characteristic behavior in the galactic plane?
The recently released map of galactic neutral hydrogen density and velocity is really beautiful. The work has been relased by the HI4PI collaboration (HI = neutral hydrogen, $4\pi$ = complete ...
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Why does Gaia use only calcium NIR lines for stellar radial velocity measurements?
I was reading this overview article about the Gaia spacecraft and I saw the following statement:
These spectra provide radial velocity information that are used to study the kinematic and dynamic ...
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What (actually) is the " deprojected half-light radius" of this almost-all-dark-matter Galaxy?
The recent news of the Ultra Diffuse Galaxy (UDG) Dragonfly 44 is an excellent example of what could be termed 'observe different' thinking. The dragonfly telescope is noted not for the size of its ...
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How to calculate a phase shift in the process of deriving Baade-Wesselinke distance?
The above is the equation used in the Baade-Wesselink method to independently get distances to Cepheid variables (in the process of deriving Period-Luminosity relation).
According to the paper New ...
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