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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Satellite slew rate with respect to a ground station [closed]
For a given satellite orbit and observation time, I have the vectors containing the elevation and azimuth angles of the satellite with respect to a ground station.
I know that the elevation slew rate ...
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Determining the speed of meteor
How to determine the velocity of a meteor from two video data?
I want to try to determine the orbit of the meteor, but before that I have to determine the meteor's entry velocity and apparent radiant ...
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Does the escape velocity formula take into account how a gravitationally bound object's distance to its primary increases before coming back down?
Confusing title, I know. Imagine a perfect, homogenous sphere with an exact radius of $1,000 \text{km}$ and an exact mass of $8 \times 10^{15} \text{kg} $.
If you use the formula for escape velocity $...
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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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The preferred way of binning (classifying) data for galaxy snapshots in Python
Let's say I have a galaxy snapshot that I load with some package (pynbody etc) and I store my spatial coordinates of stars in the galaxy in x, y, z arrays and also velocity in array vz. Now I want to ...
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Deriving the Tully-Fisher relation from the virial theorem
So I know this is a loose proof and a lot of assumptions are made, but I do not understand how these assumptions lead to the quantities we obtain so I will be asking questions at each step:
start with ...
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Can a planet with no atmosphere be orbited at extremely low altitudes?
Can a planet that has absolutely no atmosphere be orbited by a spacecraft at extremely low "altitudes" (if you'd even call it altitude at such a low orbit.
For instance, if this planet's ...
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How are CMB frame redshifts of galaxies corrected for coherent flows?
Say, if I downloaded the CMB frame redshifts of some galaxies from NED database, then what is the procedure to correct it for coherent flows?
I'm using the SNooPy(snpy) Python package to analyze some ...
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How to determine the mass of a galaxy?
I am having a slight disagreement with my professor.
We can measure the mass of a distant star cluster from:
A.Its color
B.Its radius
C.Its metallicity
D.Smearing of lines in its total spectrum
My ...
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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 orbital velocity of binary star?
I am trying to simulate the Alpha Centauri AB System. I built the simulation, it works flawlessly when trying to simulate our solar system, and I am now trying to simulate the AB System. I found all ...
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How long is the sunrise (or sunset) on North (or South) Pole? [duplicate]
I wonder how to calculate the duration of the Sun crossing the line of the horizon on equinox on Pole. For equator I used this formula:
$t = \frac{2 \times p}{\cos(\phi) \times u}$, where $u$ - is ...
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How to find x-values of fourier-transformed correlation functions in velocity space?
I am trying to extract the kinematic parameters (rotation velocity, velocity dispersion, ...) of an elliptical galaxy by extracting the kinematical broadening function using the FCQ-Algortihm first ...
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How to calculate mean line of sight velocity of stars after rotation of galaxy?
I am trying to calculate the mean line of sight velocity from a simulation snapshot of a galaxy after the galaxy is inclined by a certain angle, theta. I am coding it in python.
What I have done so ...
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Why does light accelerate instantaneously to c, while no other phenomena do it? [closed]
In physics, it always takes some time for a particle to move from rest to some speed.
However, photons (light particles) accelerate instantly from zero to c. How? (A visualization would be helpful.)
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