Questions tagged [fundamental-astronomy]
Questions involving reference frames, time scales, and how they are determined. Not for general Astronomy 101 questions.
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How long would a day be in an earth like - same size and all - planet but with double earth's orbit in time
I'm a writer, so I apologize in advance.
On an earth like planet with and orbit double to ours in days, how long would days be?
My planet would take aproximately 672 earth days to orbit around it's ...
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What is value of charge by mass ratio (q/m) for a spherical micro charged particle with surface potential 6 volts in S.I units and in e/amu units?
In Liu and Ip (2014),The Astrophysical Journal, 786:34 (8pp), the value of q/m is derived as follows :
"for a dust grain with radius 'a', from $\phi = \frac{4\pi q}{\varepsilon_0 a}$ we have $\...
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How is Earth's Rotation Angle (ERA) defined and measured
UTC typically ticks with TAI. But to keep UTC from drifting far from the rotation angle of the Earth we occasionally add leap seconds to ensure that UTC does not drift too far from the UT1 timescale. ...
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LSR and peculiar motion corrections to RAVE survey velocities
I am working towards getting a bunch of halo stars in our galaxy for my thesis. I am doing this with the help of a Toomre diagram and I am stuck. I am using the RAVE survey in conjunction with Gaia as ...
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On what basis is the information about the distance and velocity of the Voyager probes determined?
Voyager 1 was the first-ever object to reach interstellar space on
August 25, 2012 when it passed beyond the sun’s realm of plasma
influence (the heliosphere)[...]
(source)
Although some of their ...
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How does Polaris remain constant for millennia if the earth is spinning, orbiting and traveling with the galaxy? [duplicate]
Look at Polaris. Understand heliocentric theory and then reason.
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What is a "fundamental location", and why is Mosting A defined as one for the moon?
The crater Mosting A was chosen to be the "fundamental location" for the Moon's coordinate system (latitude and longitude). But what exactly is a "fundamental location"? What does ...
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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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How can the IAU 2000A vs IAU 2000B nutation comparison be reproduced?
I am attempting to plot how the IAU 2000A nutation model degrades as its terms are omitted. As a spot-check, I decided to compare it to IAU 2000B, which includes only the 77 most important lunisolar ...
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Have there been studies of "old photons" to see just how constant things like Planck constant has been?
The question Are photons aged? and answers therein have got me thinking:
I vaguely remember hearing something about experiments where "old photons" were collected by large telescopes from very ...
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Difference between J2000, FK5 and ICRS coordinate systems? Which one does the Yale Bright Star Catalog use?
I have no background in astronomy. I have been wanting to write code to make star charts for a given location and time, which led to this question.
I figured out that I would need to convert the ...
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Why do astronomers use the equatorial coordinate system that moves, instead of one based on fixed, distant stars?
As an outsider to the field, I am surprised to learn that astronomers commonly use the equatorial coordinate system, in which fixed stars are not actually fixed.
Isn't that making life harder than it ...
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Is TDB monotonic? Does it or any of its derivatives have yearly discontinuities with respect to an atomic clock?
This in-depth answer mentions that
...TDB is updated every year. As technology improves, these subtle updates change the timing of past events.
This makes me wonder...
Does this updating result ...
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evaluate solar eclipse Besselian elements? [closed]
I found this NASA website which says that to predict eclipse, we should solve the Besselian elements ..what does this mean, how can I solve for Besselian elements? Is there a numerical method? I need ...
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Can a magnetic field of an object be stronger than its gravity?
Can a planet, star or otherwise have a magnetic field that is stronger or have more range than its gravity?
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How Did Early Astronomers Measure Distances?
Prior to the era of radar and other forms of radio/RF/EM ranging, what approaches, methods, and techniques did early astronomers (e.g., Kepler, Cassini, Copernicus) use to measure the distance(s) from ...
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Question on dec 2013 answer to"How to measure the altitude and azimuth of a star?"
I am looking at your response to the above question. You stated:
For Northern Hemisphere, a star that is crossing the North local meridian (that is, between the Zenith and the North Horizon) the ...
user28084
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Basis of color index
As an amateur astronomer for 60 years and always as interested in the science as in the observing, I thought I had a pretty good understanding of the fundamentals. But I'm distance-auditing a third-...
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How to determine the eccentricity, knowing the orbital speed and distance
How to determine the orbital eccentricity of a planet, knowing the instantaneous orbital speed of it and the distance from the Sun to the planet at that moment?
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Does any asteroid we have ever seen have a hot core like earth.?
I was wondering if any of the asteroids we have ever seen has a hot core like Earth's.
I'm thinking that Earth has a strong gravitational field and so formation would have involved a lot of ...
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Making sense of the lomb-scargle periodogram
I am trying to use the periodogram to tell when a signal is periodic or not by following the tutorial for the astropy Lomb-scargle periodogram here.
http://docs.astropy.org/en/stable/stats/...
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How to calculate declination of Moon?
Is there any way to calculate declination of Moon for any day?I'll subtract inclination of Earth on the ecliptic from the result. I'll get Moon's the shortest angular distance from Sun.
Thanks for all ...
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Why the more-luminous star has larger surface area when two stars have the same temperature?
If two stars have the same temperature but one is more luminous than
the other, the more-luminous star must have a larger surface area, and
therefore a larger radius than the dimmer star.
The ...
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What do the months and hours mean in Tomas Filsinger's Map of The Universe
I have had one of these in my room for decades:
I don't have the booklet that seems to usually come with it, can someone explain to me what the months (with days below it) and hours mean? I imagine ...
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Do interstellar asteroids decelerate and eventually stop?
I do wonder, do interstellar asteroids eventually stop at one point in space after they gradually decelerate (or) even do they decelerate?
Though there is no air like on earth and thus asteroids ...
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What does half-lit means?
Aristarchus estimated the relative distance of the Sun and Moon by
observing the angle between the Sun and the Moon (α in the diagram)
when the Moon is exactly half lit. Angle β must be 90° for ...
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Necessary steps to calculate photon's path by using null geodesic equation
Can anyone please give me an explanation on how to calculate photon's path by using the null geodesic equation? N.B. I know all of the non-zero values of Christoffel symbols.
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Luminosities and Apparent Brightness of Two Stars of which one is 8 times the distance of the first star [duplicate]
Suppose two stars have the same apparent brightness, but one star is 8 times further away than the other. What is the ratio of their luminosities? Which one is more luminous, the closer or the further ...
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The Luminosity of two stars with same brightness but at different PC away
Stars A and B are both equally bright as seen from Earth, but A is 120 pc away while B is 24 pc away. Which star has the greater luminosity? How many times brighter is it?
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Why do most of the myths behind constellations originate from Greek? [closed]
Why do most of the myths regarding constellations happen to have begun from Greek civilization? Why not other civilizations?
Most people who lived in the past era probably observed star patterns in ...
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Simulating Noise in Astronomical Images
I want to add realistic noise to a simulated image but I am a little confused about the process. I want to have some Gaussian random noise representing the readout noise and to also add Poisson noise ...
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Any ideas for an astronomy + ML project? [closed]
I wish to do an astronomy related project which incorporates machine learning.Do you have any suggestions?
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How to find the radius of a satellite not knowing the mass
If I know the semi-major axis, the density of the planet, and orbital period.. how can I find the radius of the satellite? I can't think of any formula to use.
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How strong are the stellar flares on YZ Ceti?
Doing research for a game and trying to understand the implications of the stellar flares from YZ Ceti. In short (ignoring the planets for now), if people were to build large space stations of various ...
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What liquids can be found in the void space?
Is there any material natural or otherwise a free floating liquid that can exist in space?
https://space.stackexchange.com/questions/32274/what-liquids-last-the-longest-in-space
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What was the length of the solar day 73 million years ago?
How could this be estimated, or how accurately could it be extrapolated from a present-day measurement of the Earth's spin-down rate?
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Need help with the calculations/conversion of a celestial object
I'm developing a telescope controller open-source application. I started this project with a very little knowledge of Astronomy.
Basically, the app is going to send data to telescope over a wireless ...
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The Solar Motion and the peculiar velocities of stars
Local standard Of Rest is the hypothetical origin of a reference system with respect to which the motions of all stars in some neighborhood of the sun average out to be zero
which type of motions of ...
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What factors determines the size of a galaxy?
Recently i saw a post comparing sizes of different galaxies with the Milky Way. The largest one being the Ic 1011.What makes this galaxy so large? What factors decide the size of a galaxy?
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Directions to Proxima Centauri
I'm writing a sci-fi novel in which humans venture to the stars for the first time. Their "shake down" cruise takes them to Proxima Centauri. I'm trying to understand where Proxima Centauri is located ...
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Account for radiation energy in the statement "total energy of universe is zero"
I've read in Hawking's book The Theory of Everything that total energy of the Universe is zero. He explained this by saying that if there are two bodies separated by a distance and having some mass, ...
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When black holes forms out of a supernova do they have a very high velocity?
When black holes forms out of a supernova do they have a very high velocity ?? Or do they remains at the position of parent star ??
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How can the temperature of stars can be determined by their color?
How do you determine the temperature of a star by color?
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Relation between angular resolution and aperture?
The angular resolution of a telescope is given by $\frac{1.22\lambda}{D}$.
This should mean that the smaller the aperture D, the higher the angular resolution. But it is exactly the opposite - why?
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Obtain IR diffuse data from WISE
I need some help obtaining IR background diffuse data from the WISE observation. There is already some work done in this regard; see: http://wise.skymaps.info/ . These are .fits files. How do I find ...
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Tips for a beginer who wants to learn more about astronomy [closed]
I have completely no idea about astronomy, but I am starting growing interest in it as I have been always wondering on what has been discovered out there and since I am studying CS, maybe I will learn ...
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Flatness of celestial systems like galaxies and Solar System [duplicate]
If we look around the cosmos, we will see most of the systems are just flat disks. Either it is solar system, galaxies, or the rings of Saturn. What is the matter, does it depend on how they were ...
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Finding the radius of a star in arcsec
If i know the radius r of a star in cm, how can I convert it to arcseconds?
For example, if I have a star with r = 3.18e13 cm, and distance to the star d = 220 parsecs, what is the relation to ...
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What happens if one day aliens want to talk to us. How can we talk to them? [closed]
Always I wonder about that if some day alien wants to talk to us, then how can we talk to them? They didn't know any of the language on the Earth.
What will be the basic building blocks for it?
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How can I contribute to the scientific community using my telescope?
I've been using my Meade 90 ETX for a few years trying to become a better astronomer and am familiar enough with the basics to navigate my way around. I was wondering in what way an amateur astronomer ...
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