Questions tagged [astronomy]
The science dealing with objects and phenomena located beyond Earth. In particular, this applies to observations and data. At its core, astronomy is the physically informed cataloging and classifying of the contents of the universe in order to better understand what is out there.
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About special Relativity, Universe expansion and possible alien life [closed]
This topic may be kind of off-topic in this forum but I think the idea has sufficient physics material to create a possible debate.
We know from Einstein's theory that two different possitions of ...
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What is the reason that the unstable Lagrange point $L_2$ is used for the JWST instead of the stable $L_4$ or $L_5$ points?
I understand how the Lagrange points work in the two-body problem. I can do that math. I understand that for L1, L2, or L3, if the object is perturbed to deviate away from that point, the ...
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Does the CMB have a digital ‘structure’, if so how large individually and how many total pieces are there? [closed]
I would swear Neil Turok made a statement in one of his talks that the CMB is digital in structure. If I understood correctly, is there an individual size and total number to the ‘bits’ that make up ...
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Question about two planets orbiting a sun [closed]
I’ve come up with an astronomy question that I cannot seem to resolve and could really use some help.
I’m working on a problem involving two planets orbiting a star in circular orbits. The star has a ...
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Problem understanding the bending of space-time curve as gravitational force! [duplicate]
I got the point of considering gravitational force as curvature on space-time fabric for bigger objects like stars, planets, blackholes. But my doubt is over the objects like us, what keeps us on this ...
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Issue with the roots of the Equation of Time
Regarding the famous derivation of the Equation of Time available here that i'm trying to rewrite a modern version with much more detailed steps:
http://info.ifpan.edu.pl/firststep/aw-works/fsII/mul/...
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Has any astronomer ever observed that after a specific star going supernova it became a Black Hole?
Do we have any observational direct verification and historic record of a star after going supernova was turned into a Black hole?
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AStronomic nova or supernova (Ia), what peak intensity and wavelength to expect in the UV, extinction coefficient of ozone layer?
see https://www.nasa.gov/centers-and-facilities/marshall/nasa-global-astronomers-await-rare-nova-explosion/. T Coronae Borealis is expected to go nova. Distance 2630 light-years. Its magnitude is ...
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Kepler's measurements in solar system
I am interested in knowing that does Kepler measured distances in solar system or only relative distances to a astronomical unit which he doesn't know how long is it in our meters.
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Do magnetar stars relatively produce stronger gravitational waves than neutron stars? [closed]
According to Reissner-Nordstrom solution to Einstein's gravitational field equations in astronomy the electric or magnetic or both, field of a charged body of mass generates its own gravitational ...
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Converting Multiple FITS files into one dataset?
I am doing a project involving data from LASCO C2 on the SOHO spacecraft. I tried to download the data from the SOHO science archive and it comes out as multiple FITS files. Is there a way to convert ...
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Centrepetal force at the north or south pole
If you're, for example, 5 m away from the geographic north or south pole, gravitational force points inward, but centrepetal force points almost directly perpendicular, out into space. In that case, ...
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Continuous $4\pi$ steradian monitoring of space
What would it take to constantly survey space at a selection of frequencies? I'm imagining a set of satellites pointing away from the Earth and scanning all sectors of space. Can anyone point me to ...
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Is any planets angular speed roughly constant?
The duration of a sidereal day stays pretty much constant on Earth as far as I know. But I was wondering if that is typical or even always the case. For example, can moons influence it? Or can ...
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What is the velocity anisotropy in galaxies?
I came across this term recenlty, and it seems that there aren't many sites explaining it well.
What is galaxy anisotropy velocity?
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Astronomy Without Fusion
Let us begin with diffuse clouds of atomic hydrogen as we believe was the case in the early universe, but assume that nuclear fusion is not an existing mechanism.
What would happen under the influence ...
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What is the relative density contrast?
I was reading a paper talking about the KBC Void, a local underdensity in the Universe which we are also part of.
The authors calculated: "[...] the observed relative density contrast δ ≡ 1 − ρ/...
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Will the new atronomy, big data and AI generated algorithms, be able to extend the red shift - distance graph to double digit red shifts anytime soon? [closed]
So far, distances in the universe, using standard candles, have been measured out to a red shift of around 3, at a co-moving distance of around 20 billion light years. It was these measurements that ...
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Drake Equation with Random Walks
Goal
I'd like to use the Drake Equation with random walk theory to estimate the probability of aliens reaching Earth.
Drake Equation
The Drake Equation estimates the number of advanced civilizations ...
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Discovery of a Formula for Geostationary Orbit Distance: Seeking Expert Feedback [closed]
I’m an amateur enthusiast without a formal academic background in mathematics or science. Recently, I stumbled upon an idea and derived a formula that I believe calculates the distance traveled along ...
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Is there a reason why in the astronomic pictures of galaxies and nebulosas there is so little green color?
From a quantum physics standpoint, why do astronomical images of galaxies and nebulae exhibit so little green color in their spectral composition?
When we look at the pictures of galaxies provided by ...
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About redshift and distant objects observation
I did a few Time&Length dilation factor calculations. This is for a distant clock away from any field and a clock on Earth on the equator with the moon passing over clock coordinates, the factors ...
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Is there a database or catalog of all black hole candidates?
I am searching for a catalog, list, database, etc. That should show astronomical observations of known black hole candidates. I am primarily interested in knowing the mass of these candidates.
I have ...
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Is the information or energy in a black hole converted to another form of energy during decay of Hawking radiation?
The Hawking temperature equation states that the temperature of a black hole is inversely proportional to it's mass, and and the black hole loses mass when it emits particles in the form of radiation, ...
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Geocentrism and annual tide variation
I have read that in the before common era, Seleucus of Seleucia have studied tides and probably used annual variation as an evidence of heliocentric. However, tides are known to be affected by ...
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What is emission line ratio?
As the header stated, what exactly is the 'emission line ratio'? Like, [O III]/Hβ or [Ne V]/[Ne II]. Recently I've been reading some research papers in astronomy and astrophysics pertaining to ...
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Assessing the quality of wavefront correction in adaptive optics systems: the case of single and multiple radiation sources
Generalized diagram of an adaptive optical system is as follows:
Wavefront from the observation object passes through the atmosphere and is distorted. It is then reflected from the deformable mirror ...
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Stars that have fairly high gravitational redshift and calculation of their surface temperature by Planck emition spectra?
How high can the ratio between gravitational redshift and planck emition spectra be depending on the mass of the star so by how much this gravitational redshift could elongate the Planck spectra of ...
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What is the function that demonstrates a planetary transit light curve given a planet's projected distance from its star?
Last night I was measuring the brightness of a Hot-Jupiter parent star to try and isolate the transit light curve (specifically Tres-2b). I have been wondering how to obtain the function that ...
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Using helioseismology what are the equations astrophysicists use to determine the age of the Sun?
Astrophysicists talk about solar models when determining parameters of the Sun. But these models must be built from equations. When explaining to the general public what these equations are would be ...
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Does the Kardashev Scale have any practical application?
As the question states: are there any practical applications of the Kardashev Scale?
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Is it possible to predict the appearance of auroras?
Yesterday I saw online a lot of people seeing auroras both in the North and in the South of the globe. Unfortunately, I wasn't one of these people, and this got me curious about how much we can ...
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Trajectory of supergiants on HR diagrams
I am a secondary school student currently studying cosmology. My A Level textbook supplies the following HR diagram with regards to what trajectories different stars follow:
I found myself unable to ...
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Magnetic tubes or magnetic field lines around a black hole?
A picture is worth thousand words:
Magnetic field lines, unlike magnetic tubes, have a continuous distribution. Recent pictures of black hole magnetic structure show tubes. Is there a model that ...
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Which of the blocked radiation windows will (mostly) open if one where to observe from the surface of Mars, instead of the Earth?
Earth’s atmosphere is composed of about 78 percent nitrogen, 21 percent oxygen, 0.9 percent argon, and 0.1 percent other gases. Trace amounts of carbon dioxide, methane, water vapor, and neon are some ...
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Galaxy harassment; flyby encounter (tidal interaction)
This following image is from the paper https://adsabs.harvard.edu/pdf/1978AJ.....83..219R#page=4
It shows the path of a flyby encounter of NGC 3627 (M66) with the galaxy NGC 3628 (the Hamburger galaxy)...
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How can I see Orion's Belt in winter and summer?
How can the 23 degree tilt of the Earth enable someone in Argentina to see the same constellation (Orion's Belt) in winter as someone in Britain in summer?
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The astonomer's method of color differencing as applied to proving Einsteinian relativity during a total solar eclipse
I'm looking to see if the astonomers' method of color differencing was ever applied to the stars near the Sun during a total solar eclipse, for example, to demonstrate Einsteinian relativity visually ...
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Speed at which the Moon moves past a point on Earth's surface?
I'm trying to calculate how fast a point on the surface of the Moon is moving past a point on the surface of the Earth (I assume a point on the equator of each for simplicity).
I know the Earth is ...
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Why does the peak of quasar distribution move from near to far with increasing magnitude?
I made a little tool to examine the distribution of quasars in various catalogs, including SDSS DR16Q:
If you check the +/- box, and move the magnitude slider from low (-20) to high (-30), the peak of ...
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Clarification regarding the meaning of Universal Time UT1
I've been reading the book "From Sundials to Atomic Clocks: Understanding Time and Frequency" by James Jespersen and Jane Fitz-Randolph which is available at https://www.nist.gov/system/...
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Authoritative Reference for Astronomical Constants
Is there a reference that is considered authoritative when it comes to astronomical data, especially for the planets and their satellites and the Sun?
I've been using the most recent CRC Handbook of ...
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What creates the Global Dipole Magnetic Field in the Sun?
I understand that the Sun undergoes convection and with rotation, the convective cells have a helical motion because of the Coriolis Force. My confusion comes from the fact that via the right-hand ...
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Luminosity and absolute magnitude relationship
Context : an exercise gives the temperature, mass, distance and apparent magnitude of Sirius B and asks to calculate its density.
One key step of the calculation is to get the luminosity from the ...
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Is it possible, by monitoring the brightness of stars, to find a “copy of the Earth + Moon” near them?
More than a dozen Earth-like planets have been discovered around nearby stars based on observations of changes in the brightness of their sun as they pass across its disk (transit events). If an Earth-...
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How is a complete image of a distant object formed with an obstruction in the line of sight? [duplicate]
Can anyone please link to or sketch a diagram demonstrating how a complete (and clear) image can be formed of a distant celestial object with a central obstruction blocking part of the line of sight ...
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Why does a total solar eclipse happen every 18 Months?
What is the math involved in calculating how often a total solar eclipse happens. Can you predict it by just looking at the period of the moon around the earth and the period of the earth around the ...
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The expectation value of intersecting particles
If I have a light beam (a straight line)
it goes through a box of dust, which has travelling length $l$, dust molecule cross section $\sigma$, dust number density $n$.
how to calculate the expectation ...
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$1°$ shift in sun's sidereal position over a day
I couldn't understand the bold lines in the following excerpt (from the book "Astronomy - Principles and Practice 4th ed. - A. Roy, D. Clarke")
The month is the next period of any ...
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Determining star position and velocity to deduce closest approach?
I am trying to replicate the results found for Gliese 710's closest approach of ~0.05 parsecs in 1.3 million years approximately. I thought that by plotting the sun at (0,0) and using the stars ra,dec,...
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