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Questions regarding the amount of space between two objects, the units, or measurement thereof.
364 questions
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How far apart are the centers of the interacting galaxy pair Whirlpool Galaxy (NGC 5194) and NGC 5195?
Also known as M51a and M51b. Looking for a distance in light years, not in degrees of arc.
According to the info boxes on Wikipedia, the distance to the Whirlpool Galaxy is 23.5 M ly ± 6.95 M ly, and ...
- 113
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Distance Moon-Earth
I calculated the distance from the moon to the earth (because I want to find out how big the moon currently looks in percent compared to the biggest possible moon = 100 %).
I ran skyfield and searched ...
- 107
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4
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Cepheids/supernova vs redshift (for estimating distances)
(Note: original title didn't include the "distances" qualification)
I'm following this story of expansion of the universe from an amateur perspective, recently reading this article (a)
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- 563
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Relating distance modulus to age of the universe without involving redshift
I'm trying to replicate some plots from Perlmutter (2003) in Physics Today, specifically Figures 3 and 4. The x-axis of Figure 3 and the y-axis of Figure 4 are redshift and the scale factor; the ...
- 51
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Is there a list of known stars approximately 2000 light years from Earth?
I am writing a story, the location of which is on a planet orbiting a sun like star around 2000 light years from Earth.
I want to know if there is a list of real life stars I can pick from?
My amateur ...
- 377
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139
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How could a human decode the position of Earth from the Golden Record from the distance of light years?
Based on our knowledge of mathematics, astronomy, and physics, what could be the most likely algorithm for decoding the position of our planet from the Golden Record at a distance of light years?
user65215
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4
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How do astronomers know that two objects appearing near one another are in fact close?
This is something I've been wondering since I started photographing stars at night a month ago.
To observers from Earth other stars appear close to each other if they have similar position on the ...
- 193
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What is the distance of JADES-GS-z14-0
I read everywhere "Webb finds most distant known galaxy (JADES-GS-z14-0)"
In every article/wiki/etc, I can read: redshift ~ 14, it's age ~ 13.5B years, but nowhere I could see the real ...
- 255
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Naive deduction of Hubble's law from Cosmicflows-4 dataset
Mathematician here, with very poor background in astronomy and astrophysics.
I'm teaching a statistics course this semester, and I try to supply my students with real datasets and real-world examples ...
- 101
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Why do we have this ratio equation?
In this video, they just throw us this equation below.
$$\frac{\text{2 minutes}}{\text{24 hours}} = \frac{2R_M}{2\pi D_M}$$
I can understand the earlier equation about the radius of earth and the ...
- 135
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What are the chances that a star currently in the Sun's galactic neighbourhood will eventually revisit the Sun in the distant future?
There are thousands of known stars visible to the naked eye, and have been mapped in constellations for millennia.
However, the stars that exist in our neighbourhood are currently there by chance, and ...
- 309
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Odds of hitting a star with a "laser" shone in a random direction
In this What If, Randall answers what would happen if we shine a laser in a random direction.
When it comes to hitting a star, he says only that it is near impossible to hit one in our galaxy, even if ...
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Are there any star clusters associated with nebulae that have well defined 3D positioning of the stars in them?
I am doing a project where I am trying to recreate a star cluster in 3D space using some cool retro? neon Nixie tube indicators.
My first choice was LBN 1015, a nice group of stars with a small ...
- 431
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How Greeks proved that solar parallax is negligible?
A quick search on web or books leads to Hipparchus evaluation of the distance to the moon from Earth, as sketched below, where left is the sun, middle is Earth, and right is the moon.
In the method, ...
- 295
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What were the estimated distances of planets from the Earth in the geocentric model?
The geocentric model was used before the 16th century, and was standardized by Ptolemy in the 2nd century. What were the estimated distances of each planet from the Earth, and what are the same ...
user60906