Sorting out Julian Day, Julian Date, Julian Day number, Julian Day Calendar,...
In this answer I mention day number which is 1 on the first day of each calendar year (January 1) and increments to 365 or 366 on December 31 of that year.There was an edit proposed, which included a...
View ArticleMore recent data and simulations of "Milkomeda", the collision of the Milky...
The Space.com headline Hubble Telescope Spots Two Galaxies in a Doomed (but Dazzling) Dance; The galaxies will ultimately crash into each other was probably overstated as seems to be policy in some...
View ArticleComment by uhoh on What could kick a comet out of a solar system at 58 km/s?
Thanks for the citationl
View ArticleClik here to view.
First scientific use of a CCD device for astronomical observation?
Quanta Magazine's July 11, 2025 The Biggest-Ever Digital Camera Is This Cosmologist’s Magnum Opus chronicles UC Davis cosmologist and Vera C. Rubin Observatory chief scientist Tony Tyson path from...
View ArticleWhat could kick a comet out of a solar system at 58 km/s?
Wikipedia's 3I/ATLAS gives the object's hyperbolic excess velocity$v_{\infty}$ as 58 km/s with respect to the Sun.In other words when far from the Sun or other stars in interstellar space, it would be...
View ArticleComment by uhoh on At what stage (or by what mechanism) do protons and alpha...
"the electrons have so much energy that they escape from their orbits around the nucleus" As Thomas points out, is just plain wrong as currently written. You can't just make stuff up -- wait,...
View ArticleComment by uhoh on What are the major features of the radio sky at 1.575 GHz...
Welcome to Stack Exchange. Excellent first post! This is very informative; now I understand much better the nature of the transients.
View ArticleComment by uhoh on In 2023, is space still thought to be "filled with a...
Where is the quote from? Can you cite the source? Did you just remember it, or did you look it up in a book or video or webpage and then fail to credit it?
View ArticleComment by uhoh on Could orbital resonances avoid the eventual decay and...
Hi @vengaq Your question is actually very interesting, and the comments from others probably comes from their simply not knowing the answer. In other words, it's too hard for them.
View ArticleComment by uhoh on Angular resolution of naked eye at night; type of vision used
This is interesting! One might first guess that with a larger aperture the acuity or resolution (due to diffraction) improves. But for an realistic imperfect lens, it makes sense that a larger aperture...
View ArticleComment by uhoh on First scientific use of a CCD device for astronomical...
@RonJohn "Where does demonstration end and science begin?" When the results are used to deduce something new in science, that wasn't known before or when it enables a better analysis than was possible...
View ArticleComment by uhoh on How to measure the angle that defines the apparent...
GREAT QUESTION! Partial answers may be found in Space SE How to get lunar L, B, C parameters from the Moon's 3x3 rotation matrix from the Python package Skyfield? and What are the "Moon L, B, C" angles...
View ArticleComment by uhoh on First scientific use of a CCD device for astronomical...
Do your sources differentiate between first demonstrations and "First scientific use... for astronomical observation"? For example, could they learn something from a CCD image of Uranus that they...
View ArticleComment by uhoh on Do stars made primarily of carbon exist?
I've deleted my objection - I've shared vexing/humorous content once or twice myself, and perhaps others didn't recognize it the same way I didn't here.
View ArticleComment by uhoh on What is the evidence that Earth has remained a constant...
additional reading: Is Earth getting heavier or lighter?
View ArticleComment by uhoh on What celestial body (inside the solar system) has the...
@Fattie I'm pretty sure that "a body" would consist of an arrangement of material in mutual contact. Even in a rubble pile, it's continuous, or at least frequent, repeated mechanical contact that...
View ArticleComment by uhoh on How much integration time do I need to take decent photos...
slightly related in Photography SE Milky Way with a cell phone, how is this possible? and be careful - Is it generally accepted that "Samsung 'space zoom' moon shots are fake" and that some cellphones...
View ArticleComment by uhoh on How long before we get confirmation about the Planet Nine...
@ksousa one might check to see if there is any approved observing time for the "Dark Energy Camera (DECam) Imager mounted on the Blanco telescope" mentioned near the end of the discussion.
View ArticleComment by uhoh on Are binary neutron star mergers needed to explain the...
magnetar flares too? iopscience.iop.org/article/10.3847/2041-8213/adc9b0
View ArticleComment by uhoh on What color is a neutron star?
Cool! (pun intended) It turns out that normal stars may be much less shiny
View Article
/pic9814888.png)
/fit-in/580x348/filters:format(webp)/english-betterindia/media/media_files/2026/09/17/balaghat-3-2026-09-17-18-46-40.png)
