I get how this would work for objects that never travel close to earth. But Earth has abundance of Artificially made light. They used the Yarkovsky equations to determine Apothis won't hit it's next go round not 2029.

How can they calculate what is and what isn't going to be lit up when comes through in 2029. And what about the satellites that's a continuous ring now and they emit light also. We dont know how many satellites will be up there in 2 years let alone 4-40. Are we able to predict Solar Flares also? . If there's a Solar Flare that's going to change the equations by a lot. If we have more satellites that's going to change it also.

Small chance in 2036 and 2068. Looking at how the Yarkovsky effect is determined. The Yarkovsky effects main variable is Light Force, just seems a bit far fetched to be able to just know every time this comes around excatly how may satellites and/or Solar flares Apohis is going to encounter the next 40+ years.

I’ve been tinkering with the simulation here: https://phet.colorado.edu/en/simulations/gravity-and-orbits and noticed that when I increase the velocity of the planet, it actually increases the orbital period and radius.

Now, it makes sense to me why this is happening (kinetic energy increase -> greater ability to escape gravitational pull) but I can’t seem to relate this to any equations I know. There’s v^2 = GM/r but it doesn’t make sense for what’s happening (and it’s for circular orbits only anyways). There’s Kepler’s third law but that only relates orbital period and radius, not either to velocity. General wisdom seems to suggest orbital period would be inversely proportional to orbital velocity too.

Inspired by a recent post about a faint distant galaxy I looked over some of my old broadband data of M45 and found UGC2839 at a distance of 300Mly.

My old data

Looking around the area on Sinbad I quickly discovered what appears to be a much more distant small galaxy cluster.

Any idea if it is described? Looks like a very interesting let's say "advanced" astrophotography target.

Sinbad unknown cluster

is there any update about the T Coronae Borealis (T CrB) nova explosion? As it was hyped last year

I find myself thinking occasionally that saturn looks particularly bigger/brighter some days. Made me wonder if planets can do that- unlike stars- cuz they are closer some days/ or we see phases like the moon? Is that a thing? Can't seem to find any answer with a Google search..

So I’ve seen shooting stars before but just now, a huge white ball of light (almost as if someone shot a flare) appeared in the sky and then kinda fell back down. Just wondering if it was just abnormally big shooting star or what else it could be?

I was messing around with a new camera, getting a feel for settings w/ night photography and noticed this... green swirly thing... underneath Orion. It shows up in every photo I took of this section of the sky but this is the most clear image. I have not done anything to the image other than add the red circle of death.

I have no idea what to search, google did not show up with anything, though to be fair, I have no idea what to search for.

I also tried to find it in Sky Tonight and Skysafari with no luck.

Edit: I'm in Northern Colorado, USA if that helps

https://preview.redd.it/npmivwdm09ge1.jpg?width=8288&format=pjpg&auto=webp&s=f9a711eaf06983b483c45f5d4665b35988a05560

In the city of Barbate, Spain, there is a plaza paved as a giant analemmatic sundial, with a lighthouse as the gnomon. I haven't found an explanation anywhere as to how this dial works and how it is read. Would a dial of this kind really be accurate? And if not, is there a better way that the face of the dial could be designed to show time more accurately?

What is the length of time that it is viewable in the morning, "invisible" behind the sun, viewable in the evening, and "invisible in front of the sun?

It feels like the best celestial events are in the bitter cold.

In the night sky proxima Centauri B is roughly just barely smaller in arcseconds compared to Sgr A, which we have imaged. Proxima Centauri C is even bigger than B is as well! So why don't we attempt to take the first image of an exoplanet?

The title is not clickbait. Isn't the sun supposed to rise from East and set in West? I'll link two videos I found where clearly the sun rises from the West and sets in East.

Nome (Alaska): https://youtu.be/AVf9IenF2jg?si=2UnKQG4WU0bkqYSl

Bristol (UK): https://youtu.be/Ys1w9A4DrO4?si=M_LG_Cy244CRzNqr

can someone explain?

What's a good way to tell constellations apart