Have had the old version of period04 installed for ages, decided to delete and download the newest version 1.2.9 but says I don't have java environment downloaded. Download java from the link, but I get the same error. Has anybody had any similar issues? I really need the newest version for my master's, any help would be appreciated! submitted by /u/ZoFReddit [visit reddit] [comments ..read more

I was looking at a map of our interstellar neighborhood and was wondering how far we'd be able to colonised. How far would we be able to colonise? Would we be able to escape our neighborhood even? submitted by /u/AethelstanOfEngland [visit reddit] [comments ..read more

submitted by /u/Revolutionary-Egg-46 [visit reddit] [comments ..read more

I was just watching the new Veritasium video about how something strange happens when you follow Einstein‘s math and I heard Derek say something about imagining space-time flowing into a black hole. Something clicked in my head and now I have a question. Let’s say the fabric of space-time does flow into a black hole, so space-time is then being pulled and stretched by all the black holes out there. From our frame of reference wouldn’t this also look like the universe was expanding? Is there any way to distinguish the two? submitted by /u/SnitGTS [visit reddit] [comments ..read more

Lets say that earth is a rogue planet but it still keeps its moon. Would it be possible for a person standing on the moon to figure out that they are rotating around earth without having to refer the sun or any other star? Or would it seem like earth if rotating around them from moon's perspective. My basic question is that if a body is revolving around another body is it possible for it to seem like that the other body is revolving around them from the point of view of both? submitted by /u/sjnonweb [visit reddit] [comments ..read more

I'm working on a worldbuilding project and this seems like to right place to ask. Earth's average distance form the sun is roughly 150 million km (93 million mi), but the distance can vary by about 4.8 million km (3 million mi). How much larger would the average distance between Earth and the sun need to be, so that the average temperature on Earth (which is about 15° C) would be one degree colder? submitted by /u/PrequelFan111 [visit reddit] [comments ..read more

Hi, I often struggle to get APT to plate solve. I've set up the plate solving apps, ASTAP etc and I find they are very sensitive to poor focus or the distance from the expected position or a lack of stars or whatever. It's very hit and miss, some nights it works fine, some nights I can spend an hour just getting any alignment. I have found that when APT is failing to solve I can throw the image at Astrometry.net and get a solution back in a couple of minutes. My question is - is there a way of taking this solution and telling APT that this is the actual position of the scope? I can't find any ..read more

Apologies, I’m not entirely sure how to word this question. Basically, I’m wondering if we’re able to know, on average, how “big” an element would be when it’s created during a kilonova or supernova. Not in a total quantity, exactly, but more the size of each individual element at the time of their genesis. As an example, are there just individual atoms of gold crop dusting the universe, do “clumps” get created, or is it something else? submitted by /u/bellaphile [visit reddit] [comments ..read more

I have a canopy in my garden in which I want to cut some holes to align with certain constellations I enjoy looking at. I was wondering if I could do something similar with the moon and I am finding it hard to get a simple answer. Lets say I wanted to cut a large hole to view the moon in the same position in the night sky, how often would the moon be in that position or close to it? Is it every month, year, decade or more ? submitted by /u/deejeebee [visit reddit] [comments ..read more

EDIT: I guess I need to make it clearer that this is purely a theoretical question ignoring any practical manufacturing considerations. When reading about microscopes I learned there is a limit to how far optics can magnify due to the size of light waves themselves. So you have to use things like scanning electrons to see further. I've read many articles calculating how many miles wide a theoretical telescope mirror would need to be to see certain things. But they never mention if there is a limit to the nature of light itself beyond which you would not see any more detail. submitted by /u/r ..read more