in general I'm just looking for people who create custom physical items (whether that's traditional art, sculptural works, etc) who might be done in time for Christmas -- would like to purchase all my Christmas gifts from indie sources this year. please advertise at me, or let me know if you know anyone else who has commissions open! I have no budget.
notably I am in the US if that makes a difference wrt anything
I'm looking for my next software or data engineering role after a recent layoff from Barnacle Systems. That's startup life; I wish the team every success.
I'm a senior software engineer with ten years of experience doing web dev and data engineering work.
I'm particularly interested in:
* Energy transition, climate mitigation/adaptation, and forecasting * Infrastructure and tooling that supports domain experts * Mission-driven organizations in health, education, or climate
Open to full-time, contract, or fractional work.
If you're hiring or know someone who is, let's talk!
It's so insane that ARPANET was explicitly designed to keep working during a war and now a kid in Redmond can click the wrong button and take down half the internet.
I just learned that I need to put alt text on URLs for more accessible PDFs, but -- what should it say?
I am formatting academic citations that include a URL, so all the information about where that link will take you is in the text. I don't want it to read the URL to you and I don't want to just repeat the same information you just heard. What do you find most helpful in this situation?
I’m a low vision user. I get both the idea behind the new rule and its apparent absurdity. But on my bad days, I would want the URL alt text to tell me the title and author of the article. This would be a double check on my brain foggy days, when I’ve scrolled past the citation and then gone back up.
Alt text is for images or other non-text content. Not URLs, they are text, although a link may have a title.
Titles may or may not be read out by screenreaders depending on the user's settings. You can't rely on them.
Use meaningful link text describing what the link does or where it goes. If you must include the URLs in the text, because for example the document may be printed, add an appendix headed References or Citations.
@WeirdWriter Ooh, maybe I do? Maybe the higher ups who have given me this list don't know enough to know they are using the wrong terms? I certainly don't know if it's the wrong term, myself!
I feel like I know a lot about making a web page accessible, but much less about making PDFs accessible. I think I'm going to have to get on Duck Duck Go and see if I can find a good PDF-focused accessibility resource.
Thank you for letting me know your preference! It's very helpful!
How did you go with this? Do you have a link to anything saying you need alt text on links? Everything I learnt is that you need MEANINGFUL TEXT on links, ie <a href="nvaccess.org">NV Access website</a>. Reading sites like w3schools.com/tags/tag_a.asp the only thing I can think is using alt text if you use an image as a link? But that is for the image, not the link. PDF should be similar. Creating from Word for instance, there is no provision for alt text on a link in Word.
W3Schools offers free online tutorials, references and exercises in all the major languages of the web. Covering popular subjects like HTML, CSS, JavaScript, Python, SQL, Java, and many, many more.
out for maintanance. one of the 0603 bulk caps in the 12V rail to the fans blew shorting it all. Had to remove the 7805 and then cap by cap to find that out. Aaaaaaaand it's wurkin again...
I think there's maybe more risk with the solar system being thrown off balance with other gravitational forces pulling things out of orbit. Even if earth just gets pulled away from the sun a little we are screwed. Or even the moon pulled away from earth somewhat.
Even if earth just gets pulled away from the sun a little we are screwed.
I get what you're saying, but had to laugh at the use of "a little" here. The goldilocks zone in the solar system is roughly the between the orbits of Venus and Mars, and we're almost right in the middle of it, so "a little" is like 150 million km.
I would imagine that the first issue we would experience would be that the moon would be pulled out of Earth's orbit first and then we lose the ocean tides and the stable tilt of the earth. It would probably get worse from there.
Goldilocks zone is basically just where life can survive.
Even if we stay within the Goldilocks zone doesn't mean that most of the species alive today won't go extinct because it fucks up the seasons or the magnetic poles or tilt of the earth, etc.
It's even safer. The odds that it's coming directly at us to "collide" is low. Moving towards us doesn't mean it's moving directly at us. If you're driving down the road, all cars going in the other direction get doppler shifted. They're coming towards you, they pass beside you (hopefully), and then they're moving away from you.
You know how the sound of things moving from you changes? Towards you the pitch is higher, away from you it is lower. The same happens with light. We know how some things should look like, so if they are more toward red or blue, we know their speed relative to us. Blue = towards us = "we will collide" (you also do not collide with every car with a siren where you hear that effect).
If something is red shifting, it's accelerating away from you. If something is blue shifting, it's accelerating towards you. An entire galaxy accelerating towards you is somewhat concerning.
On top of that, we've found that basically everything is redshifting as the universe expands. So to see a blueshifting galaxy would mean something potentially unnatural.
Redshift comes from relative velocity (and other effects), not acceleration. Andromeda's light is blueshifted as it's moving towards us, but it's not accelerating.
I was going to argue with this too, but the meme says blueshifting, not blueshifted. They're right, but mostly because the meme is probably written poorly. Maybe they meant it's accelerating toward us though. Idk.
Right, but I don't get why this thread is full of people talking about collisions. Even if it was moving at the speed of light (it's not) it's still billions of years away.
It would just prove our theory of universe inflation to be incorrect.
I know you can't see this comment but maybe someone else will find it useful
Just like how a siren changes pitch when it's coming from a vehicle passing by due to the Doppler effect, the same thing happens to moving light sources due to relativistic effects.
Usually astronomical objects are redshifting because the universe is expanding and are thus receding away from Earth's frame of reference. Most of them are forever unreachable even if we could travel at the speed of light.
Something blueshifting means it's coming closer from Earth's frame of reference. In some cases, this could result in the galaxy colliding with ours, such as the hypothesized collision between the Andromeda Galaxy and the Milky Way
Could it potentially be an object orbiting around the cosmic center that just so happens to have an orbital path that crosses us?
I have to admit that astronomy is what caused me to change majors, but that's because I stopped going to class when the lesson was, "This is a terrestrial planet, it's rocky," and my first exam was like, "If it's 5:45pm in Tanzina on October 15th, how many degrees is the moon above the horizon?"
Since the speed something is moving away is dependent on the distance, something billions of light years away is absolutely not going to be moving towards us, regardless of its local orbits.
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It is gigantic & very luminous but it's also just too far away to be really noticeable - on its own is just on the limit of the best of human eyes if there would be no other star in the sky (very dim, with the visible/luminous core being only about the size of the Moon or smaller - the full galaxy is 5× larger on the sky compared to Moon, but that's not comparable in luminosity).
Disregarding human pollution there are just too many starts from Milfky Way way closer to us.
Blue shift, it's moving towards you, the photons are being "compressed" to a higher, bluer frequency. Redshift, the light is being "stretched" to a lower, redder frequency. Both only noticeable at significant fractions of the spped of light, relativistic speed.
Something ominous about the post is that a cosmic object that is moving towards you at a steady rate is consided "blueshifted" in the past tense, it's velocity is steady. If a galaxy is "Blueshifting" in the present tense, then that galzy is somehow accelerating at you, which is impossible unless it's under direct control by an entity, presumably a kardeshev level 3 civilization.
This entry was edited (Sunday, September 21, 2025, 1:41 AM)
Isn't the rate of expansion in the universe increasing, and at an uneven rate at that? Meaning it could just as easily be an as of yet unknown natural phenomenon?
This entry was edited (Sunday, September 21, 2025, 1:46 AM)
The expansion is supposed to be happening everywhere at the same time, not just at the edges. For example, tomorrow there should be more space between the Sol and Alpha Centauri systems than there was yesterday. Our present understanding suggests that 'normal' universal expansion should not (in and of itself) result in anything moving towards us.
Yes, but not because of universal expansion really, they're just headed in a direction that is going to intersect at some point, likely combining the two galaxies together. This'll be so far in the future we'll all be long dead though, on top of it being unlikely that anything is going to even come close to our solar system
It's not just that, but it is unlikely that any star in our galaxy will collide with any star in Andromeda.
I think it's easy to think of galaxies as individual things, like these nodes in the universe where all the stuff is stored. But galaxies are incredibly vast and incredibly empty.
The part that stuck with me is that if you made the Milky Way the size of the United States, our gigantic sun holding 99.86% of the matter in the solar system would be microscopic -- the size of a red blood cell. And iirc, the planet earth would be all the way down to the size of a virus.
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Yep. Space is expanding everywhere at once, but the effect is minuscule at the scales we're used to. And even at galactic scales the "speed" of expansion might seem like a lot to us, but it still isn't enough to overcome the motion of objects. I looked up some rough numbers to give you an idea:
The rate of expansion of space is 73 km/s/Mpc. So for every 3.26 million light-years between you and a distant galaxy, the space between you and that galaxy is expanding by 73 kilometers per second.
Andromeda's blue shift indicates it's headed towards us at 110 km/s. And in my non-expert head I'm thinking that blueshifted light must have already been redshifted by the millions of years traveling through space to reach us. So the galaxy's speed through space towards us when the light was emitted was considerably higher.
Andromeda is 2.5 Million light-years away, btw. So the cumulative distance of space between here and there is expanding at something like 73 km/s/Mpc * 2.5 Mly * 1Mpc/3.26Mly = 57 km/s.
But when talking about relativistic distances and speeds, basic te
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Yep. Space is expanding everywhere at once, but the effect is minuscule at the scales we're used to. And even at galactic scales the "speed" of expansion might seem like a lot to us, but it still isn't enough to overcome the motion of objects. I looked up some rough numbers to give you an idea:
The rate of expansion of space is 73 km/s/Mpc. So for every 3.26 million light-years between you and a distant galaxy, the space between you and that galaxy is expanding by 73 kilometers per second.
Andromeda's blue shift indicates it's headed towards us at 110 km/s. And in my non-expert head I'm thinking that blueshifted light must have already been redshifted by the millions of years traveling through space to reach us. So the galaxy's speed through space towards us when the light was emitted was considerably higher.
Andromeda is 2.5 Million light-years away, btw. So the cumulative distance of space between here and there is expanding at something like 73 km/s/Mpc * 2.5 Mly * 1Mpc/3.26Mly = 57 km/s.
But when talking about relativistic distances and speeds, basic terms regarding time and location don't always make sense.
It's the doppler effect, but with light instead of sound, and for the same reason.
Thing emits sound/light waves at a constant rate: sound/light waves hit you at a constant rate.
Thing continues to emit the same sound/light at the same rate, but starts to move toward you: sound/light waves hit you at a faster rate, causing the sound/light to turn higher-pitched/bluer.
Thing continues to emit the same sound/light at the same rate, but starts to move away from you: sound/light waves hit you at a slower rate, causing the sound/light to turn lower-pitched/redder.
Milky Way is going to collide with Andromeda… over the course of millions of years, and due to the distance between stars and other objects the two galaxies are just going to merge with each other and very few things will actually make physical contact.
Well, if they collide (and merge), they'll also fling a lot of stars into the void, but we aren't too sure anymore that's actually gonna happen. NASA explains why (YT, 2:30min).
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Might be a dumb question, but if it's blue-shifting surely we wouldn't know it's far away in the first place? I thought the amount of redshift is broadly how we determine cosmic distances?
From my understanding blue and red shifting is mostly related to movement. Like when a firetruck run past you with sirens on, you can hear change in pitch when compared it moving towards you vs away from you. It's a similar effect with galaxies, red shifting means that after the light was emitted the space between us has increased and the light kind of stretched out to longer wave.
Now anyone with more knowledge on the subject, please correct me.
Yes, but everything red shifts "naturally" as well as the light travels because of the expansion of the universe. So something traveling towards us will still red shift, just slightly less so. To determine distance you have to use something called the cosmic distance ladder. It consists of known properties of stellar objects that we can measure to determine the distance of objects.
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You're missing the point that the universe is expanding uniformly. That means two points acceleration away from each other is dependent on their distance apart. The further they are from each other the faster they accelerate from each other.
So GP is right. We measure red shift and infer distance.
Also a quick question about NVDA. I was the one to help people with this same thing before, but I forgot what I did and now is a time for doing, not thinking so much. What setting do I tweak on NVDA to make it read each link on a separate line? Thanks.
arti
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