Dark Energy

It's funny you mention how bad of a name "Dark Energy" is because I, with no background in Physics, have started watching this video because I assumed it's a continuation to your dark matter related videos, thinking that the "dark x" namings are all related to each other in Physics.

If a nearby star in our galaxy would go SN Ia, would the resulting radiation be dangerous to us? Sorry if that's a silly question but I'm not a physicist and your comment on that sounded like ... maybe? So: If yes, how dangerous? Only like killing some satellites, or more extinction level event?

IMO this is one of your best videos. I never really understood what dark energy was before. This was fascinating you should put it on your main channel

God, that was terrifying. I hate dark energy. I'm so sorry, it's obviously fascinating! great great video as always. I love it. I just can't make it not be depressing. Like, idk. I think it just used to be that while watching everything going to pieces here, there was always space. The stars. And now they're going to pieces, too. I guess it just makes me human with a need for comfort, like people smarter than me invented religion and spirituality for. Anyways, sorry! I hope you're all better and there will be a time where you won't have to work sick. All the best.

it wasn't as prominent in this video, but sometimes when you post graphics, they're partially covered up by the YouTube subtitles! absolutely not the end of the world and doesn't detract from the (amazing!!) quality and content, just wanted to pass along the note as something to consider when placing graphics !

lord good science content is so refreshing. i think being proactive and open about how your (and others) perspective can effect the info and content should be a priority for any public science communication tbh. anyway, i imagine youre probably sick of this type of thing, but i would absolutely love to hear your thoughts, even if brief, on some of the minds that seem to be "riding the fringe" of crackpottery. youve mentioned wolframs project before, and i feel mostly the same about it as you do, though (i havnt looked at every paper or anything), the sorta "protogé", Jonathan Gorard, atleast seems to both know what hes doing physics wise and fully embraces wolfram physics, seemingly without that same desire for notoriety? im not sure other names id throw in that pot are the likes of Michael Levin. both just listening to him talk and even still when reading his papers, a lot of shit feels like sci-fi crackpottery, though i cant prove it and again, he seems to know what hes doing really really well actually. Joscha Bach? hes probably less fringe in the "hard science" sense, and honestly kinda repetitive to listen to, but certainly has radical seeming ideas in compsci-ish and ai-ish?? tl;dr - would love to hear some of your thoughts on the handful of "wolfram syndrome" scientists out there. names like Michael Levin (seems legit but man its hard not to think his papers are sci-fi), Jonathan Gorard (completely embraces wolfram physics but basically without any of the notoriety?), Lee Cronin (DYING to know what you, as a computational and cosmos person, think of his assembly theory). anyway, deeply appreciate the content, and all love for any of the people i mentioned

I think you should put this on your main channel. Also, just because some people didn’t understand your dark matter video doesn’t mean it was a failure. I understood it and it really helped me understand dark matter and I’m sure that’s true for a lot of people. Hope you’re feeling better.

I think you’ve got an error in your density vs inverse temperature plot for the cosmological constant term. You’ve written the equation rho ~ T^1 (rho is linear with T) but the horizontal line you’ve drawn is rho ~ T^0 (rho is a constant independent of T).

Spectroscopy is my favourite thing ever

Ya picks yer poisons. I used to hate Apple because they locked the environment up so tight that, if you wanted to do something that they hadn't decided to give you, there was no way to do it. Microsoft used to be much better about allowing you to find workarounds or write your own. But everything in Apple actually works as promised; you may dislike the constraints (e.g., can't put an MP3 file onto an iPhone without going through iTunes), but it does work. Microsoft is now impossible to work with, and the stuff doesn't work as promised. No wonder these guys a billionaires, huh

Update: I bought a windows machine and I hate it so much! You really shouldn't have to spend 3 hours googling to make the new computer you just bought useable. I hope the spectra are worth it lol.

Definitely worth moving this video to the main channel when you feel like you could. This is the kind of discussion people are actually craving on this topic. GG.

what is up with disappearing comments? all I said is I love your content. it's fine

So okay, maybe I'm confused. But if light is being more redshifted as it travels through space so that its energy density goes down by t^4 while space increases in volume by t^3, then where does that lost energy go? Is it lost to the fabric of space? Is that a plausible source of the vacuum energy? Is this an ignorant question? Does the same thing happen with neutrinos? Can neutrinos be "red shifted"?

thank u angela hope u feel better soon!!

Heyyy just noticed that the mic you're using in the editor insert is a side address mic, so in that orientation its actually pointing at the floor instead of your face.

Feel better!

"..then individual molecules will break apart until the universe is this isotropic distribution of single protons." -- Neet... Thanks for the video, good stuff - Be well. - Cheers

Please please please post this to your main channel. Worth it for the "dark energy is the worst name in science" rant, but really this is just phenomenal communication of the history of possibly the most import mystery in all of physics.

Thank you, Angela! That plot of the type 1a supernova brightness was a huge missing piece for me.

[explains how dark energy will rip everything apart until there are just protons left] "so, that's fun." :|

Ok, I can't hit Enter. So this is a question that's been rolling around in my head for a while, and this video gives me the context to ask it. I've tried searching the Goggle for it, but that's given me nothing. So the Standard Candle method of measuring the Hubble Constant is always explained as 1) Look at the brightness of this thing to determine distance. 2) look at the red shift to determine speed. 3) Divide these numbers. Done. But, that's not all it is, right? If space is expanding, the light from this thing will be traveling through that expanding space, so will be spread out more and appear farther away than it was when the light was emitted, right? And as it's traveling through that expanding space, it will also get red-shifted by the expansion of space, so it will appear that the object was moving faster than it was. Maybe these two things cancel out? Maybe the actual method is just more complicated than the simple description that's usually given. So... great video as always. :-)

Correction: at 30 seconds, general relativity wasn’t 1905.

interpolate/extrapolate, centrifugal/centripetal, spectrum/spectra. So much latin in modern science. -fugal is fleeing. -petal is seeking, -polare is between. Two ums make an a. I only took one typing class in high school and I got a C, which probably cost me the valedictorian position. I should of [sic] studied Latin instead.

Sorry you have to work while sick. Hopefully at the weekend you can rest, be brought food, and listen to 90s country music.

Don't burn your spectrometer out looking directly into the sun!

You're not an expert so shut up. Totally kidding! Totally kidding. Please don't block me. My favorite channel though I'd be hard pressed to say exactly why.

I'm curious if you've read about the new DESI results. There was a very interesting talk about it at APS. It still doesn't solve the hubble tension, but it is very interesting (it seems like Lambda is non constant maybe?)

First comment. I have finally reached my full PE.

Third!