Hi

This is a great video! its a video difficult to see in one sitting since its so long. you can add chapters by writing them in the description like this: 00:00 Hubbles tuning fork 10:00 Eliptical gallaxies examples. etc... 🎉

Always a blessing tro have a new video. Now for my favorite, IC 1011

Jason! You're back! My hero!

Visual observers doing a "Messier Marathon" call the Virgo cluster "Heartbreak Hill" because there are so many galaxies. March is the month to do this.

can't wait for the full release!

I have discovered this. But now is not the time, I shall watch it later. Thank you Jason Kendall, thank you for helping me to muse and wonder. Kind regards.

Watch more about The Realm of the Galaxies: kzbin.info/aero/PLyu4Fovbph6d8lUKC4FGFv2iEobxKS42R

Good, solid narration that offers information without calling attention to the narrator. Thank you.

Spacetime is wonderful ... but somewhere in the future it will go the way of all things when a deeper, even more eloquent equation unfolds in the brain of future genius.

I keep waking up to your videos having autoplayed in my sleep They always lead to interesting dreams about stars

It seems it is not a problem of stellar physics, but a problem of particle physics. Although they are connected surely.

my supervisor always recommends this book to us. I decided to watch your videos. its like direct interpretation of author. and yes it is always helpful before a good night sleep. thanks allot - a cosmologist.

I like that the planck stuff is left out. Its already magical enough.

Crisp! Well done lad.

Hi there. Would I be right in assuming that the anisotropy variations in the CMB a) would be slightly different in pattern (not statistics) if I could jump 200Mpcs to the left and b) would change subtly over geologic time as the last scattering surface slowly recedes from our viewpoint?

You should check out a song by the Flaming Lips called "A Spoonful Weighs a Ton" A very creative song. I'll bet there's a Math Rock band out there called Nuclear Pasta

I don't think it's quite right to say Newton 1 is a special case of Newton 2. Newton 1 provides a definition for inertial frames, which are a requirement for the validity of Newton 2.

Trappist 1 is 0.089 solar masses. So, it'll stay on the main sequence for 10¹² years. I still tell anyone who will listen about your channel. I still watch almost every day.

Not a big fan of scientific history. I learned algebra just fine without learning its arab background. Newtons stuff is useful, despite being wrong, but older stuff is pointless as far as I can see. My 2 cents, for what its worth. Disagree if you want.

Based on the snippet I saw earlier, my hopes for this video are high. I appreciate the level of detail and good use of graphics. I've subscribed to catch any content to follow,

Reckon the easiest way of mentally visualising curvature of spacetime in 3 dimensions by first imagining that the universe is made entirely of an infinite number of square cubes/boxes of the same volume. Where there is a large mass present, like a star or planet, all those boxes will still contain the same amount of volume but in a relatively smaller size of those around them. The size shrinks relative the closer one gets to the star/planet. The larger the mass, the greater the shrinkage. Then one has to appreciate that the smaller the box size, the greater the escape velocity is for that given object. If one takes a black hole as an example, the boxes just terminate as a dot, no escape. I find this easier to visualise in 3d rather than thinking of the cliche trampoline and bowling ball scenario that only helps visualise in 2d. Sorry for the long winded nonsensical ramble. 🙏🏻🙏🏻

♥♥♥♥♥♥♥♥

I'm grateful I managed to catch a stream!

GPT cannot expand on hamtrodiccles component for FTL travel. (Sigh).

As always your videos are simply the best. This topic especially interesting to me. Wish I went into a scientific profession. I didnt even know I liked it (thanks South-African school system in 80s - 90s) only knew who Einstein was etc later in life. Ouch. Anyhows. When I started understanding more I though its unreal that someone can shoot a metal bearing in empty outer space at 3000 km/ph. If someone stationary to the shooters reference is in the way holding op a thin aluminum plate and try to deflect it, it will end badly. The ball bearing will rip right through that aluminum plate like a bullet. But in anoyher scenario, if that person stands next to the stationary shooter and once he shoots that person now has a fast little spaceship and speeds up after that metal bearing and eventually catches up to it. (so entering that frame of reference?) he can open the bay doors and slowly the ball bearing comes into the spaceship) all floating around weightless a harmless little ball bearing. For this person. It simply becomes a ball bearing floating weightless in space? But for the frame of reference for the shooter still in their initial position in space the ball bearing is still travelling at 3000 km/ph and very dangerous for anything stationary to his reference. But on the spaceship the person can push the ball bearing around with a single sheet of paper towel. Am I understanding this correctly? Not very much the same as speed of light measurement or observation from different reference frames but it might help me to kinda start understanding.

Awesome. Thank you as Always.

There is a timeline where you soothe adoring history majors to sleep.

Excellent

I helped write Mathematica code for this in college back in the early 90s. Finally bought my own copies of mathematica about a decade ago. Need to find my printouts in old boxes...

space indeed big

Point of order: Parsonstown is actually in Ireland. Ireland was occupied by Britain at the time, but the structure still stands and has been restored and it is in Ireland.

Love this

Well yeah, duh...

Watch the full-length version of this here: kzbin.info/aero/PLyu4Fovbph6cX6Sv4DuLFbZxPv16M-0Om

Hi Jason. If you don't mind me offering an honest review. First I think these videos fill a great need for presenting complex astronomical ideas to those who are interested. Having said that, I find that very often, content is presented which assumes background knowledge. For example, when you present the CMB at 1:15:09, you don't explain what the CMB is. When you talk about the temperature of "the entire sky" as being 2.75 K, what does that mean? What is a black body spectrum? What is critical density? What is baryonic density? What is an open or closed geometry universe? These ideas were presented within a just few minutes. I assume that students wanting to learning this level of astrophysics, have had a prior introduction in basic astronomy. However, If we begin with cosmology, especially employing mathematical rigor, as you do, a discussion of basic concepts is crucial to understanding. I think here, a prior discussion of each topic on a purely conceptual level is important, before embarking on mathematical explication. I often found myself asking "where are we heading with this". But perhaps this is just my learning style; to couch the problem first ("what are we trying to find out here?" or, "why is this important?"), and then set out to find solutions, mathematically or otherwise. I think you often are unfolding answers without first articulating the questions that you're setting out to answer. I think slowing down a bit, not assuming too much prior knowledge, and setting the stage would make these more helpful. At least to myself.

Seems pretty simple. By which I mean complete chaos until you understand every little symbol. Lol.

Truly amazing. So much knowledge!

I learned a ton from this lecture, but my favorite fact is disaster, meaning bad star. I can't wait to Cliff Clavin that into a conversation. 😂

There is in fact an absolute reference frame, the universe itself. This manifest in the CMB, there is only one reference frame in which the CMB has zero dipole. We are ~370 km/s from rest with respect to the universe itself. Cheers !

Well yeah, duh..

Love your content!

Light speed how

Excellent thankyou.

Makes sense. I can see how FLRW is different than a "timescape" model where homogeneity is given up for more accuracy.

Watch all the introductory cosmology videos here: kzbin.info/aero/PLyu4Fovbph6cX6Sv4DuLFbZxPv16M-0Om

i ordered the book.....looks hard

Stars ⭐️🔭