- Intro
-second) refresher on the Doppler effect to remind viewers how observed red shift translates via Hubble’s Law to estimate distance; but far more “mind-boggling” than the “scale of the universe” mentioned at is how a single human individual can plan, storyboard, design, code, render, edit, produce, and post-edit based on feedback from Patreon supporters a 25+-minute video of this depth, breadth, and scale in 2 Earth weeks :O
- Distance to Venus
uncover for Britain
this is the best animation I’ve ever seen to describe the parallax on a global scale. Really clean and clear 👍
That's the most earthy earth I have ever seen
At , that visualization showing the moon’s orbit as it pans out to show Venus’s orbit - no space visualization or metaphor has illustrated the distance quite as effectively as this. Fantastic job. Now I want to see everything else in terms of moon-earth distances
the north and south examples seem to be reversed in this one
measuring the duration of the transit is such a beautiful solution
I knew the Guillaume Le Gentil story! from Vsauce's "How People Disappear" from 2013
To say he was done dirty would be such an understatement...
You can't just tell a tragic story of a man and cut it off right after telling it like that! 😂
On a side note, casually exposing a man's scandal without real purpose was such a stray. 😂
- Speed of light
I'm a bit puzzled by how the computation of the speed of light was derived from Romer's observation of Io's period @ . Why does the longer distance mean an increase in Io's revolution period? Isn't that distance applied to every cycle? I was thinking more of a doppler-like effect, but I feel like I'm missing something.
"It's whippin" 🌝💨
what a circle! 👏
If at like it says the moon took 20min longer total, not just a later start-finish(which was probably what he(mr Tao)meant ), then this would not mean a speed of light diff or indication situation, but that the 0.01(or whatever)percent of light that was bouncing off the tiny distant planet and coming back to earth, had a greater arc of the same < to cover on the far side... the observer on earth would see a greater amount of the light reflected because of the greater arc. I think anyway...edit(seems like it should be less than 20min based on this alone(arc diff thing-), such a small change front-to-back over the total distance(very large)).
At the implication that I got at first was that the Earth being farther away from Jupiter causes Io to appear 20m later because light has to traverse two extra AUs. But Io also disappears from view 20min later because of the same delay. So the total eclipse time shouldn't change. In case anyone else is confused by it: what it describes, I think, is that when we're closest to Jupiter we calculate the schedule of when Io's eclipses happen for half a year later. Then we wait half a year and look at Io and measure how far off our calculations were, which gives us the speed of light.
Clever indeed. My exact same reaction. Haha.I'm quite amazed at how accurate their instruments were at the time. I think I understand parallax, but if I would time travel I could not build those instruments back in the day. But I have learned through this vid they used women as computers!! That's hilarious. Who knew? (They also used women for calculations for the Apollo missions if I'm not mistaken. Correct me if I'm wrong.)
imo this is the most profound moment so far in the video. Would make a great short. Seeing light perform its journey in real time across the celestial distances is... Absurd. Because it is such an instant phenomenon to the casual observer. Outstanding video and interview.
Seeing the speed of light in action at between various celestial bodies is mind-blowing. That simple animation is worth thousands of words.
- Nearby stars
wait I don't understand. I mean I get how impressive that is, but it's so impressive that now I really want to know HOW they were able to measure the angle of a dime a mile away! 🤯
- The Milky Way
the cameraman gets turned to jelly by the Tao-Beam
Can a star can beso distant so we can not observe any photons from it, because it's apparent brightness is so spread out?And if yes, what's that distance? I imagine it to be extreeeeeme
more intuitive if you label the X axis as wavelength instead of frequency.
as an astronomy student, I got embarrassingly excited when I realized Grant was going to show a HR diagram here. great video! ❤
@ Why does the plot of color vs absolute brightness look like the 3rd dimension of the Mandelbrot set?
seeing all those Billions n Billions of stars that are crammed into every pixel of our screen within the galaxy, yet, they're so far apart in reality its so mind boggling. We see no spread in the imagery, yet in reality it would be nearly only spread.
What is the technique at called? Also two great videos you’ve made, and also also Kepler was a genius.
And then at ... the painting animation... so awesome
Just making sure I'm thinking about this correctly. You can determine the type of star from the variations in the wavelengths it releases. Then with those wavelengths, you can estimate the absolute brightness of the star. Then you can use the apparent brightness and absolute brightness to calculate the distance?
Can we really measure the entire Milky Way with this method?
- Nearby Galaxies
is actually the year that Henrietta Leavitt published her results, and that is the only step I knew from the start because of the Lost Women of Science podcast 🙌
I’ve rewatched the part at so much. I still don’t get it. The observations just showed that brighter cepheids had longer periods. So if you know the period, you know it’s brighter than others but how do you know absolute brightness where you can use inverse square law?
- Distant Galaxies
Was Hubble the one to discover the redshift of galaxies?
- I was able to track everything up until: "...general relativity predicts that the universe is expanding at a uniform rate. The further away things are, the more they recede and the more red shift they have."
When Terrance was talking about the receding universe, he said that the further away bodies are, the faster they recede. How do we know that it is receding faster (either absolutely or relative to us observing it)? Is it some sort of coaxial parallax?
Does general relativity alone predict a uniformly expanding universe?
Great video as always, learnt a lot. Minor nitpick at . General relativity doesn't predict an expanding universe per se. Einstein's field equations simply permit an ad-hoc addition of a scalar field, the cosmological constant (lambda), that we use to explain dark energy and the expanding universe. There are other theories out there that are perfectly consistent with lambda-free GR
Loved the starwars reference at
And at , the star wars text animation 😆
galaxy far far away,where jedi council tried to save the day😂
he couldn't hold himself enough not to include this awesome reference there 😂
Star Wars! 😀
Is Hubble’s original law sufficiently accurate to allow for good measurements of distances at the scale of the observable universe?
"The observable universe is, we think, about 20 percent of the whole universe..." This is-- by far-- the most extraordinary claim of the entire video, and yet there is no reference or follow up. Any clue where this comes from?
"We think the observable universe is 20% of the entire universe, we don't know." I've never heard this before.
At , Tao says we think the observable universe is ~20% of the whole universe. What evidence do we have that supports that (even though we don't actually know)? I thought the prevailing theory was that the universe is infinite.
This is the first I'm hearing for an estimate of the proportion of the entire universe taken by the observable universe. Would very much like to know more about that "maybe 20%, we think" reasoning. Great video!
"Observable Universe is 20% of the whole Universe" caught me by surprise. Where does it come from?
At Terence Tao says that the observable universe is about 20% of the entire universe. I looked through his corrections for this video on his blog and he states "The 20% number was a guess based on my vague recollection of these works, but there is no consensus currently on what the ratio truly is".
Where did this guess of the observable universe being about 20% of the full universe come from?
it is so so humbling 🥶
it had never occurred to me too consider what percentage the observable universe is of the universe as a whole 🌌 hearing 20 per cent shocked me for some reason.
The disk of our own galaxy obscures what we can see, so that entire middle section that appears empty will remain unknown to us.
- Lingering mysteries
Camera felt a collision there 😂😂
Is there any keyword we can search for further explanations or research on the 10% anomaly? This is very interesting and I would like to learn more.
If you length contract with relativistic effects, do light wave lengths change?
How comforting to hear this guy laugh.I had a friend, so super intelligent he taught himself calculus from a book so he could write computer code, he never laughed.Every conversation I had with him I could see his discomfort with a pointless human interaction.
Tao’s laugh is delightful
