How Do We Measure How Big the Universe Is?

Galaxies are red, galaxies are blue Depending on their velocity Relative to you!

Hey Joe, smart people here ✌️😅

My favourite part about the distance ladder concept is how simple (yet useful) it is! Last year in my final astrophysics course at university we were tasked with constructing a distance ladder (just as real astronomer had over the last ~100 years) using data from a simulated universe! Using parallax, variable stars and X-ray flash data my Universe was found to be CONTRACTING at an extremely fast rate (~5000 km/s/Mpc). This gave my theoretical Universe just 200 million years left before it would meet its ultimate demise. In the process of constructing the distance ladder, we learnt so much about the Universe (stellar classifications, galaxy types and cluster distribution throughout the Universe, we found SMBHs existed and disproved dark matter, assessed the homogeneity and isotropy of the Universe etc), much like the real history of astronomy you covered in this video! All this to say that this video is great and the distance ladder concept is maybe the most fruitful tool ever developed in astronomy, literally unlocking the cosmos from Earth.

Can we appreciate how using angles and equations people were able to find the distance of astronomical objects before modern tech? It really speaks volumes to our human intelligence to find solutions to 'impossible' problems

"Hey, smart people" Me: Oh. Excuse me. clicks off

I learned about our universe expanding just over a year plus ago, and it still blows my mind thinking about it. Astronomy and astrophysics truly are cool.

The Standard Candles would be a good band name.

Day by day Joe is starting to look like Bruce Banner 😃😃😃. I hope there's no Gamma radiation experiment going on at your home/studio 😂😂😂

This seems more important than the work I have to do now…

I've recently learned that the universe will double in size in 10 billion years. The thing that blows my mind is the fact that 1 cm of space will also take 10 billion years to double in size.

No joke, I was literally up at 3am this morning thinking about measurements in space. Perfect timing!

I found out about the parallax thing by myself as a kid and kept asking adults why the place of an object seemed different for either one of my eyes

I wish you'd go deeper into the topic. I almost felt nostalgic, you took me back to when first started watching PBS Space Time!

I once asked a little kid how far away the moon was and he said, "It's right there. I can see it."

What a great video. You and your teams content is always such high quality

0:24 This graphic is incorrect. Since the mirrors on the moon are retro reflectors, the incident ray and the reflected ray would overlap.

So much information in a single video, I am overwhelmed.

It's time to sleep but I can't wait for next day 😂

5:45 As a thinking human I understand what you mean, yet as I photographer say that the highlights in the area of both lights are blown and in this image there is no measurable difference.

That example u used for standard candle was brilliant I hope more science channel use such comprehensible example