> cosmo-astro > the-refsdal-supernovae-veritasium

How One Supernova Measured The Universe

Veritasium - 2020-10-20

In 2015 astronomers successfully predicted the appearance of a supernova within a couple weeks. How did they do it? Win your Ultimate Tech Bundle by entering Fasthosts’ Techie Test here: https://fasthosts.com/veritasium (Competition now closed) This video was sponsored by Fasthosts.

Special thanks to Geraint Lewis for consulting on gravitational lensing. Check out his YouTube channel: https://ve42.co/gfl and books: https://ve42.co/GFLbooks

The supernova image in the thumbnail is from my documentary, Uranium: Twisting The Dragon's Tail. Check it out here: https://genepoolproductions.com/uranium-project

P. L. Kelly et al. https://arxiv.org/abs/1512.04654

Predicted properties of multiple images of the strongly lensed supernova SN Refsdal 
Masamune Oguri. Monthly Notices of the Royal Astronomical Society: Letters, Volume 449, Issue 1, 01 May 2015, Pages L86–L89, https://arxiv.org/abs/1411.6443

Multiple Images of a Highly Magnified Supernova Formed by an Early-Type Cluster Galaxy Lens
Patrick L. Kelly et al. https://arxiv.org/abs/1411.6009

"Refsdal" meets Popper: comparing predictions of the re-appearance of the multiply imaged supernova behind MACSJ1149.5+2223. T. Treu et al. https://arxiv.org/abs/1510.05750

Irwin I. Shapiro (1964). "Fourth Test of General Relativity". Physical Review Letters. 13 (26): 789–791. doi:10.1103/PhysRevLett.13.789

Irwin I. Shapiro; Gordon H. Pettengill; Michael E. Ash; Melvin L. Stone; et al. (1968). "Fourth Test of General Relativity: Preliminary Results". Physical Review Letters. 20 (22): 1265–1269. doi:10.1103/PhysRevLett.20.1265

Research & Writing by Stephanie Hamilton, Ralph Crewe, Petr Lebedev, Derek Muller, and Jonny Hyman
Animations & VFX by Jonny Hyman & Ivàn Tello
Thanks to Jaime Portsmouth for his gravitational lensing simulator and help enabling it to render simulations.
Supernova simulations courtesy of Adam Burrows
Numerous hubble images by Hubble Legacy Archive, NASA/ESA/STScI
Numerous images by ESO / NASA

Dumack - 2020-10-20

Its incredible how much info scientists can extract from these tiny little smears of light

Genie Le Bottle - 2021-03-02

@KyZe NickX I agRee wItH yOu. I don't know how cosmology is shockingly not that related to biology.

Shravya Srivastava - 2021-03-05

you have no idea what they can do you can do it too

Qespyish Gaming YT - 2021-03-16


Simp Boi - 2021-03-19

@Sponge ofc there is climate change but the thing is people just cry about it but they don't give a efficient way of reducing it.

Simp Boi - 2021-03-19

@thePhuntastics ay why didn't you respond to the BamBoomBots guy? Are you running away like a lil bitch?

Branimir Markovic - 2021-03-08

So this indicates that multiple generations of aliens would see me getting rejected by my crush. Interesting.

TheShadowMonster - 2021-03-23

Eh Branimire branimire

Ric Ric - 2020-11-03

wow they named a lotta things after this “einstein” guy. he mustve been smart

Elias Kjærbo - 2021-03-17

@Louis Robitaille that’s the joke he is sarcastically saying that Einstein plagiarised, which he obviously did not

Elias Kjærbo - 2021-03-17

@Rhythmic Nebula i understand why you would think that it is possible for people to be that stupid but I’m pretty sure he was joking

Elias Kjærbo - 2021-03-17

@Mehdi Ardebili yes we are kidding you

Paul Freedman - 2021-03-17

@Nirek Setty Ah yes, he is THE one stone.

drashni cioulette - 2021-03-23

he still is very smart, but not alive☠️

Zünder - 2020-10-24

That is legitimately mind blowing. To see the exact same event not just on multiple places, but also at different times. And not only twice but six times? Imagine that in an ordinary world setting. Literally deja vu.

Finland Journey - 2021-01-02

Sounds very sci-fi

Finland Journey - 2021-01-02

@Pavel No sane civilization would travel for billions or even millions of years to see something like us for example. The problem with long distance travel like that is that you literally cannot even see the star having formed yet, cos it's light hasn't reached you yet, so how the heck would they know there is something to be going after? Or how to know the location of something that doesn't even exist yet according to what can be seen? This makes no sense. Only way any of this would be possible is if they'd have overcome lightspeed, but which may be impossible, and anyway in that case such a civilization would probably be the masters of the universe and should already be here, but at this point i refer you back to my first sentence.

Pavel - 2021-01-02

@Finland Journey Thanks for the reply. Interesting comments worth reading are rare beasts ;) I agree with everything you wrote. I was only replying to someone suggesting a very advanced civilization would not know about gravity lensing. In addition to what you wrote, expansion of the space will complicate long-range travels further. Probably maximum universe available to future humanity would be within 1 bln light-years, due to the fact that beyond this point space-time would start expanding quicker and quicker, so the effective travel speed would decrease.

Personally, I think we will colonize neighbouring stars, as hopping from star to star (about 5 ly apart) is very doable. Perhaps entire of the Milky Way could be colonized this way. Some of the satellite galaxies are closer to us than the other side of Milky way, so we could target these as well, although it would require far longer jumps between systems, as there are very little stars between galaxies. Flying towards very distant targets, even with relativistic speeds, does not make much sense.

rooster700rr - 2021-01-05

Wait, did you just discover the secret to the Mandela Effect?

Brotato - 2021-01-06

Deja vu! I've just been in this place before

martixy - 2020-12-07

What I learned from this video: Cosmologists are smart AF.

biRb - 2021-02-23

@x mamBut i must say my sencere apolagies and end this little petty argument right here, because you dont have the maximum brain capacity to understand and accept your flaws , i will thank you dearly and leave you to your idiotic attitude and laugh as i watch others like me try to condemn your stupidity.

dagva tuya - 2021-02-23

@biRb i agree with you they were really stupid but you didnt have to say that they were salty but other than that i agree lol

No u - 2021-03-22

@Bobazo Vamoh Chile HAHHAHA NOO. Astrology is wrong. Its trash people made up. Astronomy and astrophysics is amazing. They are real and don't make stuff up

delusional celery - 2021-03-23

@Star Nutron r/woooosh

Star Nutron - 2021-03-23

@delusional celery why.......he was not sarcastic bro........he is serious

Flammable Maths - 2020-10-21

Spacetime be like: But, will it bend?

peabnuts123 - 2020-12-09

Never thought I'd see a Will It Blend reference in 2020

Aaron Seet - 2021-01-01

That is the question.

Kane Sonny - 2021-03-19

Dont know if anyone gives a damn but I just hacked my girl friends Instagram account using InstaPortal. Cant link here so search for it on google enjoy!

Chaim Kade - 2021-03-19

@Kane Sonny I am trying it out now. Looks promising.

sokin jon - 2020-11-14

The Real Question: How do scientists notice a tiny dot of a star in the middle of so many blurs and other stars?!

Faykat Ahmed - 2021-03-16

Well there are some cosmological objects that can measure the intensity in a picture with a great precision. If it fluctuate a certain amount from the previous pictures they could normally guess where it is. We have to take into account that it's not a paper picture but pixels picture. You just have to have a device that has the precision yo found that fluctuation at a very precise number that is really small.
It does exist 😉.

Mislav Horvat - 2021-03-17

I'd imagine there is a virtual model of the universe that automatically gets updated when anything new is found, meaning it constantly checks itself for validity, and then promptly adds or deletes stuff. Data gathering en masse with something easily detectable (duh, light) is very simple.

Louis Robitaille - 2021-03-22

@Amazing Username Your "spot" spans millions of light years btw... They capture the whole sky in a couple months, then start over 🤷‍♂️ As you said, it's more complex, but still closer than what you said as there's always something interesting going on.

Louis Robitaille - 2021-03-22

@Mislav Horvat there is no such virtual model... it'd be WAYYY too big for our computers to compute...

Jazla111 - 2021-03-23

Imagination is a pretty crazy thing.

Ravi Kumar - 2021-02-09

Man: No one bends like her
Universe : Hold my gravitational Lenses

Laimonas Ratkevicius - 2021-02-21


Santiago Arbelaez - 2021-03-03

" almost perfectly line up with where the earth would eventually be" i feel mindblown

an sa - 2020-11-01

1:40 "In the next



years." :(

kingsoonkit - 2021-02-22

That caught me off guard

lizard legend - 2021-02-24

But that could still be sooner rather than later

Hendlton - 2021-03-01

Like he said, it's hard to predict. It could happen tomorrow.

Abhinav Doma - 2021-03-02

@Hendlton it didn't im afraid

Hendlton - 2021-03-03

@Abhinav Doma Oh well. There's always tomorrow.

Alfredo Alfaro - 2020-10-20

One of the few youtubers that always produces top notch content is now pouring it in mass! Guess not all is bad for 2020.

deleted account - 2020-11-03

9:01 So that tiny dot is a supernova as bright as an entire galaxy ? Or its just superwishfull thinking ? They sooo wanted to see a supernova so they did. Even if it was BARELY visible. So it doesnt even fit the description of a supernova. But fits the description of a superartefact from supernoise and superinterpolated pixels in what is a superexposed and supernoisy image. I can see at least one more similar artefact around the second star directly above it. Is that a supernova too ? Incredible, 2 supernovas in the same picture !

iSwanqa - 2020-11-03

@stmounts cry some more liberal!

deleted account - 2020-11-03

9:01 So that tiny dot is a supernova as bright as an entire galaxy ? Or its just superwishfull thinking ? They sooo wanted to see a supernova so they did. Even if it was BARELY visible. So it doesnt even fit the description of a supernova. But fits the description of a superartefact from supernoise and superinterpolated pixels in what is a superexposed and superpixelated image. I can see at least one more similar artefact around the second star directly above it. Is that a supernova too ? Incredible, 2 supernovas in the same picture !

FlyingSavannahs - 2020-11-11

@Stranger with Science Except maybe supernovas in the Milky Way galaxy.

Big Dogo - 2020-11-22

“You will be able to see beetle juice’s supernova”


movax20h - 2020-10-24

Crazy. Some people's think earth is flat. Just let it sink in.

Ethan Jacuuzito - 2021-02-25

@Maza just untrue lol

KyZe NickX - 2021-03-01

@d4TheViewer wait i remember watching the vsauce video about that, kansas is literally flatter than a pancake

KyZe NickX - 2021-03-01

@BEARD believing in something that has no evidence against or towards it means nothing
a lot of scientists believe in god, you have nothing to loose but everything to gain

KyZe NickX - 2021-03-01

@Avanish Pandey no trust me, they exist. seen them with my two eyes.

Frank Boff - 2021-03-13

Well some parts of it are. Lol

Tamzid Tonoy - 2021-01-26

who's Waiting like me for Betelgeuse to explode ?

Taiga 20K - 2021-02-18

Can't wait man I'm so stoked!!!

Sharath Gowtham - 2021-02-24

2021 maybe

Skeil - 2021-02-26

Cmon do something

AG Games - 2021-03-19

The thing is it probably did

you know me - 2021-01-07

me: depressed
opens yt for some songs
sees veritasium video

guess I'm not depressed anymore
I'm mindblown

Simon Zhu - 2021-01-05

Is it just me or is that thing looking at me and smiling weirdly

zopic 13 - 2021-03-11


you are not alone >:)

Theta Fritz - 2021-03-21

It is staring at everyone

Daniel Stephenson - 2020-10-23

Gravitational lensing blows my mind.

"Oh, those four galaxies you can see over there? Yeah, they're the same one..."


Zalamedas - 2020-10-25

It's crazier than the looks. It appears not only in different locations, but different times. It's really mind boggling

YCbCr - 2020-11-05

@Zalamedas It's not just looking in the past, but you can choose which past are you looking at. 20 years, yet lightspeed. What had it got to go through...Fascinating.

FlyingSavannahs - 2020-11-11


Bloop 907 - 2020-11-07

“You will be able to see beetle juice’s supernova”


John Garfitt - 2020-12-26

You will probably be able to get a tan from it.

Mulindwa Joseph - 2021-01-01

And then he said...any time *soon*, in the next few 100,000 years.

Cat And Comparator - 2021-01-03

Beteleguese Beteleguese Beteleguese!

Residober - 2021-01-06

what number comes between two and four?

Beetlejuice: *Explodes*

bumbum420 - 2021-02-15

@John Garfitt yeah tan from radiation

RomanLegion - 2020-10-24

This is one of those videos where I went really violently back and forth between understanding and not understanding this video 😂

FOSSEL_san ಠ ͜ʖ ಠ - 2021-02-07

I don't know if things are flattering or depressing. We find out so many things but the limits we have in space exploration are not even conquered by speed of light

Justin Bassett-Green - 2020-10-21

"Do you notice that the same galaxy appears three times in the image?"
Yeah I totally noticed

Person Man Man - 2020-10-21

Todally man

Hagen von Eitzen - 2020-10-21

Remember how flat earthers use to complain about the same cloud pattern repeated in composed images of the earth? (which was in a way due to the same reason: pictures of different parts taken at different times)

OvalWingNut - 2020-10-22

I noticed before the video even started... 🤔

Gshady - 2020-10-22

😂 thank you !

Christian Sutterlin - 2020-10-23

It’s a watered-down vision for children. Relativity is the Truth and nothing can exist apart from the Truth! Amen!

Reality is darker! This video only talks about two or three phenomena consistent with relativity.

What about black mass? What about dark energy? What about the total incompatibility between the mathematical and therefore continuous relativistic view and the discontinuous view of quantum mechanics? What about the Sagnac experience? What about Professor Allais's statistics? And so on and so forth, and some of the best! Check out the list in the video: the collapse of physics https://www.youtube.com/watch?v=QA5b-moh4o0

Darren DIY - 2020-10-25

He had us in the first half ngl😂😂😂

Shreesh Chhabbi - 2021-02-15

This is incredible validation of the theory.

NAWW - 2020-12-07

How do they look at a dot and go "HAHA Look at dat Supernova" "Super nova go brrrrrrrrrrrrrrrr"

Jim Sagubigula - 2021-01-14

When you all of a sudden see a star that appears out of nowhere and can outshine a galaxy, you can be pretty sure that this is a supernova.

KyZe NickX - 2021-03-01

@Jim Sagubigula "look at it go" "omg broo it's so bright, wait how far away is it exactly?"

Daniel Bang - 2021-01-09

04:49 Yeah, I remember that date, it was fun, we had a great dinner and saw a movie...

RedKB - 2020-10-21

So cool.

Sangsang Singsit - 2020-10-23


Zach - 2020-10-23

You make the best cubing videos RedKB!

akshat saxena - 2020-10-23

You got me into speed cubing😁

KyZe NickX - 2021-03-01

yo dude you got me into cubing, my fastest time was 21 seconds or something like that but I can't complain

Theta Fritz - 2021-03-21

Hi Red, sice to see you here!

EnergeX - 2021-03-23

6:26 who else sees the smiley face 🙂

G M - 2020-11-06

"spooky action at a distance" I know Einstein said that. Without looking it up, I'm gonna say Einstein is responsible for the quote. But of course, that seems too obvious. Who was it?

Ayanna Ordonez - 2021-03-21

6:27 Hello there, mere human. Would you like to be my friend?

klaas victor - 2020-11-19

This is the most surprising video I have seen in my life! It got me Goosebumps! Humans are incredible to have discovered this!

Rishikesh Wagh - 2020-12-18

I already knew about all the cool stuff mentioned in this video. But it still blows my mind. Just amazing how far we've come as a species.

klaas victor - 2020-12-18

@Rishikesh Wagh So amazing...humans are incredible...

Pouly _4531_ - 2021-01-05

@Rishikesh Wagh Yet there are fools like flat earthers.

ryuhjn yguh - 2020-11-30

I cant even visualise that when a supernova explodes, in less than a second tens of thousands of miles of matter and gas covers the surrounding space.

Trowa71 - 2021-03-23

Would a civilization in that galaxy see 6 of us watching it at different times? We should wave at each other.

Pritam Jain - 2021-03-15

He : Hey i saw a supernova.
Me : wow when it happened
He : 9.3 billion years ago.

firedragon159 - 2021-03-01

Well I'll be damned, I thought it was already far out enough to hear that looking into space was looking into the past, but now I get to also know that space has multiple recordings.

ashish sharma - 2020-10-20


Nicolás97 - 2020-10-21

It's the beetlejuice bro

nineball039 - 2020-10-23

@Larry Scott We are all better for Derek and Matt posting on YouTube.

Larry Scott - 2020-10-23

PBS space time is brilliant. As is this.

Vodhin - 2020-12-20

That's because you're watching his videos "all at once" through gravitational lensing caused by the weight of all his knowledge ;)

Prateek Gupta - 2020-12-30

@Veritasium your reply has more likes than the orginal comment .
Just veritasium things

Shablé - 2020-11-11

6:27 the universe is smiling upon veritasium, Derrick müller is a genius, yes I put the diaerisis in last name as an understanding of observation as Derrick does for all of us. Thank you sir Derrick, your work teaching us troglodytes is appreciated

Christian Taylor - 2021-02-06

Bro imagine how badass it would be to see a supernova in the sky and later see andromeda in full view in the sky

Matt H - 2021-03-24

Someday scientists will find it. Caught beneath the landslide.

Ace World of Fiction and Fantsa - 2021-02-17

1:46 and every other star, except sun, that you mentioned could already have exploded,but we haven’t seen it.

Ninad Naik - 2020-10-21

Teacher in online class: why are you late?
Me: gravitational time delay.

Dennis - 2020-10-31

But youre a year late...


SHIVA SURYA - 2020-11-08

If so you must have attended the class before the actual class time cox gravitational time delay makes time slower in high gravitational field

Ninad Naik - 2020-11-08

@SHIVA SURYA so the teacher will be ahead in time

Its L - 2020-12-13

@Opecuted What materials did he used to build it.

Opecuted - 2020-12-13

@Its L ask him not me

Juan Lopez - 2021-03-18

The soundtrack sounds just like the one in halo reach, but with added sound effects on top of it

SUPER_OJGAMING - 2021-01-09

I watched this 4times and then I tryed to use my 200$ and tryed yo see something of course I didn't find anything cool like that.

dolita windo - 2020-11-06

I love watching your vid it is just so interesting and I 13 years old.I would love to grow up to be an assternot it is my drem job. thanks for teching me something new

Pognakvuth Meth - 2020-10-23

“A dying star in a galaxy far far away”. May the force be with you ^^

Experience Daliona Science - 2020-10-30

This is one of my favorite events to reference when talking to people about astrophysics! You can make awesome scicomm visuals using the 4x supernova 😁

Pariniti Verma - 2020-10-24

God! I'm already jealous of the people living a hundred thousand years away

Prithiviraj - 2020-10-25

a hundred thousand years! I think humans won't be surviving that long or we will have evolved into a different species.

Osmone Everony - 2020-10-24

I am waiting for the day when I finally read an intelligent comment either here or on PBS Space Time. smh

S. M. Henderson - 2020-10-23

Thanks for talking about the stuff that actually interests and concerns me bd occupies my mind every day!

Lukas Wenzl - 2020-10-20

It is awesome to see you talk about such current research in Astrophysics. As a Phd student who grinds these papers every day it is a joy to see you manage to share these concepts so understandable and yet very accurately. It is a joy to watch!

Gilgamesh - 2020-10-21

"phd student" XD why would you do this to yourself

Lukas Wenzl - 2020-10-21

@Darshil Makwana I am happy to share some insights! Just shoot me an email

Raimon Estañol - 2020-10-22

Yet I fail to understand which law made the "shorter" path "longer" for light to travel. Also how do X-rays show us the early universe? Also a gravitational lens?

J J - 2020-10-24

I was the 669th like of your comment.

Prateek Gupta - 2020-12-30

@Lukas Wenzl what's your email ID . Please tell me , I have some queries. It'll Helpful for us both as I will ask you questions and you will be able to think about them. :)

James Bates - 2020-12-03

I believe it was Newton himself, who expressed those reservations about the mechanism of gravity.

Chuck Borris - 2021-03-11

What if light didnt interact with dark energy and dark matter but it it "charges it" expanding it like a balloon, in all directions