Gravitational Lensing

20 okt 2020
1 365 686 Vaatamised

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: (Competition now closed) This video was sponsored by Fasthosts.
Special thanks to Geraint Lewis for consulting on gravitational lensing. Check out his EEworld channel: and books:
The supernova image in the thumbnail is from my documentary, Uranium: Twisting The Dragon's Tail. Check it out here:
P. L. Kelly et al.
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,
Multiple Images of a Highly Magnified Supernova Formed by an Early-Type Cluster Galaxy Lens
Patrick L. Kelly et al.
"Refsdal" meets Popper: comparing predictions of the re-appearance of the multiply imaged supernova behind MACSJ1149.5+2223. T. Treu et al.
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


    random emailrandom email37 minutit tagasi
  • Dear chat and @Veritasium can black give rise to star or explode to create new stars. Is this possible. Plz help

    MickMick5 tundi tagasi
  • Spacetime be like: But, will it bend?

    Adobe ReviewsAdobe Reviews9 tundi tagasi
  • I wonder how we can be sure all our cosmological conclusions and theories can be true if everything we can observe is based on the electromagnetic spectrum we get through our different kinds of detecting instruments and at same time we know that all these objects in the sky are no longer where we locate them and also that their emitted EM waves are all distorted and scattered during their so long journeys to reach us “ now “

    Amedeo FilippiAmedeo Filippi9 tundi tagasi
  • 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.

    ryuhjn yguhryuhjn yguh18 tundi tagasi
  • Mind blown… again

    Pax WebbPax WebbPäev tagasi
  • Theoretically let's say you could teleport anywhere instantaneously and no matter where you were you could survive for a set amount of time if you traveled somewhere off in the distance of space and looked at earth would that be considered time travel because you are looking at light that has been reflected off the earth in the past now traveling to the planet you are on

    Shay DetertShay DetertPäev tagasi
  • 6:29 *:)*

    Aaron GayodAaron GayodPäev tagasi
  • Can you make a video on Super Symmetry please???

    Akash GuptaAkash Gupta2 päeva tagasi
  • part time-machine-like observation ..?... to see time like this makes you wonder. If time is this "easy "to watch how can we " put some tools to it" so we can use it in different way's. B.D.W is it : Hawkeye

    MrLaTEchno Reality,Stop Fake News.MrLaTEchno Reality,Stop Fake News.3 päeva tagasi
  • I have long waited for a mind blow like this. thank you for granting me such a treasure

    Weiss MerlinWeiss Merlin4 päeva tagasi
  • "Hey there's a new supernova on that galaxy! Never mind, it's just the same galaxy's lensed pic delayed due to gravity".

    AstropjAstropj4 päeva tagasi
  • The universal equivalent of a photo bomb

    Julian HarleyJulian Harley4 päeva tagasi
  • so well explained.

    9B 34 Dominic9B 34 Dominic5 päeva tagasi
  • Einstein?

    RIZE RenNerdClubRIZE RenNerdClub5 päeva tagasi
  • *BeetleJuice, BeetleJuice, BeetleJu-*

    JustMoseyinAroundJustMoseyinAround6 päeva tagasi
  • About a year to late. On astronomy I had to write a paper about Gravitational lensing. Good thing your video about Black Hole and how it looks like helped. I even linked than video in that.

    pokfenpokfen6 päeva tagasi
  • I'm absolutely goob smacked!

    ronkirk50ronkirk506 päeva tagasi
  • WIth this information we should be able to create a concrete equation on how much our movement is effecting redshift, why do we not see this equation when calculating the Hobble Constant?

    SutairnSutairn6 päeva tagasi
  • any day now ... *in the next 100,000 years*

    Jacob SawyerJacob Sawyer6 päeva tagasi
  • I'm on this guys wavelength so frickn happy you made this rite on man

    Bo ReedBo Reed7 päeva tagasi
  • Do galaxies revolves around some things?🤔

    SKM GAMERSKM GAMER8 päeva tagasi
  • Looks like the supernova came to bargain.

    h.s.mani deeph.s.mani deep8 päeva tagasi
  • 1:40 "In the next hundred THOUSAND years." :(

    Big DogoBig Dogo8 päeva tagasi
  • Gravitational lensing blows my mind. "Oh, those four galaxies you can see over there? Yeah, they're the same one..." Madness.

    Big DogoBig Dogo8 päeva tagasi
  • What I thought of this ?? Wowweee... please teach me how did they measure the trajectories and times so accurately.... what math is behind this?? If they published a paper??

    Sourav DeySourav Dey8 päeva tagasi
  • One of my favorites video! Thank you so much

    Alberto MalvidoAlberto Malvido8 päeva tagasi
  • "In 2015 astronomers successfully predicted the appearance of a supernova within a couple weeks." Technically, that was not successfully predicted a supernova(the event happened at the end life circle of the star far far away), just predicted what image(what we would see from the Earth) the Hubble telescope would get according to the video, which were two different things. Am i right?😉😉😉😉

    GplayerGplayer8 päeva tagasi
    • That's the actual image. Yes, it already happened and we are only seeing it now. Not exactly a prediction but it takes time for information to pass.

      Wandering DustWandering Dust5 päeva tagasi
  • He said stars in nearby universe by mistake. Lol 9:31

    Makaveli ThedonMakaveli Thedon9 päeva tagasi
  • Where’s the universe expanding FROM?

    Diego FerreyraDiego Ferreyra9 päeva tagasi
  • We are so lucky to have Einsten

    a ba b9 päeva tagasi
  • This is incredible. I don't know what else to say.

    Unknown ProdigyUnknown Prodigy9 päeva tagasi
  • Makes you realize space is mind blowingly massive.

    Reuben SternReuben Stern10 päeva tagasi
  • A long time ago In a galaxy far far away?... Proof of Darth sidius and his death star.

    Reuben SternReuben Stern10 päeva tagasi
  • Einstein cross Jesus Christ!

    arnav soodarnav sood10 päeva tagasi
  • Soo... Does it mean that if we have a telescope sharp enough to see individual planet on galaxies far far away, and strong enough to catch light reflected from earth, we can technically see our past?

    Yuda DwiYuda Dwi10 päeva tagasi
  • Good hosting, not everyday i see.

    James BlackstarJames Blackstar10 päeva tagasi
  • A lens made of "graveity". Yeah right, what sorcery is this? Gravity doesn't even existt

    JebClangJebClang10 päeva tagasi
  • We can predict a supernova but not corona?

    Denzyl CasuelaDenzyl Casuela11 päeva tagasi
    • Maybe because universe changes but very slowly compared to it's size, when viruses mutate fast, thus we can't predict all mutations.

      Maciej CholewaMaciej Cholewa11 päeva tagasi
  • I wish i was not in a city so i could see this rare phenomenon

    Harish DubeyHarish Dubey11 päeva tagasi
  • This is the most surprising video I have seen in my life! It got me Goosebumps! Humans are incredible to have discovered this!

    klaas victorklaas victor11 päeva tagasi
  • The previous video title was more juicy, at least I feel

    Bhaskar BhardwajBhaskar Bhardwaj11 päeva tagasi
  • Amazing

    WillianWillian11 päeva tagasi
  • absolutely adoreable to be able to work on such topics!

    PanarborePanarbore12 päeva tagasi
  • So...The flat earthers are not wrong! They are right in another perspective

    Rama BandyopadhyayRama Bandyopadhyay12 päeva tagasi
  • Your videos are lit 👍🏻

    Mohd SameerMohd Sameer12 päeva tagasi
  • Thank you! Ah...I thought it will be about building a lens for a gravity laser. But this is very interesting too.

    Andrey SergeevAndrey Sergeev12 päeva tagasi
  • Meanwhile supernovas image giving us a creepy smile at 6:25

    Phantomrocks #phaniPhantomrocks #phani13 päeva tagasi
  • Can anyone tell me how light is traveling in a curved path..I have learned that light travels in straight line.

    yogesh jangidyogesh jangid13 päeva tagasi
    • I don't know what does really moving straight means but let's say it is moving while being not affected (accelerated) by any force. That means nothing is changing the momentum of a photon I guess. I would naively say that light indeed travels in a straight line through space but if you bend space itself then that line is no longer straight. Photons have no mass - gravity does not pull them as regular objects with mass. The gravity is bending space and time therefore anything in that space is bent too. You can draw a straight line on a paper sheet then crumple that paper - so the line will be straight relative to the paper but not to the world around it. That way path of light is curved. That means that the direction of a photon is changed - so its momentum. So I will guess you need to spend some gravitational energy on that. But what is the least possible degree of that curvature? That I don't know. If you look at curved lines on a display they are made from pixels - so any circle is in fact a sum of small straight segments. If that is the case for space curving then there are always some parts of space where light indeed travels in a straight line - because it can't be affected by any force. If not then you can arrange a bending of any degree at any place so it's not necessary to have any straight segments at all.

      Andrey SergeevAndrey Sergeev12 päeva tagasi
  • Wait til' the UK viewers find out that the 5000 pound Techie Bundle actually weighs 5000 pounds (

    John BerryJohn Berry13 päeva tagasi
  • it was Isaac Newton.

    Mahmoud MostafaMahmoud Mostafa13 päeva tagasi
  • when my boss catches me in a foto somewhere else..can i explain that its perhaps gravitational lensing...both time and place r incorrect..i was actually working at home ;)

    DevNDevN13 päeva tagasi
  • and millions of people r convinced they know it all from 1 holy book.

    DevNDevN13 päeva tagasi
  • It sucks

    Trying1 /Trying1 /13 päeva tagasi
  • amazing !!!!

    Ryan JohnstoneRyan Johnstone14 päeva tagasi
  • This just reinforces a question I have had for over 10 years. Using the discipline of the null hypothesis prove to me that every galaxy you see in the cosmos isn't the same galaxy seen from a different angle at a different time? The cosmos as a hall of mirrors.

    Chris MethotChris Methot14 päeva tagasi
    • The first answer might be how could we see galaxies merging if there were only one.

      Chris MethotChris Methot11 päeva tagasi
  • Gravitational lensing is one of my favourite concepts!! And this is amazing!!! Loved the way the video is made. Seemed like we are in space!!!🌌

    Kinnari BhaleraoKinnari Bhalerao14 päeva tagasi
  • Space has always been an inspiration for me. Hubble is fascinating my heart day by day.

    Muhammad Hamza TahirMuhammad Hamza Tahir14 päeva tagasi
  • Star: Betelgeuse Me: Be tel gese Veritasium: Bettle Juice

    Gabriel FerrãoGabriel Ferrão14 päeva tagasi
  • Its incredible how much info scientists can extract from these tiny little smears of light

    FezRezFezRez14 päeva tagasi
  • 1:32 beetlejuice

    Wu ChenglinWu Chenglin14 päeva tagasi
  • It's fascinating that how much information astronomers can get from pictures, from a normal person, not so much.

    Prince Fel Ezekiel R. LicardoPrince Fel Ezekiel R. Licardo14 päeva tagasi
  • And here I struggle getting a decent pic of my dog.

    Dennis DDennis D14 päeva tagasi
  • Is this one of the first generation stars in the universe ?

    Nae DolorNae Dolor15 päeva tagasi
  • Great video Derek, thank you for teaching me so many interesting things! By the way, I'm just thinking... I've been following you since 2013. Most of my closest friends I've known for less time than that. And your videos continue to amaze me! Take care Derek, and keep up the excellent work! (no pressure :-)

    David M. JohnstonDavid M. Johnston15 päeva tagasi
  • did you break the space time continuum? no worries, just seal it with FLEX TAPE! *slaps tape on spacetime*

    Learning UnityLearning Unity15 päeva tagasi
  • Only Legends Know the Title of This Video Has Been Changed

    Ninty 9Ninty 915 päeva tagasi
  • I love your videos! You make them entertaining and you have a catchy voice.

    Mr. Thomas A. AndersonMr. Thomas A. Anderson15 päeva tagasi
  • Varitasium and 3brown1 blue are best ones also PBS videos too

    Soumen BhattacharyaSoumen Bhattacharya15 päeva tagasi
  • Does this mean that light can «move» an object aswell? Like airflow over a wing creating lift?

    Fredrik Attila FarkasFredrik Attila Farkas15 päeva tagasi
    • You can push stuff with light. There's the idea of "light sails", large reflective structures that can be put on a probe or satellite of some kind and allow it to use the solar wind. And last year or the year before that the nobel prize in physics got awarded to a team who created a kind of "tweezers" with light.

      LünkelLünkel4 päeva tagasi
  • 3:48 Damn that looks creepy lmao

    Mohammed ShaikMohammed Shaik15 päeva tagasi
  • This is mindblowing sorta. Also makes me feel incredicle dumb compared to actual smart people. I knew math was important and read electronics in high school so did alot of math. But counting math that bends light by gravity and mass vs distance and time to the object and beeing able to count that far back including by my guess a ton of gravity bends/warps between stars, galaxies of the fabric of space, with an end result of different years and times to the day, which you can view the same exact thing happening. 🤯 Now thats some hardcore math right there.🧠 Also how isnt Einstein an Emoji by now. 😎✌

    Balubish TechBalubish Tech15 päeva tagasi
  • Oh its such crap.

    seachangeauseachangeau15 päeva tagasi
  • Wow, this really opens your mind! It’s like taking drugs OMG. Loved it!

    Jimmy JohnsJimmy Johns16 päeva tagasi
  • 6:29 Seems deep space is smiling on us!..with a cigarette in its mouth! 😵

    Mohd ShariqMohd Shariq16 päeva tagasi
  • What if, as the universe expands, the general speed of light increases? Meaning, if we had a window into the future we would observe everything moving faster. This does not affect the Doppler shift, which only cares about the 'stretching out' of light as it moves, since all 'parts' of light will be speeding up at the same time so there will be no differential that would be evidenced in the color shift. However it may 'speed up' other observable cosmic activity, meaning light reaches us faster than expected if it were moving at a 'constant' speed. Therefore the calculated expansion rate of some methods gives a lower result.

    Lar Wor TsomvLar Wor Tsomv16 päeva tagasi
  • Am I still on time to answer the question? Which is actually wrong it was Sir Isaac Newton who answered to RICHARD BENTLEY (theologian and philologist) “That gravity should be innate, inherent, and essential to matter, so that one body may act upon another at a distance through a vacuum, without the mediation of anything else, by and through which their action and force may be conveyed from one to another, is to me so great an absurdity that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it. Gravity must be caused by an agent acting constantly according to certain laws; but whether this agent be material or immaterial, I have left open to the consideration of my readers” this was in answer to And what Richard Bentley wrote that generated Sir Isaac Newton’s answer was And as for gravitation, tis impossible that that should either be coeternal and essential to matter, or ever acquired by it. Not essential and coeternal to matter; for then even our system would have been eternal (if gravity could form it) against our atheist's supposition and what we have proved in our last. For let them assign any given time, that matter convened from a chaos into our system, they must affirm that before the given time matter gravitated eternally without convening, which is absurd. {Sir, I make account, that your courteous suggestion by your last, that a chaos is inconsistent with the hypothesis of innate gravity, is included in this paragraph of mine.} and again, tis unconceivable, that inanimate brute matter should (without a divine impression) operate upon and affect other matter without mutual contact: as it must, if gravitation be essential and inherent in it.

    raedtrabraedtrab16 päeva tagasi
  • Gravitational lens smears images from Hubble telescope. What is the cure for distortion? Apart from making intelligent assumptions/guesses, there seems to be no other method to give a clearer image.

    Kumar Digvijay MishraKumar Digvijay Mishra16 päeva tagasi
  • The Real Question: How do scientists notice a tiny dot of a star in the middle of so many blurs and other stars?!

    sokin jonsokin jon16 päeva tagasi
    • “You will be able to see beetle juice’s supernova” Me: “Hmm”

      ryuhjn yguhryuhjn yguh18 tundi tagasi
    • Generally, you can find the difference between two consecutive images by subtracting one from the other. Everything that's the same cancels, and only the changes remain. Also, in the case of the supernova in the video, they were expecting it to appear in a specific location.

      Michael PolakowskiMichael Polakowski4 päeva tagasi
    • They don't. No, but with the power of modern technology, devoted people, and some of the smartest people on the globe many things are possible.

      A GA G8 päeva tagasi
    • Unstoppable curiosity does it all...I am more surprised to know that there is actually stuff like time dilation.5 years out from physics and I thought it is all theoretical.Guess that's why flat earthers still exit.Might be of my kind:)

      Aadil PeerAadil Peer8 päeva tagasi
    • It’s their passion... they love to do that.. isn’t that amazing??

      Sourav DeySourav Dey8 päeva tagasi
  • I want to live hundreds of years to observe and study all the knowledge in universe. Sadly humans life span isn't long enough for such thing. I want to discover new planets, understand what is behind this universe. I don't wanna die without knowing why I was here.

    ilkercan Kayailkercan Kaya17 päeva tagasi
  • Veritasium pumping out superlative quality content is one of the rare positive things about 2020 - How do they do it? That's the real mystery

    Amadley GamingAmadley Gaming17 päeva tagasi
  • Gravitational lensing maybe a misinterpretation, this lensing could also be produced by cosmic space, becaused *space is not completely empty-it is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium.* It is the space medium itself that causes this light refraction phenomena. Then it becomes understandable that galaxies tend to form a higher density of this space medium ( Halo) , which produces the lensing effect, and has nothing to do with gravitational fields.

    Ruben Anthony MartinezRuben Anthony Martinez17 päeva tagasi
    • So here is a neat trick folks! This will help you understand the universe and that Big Bang everyone keeps babbling on about. Take a stone, throw it in the pool, watch the rippl

      sokin jonsokin jon16 päeva tagasi
  • 30 October 2020 - I started to study stars and supernova. 14 November 2020 (today) I am watching this video. 11 December 2020 is my birthday. Now skip to 2:30

    Gagandeep SinghGagandeep Singh17 päeva tagasi
  • I don't know why I just thought of this question weeks after the video, but if gravitational lensing can allow us to see the same light source appear at multiple points and over different time periods, how can we know a lot of what we see in the sky isn't lensed from somewhere or someWHEN else? We would be counting some of the pinpoints of light in the sky multiple times, skewing our data right?

    CyberBeast66CyberBeast6617 päeva tagasi
  • Space time would seem to not be homogenous in the universe thus various gravitational lensing effects.

    Ry V.Ry V.17 päeva tagasi
  • 6:30 creepy smiley face

    Ayoub BerradaAyoub Berrada17 päeva tagasi
  • My brain hurts now

    Charles RogersCharles Rogers17 päeva tagasi
  • He is cool🤯

    MH PromitMH Promit17 päeva tagasi
  • Can you please make a video that proves Universe is infinite?

    Aditya RayapureddyAditya Rayapureddy17 päeva tagasi
  • 6:31 oh a luck smiley

    RobloxGamezRobloxGamez17 päeva tagasi
  • Splendid and extraordinary video on lensing. Made me case study it intuitively. May god bless you.

    Chitra LekhaChitra Lekha17 päeva tagasi
  • Before I thought something else After - ohh so this is what happens!

    • able to travel the galaxy/ies but have died off millions/billions years ago?

      bilishu alissbilishu aliss17 päeva tagasi
  • Great video, but all this astronomy talk is so pointless really. How about giving the wasted money to buy food for the hungry.

    jake friesenjake friesen17 päeva tagasi
    • I hope Fasthosts got better in the last 10 years, because they used to be shockingly bad!

      bilishu alissbilishu aliss17 päeva tagasi
  • I'm glad we have Derek as the cosmological information lense in our time. 1000 years later, he'll reappear on an other planet

    Thinkclear BellThinkclear Bell18 päeva tagasi
  • can sit still through this entire video.. Well done man.

    aola wiliaola wili18 päeva tagasi
  • 🤔👍

    Gacheru MburuGacheru Mburu18 päeva tagasi
  • One thing Veritasium talks about in a future video is how currently we can't confirm the speed of light in one direction. Therefore, given that we don't know if the speed of light is the same in all directions doesn't that make our current methods of measuring universal expansion inherently flawed? They would be working upon an assumption that hasn't been confirmed, so like light, the universe could be expanding at different rates given the direction you are facing.

    SveredianSveredian18 päeva tagasi
  • So here is a neat trick folks! This will help you understand the universe and that Big Bang everyone keeps babbling on about. Take a stone, throw it in the pool, watch the ripples expand faster and fast and faster until they reach the edge of the pool! Did you notice how they kept getting faster and faster? No? Well guess what, I just lied to you. THINK ABOUT IT!

    Nevermore77Nevermore7719 päeva tagasi
    • Tony Stark: No amount of money has ever bought a second of time. Veritasium: How about the cost of Hubble telescope?

      aola wiliaola wili18 päeva tagasi
  • But you didn't explain how this latest method of measuring the Hubble constant works. How you get the Hubble constant by measuring the time delay between different images of a supernova? Now, I'll have to check all the referred articles in the description.

    will2seewill2see19 päeva tagasi
  • 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

    ShabléShablé19 päeva tagasi