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The Strange Universe of Gravitational Lensing | Space Time | PBS Digital Studios

November 30, 2019

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  • Reply night3x December 17, 2017 at 1:52 pm

    5:06 why there is 4 spots, not for exemple 7 or 8 etc?

  • Reply ViciousCrabs December 27, 2017 at 6:40 am

    Love the show man I gotta watch you a few times but you do a great job of explain explaining the complicated stuff. Still wish I understood all of it but you've taught me a tonne. Keep it coming.

  • Reply Science Guy January 5, 2018 at 7:13 pm

    Is there a reason, the photons orbiting the black hole form a disc instead of a sphere?

  • Reply weeral1 January 6, 2018 at 1:53 am

    A lot less flat earthers here than I would have guessed. So refreshing!

  • Reply Emilio Hernandez January 27, 2018 at 8:36 am

    Haha what if Matt is secretly Tyrion's twin brother, who somehow floated too close to a black hole, got stretched, and travelled forward in time to the present day?
    Think about it…

  • Reply Shepard February 2, 2018 at 6:54 pm

    Matt just share my pain here! How does one enter and survive a black hole! Ughhh! Chris! Such a disappointing 2nd half for such a great 1st half!!

  • Reply Ritesh Bachhar February 3, 2018 at 7:18 am

    why we see just 4 images of the quasar, why not a series of images?

  • Reply Ron Morales February 8, 2018 at 3:14 am

    The Brennan-monster in Niven’s Protector made a telescope to peer into Sagittarius A based on the same principle. Plausible?

  • Reply merdemoiii - March 11, 2018 at 3:42 pm

    I find photos of gravitational lensing so amazing

  • Reply piccolonijel March 14, 2018 at 11:58 am

    are diffraction and refraction and consequently speed-changing light considered, due to changing plasma density regions, while counting the associated light deviation in the overall distance traveled by light in the universe?

  • Reply Lee Kelly March 15, 2018 at 5:09 am

    Is it possible for light from a star or galaxy to bend around a black hole such that an observer would see the same star/galaxy in two points in space at the same time? Albeit from different sides, similar to observing an object in front of a mirror from behind and seeing both front and back simultaneously…

  • Reply Uncle Stan March 30, 2018 at 11:19 pm

    Man FUCK the universe why it gotta be so fucking weird

  • Reply Matheus Traldi April 1, 2018 at 4:46 am

    Techno on background. Dope

  • Reply Victor Vaca April 11, 2018 at 3:22 am

    Why does his tongue do that at 2:12 when he says "SUN?"

  • Reply Poseidonc12 April 12, 2018 at 4:42 am

    Jesus christ! This channel has the most poetic rhetoric I’ve ever heard. Every episode is inspirational beyond belief. Thanks for revealing these discoveries in a manner that allows so many people to more easily comprehend this complex universe!

  • Reply fgcbrooklyn April 29, 2018 at 2:00 am

    I can't stand this guy and his overdone accent. Why must PBS recur to a person who has such a heavy non-standard US accent? Is it because he can get away with a British accent? What would be the response to someone with an Hispanic accent, or Indian, Middle Eastern? There is a nauseating bias in favor of British accents. I feel the exact opposite. I find them off-putting and conceited. This guy in particular seems (to me) he is pushing it as much as possible. And I can't stand it. I can't stand it.

  • Reply n balaboon May 10, 2018 at 8:38 am


  • Reply DoJo Starfox June 7, 2018 at 4:16 am

    So why does lensing seperate light into 4 instances?

  • Reply gotama420 June 12, 2018 at 1:05 am

    when i first heard of G.l. i could not help but remember taking a magnifying glass to an anthill…

  • Reply Jason Gruber June 12, 2018 at 2:12 pm

    Can gravitational lensing be used to measure the gravitational field of the foreground source? I would like to test to see if the source follows the inverse square law of gravity.

    My hypothesis that Dark Matter is not a WIMP, but maybe is a deformation of space-time by which the curvature of space-time ALONE is the cause of the gravitational effect. Gravity is the consequence of the curvature of space-time. It may be possible that the structure of space-time itself could be warped without the presence of mass. Space-time has been shown to react like a fabric by warping, twisting, and propagating independent of mass. These properties have been proven with observations of gravitational lensing, frame dragging, and now gravitational waves. Fabrics can be stretched, pressured, and/or heated to the point of deformation. Such extreme conditions were all present during inflation, so it is plausible that space-time’s elastic nature could have hit its yield point and permanently deformed. Therefore, if gravity is the consequence of the warping of space-time, and fabrics can be permanently deformed, then a deformation could create a gravitational effect independent of mass. DM could be a microscopic black holes with no mass at the center, so they wouldn't lose their strength via Hawking Radiation.

    Prediction: Spacetime's elastic property hits a yield point, so only that part of geodesic's "stretch marks" would remain after inflation stopped. These steep gravitational wells would not follow the inverse square law.

    They would be steep tiny gravity wells.

  • Reply Ed Thoreum July 1, 2018 at 2:46 am

    any video on methane hydrate in artic? Compared to venus greenhouse?

  • Reply White Night July 2, 2018 at 2:20 pm

    And everyone Thought I Was Crazy where I Told Them Not to trust" Your wisdom, Because it Will fail you.Thats why we need Each Other To pull The other one Out,Out Of what ?A black Hole, Hahaha

  • Reply Pedro Honrado July 17, 2018 at 5:30 pm

    Does this mean that Newton was wrong? That massless objects are also affected by gravity?

  • Reply David Wilkie July 18, 2018 at 2:15 pm

    Shouldn't "lensing" be entirely Quantum in the general cause-effect wave-package of QM-Time modulation principle?, and the "gravitational" lable assumed to be like a "temperature" energy averaging concept of "space(ing)-bonding", =quantum, emissions and absorption/integration of QM-Time modulation (?) Ie Gravity Quantum identification of the specific phenomena is part of the spectrum of lensing, and "Quantum Gravity" as an identity, has the lack of reversiblity of Quantum Operators, ..does not compute Quantum Mechanically.

  • Reply Eddie Lopez July 24, 2018 at 6:51 am

    Tell me you guys don’t believe this lensing effect isn’t a coincidence for us the observer or any other intelligent beings looking into the cosmos. We can spot galaxies behind this effect that we wouldn’t be able to study our telescopes. So when our new James Webb telescope peering through the infant stages of the universe imagine what gravitational lenses will be seen at that distance something about our universe seems to work in our favor. The more I think about how nature works the more I begin to think that we are actually living in a simulated universe. Maybe one that we created with our minds… thought created the Big Bang and that time and space are interlocking even at the quantum levels in we can see the smallest of smallest quantum particles smaller then string theory we will be peeking at the universe it’s self. The further we look away into the cosmos the smaller the universe gets remember the Big Bang all matter was a singularity.

  • Reply Jim Hart July 27, 2018 at 3:33 pm

    I've been curious about how the universe really looks without the augmentations we get for so many of the photos we get….

  • Reply TheProdigalFrog July 29, 2018 at 7:00 am

    I really really don't understand Photons. How do these particles fight their way out of stars, travel billions of light years, often colliding with other particles and being absorbed, or traveling curved space including red shifting etc , and THEN enter our telescopes and reassemble to give us an image of the original object?

  • Reply Ashyo Sings July 29, 2018 at 5:41 pm

    Then light has such little mass that it has the lowest form of energy possible. Yet the sun can give us solar power! We need a theoretic physicist to figure this out so we can get ahead in technology

  • Reply Penny and Jakes Mom August 11, 2018 at 2:04 am

    I watched your mini documentary. very cool. thank you for sharing with us.

  • Reply Katherine Kruikshank August 24, 2018 at 6:13 pm

    Is this guy high? His voice is so mellow.

  • Reply naresh sahu August 25, 2018 at 5:25 pm

    the universe is full of awesome stuff, we'll never run out of things that make us wanna know more.

  • Reply Sister Satan August 25, 2018 at 11:13 pm

    yes THIS thank you

  • Reply White Night September 12, 2018 at 2:55 pm

    Doesn't that mean we can predict Where the next Or same electron Is going or appear ? Predict.

  • Reply White Night September 12, 2018 at 3:21 pm

    Sense the beginning when the Earth was one Bubble god has separated them more and more to protect himself and keep power" with Quantum Computers we can Repair the Lattice's back to One,And Control our own Destiny's .

  • Reply El PresiDanTei September 14, 2018 at 10:03 pm

    Would it be possible to live in a galaxy with a quasar? Or would the radiation emanating from the black hole, accretion disc, and subsequent jet be to much?

  • Reply gut viol September 23, 2018 at 9:41 pm

    these days

  • Reply entimonGER September 25, 2018 at 2:14 pm

    I really like your Explanation skills. TY PBS
    but here comes my but:
    how real is G-lensing? recently NASA confirmed the "hydrogen wall" near the 'end' of our solar system. so there is a wall with another density. When light shines through it will be refracted. So other stellar objects will have a simular wall of matter with another density. when we shine light through those circular walls, light will also be refraced and forming a lense.
    so there is no need for g-lensing or spacetime or einstein.
    wake up

  • Reply E Loesch October 21, 2018 at 11:12 am

    Please do an objective video on the Electric Universe and Plasma physics. Thank you.

  • Reply paulczar October 26, 2018 at 3:25 am

    Feel like these guys know more than their saying. Kinda like they may have already cracked the code.

  • Reply Daniel Clarke October 27, 2018 at 2:28 pm

    warning, incoming game

  • Reply 250txc October 27, 2018 at 4:32 pm

    Weird is listening to english being spoken, understanding every word that is spoken, and yet not having a clue as to what the speaker is saying 🙂

  • Reply putipong thawonwong October 28, 2018 at 3:34 pm

  • Reply alimiel October 28, 2018 at 10:48 pm

    The Lensing researchers need to collaborate with the spectroscopist so they can account for how gravity shifts spectra as well as from doppler shift. Our assumption in measuring the Hubble constant is invalid if intervening masses are shifting spectra and our distance measurements would be off more and more the further off we look. Einstein could be right about the universe being static and infinite.

  • Reply Mr. Sanders October 29, 2018 at 6:25 pm

    Must pay to watch a video from 2016? WTF PBS?

  • Reply Douglas Dorman October 30, 2018 at 6:57 pm

    Thank you Family that is beautiful, peace and love, Doug:)<3.

  • Reply Mübin Icyer October 31, 2018 at 2:01 pm

    What is the background music?

  • Reply it's ok to smirk November 2, 2018 at 11:49 am

    I wish the word "agog" from the old timey news paper was still used in every day conversation

  • Reply Adrian Hera November 14, 2018 at 7:24 pm

    If we can lense with gravity can we make a mirror with gravity?

  • Reply Kyle Warren November 17, 2018 at 6:32 pm

    But why/how are photons (massless particles) affected by gravity?

  • Reply Nebula Games November 20, 2018 at 10:13 pm

    Wouldn't finding the gravitation Lensing "solution" to find the "true" configuration, without multiple source verification, lead to possible false positives, which in turn could cascade into bad math propagation?..

  • Reply Toughen Up, Fluffy November 21, 2018 at 4:40 am

    How can you use gravity waves to demonstrate gravitational lensing? Hint: trick question.

  • Reply Toughen Up, Fluffy November 21, 2018 at 4:42 am

    Lose the stinkin ambient music! Bwah!

  • Reply Steve Davis November 21, 2018 at 9:09 pm

    glowing nads at 3:28!

  • Reply Tadesan November 21, 2018 at 10:58 pm

    Wow dude. The thought process at 3:50 is great and is described incredibly well. Bravo!

  • Reply onehit pick December 5, 2018 at 6:57 am

    It's absolutely unbelievable and amazing that normal lensing isn't predominant. Significant lensing happens over the hood of a car with just a minor variation of pressure. It's amazing, almost unbelievable, that this phenomenon isn't considered commonly in the cosmos with all the significant variations of density that are around. The arguments against normal lensing are the missing dispersion, but I don't see any rainbows over the hood of a car, and I don't expect any rainbows from a varying density of simple particles.

  • Reply Me Games December 13, 2018 at 10:44 pm

    I use gravitational lensing in video games.

  • Reply Life-Row-Toll December 14, 2018 at 6:52 am

    2 years later, and this video has already been debunked.

  • Reply Debraj Chakraborty December 14, 2018 at 5:31 pm

    Eloquent vivid description with acoustics background and Einstein should be awarded prize for General and Special theory of Relativity it's something his thinking visionary and ultimate Triumphs of Science

  • Reply Debraj Chakraborty December 14, 2018 at 5:42 pm

    Ultimate Genius of Mathematical Physics and for his contribution those Ringing beauty sparkles from quasars is Albert Einstein's showering and levels

  • Reply Daniele Odorico December 17, 2018 at 3:00 pm

    If we could have a magnify lens big enough to literally see particles… should this considered as an observation that alters and make the function collapse? Even if we don't interact with the particles but just look in the lens?

  • Reply statikreg December 18, 2018 at 5:29 am

    You're my favorite presenter b/c you don't do awkward hand movements. Your arms and hands stay close to your body and only serve their limited purpose in expression – 99% of what I "get" comes out of your mouth. Most presenters on this channel are too animated and it feels somehow awkward to me. It's probably 100% subjective but I hope you have a long career here lol

  • Reply Aaron Reid December 20, 2018 at 3:08 am

    It is possible to see Einstein's Cross with an amateur telescope from very dark skies. For reflecting telescopes, the mirror diameter needs be 16-18" (IIRC, the apparent magnitude of the Cross is 16+)

  • Reply Thomas Callahan December 22, 2018 at 5:36 pm

    No such thing, it's just refraction of light though a different density. Like how a straw breaks when looking at it from the side of a glass. Search Thunderbolt project and get un plugged from the matrix. Its electricity, not gravity that drives the universe.

  • Reply Yannis Constantinides December 23, 2018 at 11:17 am

    Since the path of the light is bent, does it take longer to get here than it would otherwise? And since mass distorts time as well, are both courses the same length from the photon's perspective?

  • Reply Samwisegamgee The Brave December 29, 2018 at 4:35 pm

    I love quantum mechanics 👍😘

  • Reply Kilraun Last name redacted January 11, 2019 at 6:01 am

    so, how much affect does Earth's gravity have on how we perceive the universe? i'm sure that Earth's gravitational lensing is minute, but do our maths account for it? also, if our maths do not account for gravitational lensing, what is correct? maybe the stars shine brighter through our atomosphere because of gravitational lensing, maybe not.

  • Reply Michael Lowe January 13, 2019 at 4:43 am

    Possible thought experiment: a photon leaves earth. Through multiple near passes of massive objects, it is redirected multiple times until its final path causes it to intercept earth's path again. In effect could you see a photon from your own past? If every photon reaching earth were able to be mapped, could you see events of the past? Obviously a tall order, but just one photon proves the concept.

  • Reply HakWilliams February 3, 2019 at 7:21 pm

    this gravitational lensing is making it hard for me to get off the couch

  • Reply Shawn Elliott February 16, 2019 at 8:48 am

    Why does the Einstein Cross produce four distinct images of the distant quasar instead of a continuous donut-shaped image?

  • Reply 4Elevation February 16, 2019 at 6:50 pm

    See also on youtube: Milky Way's Magnetic Field and consider that magnetic fields bend light.

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  • Reply Don't, Jimm March 22, 2019 at 1:20 am

    Awesome video!

  • Reply siwa69 April 9, 2019 at 1:13 am

    You are hot

  • Reply Craig Bleakley April 12, 2019 at 5:20 am

    I have enjoyed this logic several times. My thought is, could this process reflect an image of our earth in the past if the lensing could be at 180 deg. Depending on the distance to the gravitational body. This would blow our minds.

  • Reply MonochromeWench April 26, 2019 at 3:25 pm

    when this video was made we hadn't imaged a black hole but as of now we have

  • Reply Hose2wAcKiEr May 12, 2019 at 4:16 pm

    9:00 LUL this video needs to be updated

  • Reply Dedrick Howell May 13, 2019 at 4:52 pm

    They only come out at night…..mostly.

  • Reply Chilledfish May 28, 2019 at 4:10 am

    Wait a minute… I've watched a few "PBS Space Time" videos today, and the one called "The Crisis in Cosmology" was about how we have conflicting measurements of the Hubble Constant. So which is it?

  • Reply zealman79 June 5, 2019 at 3:36 am

    Newt: "They Mostly come out at night….MOOOOOOHSTLY"

  • Reply Aubrey De Bliquy June 26, 2019 at 8:56 am

    Einstein said that if any of his three proofs of failed, his theory failed.
    Eddington simply confirmed lensing at the solar plasma limb which is refraction @ 1.75 arc seconds every time since defined by the refractive index of a plasma sphere of sun diameter.
    The fact that other than 1.75 arc seconds has never been observed proves relativity is wrong and Eddington just proved refraction which the telescope he was using ironicly used. LOL

  • Reply Viking Child June 28, 2019 at 8:52 am

    Rod Sterling would be proud of this video. I see him smoking his cigarette right now. Lol

  • Reply sirnukesalot24 July 12, 2019 at 9:57 am

    Is there any explanation given for why the Einstein cross consists of exactly four images, rather than a vague ring of light?

  • Reply kingpest13 August 18, 2019 at 4:43 am

    The rocket equation, it's a beautiful thing…. I would think that astronauts hate it.

  • Reply PoE September 1, 2019 at 1:02 am

    It wasn't exactly as Einstein predicted, it was roughly close.

  • Reply Colbert Philippe September 2, 2019 at 12:29 am

    Can gravitational lensing allow us to view a bit outside of the visible universe?

  • Reply Tom Atkinson September 12, 2019 at 1:56 pm

    You'd probably be shocked to know you are likely spreading dis-information. Einstein rings theory has recently been dis-credited by Dr Ed Dowdye, see:

  • Reply Monte D Young September 12, 2019 at 7:02 pm

    The euclidean space is not boring, that’s the way it really looks without all of the lensing Tricks.

  • Reply Geeta arora September 17, 2019 at 7:41 am

    Why does lensing occur when photons have no mass shouldn't they feel no effect of gravity

  • Reply I Kaymon9 September 18, 2019 at 2:25 pm

    Then why don't we see some stars as circles of light in the sky as this "Gravitational lensing" is caused by round bodies?,Hhhmmm…..
    Or maybe you're trying to say that a light source emits four light beams?

  • Reply Christopher Speirs November 3, 2019 at 7:38 pm

    Your name is not in the credits of the linked video with the Museum of Natural History.

  • Reply NameNotAlreadyTaken2 November 4, 2019 at 10:18 pm

    "Here's our playlist on curved spacetime…" (No annotation, no link in description, no idea what he's specifically referring to)

  • Reply Richard Stiles November 6, 2019 at 7:38 pm

    It seems counter-intuitive for gravitational lensing to refract light around the gravitational source rather than to pull it inward and cause a shadowing effect, as in the 'black hole' affect within the event horizon. Every model I have seen of gravitational force acting on a time/space euclidean model shows the linear lines being pulled inward toward the source of gravity. So why would photons decide to go around it?

  • Reply sherab dorje November 14, 2019 at 6:30 pm

    if i can make the density of the air to waters can i swim in air without having problem breathing ?

  • Reply Wizard Clip Audio November 15, 2019 at 4:39 am

    I'd like to have second breakfast with this dude.

  • Reply Pronator Tendon November 18, 2019 at 5:03 am

    Is it hypothetically possible that a distant black hole could gravitationally lens an ultra-intense Gamma Ray burst from an even more distant quasar directly toward the earth, causing negative effects? It seems immensely improbable, but possible nonetheless.

  • Reply Justin Todd November 19, 2019 at 3:46 am

    I figured this out recently on my own. The Universe is not big. We're seeing the same stars over and over again just different perceptions. Also our view on time dilation is wrong. Great vid.

    Also around black holes photons are not only orbiting around but also locked into place. Creating a solid light barrier around the black hole just above the event horizen. That can't be seen until you pass through it. 😁

  • Reply Mike Smith November 22, 2019 at 6:04 am

    World's tallest hobbit

  • Reply pete robinson November 24, 2019 at 5:48 am

    Bugger. I was about to capitalise NEXIIIIII!!!!!

    Then I googled it, and, 'nexuses' is correct.
    I fucking hate Latin. It moves the goalposts an awful lot for a dead language… :/

  • Reply Omnipresent Spirit November 25, 2019 at 9:11 pm

    There is no such thing as gravitational lensing. The effect we see and miss describe is simple refractive lensing😳.

  • Reply Omnipresent Spirit November 25, 2019 at 9:13 pm

    The notion of curved space and time is beyond ridiculous and absurd!

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