Satellites Use ‘This Weird Trick’ To See More Than They Should – Synthetic Aperture Radar Explained.

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Synthetic Aperture Radar is a technology which was invented in the 1950’s to enable aircraft to map terrain in high detail. It uses the motion of the radar and some fancy mathematics to get much higher detail images than should be possible from an antenna small enough to fit on an aircraft.
This process has been extended to satellites and applies to not just the earth, but to other terrestrial bodies in the solar system, notably Venus and Titan which are eternally shrouded in clouds.

For further reading I suggest looking at NASA’s SAR Handbook

And if you want to look at real SAR data the Alaska Satellite Facility has lots of public data

Commercial images in this video come from
Capella Space –
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  1. Jonathan Trevatt

    I thought he said “it sees through clothes” instead of clouds 🤣😅

  2. Lieutenant Lubricant

    So if I pay enough I get a 3d picture of area 51

  3. Chase Graham

    Why do I *have* to click anything with “weird trick” in the title?

  4. jim Parr

    Thank you. Your perspective is always appreciated by me.

  5. jrmorrisjr

    16:01 I see what you did there!

  6. zanec14

    Waiting for the day when you say: “Hello, it’s Scott Manley here! … Or is it?” **vsauce music starts**

  7. aterack833

    Anyone remember the show “Continuum”?

  8. Nuovoswiss

    I wonder if you could use this to find gold nuggets near the surface given how strongly it reflects radar…

  9. Agenda69

    “Generally you can’t see inside most buildings” ,,,,, YET !

  10. Supernova

    I work with SAR images, we use it for tracking ships and oil pollution at sea

  11. ArchytypeNet

    “I’m Scott Manley, making applied science accessible!” Thanks for the super explanation in this video! Very useful. 👍😎

  12. DUCK_

    1:18 “the radar satelites can work at night and they can work through clothes” … creeps

  13. Timothy Whitman

    I love how YouTube asked for feedback… “was this video informative, useful, entertaining, calming?” Well yea, it’s Scott Freakin’ Manley! Even if you have no applicable use for SAR, he told you to fly safe, and that alone is useful…

  14. Derek Moss

    It’s amazing how much influence one can contain in a generation. Continue forth, strong-willed men and women will strive because this moment differentiates the strong from the weak.

  15. Charles Winstead

    Amazing technology, I can only imagine what classified tech’s flying around.

  16. Kevin Street

    Wow, thank you for this video! It’s a really comprehensive introduction to a subject I’d never even heard of until now. Definitely one to bookmark and watch again.

  17. Michael Thiesen

    Man, I love his Accent .. God bless and a happy New Year to ya’ll

  18. J Snyper

    25 years ago I was an imagery analyst in the US Army and we used SAR imagery. Back then resolution was measured in feet, this new stuff blows my mind.

  19. XANi

    Is that TD-3 in the background ? :D

  20. Palaeogeobicho

    and SAR is a very important tool to detect oil spills at the surface of the water (VV)

  21. Michael Nord

    SAR does not actually use the “instantaneous” doppler, or the frequency shift due to the velocity in the relativistic sense. It does use phase shifts over time. I’m a SAR subject matter expert if anyone has questions.

  22. Minesweeper

    I did two theses on polarimetry and also read into the radar aspect. It’s great to hear about this topic again and it brings back that excitement about all the things you can do in remote sensing. I find it hilarious how radar tech works: you can first record the data without “lens”, then afterwards run it through a “lens” to get your image. (Fourier transform is in essence what a lens does.) It doesn’t work in the visible yet, because we would need to record the electromagnetic field amplitudes, which are oscillating to quickly.

  23. Paul Oksnee

    One way to foil this intrusive type of satellite is to emit your own interfering radar signal.

  24. Scott Franco

    Now I know how dogs feel when they listen to people talk…

  25. Lisa Mccartney

    Scott, could you do a presentation on “electro tellurics”–In the 80’s-I could map subsurface details down to about 16k feet with less than 1 meter detail-( structural mapping for oil exploration)-blew the socks off many skeptics. Thanks for your channel!

  26. wattsmichaele

    Maybe the folks wearing tin foil hats were on to something. It sure seems like we are getting bombarded by all kinds of space, planes, drones, and cellphone tower electronic wavelengths constantly. Now if someone can explain this 5g paranoia I’ll decide if I need a hat…or suit. ;)

  27. John Davies

    I absolutely love how whole heartedly nerdy scots back drop is there is something so fun about someone being 100% genuine.

  28. BlackPhoenix Family

    “Hullo it’s Scott Manley here, the Manly Scott!” ……/chuckle

  29. Tokath1988

    Your bookcase is the stuff of insane – I love it. Happy new year my man.

  30. Lucas Ruff

    Scott: Demonstrating circular back propagation
    “Using a clever mathematical trick”
    Me: cries in Huygens wavelets and Stolt formatting
    Scott why do you have to bring back these painful grad school memories

  31. Philip S

    At around 10:15 you mention that high dielectric constant materials reflect radio waves. In this instance, that’s true, but the more accurate description is that it’s interfaces with a high contrast in dielectric constants. That means that the opposite also works and you can see objects with lower impedance contrast, which is how ground penetrating radar is able to range, and describe, objects underground.

  32. Dave P.

    8:48 The next time when I get invited to a party I will just tell them “Sorry, I have to reshape all my lenses.”.

  33. Robert Caldwell

    oh i can hear the conspiracy nuts now:

    flat earther: these are doctored images, they’re not real!
    anti-5g people: omg, they are radiating everyone from orbit!!! How can they get away with this??

  34. George Tsiros

    “Hello it’s Scott Manley here!” No… 😮

  35. Gerard

    Saving the best for last? I was very much intrigued by the title, and this turned out to be the most educational video of the year!

  36. Jason Kaler

    This was really invented to track people wearing tin hats.
    Great, now I can sell pyramidal hats!

  37. IsometricGaming

    I hope scott sits proud on the throne of this channel, a distinguished and successful educator that’s reached millions and millions of people.

  38. Russoft

    man, the FFT never ceases to amaze.

  39. Chris J

    Scott, as an airman on the E-8C JSTARS, I have no comment.

  40. Enpsychlodelica

    Is it just me or should we all love this shit.

  41. Ozzy Explains

    The title absolutely stole my heart, Manley, it was so good! 😂😭🙌🏽💯🎊

  42. just another average kid

    Him : SAR synthetic aperture radar
    Me : SAR supplied air respirator

  43. Dalton Hayhurst

    “ I want to understand.” Scott, “say no more.”

  44. WacKEDmaN

    “Cave Johnson here…”

  45. Blair S

    The fact that they figured out how to do this analogue blows my mind… I understand we do it now with computers, but the people who blazed the trail deserve recognition beyond most. Truly we stand on the shoulders of giants

  46. ned ard

    “This weird trick the banks do not want you to know!”

  47. Arno nümuss

    When I was young, SAR meant search and rescue.

  48. bret hammell

    Scott: You must have spent a great deal of time studying up on this. This is one of those watch several times videos. Thanks!

  49. Paul Haynes

    Brilliant stuff. A 16 minute video on a topic I knew almost nothing about, but which I (mostly) understood! No discord channel, no patreons, no researchers, no irritating ads or sponsoship, not even an obvious script! – just a bloke who knows his stuff and knows how to get it across. Thanks, Scott. Great title too!

  50. Dayanto

    Another really interesting technology is hyperspectral imaging, which can be used see what things are made of by looking at a wide range of different wavelengths in parallel.

  51. Ingmar Hendriks

    FUN FACT: at the company I work for we developed a system that does the same with ultrasound on metal welds to see welding defects. The technique is basically the same.

  52. Fozzy Bear

    Oh there are plenty of military applications. Back in the 1970s when the US first released satellite radar images of subterranean rivers in Egypt, the true message was to tell the USSR “We can see inside your missile silos and bunkers”.

  53. Oodles

    SAR elevation models were extremely important for my research on landslides in southeast Alaska

  54. flantc

    Fun fact. Water’s dielectric constant changes significantly when it freezes. This is used by radar to determine the amount of ice vs water cover.

  55. CrazyWedz

    I’d say this guy knows his stuff.

  56. HouseGurke

    first thing to do when you got your own ground penetrating imaging satelite: fly over area 51 and see what’s really there

  57. Cave Dwelin

    This is definitely one of the most interesting videos I’ve seen in a while.


    You just summed up a 1.5h lecture I had this summer. It’s an exciting topic, isn’t it?

  59. greatsilentwatcher

    “I’ll be watching you… 🎵”

  60. Hans Ulrich Johner

    Some defence applications use image processing of SAR pictures to track moving objects. A helicopter for instance can be hard to be seen on a SAR picture but with multiple pictures you can visualize the rotors, even when it is hovering.

  61. Crush Vanderspleen

    (2:45) A moment of silence for Arecibo.

  62. Jon Jon

    I came here to see the inside of charlie sheens villa, I went home disappointed.

  63. Steve Gifford

    Man you’re brilliant! I have a graduate EE degree in signal processing and I’ve never learned as much about synthetic radar as your presentation.

  64. zebop917

    Thanks, Scott. That just about the best explanation of the principles of SAR that I’ve seen.

  65. Railgap Esoterica

    I worked for one of the premier SAR algorithm shops (we had one of the co-inventors of SAR, a guy we hired out of retirement from Sandia Labs) and one of the cooler things we worked on is differential polarimetry, which enables one to see (for example) whether a road has fresh tire tracks on it vs. the day before – or not, despite no platform being able to actually _directly_ image tire tracks with spatial resolution – no open platform at the time (and possibly even black platforms even now!) have the spatial resolution to do this with conventional EO imaging. But SAR is black magic! See also “targets under trees” or FoPen (foliage penetration), finding submarines by the hump in the surface of the water created by their mass (local gravity!), land subsidence, underground tunneling operations… this is why NRO has been all-in with huge black SAR platforms since at least the 70s. Also, I worked directly – as in, I touched flight hardware – on Magellan, my signature went to Venus!

  66. Thomas Richter

    I need to get my underwater lair project going again… they’ll never find me.

  67. Tyler Costantini

    “Begin looking at the world in a different light” love it!

  68. Pump N Dump

    Man I don’t even know what you said. But I like it.

  69. Steve Scerbak

    Fourier transforms rule so much of mathematics and science. It is absolutely everywhere.

  70. Klausberger

    Wow that was interesting, thank you Scott!

    (Doc Brown was always right by saying “Great Scott!”)

  71. herIes

    SAR, basically the MRI of satellites

  72. Anton Fetzer

    There are Terabytes of data from the Sentinel missions publicly available for free, for everyone to use and the data is updated every day. So you can look at SAR images that are only a few days old.
    The free software SNAP can be used to process the raw data and extract lots of information that cannot be seen in optical images.

  73. Алексей Талейко

    Outro should be said “Spy safe”! :D

  74. KrzysztofzBagien

    You’re playing Phoenix Point, aren’t you Scott? :)

  75. Connor V

    I work on radars in the RAF (ground, not space :P ) and I learned so much from this video!

  76. Jacco van Schaik

    11:06 Oh noes! Mah secrets!

  77. Taylor Peterson

    You freaking blew my mind talking about the optical-mechanical computer that could perform fourier transforms from film data. The engineers of the past were ingenius.

  78. GA Sim Pilot

    Omg Brian overload right there.

  79. covert0overt _

    “Figuring out a nations Oil stockpile….” GOT THAT RIGHT

  80. Amaar Quadri

    8:22 The fact that you can effectively perform Fourier transforms and other image processing by passing an light through some lens completely blows my mind!

  81. OghamTheBold

    I’m downloading a file from the Alaska Satellite Facility – I don’t know what it is – but it’s going to be great

  82. Christopher Roach

    Roughness of water lets you retrieve near-surface wind fields from radar signals (both SAR and lower resolution scatterometers ala the Jason series satellites…)… Wind waves generate different scattering patterns to larger scale waves (swell and similar).

  83. Jane Tizzy

    A great explanation of a very technical subject.
    There is also a non-pulse, ultra high resolution type of radar; CWI (Continuous Wave Interferometer) that uses a combination
    of SAW (Surface Acoustical Wave) devices as the main detector. Not anything “modern”, this sort of device was used back in the early ’70s (by the military – of course). That might make an interesting complement to this video.

  84. gelisob

    You should not be wearing a tin-foil hat if you want to avoid being seen by SAR

  85. Thomas Tubebach

    “Rocket scientists are puzzled!” :D

  86. Oscar Sommerbo

    This video is impossible according to flat earthers. ;)

  87. tuffduty

    I listened to every word. I didn’t understand very much of what was said. But he explains the topic of SAR with such enthusiasm that he makes it interesting and the result is: I now have an appreciation for what is going on, as compared to my total lack of knowledge just a few minutes ago. You are a genius and I am an enthusiastic subscriber.

  88. MegaKopfschmerzen

    This is the Aperture Science we deserve!

  89. Max V.G

    There is some really cool research on techniques for the deceptive jamming of SARs using GANs to generate realistic ‘spoof’ images.

  90. Chameleon Scheimong

    “… look at the world in a different light”

    That’s such a manly pun

  91. Austin Wer

    The image of the little white and black dots being identified as Russian armored vehicles blew my mind, right after you talked about all the shit SAR can’t do lol

  92. Funny Itworkedlasttime

    “Satellites do this trick, and governments hate them for it!” Page Six

  93. Jesse Rutt

    The “were” in the arecibo telescope image is so sad 😭

  94. PsychoLucario

    I’m sure the NSA has a love/hate relationship with these companies since they provide lots of intel, but also prove that you don’t have to be the NSA to afford a spy sat program

  95. Tenns

    2:53 cries a little on the inside

  96. Larl Sagan

    Satellites use this “one weird trick” to see more; rocket scientists don’t want you to know! I fixed your title.

  97. TheLoganatorz

    Thought this was Buzzfeed space after reading the title XD

  98. Pizza Thyme Pizza FanClub

    Technology just keeps getting better I cant imagine what resolution would be available within 20 years

  99. Luke Freeman

    I was wondering if you’d do a video explaining this about two days ago. Thanks for reading my mind oh powerful one of the clan Manley!

  100. fredreick weaver

    Hot take: interferometry cool

Comments are closed.