Using Quasars to Measure the Earth: A Brief History of VLBI

  • Released Thursday, June 21, 2012
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VLBI, or Very Long Baseline Interferometry, is a technique that uses multiple radio telescopes to very precisely measure the Earth's orientation. It was originally invented back in the 1960s to take better pictures of quasars, but scientists soon found out that if you threw the process in reverse, you could measure how the ground beneath the telescopes moves around, how long days really are, and how the Earth wobbles on its axis as it revolves around the sun! Learn more about VLBI here!

This video is presented in both stereoscopic 3D and standard 2D versions. The labels below will help you pick which video is right for your display!

2D/3D VERSIONS - INDIVIDUAL LEFT/RIGHT VIDEOS: Learn more about VLBI in this video!

This version contains both the left and right videos for stereoscopic 3D presentations. If you'd like a standard (2D) version, just pick a format—either the left or the right video will work just fine! The labels below will help you identify the formats and the left/right versions.

For complete transcript, click here.

3D VERSION - SIDE-BY-SIDE: This version of the video is rendered in the side-by-side format used by some stereoscopic 3D displays.

Credits

Please give credit for this item to:
NASA/Goddard Space Flight Center

This page was originally published on Thursday, June 21, 2012.
This page was last updated on Wednesday, May 3, 2023 at 1:52 PM EDT.

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This visualization originally appeared on the following tapes:
  • Using Quasars to Measure the Earth: A Brief History of VLBI (ID: 2012060)
    Thursday, June 21, 2012 at 4:00AM
    Produced by - Brendan Antiochos (NASA)