Space Time. Artist concept of Gravity Probe B orbiting the Earth to measure space-time, a four-dimensional description of the universe including height, width, length, and time.
No copyright protection is asserted for this photograph, NASA images generally are not copyrighted. Unless otherwise noted, images and video on NASA public web sites (public sites ending with a nasa.gov address) may be used for any purpose without prior permission. The endorsement of any product or service by NASA must not be claimed or implied.
This work is in the public domain in the United States because it is a work prepared by an officer or employee of the United States Government as part of that person’s official duties under the terms of Title 17, Chapter 1, Section 105 of the US Code.
Generally speaking, works created by U.S. Government employees are not eligible for copyright protection in the United States. See Circular 1 "COPYRIGHT BASICS" PDF from the U.S. Copyright Office.
Doc Brown: I foresee two possibilities. One: coming face-to-face with herself thirty years older would put her into shock and she'd simply pass out. Or two: the encounter could create a time paradox, the result of which could cause a chain reaction that would unravel the very fabric of the spacetime continuum and destroy the entire universe! Granted, that's a worst-case scenario. The destruction might in fact be very localised, limited to merely our own galaxy.
Marty McFly: Well, that's a relief.
Back to the Future Part II (1989), written by Robert Zemeckis and Bob Gale.
Space Time. Artist concept of Gravity Probe B orbiting the Earth to measure space-time, a four-dimensional description of the universe including height, width, length, and time.