GUEST COLUMNIST: What Goes Up Still Has to Come Down

By columnist, Guest | The Tuscaloosa News, November 13, 2015 | Go to article overview

GUEST COLUMNIST: What Goes Up Still Has to Come Down


columnist, Guest, The Tuscaloosa News


It is not often that a centenarian is just as spry and vital as the day she was born, but that's the case with the general theory of relativity.

This month we are celebrating exactly 100 years since the meeting in which Albert Einstein announced the completion of his masterful theory of how gravity works. His grand theory relating the geometry of space and time to the matter and energy within it represents an extraordinary triumph of the human imagination.

Before Einstein, there was Isaac Newton, who had offered a simpler, but much less satisfying theory of gravity.

Contrary to popular myth, Newton did not discover gravity. From earliest times, no one could mistake the fact that things fall down if released from a certain height. Rather, Newton demonstrated that gravity is a universal force with certain predictable properties. This force could act over immense distances, linking, for instance, the Sun and the Earth as if an invisible string tied them together.

Although Newton's theory was very successful, it contained a logical flaw: the idea that gravity could be transmitted instantly. If the Sun suddenly disappeared, his theory predicted that Earth would immediately sense its absence, as if a thread were cut, and start traveling in a straight line through space.

Yet Einstein had showed in his special theory of relativity (the predecessor to the general theory), space has a speed limit. No signal in empty space can travel faster than the speed of light. The Sun's light takes eight minutes to reach Earth. Therefore, Earth could not possibly respond to the Sun's disappearance in less than that time period -- certainly not instantly.

Einstein's general relativity beautifully recasts gravitation as a local, rather than long-distance, phenomenon. The equations he announced in November 1915 show precisely how it is the fabric of space and time -- known in tandem as spacetime -- that conveys gravity.

Much like a turbulent wild river with eddies and currents that change the course of boats, spacetime's bumps and ripples compel planets and stars to alter their paths. In the case of Earth, a gravitational well compels Earth to travel in an elliptical orbit rather than in a straight line. The cause of that indentation in spacetime is the mass of the Sun. Or, as often expressed by the late gravitational physicist John Wheeler (who came to know Einstein well), space tells matter how to move and matter, in turn, tells space how to curve. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

GUEST COLUMNIST: What Goes Up Still Has to Come Down
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this article
  • Highlights & Notes
  • Citations
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.