Back to Home

Blackholes Forum Message

Forums: Atm · Astrophotography · Blackholes · Blackholes2 · CCD · Celestron · Domes · Education
Eyepieces · Meade · Misc. · God and Science · SETI · Software · UFO · XEphem
RSS Button

Home | Discussion Forums | Blackholes I | Post
Login

Be the first pioneers to continue the Astronomy Discussions at our new Astronomy meeting place...
The Space and Astronomy Agora
Re: A Little Something To Read..

Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To
Posted by Jim Bergquist on February 17, 2001 22:36:57 UTC

Here is a quote from Einstein's paper published in 1905 "Does the Inertia of Body Depend Upon Its Energy-Content?". Talking about the kinetic energy (K) difference in a moving frame of reference due resulting from the emission of equal plane pulses of light of energy ½L in opposite directions:

"So we have

K0 - K1 = L {1/sqrt(1-v²/c²)-1}.

The kinetic energy of the body with respect to (ξ,η,ζ) diminishes as a result of the emission of light, and the amount of diminution is indepenent of the properties of the body. Moreover, the difference K0 - K1, like the kinetic energy of the electron (§ 10), depends on the velocity.

Neglecting magnitudes of fourth and higher orders we may place

K0 - K1 = ½ L/c² v².

From this equation it directly follows that:——

If a body gives off the energy L in the form of radiation, its mass diminishes by L/c². The fact that the energy withdrawn from the body becomes energy of radiation evidently makes no difference, so that we are led to the more general conclusion that

The mass of a body is a measure of its energy-content; if the energy changes by L, the mass changes in the same sense by L/9x10²º, the energy being measured in ergs, and the mass in grammes."

It looks like Einstein was actually talking about inertial mass and gravitational mass.



Follow Ups:

    Login to Post
    Additional Information
    Google
     
    Web www.astronomy.net
    DayNightLine
    About Astronomy Net | Advertise on Astronomy Net | Contact & Comments | Privacy Policy
    Unless otherwise specified, web site content Copyright 1994-2024 John Huggins All Rights Reserved
    Forum posts are Copyright their authors as specified in the heading above the post.
    "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET"
    are trademarks of John Huggins