Welcome
Username or Email:

Password:


Missing Code




[ ]
[ ]
Online
  • Guests: 11
  • Members: 0
  • Newest Member: omjtest
  • Most ever online: 396
    Guests: 396, Members: 0 on 12 Jan : 12:51
Members Birthdays:
All today's birthdays', congrats!
kg7bz (68)
steve516 (31)


Next birthdays
05/17 Finn Hammer (72)
05/17 Blue Adept (43)
05/17 Nickel (68)
Contact
If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.


Special Thanks To:
  • Aaron Holmes
  • Aaron Wheeler
  • Adam Horden
  • Alan Scrimgeour
  • Andre
  • Andrew Haynes
  • Anonymous000
  • asabase
  • Austin Weil
  • barney
  • Barry
  • Bert Hickman
  • Bill Kukowski
  • Blitzorn
  • Brandon Paradelas
  • Bruce Bowling
  • BubeeMike
  • Byong Park
  • Cesiumsponge
  • Chris F.
  • Chris Hooper
  • Corey Worthington
  • Derek Woodroffe
  • Dalus
  • Dan Strother
  • Daniel Davis
  • Daniel Uhrenholt
  • datasheetarchive
  • Dave Billington
  • Dave Marshall
  • David F.
  • Dennis Rogers
  • drelectrix
  • Dr. John Gudenas
  • Dr. Spark
  • E.TexasTesla
  • eastvoltresearch
  • Eirik Taylor
  • Erik Dyakov
  • Erlend^SE
  • Finn Hammer
  • Firebug24k
  • GalliumMan
  • Gary Peterson
  • George Slade
  • GhostNull
  • Gordon Mcknight
  • Graham Armitage
  • Grant
  • GreySoul
  • Henry H
  • IamSmooth
  • In memory of Leo Powning
  • Jacob Cash
  • James Howells
  • James Pawson
  • Jeff Greenfield
  • Jeff Thomas
  • Jesse Frost
  • Jim Mitchell
  • jlr134
  • Joe Mastroianni
  • John Forcina
  • John Oberg
  • John Willcutt
  • Jon Newcomb
  • klugesmith
  • Leslie Wright
  • Lutz Hoffman
  • Mads Barnkob
  • Martin King
  • Mats Karlsson
  • Matt Gibson
  • Matthew Guidry
  • mbd
  • Michael D'Angelo
  • Mikkel
  • mileswaldron
  • mister_rf
  • Neil Foster
  • Nick de Smith
  • Nick Soroka
  • nicklenorp
  • Nik
  • Norman Stanley
  • Patrick Coleman
  • Paul Brodie
  • Paul Jordan
  • Paul Montgomery
  • Ped
  • Peter Krogen
  • Peter Terren
  • PhilGood
  • Richard Feldman
  • Robert Bush
  • Royce Bailey
  • Scott Fusare
  • Scott Newman
  • smiffy
  • Stella
  • Steven Busic
  • Steve Conner
  • Steve Jones
  • Steve Ward
  • Sulaiman
  • Thomas Coyle
  • Thomas A. Wallace
  • Thomas W
  • Timo
  • Torch
  • Ulf Jonsson
  • vasil
  • Vaxian
  • vladi mazzilli
  • wastehl
  • Weston
  • William Kim
  • William N.
  • William Stehl
  • Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Forums
4hv.org :: Forums :: General Science and Electronics
« Previous topic | Next topic »   

Gravitational Time Dilation on Airplane

Move Thread LAN_403
ScottH
Thu Sept 27 2018, 02:06AM Print
ScottH Registered Member #61373 Joined: Sat Dec 17 2016, 01:45PM
Location: San Antonio, TX
Posts: 87
I am trying to calculate the time dilation that I experienced while flying on a jetliner. I have already calculated my "time loss" for Special Relativity (-700ns), but I cannot find a reliable calculator for general relativity at 36,000 ft alt. I am having trouble solving the complex equation for general relativity.

I want to find out how much time I "gained" from General Relativity (99.63% of Earth's surface gravity, or 0.37% less) from flying at 36,000 ft alt over a 44 hr total flight period (relative to the ground at sea level).
Back to top
Sulaiman
Thu Sept 27 2018, 08:37AM
Sulaiman Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
Do you mean this ? Link2
Back to top
Uspring
Thu Sept 27 2018, 10:35AM
Uspring Registered Member #3988 Joined: Thu Jul 07 2011, 03:25PM
Location:
Posts: 711
It is not necessary to fully understand general relativity to calculate gravitational effects on time in this case. Say you send a laser beam from the ground up to the airplane to tell you how fast time runs on earth. Assume the laser light has a certain frequency f on the ground. The beam consists of photons, each having an energy of h*f and a corresponding mass m = E/c^2 = h*f/c^2.

The photon will loose energy as it rises up to the airplane due to its mass. This energy loss is m*g*H, where m is the photon mass, g the gravitational acceleration (10 m/s^2) and H the altitude of the plane. Since the energy of the photon is h*f, f will have decreased somewhat once it has reached the plane. This implies, that clocks on earth seem to run slow when watched from the plane.

Putting all mentioned equations together, primed values are on the airplane:

E' = E - m*g*h = h*f - h*f/c^2 * g * H = h*f*(1 - g*H/c^2)

f' = E'/h = f*(1 - g*H/c^2)

So the factor, by which time runs slower on the ground is (1 - g*H/c^2)

The gravitational time dilation leads to a peculiar effect, when you drop something into a black hole. The drop will seem to slow down, once the object comes close to the event horizon. Actually it will never seem to enter the black hole. The color of the object will turn more and more reddish until it eventually will become invisible.
Back to top
Conundrum
Fri Sept 28 2018, 04:50AM
Conundrum Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059
Indeed, its called "redshift".
Interestingly, you can now actually buy small atomic clock chips (CSAC) if you have $900 burning a hole in your pocket.
Uses about the same power as a mobile phone but accurate to one second in 270M years or so the manufacturers claim.
Compare with clock left back home to see if it drifts over a long haul flight.

Note, there can be effects with temperature but generally if it stays locked then the data is indeed valid.
Back to top
ScottH
Sun Sept 30 2018, 01:01PM
ScottH Registered Member #61373 Joined: Sat Dec 17 2016, 01:45PM
Location: San Antonio, TX
Posts: 87
Uspring wrote ...


So the factor, by which time runs slower on the ground is (1 - g*H/c^2)


So it would be ( (1-(9.807m^2)*10972m/(299792458m/s^2) )*158400 sec ??? Are my parentheses in the right place? Im using 9.807 m/s/s for an exact gravity measure.
Back to top
Uspring
Mon Oct 01 2018, 10:36AM
Uspring Registered Member #3988 Joined: Thu Jul 07 2011, 03:25PM
Location:
Posts: 711
The factor by which clocks run slower on the ground is:

1 - 9.807m/s^2 * 10972m / (299792458m/s)^2 = 1 - 1.197e-12

After 44h or 158400s you'd be about 158400s * 1.197e-12 = 190ns older than if you'd stayed on the ground. This is from gravitational effects only. There is, as you said, an extra contribution from the time dilation due to the planes speed. Its sign is opposite to that of the gravitational effect.
Back to top
ScottH
Mon Oct 01 2018, 01:51PM
ScottH Registered Member #61373 Joined: Sat Dec 17 2016, 01:45PM
Location: San Antonio, TX
Posts: 87
Uspring wrote ...

The factor by which clocks run slower on the ground is:

1 - 9.807m/s^2 * 10972m / (299792458m/s)^2 = 1 - 1.197e-12

After 44h or 158400s you'd be about 158400s * 1.197e-12 = 190ns older than if you'd stayed on the ground. This is from gravitational effects only. There is, as you said, an extra contribution from the time dilation due to the planes speed. Its sign is opposite to that of the gravitational effect.


Thank you! You made my day. Thanks everyone!
Back to top

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob

Go to:

Powered by e107 Forum System
 
Legal Information
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.