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Gravity waves

Posted: Fri Jan 01, 2010 1:10 am
by The Code
Where is the Gravity wave from the Big Bang? Through a stone in a pond. where is the reflection gravity wave? If we expanded faster than light, could this be making what we see in the universe false?

Happy new year

Mark

Re: Gravity waves

Posted: Fri Jan 01, 2010 1:36 am
by neufer
mark swain wrote:Where is the Gravity wave from the Big Bang? Through a stone in a pond. where is the reflection gravity wave? If we expanded faster than light, could this be making what we see in the universe false?

Happy new year
Thanks to inflation the quadrupole moment of the CBR is very small;
and, of course, the gravitational coupling constant is extremely small.

Happy new year to you.

Re: Gravity waves

Posted: Fri Jan 01, 2010 1:59 am
by The Code
Thanks neufer, Back at ya.

Funny how it seems gravity waves been the same for who know how long. sumot for me to look into.

Mark

Re: Gravity waves

Posted: Fri Jan 01, 2010 4:50 am
by Chris Peterson
mark swain wrote:Where is the Gravity wave from the Big Bang? Through a stone in a pond. where is the reflection gravity wave? If we expanded faster than light, could this be making what we see in the universe false?
Theory says such waves should exist. But our technology is only just now reaching the level where we stand a chance of detecting them. Evidence for or against primordial gravity waves (and gravity waves in general) should start appearing within the next few years. We live in exciting times.

Re: Gravity waves

Posted: Fri Jan 01, 2010 2:57 pm
by neufer
Chris Peterson wrote:
mark swain wrote:Where is the Gravity wave from the Big Bang? Through a stone in a pond. where is the reflection gravity wave? If we expanded faster than light, could this be making what we see in the universe false?
Theory says such waves should exist. But our technology is only just now reaching the level where we stand a chance of detecting them. Evidence for or against primordial gravity waves (and gravity waves in general) should start appearing within the next few years. We live in exciting times.
http://en.wikipedia.org/wiki/Gravitational_wave wrote:
<<An astrophysical source at the high-frequency end of the gravitational-wave spectrum (above 100 KHz and probably 10 GHz) generates relic gravitational waves that are theorized to be faint imprints of the Big Bang like the cosmic microwave background. There are currently two detectors focusing on detection at the higher end of the gravitational wave spectrum: one at University of Birmingham, England, and the other at INFN Genoa, Italy. A third is under development at Chongqing University, China. The Birmingham detector measures changes in the polarization state of a microwave beam circulating in a closed loop about one meter across. The INFN Genoa detector is a resonant antenna consisting of two coupled spherical superconducting harmonic oscillators a few centimeters in diameter. The oscillators are designed to have (when uncoupled) almost equal resonant frequencies. The Chongqing University detector is planned to detect relic high-frequency gravitational waves with the predicted typical parameters: 10 GHz and h ~ 10−30-10−31.>>

Re: Gravity waves

Posted: Sat Jan 02, 2010 10:16 pm
by The Code
We can not see past The wall, 500 million years after the bb Aprox. When i look into a glass the light is distorted. When i look into a wave on the beach, the water distorts what i can see . When look into space, or look at photos, how do i know what I am seeing is correct? Gravity distorts light. There maybe things that refract light. And most important, what if there were a humongous gravity wave heading our way? How can you tell we do not have incoming?

Re: Gravity waves

Posted: Sat Jan 02, 2010 10:40 pm
by Chris Peterson
mark swain wrote:We can not see past The wall, 500 million years after the bb Aprox.
The only limitation here is when we use photons as the source of our measurement signal. There are other measurements that we can make (at least in principle) that allow us to see further back. Right to the beginning, in fact.
When i look into a glass the light is distorted. When i look into a wave on the beach, the water distorts what i can see . When look into space, or look at photos, how do i know what I am seeing is correct?
There are models for various distortions that allow them to be compensated for. Even when compensation is impossible, we generally know when we are seeing something that has been distorted in some way. Of course, you can always suggest that we are seeing things badly distorted without realizing it, but I don't know of any evidence to support that idea.
And most important, what if there were a humongous gravity wave heading our way? How can you tell we do not have incoming?
By definition, you can't detect something until its signal reaches you. That applies to light as well as gravity. A supernova in the past may be seen in a few days as a light in the sky as bright as the Moon, but we can't know about it until that light actually arrives. Right now we have limited ability to even know if a big gravity wave passes through us. The largest amplitude gravity waves probably result from merging black holes, and even those are at the limits of our measurement technology.

Re: Gravity waves

Posted: Sat Jan 02, 2010 11:16 pm
by The Code
Chris Peterson wrote:By definition, you can't detect something until its signal reaches you. That applies to light as well as gravity. A supernova in the past may be seen in a few days as a light in the sky as bright as the Moon, but we can't know about it until that light actually arrives. Right now we have limited ability to even know if a big gravity wave passes through us. The largest amplitude gravity waves probably result from merging black holes, and even those are at the limits of our measurement technology.



That worries me Chris.

Could little fluctuations in the sun or else where, cause earth quakes?

Re: Gravity waves

Posted: Sat Jan 02, 2010 11:35 pm
by Chris Peterson
mark swain wrote:Could little fluctuations in the sun or else where, cause earth quakes?
If so, the effect is too small to show in the data. The Sun is very stable, so its gravity wave output is tiny at best. Ordinary tidal effects from the Sun or Moon are greater by many orders of magnitude, and only lunar tides have been weakly correlated to a very specific type of shallow ocean earthquake.

Re: Gravity waves

Posted: Sat Jan 02, 2010 11:44 pm
by The Code
Have you ever been at work, and thought time has gone quick today?