| Topic: |
Science > Physics |
| User: |
"Sam Wormley" |
| Date: |
30 Dec 2003 09:22:47 AM |
| Object: |
An amazing binary pulsar |
Ref: http://www.astro.ucla.edu/~wright/cosmolog.htm#News
An amazing binary pulsar
4 Dec 03 - Nature <http://www.nature.com> today published a paper
<http://arxiv.org/abs/astro-ph/0312071> (Burgay et al. 2003, Nature,
426, 531-533) about a newly announced millisecond pulsar, PSR
J0737-3039, in a relativistic binary system. Radio pulsars
<http://imagine.gsfc.nasa.gov/docs/science/know_l2/pulsars.html> are
neutron stars (NS) which have a mass of about 1.4 solar masses and a
radius of 10 km, magnetic fields billions to trillions of times larger
than the Earth's magnetic field, and spin periods from 1.6 milliseconds
to several seconds. PSR J0737-3039 is orbiting another neutron star
every 2.4 hours and the two stars will merge in 85 Myr due to
gravitational radiation. Hence LIGO <http://www.ligo.caltech.edu/> will
have many more detectable NS+NS merger events based on the statistics
of two objects instead of the previous estimate based solely on the one
merging binary pulsar PSR B1913+16 known earlier.
The program <http://www.astro.northwestern.edu/AspenW04/program.html>
for the 12-16 Jan 2004 Aspen Winter Conference on Astrophysics has a
paper by Manchester about eclipses (!!) in PSR J0737-3039 and another
paper by McLaughlin on another relativistic binary pulsar PSR J1849+24.
This should be an interesting meeting.
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| User: "Prai Jei" |
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| Title: Re: An amazing binary pulsar |
30 Dec 2003 12:18:16 PM |
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"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:3FF1983F.42E50DEF@mchsi.com...
Hence LIGO <http://www.ligo.caltech.edu/> will
have many more detectable NS+NS merger events based on the statistics
of two objects instead of the previous estimate based solely on the one
merging binary pulsar PSR B1913+16 known earlier.
Does this mean that the LIGO experiment will work? : )
--
Paul V. S. Townsend
Interchange the alphabetic elements to reply
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| User: "Uncle Al" |
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| Title: Re: An amazing binary pulsar |
30 Dec 2003 12:24:07 PM |
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Prai Jei wrote:
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:3FF1983F.42E50DEF@mchsi.com...
Hence LIGO <http://www.ligo.caltech.edu/> will
have many more detectable NS+NS merger events based on the statistics
of two objects instead of the previous estimate based solely on the one
merging binary pulsar PSR B1913+16 known earlier.
Does this mean that the LIGO experiment will work? : )
LIGO already works to spec. It hasn't yet detected signal above noise
- though it does do a fantastic job detecting gravitational signatures
of errant tumbleweeds snugging the tunnels' outside walls.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
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| User: "Shaun Webb" |
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| Title: Re: An amazing binary pulsar |
30 Dec 2003 03:26:50 PM |
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On Tue, 30 Dec 2003 10:24:07 -0800, Uncle Al wrote:
Prai Jei wrote:
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:3FF1983F.42E50DEF@mchsi.com...
Hence LIGO <http://www.ligo.caltech.edu/> will have many more
detectable NS+NS merger events based on the statistics of two objects
instead of the previous estimate based solely on the one merging
binary pulsar PSR B1913+16 known earlier.
Does this mean that the LIGO experiment will work? : )
LIGO already works to spec. It hasn't yet detected signal above noise -
though it does do a fantastic job detecting gravitational signatures of
errant tumbleweeds snugging the tunnels' outside walls.
LIGO Science Run 2 in April was a factor of 10 off design sensitivity
(which is an improvement over the factor of 100 of Science Run 1).
Science Run 3, which is supposed to run close to spec, is still in
progress. Data collection continues until January 5.
Shaun
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| User: "BllFs6" |
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| Title: Re: An amazing binary pulsar |
31 Dec 2003 08:54:58 AM |
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LIGO already works to spec. It hasn't yet detected signal above noise -
though it does do a fantastic job detecting gravitational signatures of
errant tumbleweeds snugging the tunnels' outside walls.
this reminds me of something I saw a year or two ago.....
some fancy gubment lab was suggesting the equivalent of a gravitional "cat
scan" to detect stuff being smuggled into the usa....the premise being you cant
just hide mass...... and that 100 pounds of cocaine you've tried to hide inside
that gasoline tanker truck is GONNA show up if you can do a 3d map of the mass
of the whole set up....
While I have little doubt such a thing is "possible" these days.....is it even
remotely doable/practical without a billion dollar tester and a 2 month scan
time?
take care
Blll
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| User: "John Sefton" |
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| Title: Re: An amazing binary pulsar |
30 Dec 2003 11:11:39 AM |
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Sam Wormley wrote:
...snip...and the two stars will merge in 85 Myr due to
gravitational radiation...snip...
It sounds like gravity is well-understood,
from this statement.
John
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| User: "Prai Jei" |
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| Title: Re: An amazing binary pulsar |
30 Dec 2003 12:18:57 PM |
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"John Sefton" <vegan16@accesscomm.ca> wrote in message
news:3ff1af82$1@news3.accesscomm.ca...
Sam Wormley wrote:
...snip...and the two stars will merge in 85 Myr due to
gravitational radiation...snip...
It sounds like gravity is well-understood,
from this statement.
Course it is. Nooton worked it all out three centuries ago.
--
Paul V. S. Townsend
Interchange the alphabetic elements to reply
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| User: "Uncle Al" |
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| Title: Re: An amazing binary pulsar |
30 Dec 2003 11:55:38 AM |
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John Sefton wrote:
Sam Wormley wrote:
...snip...and the two stars will merge in 85 Myr due to
gravitational radiation...snip...
It sounds like gravity is well-understood,
from this statement.
Hey stooopid, explain how spiral galaxies can persist over all visible
time given their baryonic matter distribution.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
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