From: SFPhysics@aol.com
Date: Tue May 25 2004 - 04:13:45 PDT
From: SFPhysics@aol.com Message-ID: <1cf.21d5f3ec.2de48469@aol.com> Date: Tue, 25 May 2004 07:13:45 EDT Subject: Astro Physics Questions...
1) gravity waves
>Is it true that gravitational energy waves can vary in length from a km
>to a few million miles?
2) GRBs [gamma ray bursts]
>How long is the transient, poles (sic) of gamma radiation being shot off by
>neutron stars?
3) Colliding Black Holes
>If two black holes were to hit each other, would they collide, or what
>would happen? If a super massive bh and a regular bh is getting sucked
>in, then the smaller one will spin around the larger until absorbed is
>his view.
4) Galactic Center Black Holes
>Also, why do most galaxies, with bulges at least, have black holes at the
>center? Hard to understand he says, how they come to be, why not at edge
>- do we revolve around the super massive black hole at the center of our
>galaxy, doomed to be sucked in
>This is from a 12 year old by the by
>Treena Joiful
Treena your 12 year old is asking some very astute questions:
1) Gravity waves are nothing more than disturbances in the space time
continuum caused by mass in motion. A binary star system will generate measurable
gravity waves as will a star quake on a neutron star. They travel at the speed
of light in a vacuum outward from the source. Their wavelength depends on
the causative event.
The neutron star's small size makes for a short distance for a neutron
collapse with the expulsion of protons thus will give a gravity wave that is as
short as 1 km.
The longer period waves from binary stars can be millions of km as the stars
orbit around each other. The wavelength of the gravity wave would be
determined by the distance between the two stars and the period of the orbit.
A gravity wave would also be generated by accelerating mass into a black hole
or from the mass blown off of a supernova.
2) Gamma Ray Burst pulse times vary quite widely. Many are in the
milliseconds range while some few extend to 5000 seconds. Current theory suggests that
plasma gas and free electrons trapped in super intense magnetic fields
surrounding a compacting neutron star gets energized into synchrotron radiation as
the magnetic fields move around the star's surface. Another theory of GRB
production involves "cannonball mass clustering" of material falling into black
holes. From the wide variances of time and pulse shape there may be many
mechanisms at work.
3) Black hole to black hole head on collision would simply result in a larger
black hole. The event horizon would oscillate elliptically and thus radiate
gravity waves until the energy of the collision were dissipated and the event
horizon returned to spherical shape.
Should a smaller black hole pass by close enough it could be captured into an
orbit around a larger black hole. Radiating gravity waves would eventually
slow the captured black hole until the orbital energy were reduced to a point
where the two would merge. The shape of the larger black hole would be
elliptical for some time and would oscillate thus radiating further gravity waves
until it again became spherical in the same manner as the head on collision.
4) It would now appear that all galaxies have black holes in their centers.
The reason is not yet understood. For that we might have to go to string
theory. If we are now existing because two multidimensional membranes collided
then hot spots of energy creation may not have been uniform and where the energy
was greatest that is where the greatest mass evolved from the big bang event.
Almost immediately the concentrations of mass in the hot spot galactic
centers would have collapsed into massive black holes. Observation of Quasars seem
to bare this out and we are currently looking at the distribution of
background microwave energy for clues as to how galactic evolution came out of the
highly organized structure of the primordial quantum soup of the big bang
singularity.
While we do seem to revolve around a massive black hole in the center of our
own galaxy, we will not be sucked in as is popular with science fiction.
Black holes are only very strong gravitational fields, and they behave the same as
any gravitational field. We are far enough from the galactic center and
traveling around in an orbit at an orbital speed which will keep us from being
drawn into the center just as we travel around the sun without being "sucked in."
If you are asking will we ever be pulled into the center then we would have
to know more about mysterious things like "dark matter/energy" and a repulsive
force opposite to gravity first identified by Einstein.
Mind boggling isn't it?
Treena, have your young aspiring astrophysicist read Brian Greene's *The
Fabric of the Cosmos* for starters.
Hope that helps and I only guarantee being correct 50% of the time on the
above questions so Ron and Dr. Paul will have to correct me where I have gone
asunder,
Al Sefl
Who everyone always believed was spacey anyway...
Because he has dark matter in place of gray matter...
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