Colliding Stars

Comments and questions about the APOD on the main view screen.

makc
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Post by makc » Thu Sep 22, 2005 7:33 am

Googling Britney Spears provides The Mystery of Britney's Breasts and Britney Spears guide to Semiconductor Physics

*I would argue that my post is as relevant as yours to matters I was trying to discuss here. But then, again, discussion is over. I learned few things, and you didn't :(

S. Bilderback
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Post by S. Bilderback » Thu Sep 22, 2005 11:53 am

I did not intend to state that "all" of the speed from the neutron star came from gravitational acceleration. Objects close to galactic center move much faster than the outer stars. A near collision between a neutron star and a black hole, the neutron star could rob a large amount of K-energy from the black hole or even another larger neutron star, changing its vector speed; let’s say by 90 degrees, flinging out of the galaxy.

Have you ever placed a tennis ball directly on top of a basket ball and dropped the two together? If not, the tennis ball will bounce nearly twice as high as the initial drop by robbing the K-energy from the basket ball -basically the same effect.

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Post by Fahad » Sun Sep 25, 2005 9:36 am

I'm surprised no one mentioned the possibility of stars colliding in binary starsystems. In time, it is possible that two stars will collide, provided that they werent born too far apart, and that they have enough mass. Though it is rare, I would imagine it's more possible than two single stars colliding.

S. Bilderback
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Post by S. Bilderback » Fri Oct 07, 2005 12:00 pm

http://www.sciam.com/article.cfm?chanID ... 414B7F0000

To answer the question if stars collide:


SCIENCE NEWS
October 07, 2005

Gamma-Ray Mystery Solved

A 30-year-old puzzle about the origin of short bursts of high-radiation energy in the cosmos has been solved. In the current issue of Nature, four different teams of astronomers provide a variety of evidence that, for the first time, establishes the cosmological distance of the so-called short gamma-ray bursts and points to the source as either the collision of two small but dense stars, known as neutron stars, or the collision of a neutron star with a black hole. The finding finally confirms a theory called the merger model and opens the door not only to more detailed studies of these unusual events but to the potential for detecting gravitational waves, the elusive oscillations in spacetime created by gravity.
Short gamma-ray bursts are cousin to long gamma-ray bursts, which are displays of enormous amounts of energy that last for more than two seconds and briefly outshine other energy sources before fading. In 1997 astronomers determined that the source of a long gamma-ray burst was a supernova explosion, the collapse of a massive star. They also discovered that a monthlong afterglow followed the event that could be observed with instruments used to detect optical frequencies, x-rays or radio waves.

Unfortunately, attempts to find the afterglow and therefore the source of short gamma-ray bursts proved fruitless. Some researchers theorized that these afterglows eluded detection because they occurred in a less dense region of a galaxy, where ejected material wouldn't have the opportunity to interact with lots of particles and produce a bright enough burst. Others suggested that the bright energy was there, but astronomers just didn't have their instruments pointed in the right direction.
In November 2004 NASA launched the Swift satellite, designed specifically to sense x-ray emissions and then turn rapidly in their direction to image their source. By May of this year, a team lead by Neil Gehrels from NASA's Goddard Space Flight Center, detected the first short burst with the satellite. They determined it was coming from an elliptical galaxy, which typically consists of older stars.


Shortly thereafter in July, another team lead by Jesus Noel Villasenor of the Massachusetts Institute of Technology observed a second short burst using a satellite named HETE 2. Two other teams, one lead by Derek Fox of Caltech and the other lead by Jens Hjorth of the University of Copenhagen, detected x-ray and optical afterglows from the burst. They calculated that the luminosity was about 1,000 times lower than that coming from a long gamma-ray burst.
The data indicated that although the energy output was much lower than that seen after massive stars collapsed, it was too high to be explained by other theories suggesting that the energy derives from quakes on neutron stars. "All the evidence we presented comes to provide a solid case for the merger model and it's pretty deadly to the massive star model," says Fox.

The merger model posits that two stars, which have begun life as massive entities orbiting each other, burn through their fuel in about 10 million years and collapse into highly dense neutron stars about the size of New York City. Over another 100 million to a few billion years the two objects continue to lose energy, and as they do, their orbits shrink. Eventually they collide and produce the short gamma-ray burst. (The theory also works if one star becomes a black hole that eventually devours its partner.)

From the data gathered, astronomers now estimate that for every short gamma burst that occurs, another 30 go undetected. That knowledge could advance studies being conducted using gravitational wave detectors, such as Caltech’s Laser Interferometer Gravitational Wave Observatory. These instruments are being used to measure gravitational waves from sources such as black holes, which evade understanding in part because they do not emit radiation. --Tracy Staedter

Empeda
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Post by Empeda » Fri Oct 07, 2005 2:22 pm

Yes, but again thats a decaying binary system, not a 'direct collision'.
I'm an Astrophysics Graduate from Keele University, England - doesn't mean I know anything but I might be able to help!

makc
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Post by makc » Fri Oct 07, 2005 3:20 pm

<interruption>
I think this goes along the line with this topic's title.
</interruption>

<edit>
Ah, just found S. Bilderback already posted this :oops:
</edit>

S. Bilderback
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Post by S. Bilderback » Sat Oct 08, 2005 1:35 am

After reading the article I posted I started thinking; if an object, even a neutron star, was pulled into a Black Hole, would the mass (or some of the mass) of the object be assimilated into the Black Hole or would all the entering mass be converted and ejected as high energy particles at the event horizon?

Any opinions or data?

S. Bilderback
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Post by S. Bilderback » Tue Oct 11, 2005 1:09 pm


makc
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Post by makc » Tue Oct 11, 2005 1:15 pm

S. Bilderback wrote:http://www1.nasa.gov/multimedia/imagega ... e_424.html

Visual aid to colliding stars.
In realistic picture you probably wouldn't tell a difference between NS and BH. Check chandra's images of crab nebula central star for an example of how NS looks like.

S. Bilderback
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Post by S. Bilderback » Wed Oct 12, 2005 1:22 am

Cool! - Thanks -

aif@comcast.net
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better picture

Post by aif@comcast.net » Fri Oct 21, 2005 10:59 pm

thank you for the link.

the picture(s) it shows seem a much better conception of a star collision than the picture shown on apod.
newbie, please be gentle

kovil
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stars in collision.

Post by kovil » Sun Jan 29, 2006 9:55 pm

I think I forgot the question. LOL

Two stars head on would be a lot of fireworks!! not to mention the attendant radiation.

In the thought experiment I see; as they are about a diameter apart they oblate into egg shaped, long ends toward each other.

As the gas atmospheres merge, high energy particle collisions and interaction begin the extra radiation effects.

Depending on their respective magnetic field alignments; a lot of varying scenarios play out, so I will basically hold that part of the vision.

Proceeding further to a 25% original diameter merger; the 'atmospheres' will give way outward as the denser material begins to impact together.

Depending on the stars absolute size, (and I'm visioning relative same size stars here), the distance to where fusion is happening will differ.
When the fusion shell is disrupted, by shock waves or actual collision, I expect that disruption will 'put the fire out' in one sense and in another sense change it to a different 'harmony' of how the particles are interacting. I would not expect a 'blow up' of fusion incident, but a kinetic reaction to density increases from the collision, throwing matter all over the local place 5-20 solar diameters rather rapidly.

Depending on the exact collision course, and if it is truly head on, the cores, depending on their real size and makeup, could do a nova style runaway reaction, or just a real messy splattering.

If the stars did not make a catastrophic explosion, nova style, then I see the fusion fires being extinguished from the massive disruption of both stars equilibriums. As the matter scatters energetically all over the place there will be lots of neutrinos etc activity, but as the double gravity potential now exists locally, in a while most of the particles will recollect and start a new star, probably 1-1/2 times the mass of the original size of the two identical size stars.. 1/2 being lost in the collision.

Mainly a big bang, splatter, and the fire goes out! It all slowly regroups and starts a new slightly larger star than was there before, with some small increase in the % of heavier elements in its makeup.

On second thought, imagining two paint balls in a head on collision, where the material splatters in a plane perpendicular to the vector of collision, a lot of material would have escape velocity energies, 50% of each star might escape. A lot of it depends on the initial gravity of each star, how fast they impact, and if the magnetic fields can help to contain anything before they are so disrupted they virtually disappear.

The stars collision velocity will be a very large factor in what happens.

===

It would almost be easier to postulate the environment on the surface of a neutron star! haha

Let's take a battleship weighing a million tons, and place it on a golf-tee shaped support that focuses all its weight onto one square centimeter.
That might not be enough pressure even ! to equal a neutron star surface gravity. But whatever it is, it's enough I would expect to make a near perfect sphere, depending on the rotation speed. And as dense and hard as any material imaginable, way beyond anything on earth.

What it's electromagnetic radiative qualities would be is an open question. But with the gravity so strong darn little can get away. It is near to black hole strength. Now some lesser neutron stars likely exist as there are probably several orders of magnitude in gravitational strength neutron stars possible. But even the least of which the surface gravity is so strong, everything is squashed flatter than anything imaginable. I would expect the local area is completely devoid of any loose particals.

On second thought, any particles found in the local area would be spirialing in at a very high velocity, so the surface atmosphere would be a whirl of particles being accumulated and absorbed at a great rate, and very energetically too; so again depending on the real gravitational forces involved, lots of things are going on; and much of it dependent on the local supply of matter which is being accumulated.

What we really need is a viewing platform!!

Where's Q when you need him !!
He sure was good as Beka's Uncle Sid on Andromeda !!

ps, Harry, I googled 'cricket rules' and got a real head full of a whole new language!!! I remember hearing cricket scores being reported on BBC one time in Scotland and it was so unintelligible as to be absolutely fascinating!!! and they went on and on about India and all sorts of places. I asked someone later what was going on, and all they could do was look confused and try to get started a couple of times, shake their head, and then just give up without even trying to explain it ! Which piqued my interest even more, that was about 20 years ago!
Thank heaven for google!

Now I can see what they were going thru! I'm just as baffeled as before because it is so darned complicated, but have an overall better conception of my ignorance! I can see why I waited 20 years!!

harry
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Post by harry » Mon Jan 30, 2006 4:34 am

Hello Kovil

Collision between two stars.

See link

http://www.spacetelescope.org/videos/ht ... 0211d.html

and

http://www.spacetelescope.org/videos/archive/viewall/

Videos on collisions
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as for cricket

I used to play it.
It takes along time for each game.
A short game is 1 day
A long play is 2 days

You can limit the game and reduce it to several hours.
To whatch it, I sometimes go to sleep.
Harry : Smile and live another day.

harry
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Post by harry » Mon Jan 30, 2006 6:14 am

oops forgot this links

too lazy to edit

Two neutron stars

http://www.space.com/scienceastronomy/n ... 31203.html
Harry : Smile and live another day.

kovil
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Post by kovil » Mon Jan 30, 2006 4:21 pm

Thank you Harry,

Amazing links; 396 space telescope videos !! Amazing Grace

In thinking more about neutron stars;
Bilderback's fascination with a 'hollow black hole theory' began to sink in

As space becomes 'timelike' according to Hawking, the material trying to implode by gravity, has a resistance to moving inward, because as it moves through space inward towards the singularity, it is being forced to travel through time to do so. So it can not ever reach the singularity state, as the resistance of time prevents it from collapsing that far !!!!!!!!!!

A most intrigueing and unexpected development, but a necessary one to keep the entire universe from disappearing down a proverbial 'rabbit hole' !! some day.

Now as for these energetic jets at the polar regions of black holes and maybe neutron stars as well. As most of these objects are rotating, and some rather quickly, and as their surface is as hard as polished neutrons and as slippery as a lightening bolt; and being ever so slightly oblate from their rotation, and maybe just the coriolus effect; ingressing material will tend to slide toward the poles!! Where it will likely accumulate faster than it can be quantumly absorbed by the surface.

The surface is another story also; as the electrons are disallowed from having all of 'Manhattan to hide in' as the outer surface neutron pairs are forced to 'by default' of being 'only 5 sides of a cube' in touch with other neutron pairs; they are under considerable stress and tension for sharing; and as a result may not be able to link up with new material as fast as they would like, because the incoming material is not in the proper 'form' to easily link up 'Heisenberg wise' . Thus a proceedural slowdown ensues and the excess arriving material is slung off in a rather ignominious fashion as a jet of rejection, emanating from the respective poles into the surrounding region of space !

This bottleneck in the absorption rate of material saves the universe from being sucked in too fast and thus lengthens the life span of the universe as well.

So there are two braking mechanisms, time resistance and absorption rate resistance.

==

This has been a Good Morning !!

A short side thought about cricket;
From a perusal of the rules and terminology of the sport,
It sounds like it was invented by Barristers who later became government bureaucrats !!
I can see why it sometimes is as exciting as watching a Legislature in Session.
And it almost sounds like they invent the rules as they go along!
Diplomacy is like that, they change the rules at the most inopportune times, for the opposition that is!
I did so_like finding a rather complex and well historied subject I knew nothing about; it makes for such an intrigueing challenge!!

harry
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Post by harry » Tue Jan 31, 2006 12:56 am

Kovil
"As space becomes 'timelike' according to Hawking, the material trying to implode by gravity, has a resistance to moving inward, because as it moves through space inward towards the singularity, it is being forced to travel through time to do so. So it can not ever reach the singularity state, as the resistance of time prevents it from collapsing that far !!!!!!!!!! "

If you look at Hawkins history you will understand.

In my opinion this is hoo haa.

Although we cannot see into a black hole. We know where they grow from.

And if you know the seed you can assume what the tree would look like.


A black hole is a massive matter that stops light from excaping.
You do not have to bring in time and all the hoo haa that goes with it.

Thats my opinion.
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see this link
http://www.space.com/scienceastronomy/a ... 20410.html

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There are many links on Black Holes,quasars, neutron stars, magnetos and now the so called quark star.
Harry : Smile and live another day.

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