Astronomers Strike Gravitational Gold In Colliding Neutron Stars

a reply to: intrptr


Right.

I remember the lesson being a little more complicated. Something about the sound waves hugging and constricting the matter the waves are passing through. Sound can shatter glass and ear drums, not to mention cause earthquakes here, on earth. Imagine what the roar of a super nova can do to a nearby nebula.

Here's an excerpt from an article that I just found that sort of explains the lecture, as I remember it. It's more over my head than I like!

The team's model shows that after about half a second, the collapsing inner core begins to vibrate. After about 700 milliseconds, the vibrations become so energetic that they create sound waves with audible frequencies in the range of 200 to 400 hertz, or around middle C.

"Instead of neutrino's heating up the material behind the shock, we had acoustic power doing it," Burrows told SPACE.com. "The material on the inside is oscillating like a very, very strong speaker and sending out energy via sound."
In this scenario, the sound waves replace neutrinos as energy carriers.

"The sound waves propagate out through the material and heat it up," Burrows said. "It acts in a way similar to the way neutrinos would act but with more efficiency."
www.space.com...

a reply to: intrptr

It is a crazy idea! "Let's split a laser beam; send one way the h3ll down that way and the other that way. Then reflect them back and compare them!"

All that is isolated. They have to measure the distance between the two very precisely. Then there are the calculations for possible noise sources. They started building this in the 19080s! There has been an upgrade of the device. Probably computer upgrades as well. That it work is pretty amazing! Hey, it won the designer a Nobel Prize!

Laser tech is advancing! There is talk of "attosecond lasers" which is a billionth of a billionth of a second! Crazy! Friggen' lasers!





If anybody has wondered why this takes so long...

Here is a link to one of the published articles in the journal Nature - Optical emission from a kilonova following a gravitational-wave-detected neutron-star merger.

It describes the timeline way better than I could. Also where in the sky they detected the signal (what they narrowed it down to). The 1-sigma, 2-sigma, 3-sigma data source is mentioned (the standard deviation width they have to be within to have scientifically acceptable data). That is all the work they put into it on their end. They submitted Sept. 12, was accepted Sept. 21, and published today, Oct. 16.

That is what true science looks like!

a reply to: CreationBro

Seems like all these "gravity" wave detections they're observing are more like shock waves. No waves are detected before or after the shock wave, so why assume that gravity moves in transvers waves? There simply is no proof of that. Explosions produce shock waves, and implosions produce recoil. Both shock and recoil can cause destructive interference. What if they're just detecting the transverse recoil produced by the implosion of a field resulting in a gravity well? That would mean something entirely different. It would mean gravity causes INSTANTANEOUS action, diminishing at a distance rather than the DELAY associated with waves...like shock and recoil waves.

a reply to: CreationBro

Well, some bits of it should be considered important, like Einstein was right and they could never prove where gamma rays came from, until now.

a reply to: BELIEVERpriest
The waves produced are from energy transference via frame dragging in GR. The rotation of two very heavy objects in close proximity, rather than producing a nice 1/r^2 drop off in the gravitational potential, instead produces a spiral shape space time ripple (projecting a 4D vector into a 3D space, like the classic, spacetime as presented as a flat canvas with a dip in the middle from a star)

What they hear in the 'chirp' of the event are the moments at which the objects basically orbit extremely close and make contact. They see the beginning and the completion of the event, the sudden drop off in the signal is because, as a singular object, the spiral pattern in the gravitational potential basically vanished and returns as though it is a solo compact object.

That is what the model suggests, the wave in this manner is only possible if gravity effects space-time, AT the speed of light. If Gravity was instantaneous at all points, producing the effect observed simply would be impossible as the spiral would not at all propagate.

The evidence here points at the passage of gravitational potential as travelling at the speed of light.

a reply to: windword

Quite a nice quote there. As a titbit for others, it should be noted the energy transfer here is not saying gravitational waves are similar to sound, it is speaking of the physics processes occurring around the objects as they end their binary existence and merge.

It should be noted here that sound in this case is being carried or acting as an energy transference method through an extremely dense medium. Neutron stars are thought to be basically atomic nuclei, degenerate material, their outer parts are likely a fermi-gas similar to that proposed for White dwarfs, so the physical shock, or 'sound' would transport energy very efficiently as the objects heavily distort and begin to merge.

The contained energy would be immense and the physics processes occurring around them, equally powerful

a reply to: CreationBro

Cool, now focus everything on the area for a few years to watch for alien gold-miners!

a reply to: windword

Shockwaves form super novae are comprised of sub atomic particles, heat and light (photons) and matter (the part we see we call nebulae).

Sound shockwave is one molecule knocking another into another in a chain reaction. Same in water.

Very simple demonstration of this, not meant to insult, just trying to imagine what any kind of 'wave' is comprised of and the medium it moves thru.

a reply to: TEOTWAWKIAIFF

Shortly after receiving the gravitational-wave localization, we activated our pre-approved program to search for an optical counterpart with the Las Cumbres Observatory (LCO) global network of robotic telescopes27. Given the size of the LIGO–Virgo localization region (about 30 square degrees) compared to the field of view of our cameras (about 0.2 square degrees), our search strategy involved targeting specific galaxies28 (chosen from the GLADE catalogue; aquarius.elte.hu...) at the reported distance range and location area included in the LIGO–Virgo three-dimensional localization29 (see Methods).

30 degrees? Thats some broad region of space to compare to older low resolution photographs. Seeing some blip in that region may or may not be associated with the detection event.

imo

Tanks for all the help understanding this phenomenon.

I don't understand it, but I don't understand the accepted convention about electricity either, because I am underedumakated, haven't been programmed, willing to ask 'dumb' questions.

Like I thought though nobody can tell me what 'medium' the gravity 'waves' are moving thru.

a reply to: intrptr

The waves are moving through spacetime... in a representative way they are the same contractions/warping of space time as those found around any massive object.

You are right too that the field of view is indeed very broad. However with the construction of more LIGO interferometers, this window will get narrower. The good news is also that one such model for producing Gamma Ray Bursts is coalescing neutron stars... and Gamma Ray Bursts occur all over the sky, at a rate of about 1 a day.

Why doesn't LIGO get a 1 a day detection? Well, the instrument isn't sensitive enough and would only catch the very large neutron stars .

a reply to: ErosA433

Thanks for your reply.

The waves are moving through spacetime...

To me thats akin to saying thunder moves thru air. Its an acceptable (for now) definition because we don't understand that 'realm'.

Sci fi authors used to just call it the "Ether". At least that suggests something , 'more'.

You are right too that the field of view is indeed very broad. However with the construction of more LIGO interferometers, this window will get narrower.

They need a 'dish'. Imo, they are trying to figure where lightning struck from the sound of thunder alone.

"Space / Time Continuum", lulz.

originally posted by: ErosA433
You are right too that the field of view is indeed very broad. However with the construction of more LIGO interferometers, this window will get narrower. The good news is also that one such model for producing Gamma Ray Bursts is coalescing neutron stars... and Gamma Ray Bursts occur all over the sky, at a rate of about 1 a day.

Two gamma ray telescopes in addition to Ligo/Virgo contributed to the effort to locate the source, as explained here:

Ripples of Gravity, Flashes of Light

It's interesting to see how they narrowed down the location and finally found something, they think. In the case of Virgo, the lack of detection suggested it happened in a blind spot which helped narrow the field in spite of the lack of detection, followed by a sign of visible light, so there ended up being a lot more information to track the source in this case than just LIGO and VIRGO.

originally posted by: intrptr

They need a 'dish'. Imo, they are trying to figure where lightning struck from the sound of thunder alone.

If they want their detector to work and not have to have some kind of earth sized instrument, what they have works just fine.

Also, you opinion of what they are trying to do is kind of correct... however... you should look at just how well you can figure out the origin of a sound based on the location of several microphones. You would be quite impressed how good it is.

Hell, some cosmic ray telescopes are able to figure out the direction of a cosmic ray that hit the upper atmosphere, based upon all the locations that the secondary particles 'hit' the ground (their detectors)... its a more effective method than you might think.

Pics up at space.com!!

space.com, Oct. 17, 2017 - First Glimpse of Colliding Neutron Stars Yields Stunning Pics.

I would have copied a couple but some are animated gifs (flash).

And WOW!

First we see Hubble and a zoom in. There is a tiny blue "poof" that goes red (they put a box around it) of the explosion. The big white thing is the galaxy's core. There is a x-ray photo (of course it is a reconstruction), the original Chile photo, and one in the ultraviolet range.

a reply to: ErosA433

What they may have proven is that a changing gravitational fields produces light speed transverse waves in "space-time". That is not the same as gravity moving in transverse waves. So yeah, if gravity is instantaneous at all points, then only the change in the field would cause the alleged spiral pattern. Otherwise, absent the change in the field caused by the degrading binary orbit, gravity would be undetectable via interferometry.

a reply to: TEOTWAWKIAIFF

So what do gravity waves mean? Up till now gravity as an energy field is illusive because gravity attracts instead of repulsing. Is it a field? If so, how can there be waves? If waves, does that mean there are particles (like Gravitons) that make up a gravity wave?

We can't associate it with any another than mass. Yet have never seen any 'waves' before this new science and instrument detectors.

So who can break this down as to why it's a big deal? How does that help us understand anything and how does this help us move forward technologically or in an engineering standpoint?

I see this as a minor discovery, like finding hydrogen on Enceladus...it's cool and it does move us forward, scientifically but it's a minor thing. Yes no?

I think my problem is that I can't relate it or summarize it in a way I would understand. It's like a Quasar. I can read what it is, but it does not effect me in anyway.

originally posted by: ErosA433

originally posted by: intrptr

They need a 'dish'. Imo, they are trying to figure where lightning struck from the sound of thunder alone.

If they want their detector to work and not have to have some kind of earth sized instrument, what they have works just fine.

Also, you opinion of what they are trying to do is kind of correct... however... you should look at just how well you can figure out the origin of a sound based on the location of several microphones. You would be quite impressed how good it is.

Hell, some cosmic ray telescopes are able to figure out the direction of a cosmic ray that hit the upper atmosphere, based upon all the locations that the secondary particles 'hit' the ground (their detectors)... its a more effective method than you might think.

Considering they seem to have fixed the source, yes it is (effective). Like gun shot detectors used in theaters of combat that locate the source of a shot.

What I was wondering is what is the ether that gravity waves travel thru?

I know the pat answer is space time which I replied earlier, thats as informative to me as saying sound 'travels' thru air.

originally posted by: amazing
So who can break this down as to why it's a big deal? How does that help us understand anything and how does this help us move forward technologically or in an engineering standpoint?

I see this as a minor discovery, like finding hydrogen on Enceladus...it's cool and it does move us forward, scientifically but it's a minor thing. Yes no?

Considering how big a deal discovering exo planets around other stars is... they jump for joy when they find one, even though we can't resolve it optically, can't go there, or learn anything else about it. They are on an easter egg hunt for other planets, as they are on the hunt to discover what comprises gravity.

Its one of the still unknown so it is the leading edge of discovery, for them.

You're right, you and I (or at least I) kinda go meh...

To me its like contemplating and understanding every nuance of how my body works, the brain, heart, lungs. I don't need to know all that, just go wth it.