[KaiserJeep]

Just when you least expect it, out of left field comes proof of General Relativity:

A STAR JUST GOT SWALLOWED BY A WARP IN SPACE-TIME

A star has slipped out of view thanks to the space-time warp it creates as it orbits.

The disappearing star is part of a binary star system called J1906. It's a pulsar, which means it's a rotating neutron star, the result of a massive star collapsing in on itself. Researchers have been studying the young pulsar for five years to determine what kind of companion star was orbiting around it. That is, until recently, when the pulsar vanished.

http://www.inquisitr.com/1745673/pulsar-observed-wobbling-out-of-space-time-and-vanishing-out-of-our-now/

http://www.popsci.com/fast-orbiting-pulsar-no-longer-detectable-researchers

http://science.nasa.gov/science-news/science-at-nasa/2000/geodetic/

http://iopscience.iop.org/0004-637X/798/2/118/article

[Sixstrings]

Well this is interesting.

Can you summarize the physics of it, in lay language?

Just how exactly that works, what is it about the binary pulars that's warping light / radio waves / whatever.

I guess this is not talking about a black hole?

[SeaGypsy]

KJ might be able to put it better, basically Einstein theorised that space time, despite the apparent continuum, is warped by mass, so time flows at varying pace depending on proximity to massive bodies. Assuming the experts have done their homework on this particular region of space, if the body being tracked suddenly vanishes & there is no other explaination, something must explain the disappearance, which Einstein's theory allows for. The star did not explode or get swallowed, it disappeared into its own space time continuum, away from the one we inhabit, but not ceasing to exist. Pretty cool. The theory is related to 'worm holes' or in more sci fi lingo, to portals & Dr Who & the Tardis.

[Tanada]

Gravity lensing has been well known and proven for a long time, if you are looking at a distant light source like a star or galaxy sometimes something massive will pass between it and us. When this happens the light traveling form the object towards us is bent and the position seems to rapidly change in the sky. This effect is also observed when using telescopes to observe stars on the opposite side of our orbit as we go around the sun. Sol's mass is high enough that we actually can observe stars that are near the edge of the suns visible disk that are actually still behind the visible disk as their light is bent around the edge.

[SeaGypsy]

Isn't this different? At least in that they can't see what is causing the warp? Excuse me KJ if I have missed something in your links?

[Subjectivist]

Isn't this different? At least in that they can't see what is causing the warp? Excuse me KJ if I have missed something in your links?

I presume you played wth a gyroscope at some time in your life Seagypsy? When you tap the frame around a gyroscope it will start precessing, the top end will twist around slowly making a circle. The Earth does this about once every 26,000 years.

A pulsar is a very dim remnant of a star, it is only visible in the radio frequencies as the magnetic poles point at you as it spins. The magnetic pole and geographic poles rarely line up on any spinning body with a magnetic field, so as the neutron star spins the poles point at different places through a complete rotation.

We only see those rare pulsars that have their magnetic poles pointed towards our Solar system as they rotate. In this case the pulsar being observed has precessed far enough that the magnetic poles no longer point at Earth. The pulsar did not drop into a wormhole, or fall out of our unverse, it is just tilted a little bit and no longer points at us. It's pulsing radio signal misses the Earth by some distance so radio telescopes no longer 'see' it.

Another way to think of it, when you are at sea and looking at a distant light house as you sail away from it the light will seem to suddenly disappear as it goes below the horizon. The lighthouse is still there, still working, but the curvature of the Earth has made it invisible to you.

[SeaGypsy]

Cool! Thanks Sub

[KaiserJeep]

Yes, what he said - and the observations constitute the strongest confirmation of General Relativity discovered so far.

This is just a single step in an endless journey. At some point, an observation will be made which General Relativity cannot explain. Then someone else with the intellect of an Einstein will elaborate upon a new theory which may either extend GR or replace part of it. That is the next step. Perhaps there will be some exception to the expected reappearance of this Pulsar and it's companion in approximately 170 years, or perhaps we will find such exceptions in observations of other pulsars. Equally likely is we will find something entirely new - or many entirely new things - as we examine the astronomical data.

The journey has no end, there are no bounds to knowledge.

[davep]

The journey has no end, there are no bounds to knowledge.

Equally, there are no bounds to our ignorance. It's an infinite spectrum.

[Keith_McClary]

It seems that as the pulsar spins around its companion star, the mass of the companion star makes it sink into a dip in space-time, so that its radio waves can no longer reach Earth.

No, it is just pointing in a different direction due to precession, as Sub explains.

A pulsar (short for pulsating radio star)[1] is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. This radiation can only be observed when the beam of emission is pointing toward the Earth
https://en.wikipedia.org/wiki/Pulsar

Precession is when a star actually wobbles far enough that it dips into the space-time bend that its own orbit created.

No, that is not remotely a definition of precession and relativity does not predict anything like this behavior.

These statements are just clueless "science journalism".

[dinopello]

I'm no physicist, but didn't Einstein explain the precession of large bodies by way of general relativity and the warping of space-time ? That's what causes the precession, but from there what was said about the pulsar "beam" shifting away from our observable corridor is still what caused the signal to vanish. The way it is written and the people's interpretation makes it sound like the star is actually no longer there because it went into a wormhole or something. Feel free to tell me I'm wrong.

[Tanada]

I'm no physicist, but didn't Einstein explain the precession of large bodies by way of general relativity and the warping of space-time ? That's what causes the precession, but from there what was said about the pulsar "beam" shifting away from our observable corridor is still what caused the signal to vanish. The way it is written and the people's interpretation makes it sound like the star is actually no longer there because it went into a wormhole or something. Feel free to tell me I'm wrong.

I am confident you are correct on all points there Dino, the original article is very muddy and confusing. I don't think the author knows what precession is or how it relates to space-time and relativity. A lot of sci-fi TV/Movies/books have claimed you can use pulsars as navigational beacons when traveling around out galaxy. Maybe so, but only if you are flying straight towards or away from the pulsar, as soon as you leave its signal arc you won't hear it any more. Even worse, as soon as you fly towards the one you are using as a beacon the other ones you are familiar with will go silent because Earth only hears them where they all cross paths. So sure you could fly towards a pulsar or away from it as a beacon, but why wouldn't you just use the stars to navigate by? The really bright ones are huge and distant so you will be able to track using them for hundreds of light years.

Sorry the sci-fi writer wannabe in me just reared its ugly puddin head lol.

[Timo]

I'm not a scientist, but this discovery in no way proves that humans have caused global warming, or that global warming is real, at all!

[KaiserJeep]

Correct, Timo. Nor does it prove that the USSR had JFK assassinated. It only suggests that might be true....

[Timo]

It also doesn't disprove i was Gweneth Paltrow's first true love.

[KaiserJeep]

I don't know how I missed it, but I didn't have a clue about that. Does she snore?

[Timo]

Not when she's sleeping.

[AgentR11]

Gravity Probe B proved this out a few years ago. Everyone already knew Einstein was correct on this subject.

[Sixstrings]

Gravity Probe B proved this out a few years ago. Everyone already knew Einstein was correct on this subject.

I know that much, Einstein has been proven right already, many times.

Wasn't there some kind of experiment with atomic clocks? Just flying them on airplanes? And then one clock was slightly behind the other? Thus proving that the faster you go, the more time slows down, most pronounced close to the speed of light.

As for the binary pulsars..

Some good explanations in this thread but I'm still not getting it. I think I need a Neil de Grasse Tyson to explain it to me.

[AgentR11]

that was time.
this is distance/space. you can't get a big enough effect to measure with airplanes and atomic clocks.