Astrophysics and Cosmology - Discuss the Universe here

[Caruthers612]

Pluto has a blue sky.

http://www.space.com/30784-pluto-blue-skies-new-horizons-photo.html

       Blue skies and water ice, I read it today. Note that not long ago, scientists were not at all sure there was water anywhere else in the cosmos--nor, for that matter, other planets (stuff in science has to be proven, eh what?), let alone habitable ones. Now they can't stop finding groovy, habitable planets, and there's water everywhere. I tell you, a few more years and they'll find old copies of Newsweek and a White Castle on Titan.

[zeebo]

       Blue skies and water ice, I read it today. Note that not long ago, scientists were not at all sure there was water anywhere else in the cosmos--nor, for that matter, other planets (stuff in science has to be proven, eh what?), let alone habitable ones. Now they can't stop finding groovy, habitable planets, and there's water everywhere. I tell you, a few more years and they'll find old copies of Newsweek and a White Castle on Titan.

Yes!  All those sci-fi covers with strange planets depicted might actually be out there.  I remember Carl Sagan's idea of an "Encyclopedia Galactica" from Cosmos ... We're starting to build it.

[Agent : Orange]

Hey all

Just heard Art is off the air and decided to pop in tonight. Life has been really crazy for the past year or so. Hope you are all doing well.

Meantime I'll just leave this here...
https://www.quantamagazine.org/20150922-nima-arkani-hamed-collider-physics/

[Agent : Orange]

Press event for tomorrow (Tuesday Dec 15 2015) regarding the latest high energy run of the LHC
https://webcast.web.cern.ch/webcast/

[wr250]

Hey all

Just heard Art is off the air and decided to pop in tonight. Life has been really crazy for the past year or so. Hope you are all doing well.

Meantime I'll just leave this here...
https://www.quantamagazine.org/20150922-nima-arkani-hamed-collider-physics/

wb and post often. also might consider being on the bell philes.

[Agent : Orange]

wb and post often. also might consider being on the bell philes.

Hey WR how are you?

I'm guessing the Bellphiles is a new podcast in the vein of the gabcast? I haven't heard any of it.

It was a productive year with lots of travel and a few conferences in far away lands. My work schedule is as usual insane. But now that Art is off the air, there's a renewed need to post here more than ever.

[Agent : Orange]

Hints of a new boson were announced today at the LHC. Nothing concrete yet, and the statistics have to vastly improve before it can be considered a discovery. However the rumors start here and now, and a mob of hungry theorists have begun licking their chops.
This guy has an excellent blog on particle physics with a review up: http://resonaances.blogspot.ca/2015/12/a-new-boson-at-750-gev.html

For a more popular approach (and less technical reviews) here are articles from New Scientist and Nature:
https://www.newscientist.com/article/dn28674-physicists-struggle-to-squeeze-new-particles-from-the-lhc/
http://www.nature.com/news/lhc-sees-hint-of-boson-heavier-than-higgs-1.19036

If the existence of this boson is confirmed over 2016, it will be the first sign of physics beyond the standard model. Exciting times...

[Agent : Orange]

Also released recently: The upgraded particle detector used by the LUX team to try to detect dark matter particles has a non-detection and ruled out even more low-mass WIMPs.
The next step is an even more sensitive detector LUX-ZEPLIN that will begin operations in 2016.
http://www.symmetrymagazine.org/article/lux-maps-where-dark-matter-isnt
http://luxdarkmatter.org/

[zeebo]

Good to see ya AO.  So much happening around here lately I almost forgot about the rest o' the cosmos.

[Agent : Orange]

Good to see ya AO.  So much happening around here lately I almost forgot about the rest o' the cosmos.

Good to see you too! Whenever there's any kind of development with Art, the turbulence stirs this place up something fierce.

[wr250]

Good to see you too! Whenever there's any kind of development with Art, the turbulence stirs this place up something fierce.

and that makes us vaguely loveable 

[Agent : Orange]

I'm hearing rumblings that advanced LIGO (https://www.advancedligo.mit.edu/) may have detected the gravitational wave signal of two black holes merging. If this is the case it will be a revolution in astrophysics and open a new window to the universe, since gravitational waves have not been directly observed yet. Gravitational waves are considered the last prediction of general relativity not yet directly verified.

Will keep this thread posted

[zeebo]

I'm hearing rumblings that advanced LIGO (https://www.advancedligo.mit.edu/) may have detected the gravitational wave signal of two black holes merging. If this is the case it will be a revolution in astrophysics and open a new window to the universe, since gravitational waves have not been directly observed yet. Gravitational waves are considered the last prediction of general relativity not yet directly verified.

Will keep this thread posted

Yes please do AO!  I've been casually following that one, such a cool experiment.  My understanding is that they'd be - to borrow from Star Trek - "ripples in spacetime".  It'd be a mind-boggling thing to detect. 

[Dr. MD MD]

Yes please do AO!  I've been casually following that one, such a cool experiment.  My understanding is that they'd be - to borrow from Star Trek - "ripples in spacetime".  It'd be a mind-boggling thing to detect.

Fascinating but my understanding is limited. Concept, yes. Math, not so much. So, forgive me if I says something stupid. What confuses me about gravity in regard to relativity is does gravity cause spacetime to warp or is gravity just a result of it warping from displacement? Just asking. Any illumination appreciated.

[zeebo]

Fascinating but my understanding is limited. Concept, yes. Math, not so much. So, forgive me if I says something stupid. What confuses me about gravity in regard to relativity is does gravity cause spacetime to warp or is gravity just a result of it warping from displacement? Just asking. Any illumination appreciated.

There are others who know alot more than me about this, but my squirrel brain's understanding is ... mass warps the fabric of spacetime, making a 'curvature' (in 4 dimensions) which other bodies 'feel' as gravity (in 3 dimensions).  So what seems like a force pulling us towards the earth, is actually a bending in spacetime caused by the earth's mass.

Colossal cosmic events like two black holes mixing it up would cause intense ripples that would travel through the continuum like a rogue wave through the ocean.  I believe the LIGO experiment would detect a shortening of a steady laser beam which shows that for that instant spacetime has warped/curved as the grav wave passes through it. 

[Dr. MD MD]

There are others who know alot more than me about this, but my squirrel brain's understanding is ... mass warps the fabric of spacetime, making a 'curvature' (in 4 dimensions) which other bodies 'feel' as gravity (in 3 dimensions).  So what seems like a force pulling us towards the earth, is actually a bending in spacetime caused by the earth's mass.

Colossal cosmic events like two black holes mixing it up would cause intense ripples that would travel through the continuum like a rogue wave through the ocean.  I believe the LIGO experiment would detect a shortening of a steady laser beam which shows that for that instant spacetime has warped/curved as the grav wave passes through it.

Thanks, zeebo. Do you know how far away/long ago the phenomena is?

[zeebo]

Thanks, zeebo. Do you know how far away/long ago the phenomena is?

I think grav-waves are theorized to travel vast distances, but not sure about specifics.  Hoping AO can fill us in.   

[Agent : Orange]

There are others who know alot more than me about this, but my squirrel brain's understanding is ... mass warps the fabric of spacetime, making a 'curvature' (in 4 dimensions) which other bodies 'feel' as gravity (in 3 dimensions).  So what seems like a force pulling us towards the earth, is actually a bending in spacetime caused by the earth's mass.

Colossal cosmic events like two black holes mixing it up would cause intense ripples that would travel through the continuum like a rogue wave through the ocean.  I believe the LIGO experiment would detect a shortening of a steady laser beam which shows that for that instant spacetime has warped/curved as the grav wave passes through it.

This is a good description. Gravitational waves are the analogue of electromagnetic waves, but instead of a field carrying the disturbance, space-time carries the wave. This means that gravitational waves change distances and times that observers would measure by a tiny amount that is in principle only measurable by interferometry which can be very precise and make measurements smaller than the scales of atoms. The difference between EM and gravitational waves is that the electric part of EM waves have polarization in only one direction - say, up and down - whereas gravitational waves are more complicated and oscillate in more than one direction. This is because EM waves are described mathematically by vectors, which have one index and gravitational waves are described by something called a tensor, which has two indices similar to a matrix. That also means gravitational waves can't be generated by dipoles like EM waves can, you need at least a quadrupole to do it, such as two masses spiralling in to one another that give up some portion of energy, radiated away in the form of ripples in space-time.

Thanks, zeebo. Do you know how far away/long ago the phenomena is?

You can get gravitational waves from anywhere in the universe and in fact we will be able to see more with gravitational waves than we can with electromagnetic in principle, even beyond the veil of the cosmic microwave background, the earliest radiation we know of after the big bang when space-time became transparent to electromagnetic radiation. Gravitational waves have no problem with such a boundary and can reach us directly from the origin of the universe itself which makes them useful for studying cosmology at early times. A few years ago the claim was made to have seen such relic gravitational waves in a set of observations made by an instrument called BICEP2, but these results have since been attributed to the action of galactic dust fouling the signal and are no longer taken as a serious claim.

I should also mention that gravitational waves have been seen indirectly before, the Hulse-Taylor binary pulsars show energy loss exactly what you'd expect from GR (https://en.wikipedia.org/wiki/PSR_B1913%2B16) and won it's discoverers the 1993 nobel prize.

[Philosopher]

42


The Answer to the Ultimate Question of Life, The Universe, and Everything.

[Agent : Orange]

42


The Answer to the Ultimate Question of Life, The Universe, and Everything.

To paraphrase, "This guy gets it."

[trostol]

this is all over the place today

http://nerdist.com/study-suggests-the-ninth-planet-in-our-solar-system-lurks-beyond-pluto/

[onan]

this is all over the place today

http://nerdist.com/study-suggests-the-ninth-planet-in-our-solar-system-lurks-beyond-pluto/

Yeah, I heard a news clip while driving to work this morning. I think it's Nibiru, making it's plan to come steal the gold on Earth

[Agent : Orange]

A very large body out there is pretty surprising, apparently Planet Nine is about half the mass of Neptune, which is big. But there's got to be a lot of interesting stuff out in the depths of the Kuiper belt on elongated orbits we don't know of yet. It's interesting how many questions regarding orbits of other bodies it can tie up in a seemingly nice bow. Would be amazing if it were discovered.

[onan]

A very large body out there is pretty surprising, apparently Planet Nine is about half the mass of Neptune, which is big. But there's got to be a lot of interesting stuff out in the depths of the Kuiper belt on elongated orbits we don't know of yet. It's interesting how many questions regarding orbits of other bodies it can tie up in a seemingly nice bow. Would be amazing if it were discovered.

The story I heard had a large qualifier, that it was all speculation, lots of numbers pointing to a gas giant but no proof.

[FearBoysWithBugs]

The story I heard had a large qualifier, that it was all speculation, lots of numbers pointing to a gas giant but no proof.

People have been predicting the existence of Planet X since Neptune was discovered.   A prediction is not a discovery.  And these guys, for some reason, are passing up the priceless opportunity to discover an actual fuckin planet by releasing their prediction to the media.

Yeah, okay, whatever.  They're talking about something that orbits the Sun once every ten or twenty thousand years.  IF it exists, it hasn't made a complete orbit in recorded history, much less during the time when its effects could have been observed.

I think whatever is responsible for the Pioneer anomaly is also responsible for the deviations from predicted orbits or trajectories that have been observed.  It's relativity and the orbit of Mercury all over again.

Hay A:O, dint they put something on New Horizons to test for that?  Any results thus far?

[Agent : Orange]

The story I heard had a large qualifier, that it was all speculation, lots of numbers pointing to a gas giant but no proof.

In 2014, the far-infrared view of instruments aboard the WISE satellite eliminated the possibility of Jupiter and Saturn size planets in the outer solar system. But there has been talk of smaller bodies that may explain the orbital behaviors of objects in the outer Kuiper-belt / inner Oort cloud. So now it has been again predicted by this group, 10 Earth masses is large but within the limits checked by WISE. Whether such an object is really there, no one knows yet. However it sounds like it should be detectable provided it's not at its maximum distance from the Sun.

Wait and see

[Northern Nights]

this is all over the place today

http://nerdist.com/study-suggests-the-ninth-planet-in-our-solar-system-lurks-beyond-pluto/

It will be interesting to hear what RCH has to say about this.

[Agent : Orange]

People have been predicting the existence of Planet X since Neptune was discovered.   A prediction is not a discovery.  And these guys, for some reason, are passing up the priceless opportunity to discover an actual fuckin planet by releasing their prediction to the media.

Yeah, okay, whatever.  They're talking about something that orbits the Sun once every ten or twenty thousand years.  IF it exists, it hasn't made a complete orbit in recorded history, much less during the time when its effects could have been observed.

I think whatever is responsible for the Pioneer anomaly is also responsible for the deviations from predicted orbits or trajectories that have been observed.  It's relativity and the orbit of Mercury all over again.

Hay A:O, dint they put something on New Horizons to test for that?  Any results thus far?

That's interesting, I haven't heard anything about the status of New Horizons with respect to the Pioneer anomaly, it was suggested as a test but I have not heard anything about it.
I am very skeptical of the pioneer anomaly especially since it can apparently be explained by non-uniform thermal effects.
There's also an interesting flyby anomaly which is also on shaky ground. The effects are really small, so difficult to measure. Talking about mm/s on each pass.

A short article about asymmetric heating aboard Pioneer: http://www.nature.com/nphys/journal/v8/n9/full/nphys2428.html
And an indepth discussion of the flyby anomaly:
http://issfd.org/2015/files/downloads/papers/153_Jouannic.pdf

[Agent : Orange]

It will be interesting to hear what RCH has to say about this.

Strap in for 19.5 gs of crazy

[GravitySucks]

It will be interesting to hear what RCH has to say about this.

Well it will be it is either in the model or it's not in the model. Is the inclination of the orbit at 19.5, a multiple of 19.5, or any other number that RCH can create an equation for that includes 19.5?