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Tony Darnell
owner

Space Exploration  - 
 
Hi All,

We're starting a new hangout series this month: "Footsteps to Mars".  The first Friday of each month will host a different topic with discussion from top scientists and engineers working on getting humans to Mars!

I hope you can make it, if not, you can always watch the archive but it's always better when you can interact!  I'll have the live chat turned on and ready to take your questions and comments.

Join us on YouTube:
https://www.youtube.com/watch?v=BiTGqykR3eA
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Gary Lite (369)

Discussion  - 
 
Scientists have for the first time detected gravitational waves, ripples in space and time hypothesized by Albert Einstein a century ago, in a landmark discovery announced on Thursday that opens a new window for studying the cosmos.

http://www.369universe.com/2016/02/11/einstein-was-right-gravitational-waves-detected-in-scientific-milestone/
Einstein was right, Gravitational Waves Detected in Scientific Milestone
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WOW!!
Congratulations to all HUMANS for greatest discovery!!
Respect to The Albert Einstein!!
Scientists announce discovery of clear gravitational wave signal, ripples in spacetime first predicted by Albert Einstein
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Chris Reeve's profile photoVaibhav Gilankar's profile photoAman Arora's profile photo
 
Ah, the first article I've seen which correctly points out that they observed a single wave, rather than "waves".

And if I'm reading this paper right, it is not associated with any particular event that they were watching.  They are simply inferring that it must be caused by two merging black holes somewhere.

People should put some thought into how one goes about replicating this.  What do you do?  Wait for another pair of signals to register?  What exactly have you "replicated" if you have not even identified the source?

If I am wrong about this, I would love to be corrected.

The paper states: "These observations demonstrate the existence of binary stellar-mass black hole systems."

But, how is that possible without actually correlating this wave -- singular -- with a particular source?

If people lower the bar sufficiently, then realize it becomes that much easier to allow many of the competing explanations in as well.
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SpaceTime

Discussion  - 
 
Flares heat the upper chromosphere of the sun

A solar flare is a sudden flash of brightness observed near the Sun's surface and it ejects clouds of electrons, ions, and atoms through the corona of the sun into space. Flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior, and they are powered by the sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona.
(Solar flare  --> https://en.wikipedia.org/wiki/Solar_flare)

An Alfvén wave, instead, is a type of magnetohydrodynamic wave in which ions oscillate in response to a restoring force provided by an effective tension on the magnetic field lines. The wave propagates in the direction of the magnetic field. The motion of the ions and the perturbation of the magnetic field are in the same direction and transverse to the direction of propagation.
(Alfvén waves --> https://en.wikipedia.org/wiki/Alfv%C3%A9n_wave)

In a recent paper (Reep & Russell, 2016 ApJL), the authors have developed a numerical model of flare heating due to the dissipation of Alfvenic waves propagating from the corona to the chromosphere.
They derive three important conclusions:
(1) Alfvenic waves, propagating from the corona to the chromosphere, are capable of heating the upper chromosphere and the corona.
(2) the atmospheric response to heating due to the dissipation of Alfvenic waves can be strikingly similar to heating by an electron beam
(3) this heating can produce explosive evaporation.

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Reep & Russell, 2016 ApJL
http://iopscience.iop.org/article/10.3847/2041-8205/818/1/L20/meta;jsessionid=4EBC5EC5B4C8C88F8A207A80F453515D.c5.iopscience.cld.iop.org
http://arxiv.org/abs/1601.01969

Image: Anatomy of the Sun
Credit: NASA/Jenny Mottar
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Gary Lite

Discussion  - 
 
US scientists will make a presentation about the search for gravitational waves – and will possibly announce their discovery. Astronomers have been searching for decades, as they are one of the most important variables in Einstein's theory of relativity.

http://www.369universe.com/2016/02/10/scientists-to-make-gravitational-wave-announcement-100-years-after-einsteins-theory-of-relativity/
US scientists will make a presentation about the search for gravitational waves – and will possibly announce their discovery. Astronomers have been searching for decades, as they are one of the most important variables in Einstein's theory of relativity.
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Explain?
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A new planet is about to be discovered on our solar system...!! http://www.beautyinspace.com/a-giant-new-planet-the-ninth-of-our-solar-system/
Caltech announced an incredible discovery that surprised the entire world: our Solar System has a ninth planet.
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It makes me wonder how Mandy are out there
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Thomas Wildoner

Amateur Astronomy & Telescopes  - 
 
Spiral Galaxy NGC 2403 in the Constellation Camelopardalis
Do you want to see a rather bright galaxy in a giraffe? Grab your binoculars and set your sights on NGC2403. NGC 2403 is a rather bright spiral galaxy in the constellation Camelopardalis (the giraf…
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SpaceTime

Discussion  - 
 
A new research on the Active Galactic Nuclei.
 
February 9, 2016

SUPER-EDDINGTON ACCRETION IN ACTIVE GALACTIC NUCLEI

Broad emission lines are a hallmark feature of type 1 active galactic nuclei (AGNs) and quasars. Many basic properties of the broad-line region (BLR), such as its basic geometry, dynamics, and physical connection to the accretion disk around the supermassive black hole (BH), remain illdefined. AGN spectra exhibit both tremendous diversity as well as discernable patterns of systematic regularity.

In a recent paper (Du, Wang et al. 2016) published on ApJL, the authors study correlations among three dimensionless
AGN parameters: accretion rate (or Eddington ratio), shape of the broad Hβ line, and flux ratio of optical Fe II to Hβ. A strong correlation among them is found, denoted as the fundamental plane of AGN BLRs. The BLR fundamental plane allows to conveniently explore the accretion status of the AGN central engine using single-epoch spectra, opening up many interesting avenues for exploring AGNs, including their cosmological evolution. The authors apply the plane to a sample of z < 0.8 quasars to demonstrate the prevalence of super-Eddington accreting AGNs are quite common at low redshifts.

(The Eddington limit, is the maximum luminosity a body - such as a star - can achieve when there is balance between the force of radiation acting outward and the gravitational force acting inward. The state of balance is called hydrostatic equilibrium. When a star exceeds the Eddington limit, it will initiate a very intense radiation-driven stellar wind from its outer layers).

The paper (Du, Wang et al. 2016) is available online here>>

http://iopscience.iop.org/article/10.3847/2041-8205/818/1/L14/meta;jsessionid=7B1AA9FD008AF335F6CD54EF9AE67162.ip-10-40-2-115

http://arxiv.org/abs/1601.01391

Image: Supermassive black holes at the cores of galaxies blast radiation and ultra-fast winds outward, as illustrated in this artist's conception. Credit: NASA/JPL-Caltech

Image is available online here>>
http://www.jpl.nasa.gov/news/news.php?feature=4486
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Mario Valentini

Discussion  - 
 
Buongiorno a tutta la Comunità.
 ·  Translate
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ESA Space Science image of the week - A section of #Saturn 's F ring, is featured in this image from the Cassini spacecraft. Scientists believe that a small population of differently sized moonlets were responsible for forming this feature as they collide with and perturb the core of the ring – some of the small moonlets can be seen emerging below the ring just left of the centre.

http://www.esa.int/spaceinimages/Images/2016/02/Spying_Saturn_s_moonlets

Credit: NASA/JPL/Space Science Institute
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About this community

Welcome to the Google+ Deep Astronomy Community - a home for those who would like to discuss and explore questions about cosmology, the nature of the universe, the Big Bang, life in the universe and much more. Please post on-topic, while following the primary rule: be courteous and respect others!

Mike Raven

Cosmology  - 
 
ALBERT EINSTEINS PREDICTION OF GRAVITATIONAL WAVES CONFIRMED

http://ravenskullherald.com/wire-017-feb-16.php
Scientists have announced that for the first time they have successfully detected gravitational waves. These ripples in the space-time fabric had been first been predicted by Albert Einstein in 1915, and were detected on the 14th of September 2015 by the Laser Interferometer Gravitational-Wave ...
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TNA Asylum

Discussion  - 
 
Since Albert Einstein first predicted their existence a century ago, physicists have been on the hunt for gravitational waves, ripples in the fabric of spacetime. That hunt is now over. Gravitational waves exist, and we’ve found them.
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THEY DID IT!!!!!!!
With mind-bending advance, humanity opens new eyes on the heavens
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James Emmett

Discussion  - 
 
So just what are Gravitational waves? and how will they change physics and astronomy?
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This is a very good post. Well done, its simple, gives great understanding, and opens the possibilities 
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Thomas Wildoner

Amateur Astronomy & Telescopes  - 
 
First Quarter Moon – February 15, 2016 – Moon in Taurus
The February 2016 first quarter moon finds itself in the constellation Taurus right on the edge of the Hyades Star Cluster on the evening of February 15th. From Wikipedia: The lunar phase or phase…
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SpaceTime

Discussion  - 
 
Metallicity and luminosity of SN Ia

In a recent paper (Moreno-Raya et al., 2016 ApJL) the authors investigate the role of the metallicity of the progenitor system producing a type Ia supernova in its maximum luminosity.

They found that luminosities of SNe Ia depends on the metallicity of the host galaxy. This dependence might induce to systematic errors when is not considered in deriving SNe Ia luminosities and then using them to derive cosmological distances.

Image: Combined HST and Chnadra imaging of the supernova remnant SNR 0509-67.5 in the LMC To find distances in space, astronomers use objects called "standard candles", objects that give a certain, known amount of light. Beca...
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Mike Raven

Space Exploration  - 
 
NASA's Administrator Charles Bolden gave the State of NASA yesterday.

http://ravenskullherald.com/wire-015-feb-16.php
Yesterday, NASA Administrator Charles Bolden announced that the "State of NASA is Strong." In recent years NASA has made large strides in science with the study of the cosmos and robotic exploration of the solar system like the spacecraft New Horizons that was the first to flyby Pluto.
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Vladimir Pecha

Hubble Space Telescope  - 
 
HST: The final frontier

Since October 2013 the NASA/ESA Hubble Space Telescope has been observing some of the most massive structures in the Universe -- galaxy clusters. Using the magnification effect caused by their mass, Hubble can look deeper into the Universe than ever before. In this new Hubblecast, Dr J talks about the goals and the achievements of this campaign, called the Frontier Fields programme.

http://www.spacetelescope.org/videos/hubblecast90a/?utm_medium=SocialSignIn&utm_source=Twitter
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Vladimir Pecha

Discussion  - 
 
Hickson Compact Group 92 (Stephan’s Quintet)
Subaru Telescope

Among the large, bright galaxies captured in this image, all of them except the bluish-white spiral galaxy in the lower left are members of a compact group located 300 million light-years from us. The reddish areas, like those between the galaxies, indicate locations where hydrogen excited by the ultraviolet light from young stars is emitting red light. The galaxy in the lower left is much closer to us, but just happens to be sitting between us and the galaxy group. This creates the illusion that it is crashing into the others. Because the distances between the galaxies are very short in this group, they are interacting through their mutual gravity. We know that even now within the galaxies, and within the stripped gas, chemical and structural evolution is proceeding rapidly.
In the Universe there are countless gal...
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SpaceTime

Discussion  - 
 
A new water maser discovered in the lenticular galaxy IRAS 15480-0344

Every day a new original post here>>
https://plus.google.com/collection/8dcJfB

Other posts here
https://plus.google.com/collection/I6sfx
Image: Colour composite image of Centaurus A, revealing the lobes and jets emanating from the active galaxy’s central black hole. This is a composite of images obtained with three instruments, operating at very different wave...
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Linn PJ
 
Hi
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