Universe News (miscellaneous articles)

[Draggendrop Veteran]

Longest-Lasting Stellar Eclipse Discovered

 

Illustration of binary star system which produces the longest lasting eclipses known. (Jeremy Teaford / Vanderbilt University)

 

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Imagine living on a world where, every 69 years, the sun disappears in a near-total eclipse that lasts for three and a half years.

 

That is just what happens in an unnamed binary star system nearly 10,000 light years from Earth. The newly discovered system, known only by its astronomical catalog number TYC 2505-672-1, sets a new record for both the longest duration stellar eclipse and the longest period between eclipses in a binary system.

 

Discovery of the system's extraordinary properties was made by a team of astronomers from Vanderbilt and Harvard with the assistance of colleagues at Lehigh, Ohio State and Pennsylvania State universities, Las Cumbres Observatory Global Telescope Network and the American Association of Variable Star Observers and is described in a paper accepted for publication in the Astronomical Journal.

 

"It's the longest duration stellar eclipse and the longest orbit for an eclipsing binary ever found...by far," said the paper's first author Vanderbilt doctoral student Joey Rodriguez.

 

The previous record holder is Epsilon Aurigae, a giant star that is eclipsed by its companion every 27 years for periods ranging from 640 to 730 days.

 

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The resulting analysis revealed a system similar to the one at Epsilon Aurigae, with some important differences. It appears to consist of a pair of red giant stars, one of which has been stripped down to a relatively small core and surrounded by an extremely large disk of material that produces the extended eclipse.

 

"About the only way to get these really long eclipse times is with an extended disk of opaque material. Nothing else is big enough to block out a star for months at a time," Rodriguez said.

 

TYC-2505-672-1 is so distant that the amount of data the astronomers could extract from the images was limited. However, they were able to estimate the surface temperature of the companion star and found that it is about 2,000 degrees Celsius hotter than the surface of the sun.

 

Combined with the observation that it appears to be less than half the diameter of the sun has led them to propose that it is a red giant that has had its outer layers stripped away and that this stripped material may account for the obscuring disk. However, they don't know that for certain.

 

In order to produce the 69-year interval between eclipses, the astronomers calculate that they must be orbiting at an extremely large distance, about 20 astronomical units, which is approximately the distance between the Sun and Uranus.

 

"Right now even our most powerful telescopes can't independently resolve the two objects," said Rodriguez. "Hopefully, technological advances will make that possible by 2080 when the next eclipse occurs."

more at...

http://www.spacedaily.com/reports/Longest_Lasting_Stellar_Eclipse_Discovered_999.html

 

[LOC Veteran]

So anotherwords, they found the Planet in the Pitch Black movie? Neat! I wonder if Vin Diesel is running around killing horrible creatures right now.

[Draggendrop Veteran]

17 hours ago, LOC said:

So anotherwords, they found the Planet in the Pitch Black movie? Neat! I wonder if Vin Diesel is running around killing horrible creatures right now.

    first thing I thought too......and the glow worms.....

[Draggendrop Veteran]

I was flipping through space related video's, and came across one that I have not seen for a while. It's a bit long and a few years old, but some of the images will blow you away....

 

Seeing Beyond - The James Webb Space Telescope 

video is 14:02 min.

 

 

 

[Draggendrop Veteran]

ATLASGAL Survey of Milky Way Completed

 

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A spectacular new image of the Milky Way has been released to mark the completion of the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL).

 

The APEX telescope in Chile has mapped the full area of the Galactic Plane visible from the southern hemisphere for the first time at submillimetre wavelengths between infrared light and radio waves and in finer detail than recent space-based surveys. The pioneering 12-metre APEX telescope allows astronomers to study the cold Universe: gas and dust only a few tens of degrees above absolute zero.

 

APEX, the Atacama Pathfinder EXperiment telescope, is located at 5100 metres above sea level on the Chajnantor Plateau in Chile's Atacama region. The ATLASGAL survey took advantage of the unique characteristics of the telescope to provide a detailed view of the distribution of cold dense gas along the plane of the Milky Way galaxy [1]. The new image includes most of the regions of star formation in the southern Milky Way [2].

 

The new ATLASGAL maps cover an area of sky 140 degrees long and 3 degrees wide, more than four times larger than the first ATLASGAL release [3]. The new maps are also of higher quality, as some areas were re-observed to obtain a more uniform data quality over the whole survey area.

 

The ATLASGAL survey is the single most successful APEX large programme with nearly 70 associated science papers already published, and its legacy will expand much further with all the reduced data products now available to the full astronomical community [4].

 

At the heart of APEX are its sensitive instruments. One of these, LABOCA (the LArge BOlometer Camera) was used for the ATLASGAL survey. LABOCA measures incoming radiation by registering the tiny rise in temperature it causes on its detectors and can detect emission from the cold dark dust bands obscuring the stellar light.

 

The new release of ATLASGAL complements observations from ESA's Planck satellite [5]. The combination of the Planck and APEX data allowed astronomers to detect emission spread over a larger area of sky and to estimate from it the fraction of dense gas in the inner Galaxy. The ATLASGAL data were also used to create a complete census of cold and massive clouds where new generations of stars are forming.

 

"ATLASGAL provides exciting insights into where the next generation of high-mass stars and clusters form. By combining these with observations from Planck, we can now obtain a link to the large-scale structures of giant molecular clouds," remarks Timea Csengeri from the Max Planck Institute for Radio Astronomy (MPIfR), Bonn, Germany, who led the work of combining the APEX and Planck data.

 

The APEX telescope recently celebrated ten years of successful research on the cold Universe. It plays an important role not only as pathfinder, but also as a complementary facility to ALMA, the Atacama Large Millimeter/submillimeter Array, which is also located on the Chajnantor Plateau. APEX is based on a prototype antenna constructed for the ALMA project, and it has found many targets that ALMA can study in great detail.

http://spaceref.com/astronomy/atlasgal-survey-of-milky-way-completed.html

 

Close look at the ATLASGAL image of the plane of the Milky Way

video is 8:10 min.,   scroll through it, all images are stunning

 

 

 

We are fortunate to live in such beauty......

[Draggendrop Veteran]

Hubble Observes A WolfRayet Nebula

 

WR31a                         STSCI

 

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Sparkling at the center of this beautiful NASA/ESA Hubble Space Telescope image is a WolfRayet star known as WR 31a, located about 30,000 light-years away in the constellation of Carina (The Keel).

 

The distinctive blue bubble appearing to encircle WR 31a is a WolfRayet nebula an interstellar cloud of dust, hydrogen, helium and other gases.

 

Created when speedy stellar winds interact with the outer layers of hydrogen ejected by WolfRayet stars, these nebulae are frequently ring-shaped or spherical. The bubble estimated to have formed around 20,000 years ago is expanding at a rate of around 220,000 kilometers (136,700 miles) per hour!

 

Unfortunately, the lifecycle of a WolfRayet star is only a few hundred thousand years the blink of an eye in cosmic terms. Despite beginning life with a mass at least 20 times that of the sun, WolfRayet stars typically lose half their mass in less than 100,000 years. And WR 31a is no exception to this case. It will, therefore, eventually end its life as a spectacular supernova, and the stellar material expelled from its explosion will later nourish a new generation of stars and planets.

 

Image credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt

http://spaceref.com/astronomy/hubble-observes-a-wolfrayet-nebula.html

 

[Draggendrop Veteran]

Black holes banish matter into cosmic voids

 

A slab cut from the cube generated by the Illustris simulation. It shows the distribution of dark matter, with a width and height of 350 million light-years and a thickness of 300000 light years. Galaxies are found in the small, white, high-density dots. Image courtesy Markus Haider and Illustris collaboration. 

 

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We live in a universe dominated by unseen matter, and on the largest scales, galaxies and everything they contain are concentrated into filaments that stretch around the edge of enormous voids. Thought to be almost empty until now, a group of astronomers based in Austria, Germany and the United States now believe these dark holes could contain as much as 20% of the 'normal' matter in the cosmos, and that galaxies make up only 1/500th of the volume of the universe.

 

The team, led by Dr Markus Haider of the Institute of Astro- and Particle Physics at the University of Innsbruck in Austria, publish their results in a new paper in Monthly Notices of the Royal Astronomical Society.

 

Looking at cosmic microwave radiation, modern satellite observatories like COBE, WMAP and Planck have gradually refined our understanding of the composition of the universe, and the most recent measurements suggest it consists of 4.9% 'normal' matter (i.e. the matter that makes up stars, planets, gas and dust), or 'baryons', whereas 26.8% is the mysterious and unseen 'dark matter', and 68.3% is the even more mysterious 'dark energy'.

 

Complementing these missions, ground-based observatories have mapped the positions of galaxies and, indirectly, their associated dark matter over large volumes, showing that they are located in filaments that make up a 'cosmic web'. Haider and his team investigated this in more detail, using data from the Illustris project, a large computer simulation of the evolution and formation of galaxies, to measure the mass and volume of these filaments and the galaxies within them.

 

Illustris simulates a cube of space in the universe, measuring some 350 million light years on each side. It starts when the universe was just 12 million years old, a small fraction of its current age, and tracks how gravity and the flow of matter changes the structure of the cosmos up to the present day. The simulation deals with both normal and dark matter, with the most important effect being the gravitational pull of the dark matter.

When the scientists looked at the data, they found that about 50% of the total mass of the universe is in the places where galaxies reside, compressed into a volume of 0.2% of the universe we see, and a further 44% is in the enveloping filaments. Just 6% is located in the voids, which make up 80% of the volume.

 

But Haider's team also found that a surprising fraction of normal matter - 20% - is likely to be have been transported into the voids. The culprit appears to be the supermassive black holes found in the centres of galaxies. Some of the matter falling towards the holes is converted into energy.

This energy is delivered to the surrounding gas, and leads to large outflows of matter, which stretch for hundreds of thousands of light years from the black holes, reaching far beyond the extent of their host galaxies.

 

Apart from filling the voids with more matter than thought, the result might help explain the 'missing baryon problem', where astronomers do not see the amount of normal matter predicted by their models.

 

Dr Haider comments: "This simulation, one of the most sophisticated ever run, suggests that the black holes at the centre of every galaxy are helping to send matter into the loneliest places in the universe. What we want to do now is refine our model, and confirm these initial findings."

 

Illustris is now running new simulations, and results from these should be available in a few months. It will be hard though to see the matter in the voids, as this is likely to be very tenuous and too cool to emit the X-rays that would make it detectable by orbiting observatories.

http://www.spacedaily.com/reports/Black_holes_banish_matter_into_cosmic_voids_999.html

 

[LOC Veteran]

I always find it amazing (and very interesting if you think about it) that the cosmic web so to speak, looks just like neurons in the brain. One could make a supposition about it, but that would be grandstanding on the biggest scale I guess

[Draggendrop Veteran]

The Realm of Buried Giants

 

RCW 106    ESO

 

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RCW 106 is a sprawling cloud of gas and dust located about 12 000 light-years away in the southern constellation of Norma (The Carpenter's Square).

The region gets its name from being the 106th entry in a catalogue of H II regions in the southern Milky Way [1]. H II regions like RCW 106 are clouds of hydrogen gas that are being ionised by the intense starlight of scorching-hot, young stars, causing them to glow and display weird and wonderful shapes.

 

RCW 106 itself is the red cloud above centre in this new image, although much of this huge H II region is hidden by dust and it is much more extensive than the visible part. Many other unrelated objects are also visible in this wide-field VST image. For example, the filaments to the right of the image are the remnants of an ancient supernova, and the glowing red filaments at the lower left surround an unusual and very hot star [2]. Patches of dark obscuring dust are also visible across the entire cosmic landscape.

 

Astronomers have been studying RCW 106 for some time, although it is not the crimson clouds that draw their attention, but rather the mysterious origin of the massive and powerful stars buried within. Although they are very bright, these stars cannot be seen in visible-light images such as this one as the surrounding dust is too thick, but they make their presence clear in images of the region at longer wavelengths.

 

For less massive stars like the Sun the process that brings them into existence is quite well understood -- as clouds of gas are pulled together under gravity, density and temperature increase, and nuclear fusion begins) -- but for the most massive stars buried in regions like RCW 106 this explanation does not seem to be fully adequate. These stars -- known to astronomers as O-type stars -- may have masses many dozens of times the mass of the Sun and it is not clear how they manage to gather, and keep together, enough gas to form.

 

O-type stars likely form from the densest parts of the nebular clouds like RCW 106 and they are notoriously difficult to study. Apart from obscuration by dust, another challenge is the brevity of an O-type star's life. They burn through their nuclear fuel in mere tens of millions of years, while the lightest stars have lifetimes that span many tens of billions of years. The difficulty of forming a star of this mass, and the shortness of their lifetimes, means that they are very rare -- only one in every three million stars in our cosmic neighbourhood is an O-type star. None of those that do exist are close enough for detailed investigation and so the formation of these fleeting stellar giants remains mysterious, although their outsized influence is unmistakeable in glowing H II regions like this one.

 

Notes

[1] The catalogue was compiled in 1960 by three astronomers from the Mount Stromlo Observatory in Australia whose surnames were Rodgers, Campbell and Whiteoak, hence the prefix RCW.

[2] The supernova remnant is SNR G332.4-00.4, also known as RCW 103. It is about 2000 years old. The lower filaments are RCW 104, surrounding the Wolf-Rayet star WR 75. Although these objects bear RCW numbers, detailed later investigations revealed that neither of them were HII regions.

http://spaceref.com/astronomy/the-realm-of-buried-giants.html

 

http://www.eso.org/public/news/eso1607/

 

In this huge new image clouds of crimson gas are illuminated by rare, massive stars that have only recently ignited and are still buried deep in thick dust clouds. These scorching-hot, very young stars are only fleeting characters on the cosmic stage and their origins remain mysterious. The vast nebula where these giants were born, along with its rich and fascinating surroundings, are captured here in fine detail by ESO’s VLT Survey Telescope (VST) at the Paranal Observatory in Chile.

 

http://www.eso.org/public/news/eso1607/

 

Type O stars, living it big and burning out real fast..... 

[Unobscured Vision]

Blue Supergiants. The blowtorches of the cosmos. So extreme in luminosity that if one of those beasties were parked at the same distance as Alpha Centauri (4.2 LY) it would outshine the full moon and be visible in the daytime. Trouble is, they go bang -- and at that distance, it would fry us.

 

One of my two favorite star systems, Eta Carinae (and its' associated Nebula) is thought to consist of a Type O (and may itself possibly be a Wolf-Rayet subtype) with the companion star being a Type W.  

[Draggendrop Veteran]

12 minutes ago, Unobscured Vision said:

Blue Supergiants. The blowtorches of the cosmos. So extreme in luminosity that if one of those beasties were parked at the same distance as Alpha Centauri (4.2 LY) it would outshine the full moon and be visible in the daytime. Trouble is, they go bang -- and at that distance, it would fry us.

 

One of my two favorite star systems, Eta Carinae (and its' associated Nebula) is thought to consist of a Type O (and may itself possibly be a Wolf-Rayet subtype) with the companion star being a Type W.  

We have been getting some great shots from the ESO VLT complex. 

The web page for this unit even has 1 hour daylight cam shots of the scope. (has a good write up as well)

http://www.eso.org/public/teles-instr/surveytelescopes/vst/

 

A 268 megapixel camera......

[Draggendrop Veteran]

This is an article, which I think is a possible record discovery for Hubble, but it bothers me when equipment is used at, and beyond, it's limits. I would prefer to wait for 2 years and have the JWST verify and open these further doors for us. If you guys get a chance, see what you think of this article. Thanks.

 

Hubble Breaks Cosmic Distance Record

 

GN-z11                      NASA/ESA/STSCI

 

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By pushing the NASA/ESA Hubble Space Telescope to its limits astronomers have shattered the cosmic distance record by measuring the distance to the most remote galaxy ever seen in the Universe.

 

This galaxy existed just 400 million years after the Big Bang and provides new insights into the first generation of galaxies. This is the first time that the distance of an object so far away has been measured from its spectrum, which makes the measurement extremely reliable. The results will be published in the Astrophysical Journal.

 

Using the NASA/ESA Hubble Space Telescope an international team of astronomers has measured the distance to this new galaxy, named GN-z11.

 

Although extremely faint, the galaxy is unusually bright considering its distance from Earth. The distance measurement of GN-z11 provides additional strong evidence that other unusually bright galaxies found in earlier Hubble images are really at extraordinary distances, showing that we are closing in on the first galaxies that formed in the Universe.

 

Previously, astronomers had estimated GN-z11's distance by analysing its colour in images taken with both Hubble and the NASA Spitzer Space Telescope. Now, for the first time for a galaxy at such an extreme distance, the team has used Hubble's Wide Field Camera 3 (WFC3) to precisely measure the distance to GN-z11 spectroscopically by splitting the light into its component colours.

 

"Our spectroscopic observations reveal the galaxy to be even further away than we had originally thought, right at the distance limit of what Hubble can observe," explains Gabriel Brammer of the Space Telescope Science Institute and second author of the study.

 

This puts GN-z11 at a distance that was once thought only to be reachable with the upcoming NASA/ESA/CSA James Webb Space Telescope (http://sci.esa.int/jwst/) (JWST) [1].

 

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"We've taken a major step back in time, beyond what we'd ever expected to be able to do with Hubble. We managed to look back in time to measure the distance to a galaxy when the Universe was only three percent of its current age," says Pascal Oesch of Yale University and lead author of the paper.

 

To determine large distances, like the one to GN-z11, astronomers measure the redshift (https://en.wikipedia.org/wiki/Redshift) of the observed object. This phenomenon is a result of the expansion of the Universe; every distant object in the Universe appears to be receding from us and as a result its light is stretched to longer, redder wavelengths.

 

Before astronomers determined the distance to GN-z11, the most distant measured galaxy, EGSY8p7, had a redshift of 8.68. Now, the team has confirmed GN-z11's distance to be at a redshift of 11.1, which corresponds to 400 million years after the Big Bang.

 

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"The previous record-holder was seen in the middle of the epoch when starlight from primordial galaxies was beginning to heat and lift a fog of cold, hydrogen gas," explains co-author Rychard Bouwens from the University of Leiden, the Netherlands. "This transitional period is known as the reionisation era. GN-z11 is observed 150 million years earlier, near the very beginning of this transition in the evolution of the Universe."

 

The combination of observations taken by Hubble and Spitzer revealed that the infant galaxy is 25 times smaller than the Milky Way and has just one percent of our galaxy's mass in stars. However, the number of stars in the newborn GN-z11 is growing fast: The galaxy is forming stars at a rate about 20 times greater than the Milky Way does today [2]. This high star formation rate makes the remote galaxy bright enough for Hubble to see and to perform detailed observations.

 

However, the discovery also raises many new questions as the existence of such a bright and large galaxy is not predicted by theory. "It's amazing that a galaxy so massive existed only 200 million to 300 million years after the very first stars started to form. It takes really fast growth, producing stars at a huge rate, to have formed a galaxy that is a billion solar masses so soon," explains Garth Illingworth of the University of California, Santa Cruz.

more at the link...

http://spaceref.com/astronomy/hubble-breaks-cosmic-distance-record.html

 

A previous red shift record of 8.68 is now up to 11.1 with this discovery, and I feel this is very drastic, at the edge of the equipment's design and should be taken with a "grain of salt" till JWST is up and running in 2 years time, to verify this finding....what do you think? Increased expansion velocities in the outer reaches of the universe, compound gravitational lensing, the discord around the value of the Hubble constant, to name a few, are enough to warrant a reliable cross check by a payload designed for this task, hence JWST.   

 

[Unobscured Vision]

I agree, that's a very extreme redshift for HST to be observing. Shouldn't really be possible for it to observe z11, and I suspect that some really creative post-processing was involved to pull z11 out of the imaging data.

 

I mean, it's really great and all, but I'm a bit curious how they pulled this off. HST shouldn't have been able to image this object. A redshift of 9.5 8.7 (according to everything I'm reading at https://en.wikipedia.org/wiki/Redshift ) was the limit of what HST could be expected to pick up, so this one is ... surprising.

Edited March 4, 2016 by Unobscured Vision
Added info.

[LOC Veteran]

Wait, I thought they announced that they found a galaxy that was just 380 or 280m years after the BB recently? Or maybe that was a Quasar announcement, or possibly AGN type thing? I dunno anymore, so many things being announced so quickly these days, hard to keep track sometimes

[Unobscured Vision]

11 hours ago, LOC said:

Wait, I thought they announced that they found a galaxy that was just 380 or 280m years after the BB recently? Or maybe that was a Quasar announcement, or possibly AGN type thing? I dunno anymore, so many things being announced so quickly these days, hard to keep track sometimes

Yes, that's the object at RS-11.1 that we're discussing, GN-z11. HST shouldn't have been able to observe that one, so the prevailing hypothesis is that there's a gravitational lensing event going on along with some new (improved) post-processing techniques of the data.

 

I'm still of the opinion that the redshift-distance calculation for z11 isn't correct, though.

[LOC Veteran]

I wonder what's going to happen when the JWST finds some object that basically is from a time before the BB was supposed to have occured lol

 

I mean, I know there's the whole observable universe phenominum thing, but I don't think that would apply to a deep sky view like that. Or would it, I don't know anymore heh.

[Unobscured Vision]

Well, that's really the $40,000 question. There's a period of time after the BB where temporal and relativistic physics hadn't completely kicked in yet, and from what the Theorists are saying it measures anywhere from eight to 22 billion light-years across. Something of a "borderlands region". They can't really see inside, because the CMB is obscuring it. The object GN-z11 is sitting right smack inside of that area, facing our side of that inner edge (if the data is correct) -- that's why it's such a big deal. At that point in time, cosmologically speaking, it shouldn't have that much organization. 

 

Did it form outside, then due to some trajectory it was on happen to move into that region? That would be my hypothesis. Certainly objects are not static, in any time period. Stuff still moves around.

[Unobscured Vision]

More information about GN-z11 Story (Ars Technica)

 

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Early in the Universe, the wavelength of this point was in the UV end of the spectrum. But the expansion of the Universe has redshifted it into the infrared portion of the spectrum. By determining precisely where that break occurs, it's possible to figure out how far it has been redshifted and thus how old the source is.

 

Conveniently, early galaxies are likely to have this break just on the edge of what Hubble's Wide Field Camera 3 can detect. So the authors imaged GN-z11 over multiple orbits and also obtained data on the light produced by galaxies in the same field of view, allowing that to be subtracted from the signal.

 

The ensuing analysis found a break at a wavelength of 1.47 micrometers. That means GN-z11 is the oldest object we've ever imaged, with its light emitted 13.4 billion years ago—just 400 million years after the Big Bang. For those of you who like this information in redshifts, this corresponds to a z of 11.1.

 

Using the Spitzer infrared telescope, the authors were able to determine that GN-z11 is rather bright and large for its age. They estimate that the average stellar age is only 40 million years, and yet it already has about a billion times the Sun's mass worth of stars. It also appears to be forming stars at a rapid pace.

 

The results make it clear that star and galaxy formation was already very active deep in the period of reionization, and a relatively short time after the Big Bang. And it makes it very clear that the James Webb Space Telescope, designed to image a bit deeper into the infrared, is going to have a host of targets to focus on.

They confirmed the z-reading with Spitzer .. cool. Guess its' Sigma is now at a nice, solid 4.8. Interested to see what happens from here.

 

EDIT: Aha, I see what they did now. Subtractive Post-Processing. It's a good technique when you're trying to bring out something very faint from a lot of foreground "noise".

Edited March 4, 2016 by Unobscured Vision

[LOC Veteran]

Hmmmm, interesting. I think they might have to revise when the BB occured at this rate. Maybe not by much, but a bit

[Unobscured Vision]

Nah, the current estimates are fine.

 

What fascinates me more is the picture we've got of the truly pristine environment that GN-z11 was. 40-odd million years of star formation is plenty of time for some of the real behemoths there (Type W, O, and the Wolf-Rayet Stars) to supernova and release heavier elements. We've likely got some higher-metallicity (type G, K, M, and Brown Dwarf) stars and perhaps the first rocky planets in the initial stages of formation by now (relatively speaking, of course).

 

Yeah ... what a place. There's bound to be more like it. JWST will be the instrument to tell us more.

[Draggendrop Veteran]

Great work digging up info guys. I think JWST is going to be an eye opener, and possibly cause a few revisions of accepted theories. I am still leaning toward a revision in the Hubble constant, due to the way the constant was derived and those in opposition. I will dig up some data later and see what you guys think, but either way, I think we have some treats in store, and maybe a few "exploding heads"....great times ahead...

[Unobscured Vision]

Just now, Draggendrop said:

Great work digging up info guys. I think JWST is going to be an eye opener, and possibly cause a few revisions of accepted theories. I am still leaning toward a revision in the Hubble constant, due to the way the constant was derived and those in opposition. I will dig up some data later and see what you guys think, but either way, I think we have some treats in store, and maybe a few "exploding heads"....great times ahead...

Science is a magnificent diversion when healing up from surgery.  All I've done is add up the sums.

[Draggendrop Veteran]

1 minute ago, Unobscured Vision said:

Science is a magnificent diversion when healing up from surgery.  All I've done is add up the sums.

Nice work...and hope you are feeling better.....

[Unobscured Vision]

Just now, Draggendrop said:

Nice work...and hope you are feeling better.....

Getting there, thanks bud. No use of my right arm yet, but I'm spending more time out of that infernal sling now.

[Draggendrop Veteran]

The expansion of the universe simulated

 

Ruth Durrer, UNIGE

 

image caption

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The gravitational waves generated during the formation of structures in the universe are shown. The structures (distribution of masses) are shown as bright dots, gravitational waves by ellipses. The size of the ellipse is proportional to the amplitude of the wave and its orientation represents its polarization.

article

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The Universe is constantly expanding. It changes, creating new structures that merge. But how does our Universe evolve? Physicists at the University of Geneva (UNIGE), Switzerland, have developed a new code of numerical simulations that offers a glimpse of the complex process of the formation of structures in the Universe. Based on Einstein's equations, they were able to integrate the rotation of space-time into their calculations and calculate the amplitude of gravitational waves, whose existence was confirmed for the first time on February 12, 2016. This study is published in the journal Nature Physics.

 

Until now, scientists studied the formation of large-scale cosmological structures based numerical simulations of Newtonian gravitation. These codes postulate that space itself does not change, it is said to be static, while time goes on. The simulations that it allows are very precise if the matter in the Universe moves slowly (i.e., about 300 km per second). However, when the matter particles move at high speed, this code only allows approximate calculations. Furthermore, it does not describe the fluctuations of dark energy. Constituting 70% of the total energy of the Universe (the remaining 30% is made of dark matter and ordinary matter), it is responsible for the accelerated expansion of the Universe. Therefore, it was necessary to find a new way to simulate the formation of cosmological structures and allow the study of these two phenomena.

 

The theory of general relativity applied

 

Ruth Durrer's team from the Department of Theoretical Physics in the Faculty of Science at UNIGE, has thus created a code, named gevolution, based on Einstein's Theory of general relativity. Indeed, general relativity considers space-time as being dynamical, that is to say that space and time are constantly changing, unlike the static space of Newtonian theory. The goal was to predict the amplitude and the impact of gravitational waves and frame-dragging (the rotation of space-time) induced by the formation of cosmological structures.

 

To do so, the physicists from UNIGE analysed a cubic portion in space, consisting of 60 billion zones with each containing a particle (that is to say, a portion of a galaxy), in order to study the way they move with respect to their neighbors. Thanks to the LATfield2 library (developed by David Daverio from UNIGE), which solves nonlinear partial differential equations, and the Supercomputer from the Swiss Supercomputer Center in Lugano, the researchers were able to study the motion of particles and calculate the metric (the measure of distances and time between two galaxies in the Universe) using Einstein's equations. The resulting spectra of these calculations allow to quantify the difference between the results obtained by gevolution and those coming from Newtonian codes. This allows to measure the effect of frame-dragging and gravitational waves introduced by the formation of structure in the Universe.

 

Gravitational waves and frame-dragging predicted by gevolution

 

Indeed, frame-dragging and gravitational waves have never been included in simulations until the creation of the gevolution code. This opens the way for the comparison of simulation results of the evolution of the Universe with observations. With their new code, the physicists at UNIGE will be able to test the theory of general relativity on much larger scales than at present. In order to open research to a maximum in this field, Professor Ruth Durrer and her team will make their gevolution code public. Perhaps soon light will be shed on the mysteries of dark energy.

http://www.eurekalert.org/pub_releases/2016-03/udg-teo030216.php

 

The simulations are continually getting more advanced. With the recent discovery of gravity waves, and the ensuing knowledge derived from it's future experimental refinements, we are well on our way, to once again, pursuing the understanding of how gravity and it's associated properties actually behave/misbehave. IMHO, I feel that this is a new dawn in the field of astrophysics and cosmology.