speaking of sciencey stuff

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speaking of sciencey stuff

Postby The Dr » Thu Jun 09, 2016 10:57 am

i'm sure many of us here like science so i thought it may be good to have a thread where we can discus and share news that we stumble upon.


anyway, these just blew my mind, especially the picture on the top link

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http://www.ibtimes.com/new-simulation-i ... 7?rel=rel1


New Simulation Incorporating Effect Of Gravitational Waves Could Shed Light On Dark Energy
By Avaneesh Pandey @avaneeshp88 On 03/08/16 AT 6:23 AM
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The gravitational waves generated during the formation of structures in the universe are shown in this illustration. 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. Photo: Ruth Durrer/University of Geneva

Less than a month after gravitational waves — ripples in the fabric of space-time — were discovered, scientists have created a way to incorporate them into a numerical code that can, with unprecedented accuracy, simulate the expansion of the universe. The code, named “gevolution,” is based on Einstein’s theory of general relativity, and could shed light on dark energy — the mysterious force that makes up to 70 percent of the universe and is driving its accelerating expansion.

As explained in a study published in the journal Nature Physics, the code, developed by scientists at the University of Geneva in Switzerland, incorporates, for the first time ever, the rotation of space-time — known as “frame-dragging” — and amplitude of gravitational waves in simulations of the evolution of the cosmos.

“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 [University of Geneva] will be able to test the theory of general relativity on much larger scales than at present,” the researchers said in a statement released Monday.

Gravitational waves, whose existence was first postulated by Einstein in 1915, are created during violent events such as collision black holes or neutron stars. Their discovery last month paved the path for creation of a gravitational map of the universe, and could eventually allow researchers to test how general relativity operates under extreme conditions.

Current models and simulations of the universe are built on Newton’s law of gravitation, using codes that do not incorporate the movement of space itself. While these simulations are precise if the matter in the universe is moving slowly — at about 300 kilometer (186.4 miles) per hour — it allows for only approximate estimates when particles are moving at a high speed. Moreover, it does not account for fluctuations of dark energy — one of the biggest unsolved problems of cosmology.

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“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 researchers said in the statement. “Perhaps soon light will be shed on the mysteries of dark energy.”





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Successful LISA Pathfinder Test Paves Way For Detection Of Gravitational Waves In Space
By Avaneesh Pandey @avaneeshp88 On 06/08/16 AT 7:28 AM

Earlier this year, scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) facilities in Washington state and Louisiana announced that they had discovered ripples in the fabric of space-time, also known as gravitational waves. This discovery — the first of its kind — triggered enormous excitement among scientists, who saw it as a step toward the eventual creation of a “gravitational map” of the universe that would enable us to study celestial objects and events that would otherwise remain hidden from view.

Now, just four months after the discovery, researchers from the European Space Agency (ESA) have achieved another breakthrough — one that demonstrates the technology needed to build a space-based observatory that would hunt for gravitational waves far removed from any ground-based interference.

On Tuesday, in a study published in the Physical Review Letters, researchers working on the Laser Interferometer Space Antenna (LISA) Pathfinder mission — which was sent into orbit to test elements of the laser measurement system that would be used in a future gravitational wave observatory — stated that they had exceeded the performance objectives of the mission. The satellite, which was launched in December, successfully created the closest thing to free fall ever observed in a human-made object.

“LISA Pathfinder was always intended as a stepping stone to the level of performance needed for a full-scale gravitational wave observatory, but these results tell us we’ve nearly made the full jump. A full-scale observatory with LISA Pathfinder’s performance would achieve essentially all of the ultimate science goals,” Ira Thorpe, a team member at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. “That's amazing in itself, and data from this mission will help us build on an already impressive foundation.”

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Gravitational waves are ripples in the fabric of reality itself. Albert Einstein’s general theory of relativity, which posits that gravity warps the fabric of cosmos, also tells us that violent events such as the collision of massive objects like black holes and neutron stars create ripples in the curvature of space-time.

However, detection of these waves is an extremely hard task, as, in the cosmic scale of things, they are miniscule. The LIGO collaboration successfully detected them in February by bouncing lasers along two installations located roughly 1,800 miles apart and looking for slight change in phase — a telltale sign of space-time being warped. Having two detectors is a way to sift out terrestrial disturbances, such as traffic and earthquakes, from the faint ripples of space itself.

That is why, as a precursor to the successful installation of a gravitational wave detector in space, scientists needed to reduce non-gravitational forces as much as humanly possible.

lpf_artist_impression_2015-11-24 An artist's rendering of LISA Pathfinder on its way to Earth-sun L1. Photo: ESA/C. Carreau

This is where the LISA Pathfinder mission comes in. The mission is equipped with an identical pair of 1.8-inch cubes made of a gold-platinum alloy — a material chosen for its high density and insensitivity to magnetic fields. Once in orbit, these “test masses” were unclamped and allowed to go into free fall while a high-resolution laser interferometer measured their positions.

“The measurements have exceeded our most optimistic expectations,” Paul McNamara, the LISA Pathfinder project scientist at ESA's Directorate of Science, said in the statement. “We reached the level of precision originally required for LISA Pathfinder within the first day, and so we spent the following weeks improving the results a factor of five better.”

When the ESA launches the LISA observatory in 2034, it would consist of three spacecraft arranged in a triangle, with each one carrying free-falling test masses in its heart. Lasers will then be used to detect any slight perturbations in the distance between these masses caused by passing gravitational waves.

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“You're not Dostoevsky,' said the citizeness

'Well, who knows, who knows,' he replied.

'Dostoevsky's dead,' said the citizeness, but somehow not very confidently.

'I protest!' Behemoth exclaimed hotly. 'Dostoevsky is immortal!”
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