Ligo

anonymous asked:

What would happen if a black hole collided with another ?

Thanks to a discovery just made in 2015, we don’t need to speculate about this. When two black holes collide, they merge together to make a larger black hole, but that isn’t the most interesting apart.

When two black holes start to collide, they orbit around each other. The closer they get, the faster they spin. As you might know, black holes warp the fabric of space and time, and when they start moving fast enough, they can send ripples through space. We call them “gravitational waves”, and even though they are incredibly small, if your detector is sensitive enough, you can see them.

The LIGO observatory announced that they detected gravitational waves in 2015, which was truly the discovery of the decade. Einstein had predicted them a hundred years earlier, but never believed we’d be able to see them.

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How Richard Feynman Convinced The Naysayers 60 Years Ago That Gravitational Waves Are Real

“Just as a pulse of electromagnetic radiation would cause such charges to oscillate, the same would happen in the “gravitational antenna” if a gravitational wave passed through—with the maximum effect occurring if the wave were transverse: at right angles to the stick. Upon the impact of a gravitational wave, one of the masses would accelerate relative to the other, sliding back and forth along the stick. The rubbing movement would generate friction between the free mass and the stick, releasing heat in the process. Therefore the gravitational radiation must convey energy. Otherwise, how else did the energy arise?”

Today, we take the existence of gravitational waves for granted. They were predicted by Einstein almost immediately following the first publication of general relativity, they were indirectly detected decades ago and they’ve been directly detected multiple times by the different LIGO observatories. Yet Einstein and his former student argued, back from the 1930s through the 1950s, that the waves were mere mathematical artifacts, and didn’t physically exist. Oddly enough, it was the non-specialist in general relativity, Richard Feynman, who provided the key way of thinking which resolved the argument. Rather than arguing about the mathematical subtleties of relativity, he approached the problem from a physical perspective, reasoning about how gravitational waves would be able to accelerate “gravitational charges,” a.k.a. masses. The result not only demonstrated that gravitational waves must carry energy, but provided the prototype for the design of LIGO.

Thanks to physicist and historian Paul Halpern, the full story is now available for all to read of how Feynman demonstrated the reality of gravitational waves 60 years ago!

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The Failed Experiment That Changed The World

“ This null result — the fact that there was no luminiferous aether — was actually a huge advance for modern science, as it meant that light must have been inherently different from all other waves that we knew of. The resolution came 18 years later, when Einstein’s theory of special relativity came along. And with it, we gained the recognition that the speed of light was a universal constant in all reference frames, that there was no absolute space or absolute time, and — finally — that light needed nothing more than space and time to travel through. ”

In the 1880s, it was clear that something was wrong with Newton’s formulation of the Universe. Gravitation didn’t explain everything, objects behaved bizarrely close to the speed of light, and light was exhibiting wave-like properties. But surely, even if it were a wave, it required a medium to travel through, just like all other waves? That was the standard thinking, and the genius of Albert A. Michelson was put to work to test it. Because, he reasoned, the Earth was moving around the Sun, the speed of light should get a boost in that forward direction, and then have to fight that boost on the return trip. The perpendicular direction, on the other hand, would be unaffected. This motion of light should be detectable in the form of interferometry, where light was split into two perpendicular components, sent on a journey, reflected, and then recombined.

The null results of this experiment changed the Universe, and the technology is still used today in experiments like LIGO. Come learn about the greatest failed experiment of all-time!

youtube

Gravitational Waves…explained. 

Eu estou aqui quietinha esperando você se perder. Esperando você se lembrar. Esperando você sentir falta. Eu nem ligo mais, nem corro atrás como antes, mas isso não significa que eu parei de sentir saudade. Eu só acho que você precisa daquele famoso tempo que tanto quis. Me fazer ausente na tua vida foi a melhor coisa que eu já fiz, mesmo que doa, mesmo que eu ainda chore a noite em posição fetal deitada em minha cama, encharcando meu travesseiro com lágrimas. Porque em consequência disso tirei aquele tempo pra mim, aquele famoso tempo que você quer e quis. Esse tempo pra pensar, pra sentir, pra ficar só, pra saber onde dói, e porquê.
—  Bianca Autran
3

The black-hole collision that reshaped physics

A momentous signal from space has confirmed decades of theorizing on black holes — and launched a new era of gravitational-wave astronomy.

The event was catastrophic on a cosmic scale — a merger of black holes that violently shook the surrounding fabric of space and time, and sent a blast of space-time vibrations known as gravitational waves rippling across the Universe at the speed of light.

But it was the kind of calamity that physicists on Earth had been waiting for. On 14 September, when those ripples swept across the freshly upgraded Laser Interferometer Gravitational-Wave Observatory (Advanced LIGO), they showed up as spikes in the readings from its two L-shaped detectors in Louisiana and Washington state. For the first time ever, scientists had recorded a gravitational-wave signal.

“There it was!” says LIGO team member Daniel Holz, an astrophysicist at the University of Chicago in Illinois. “And it was so strong, and so beautiful, in both detectors.” Although the shape of the signal looked familiar from the theory, Holz says, “it’s completely different when you see something in the data. It’s this transcendent moment”.

The signal, formally designated GW150914 after the date of its occurrence and informally known to its discoverers as ‘the Event’, has justly been hailed as a milestone in physics. It has provided a wealth of evidence for Albert Einstein’s century-old general theory of relativity, which holds that mass and energy can warp space-time, and that gravity is the result of such warping. Stuart Shapiro, a specialist in computer simulations of relativity at the University of Illinois at Urbana–Champaign, calls it “the most significant confirmation of the general theory of relativity since its inception”.

But the Event also marks the start of a long-promised era of gravitational-wave astronomy. Detailed analysis of the signal has already yielded insights into the nature of the black holes that merged, and how they formed. With more events such as these — the LIGO team is analysing several other candidate events captured during the detectors’ four-month run, which ended in January — researchers will be able to classify and understand the origins of black holes, just as they are doing with stars.

Still more events should appear starting in September, when Advanced LIGO is scheduled to begin joint observations with its European counterpart, the Franco–Italian-led Advanced Virgo facility near Pisa, Italy. (The two collaborations already pool data and publish papers together.) This detector will not only contribute crucial details to events, but could also help astronomers to make cosmological-distance measurements more accurately than before.

“It’s going to be a really good ride for the next few years,” says Bruce Allen, managing director of the Max Planck Institute for Gravitational Physics in Hanover, Germany.

“The more black holes they see whacking into each other, the more fun it will be,” says Roger Penrose, a theoretical physicist and mathematician at the University of Oxford, UK, whose work in the 1960s helped to lay the foundation for the theory of the objects. “Suddenly, we have a new way of looking at the Universe.”

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Você é a inconstância dá minha vida. Me tira pra voar e quando vou ver, já estou em queda livre. Eu te ignoro por uns minutos, só pra ter um pretexto pra te procurar depois. E te ligo e pergunto: me ligou? Mesmo não tendo atendido de propósito. Só pra ver sua foto por mais tempo no visor. Só pra ter a sensação que você me ligou mais que uma vez.
—  Detalhares . 
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Has LIGO already discovered evidence for quantum gravity?

“According to Einstein, a black hole’s event horizon should have specific properties, determined by its mass, charge and angular momentum. In most ideas of what quantum gravity would look like, that event horizon would be no different. Some models, however, predict notably different event horizons, and it’s those departure models that offer a glimmer of hope for quantum gravity. If we see a difference from what Einstein’s theory predicts, perhaps we can uncover not only that gravity must be a quantum theory, but what properties quantum gravity actually has.”

In 2015, LIGO collected data from a total of three candidate gravitational wave events, all of which were announced and released in 2016. These events verified the great prediction of Einstein: that decaying orbits should emit gravitational radiation with specific magnitudes and frequencies that distort spacetime in a particular, measurable way. But some quantum gravitational ideas modify the event horizon and the space just outside of it, creating the possibility that merging black holes will exhibit “echoes” superimposed atop the Einsteinian signal. For the first time, a team of theorists dove into the LIGO data to test this, and may have just uncovered the first evidence for quantum gravity in our Universe.

With the next run of LIGO already underway, be prepared to find out that gravity may be inherently quantum after all!

The black-hole collision that reshaped physics

A momentous signal from space has confirmed decades of theorizing on black holes — and launched a new era of gravitational-wave astronomy.

By Davide Castelvecchi

The event was catastrophic on a cosmic scale — a merger of black holes that violently shook the surrounding fabric of space and time, and sent a blast of space-time vibrations known as gravitational waves rippling across the Universe at the speed of light.

But it was the kind of calamity that physicists on Earth had been waiting for. On 14 September, when those ripples swept across the freshly upgraded Laser Interferometer Gravitational-Wave Observatory (Advanced LIGO), they showed up as spikes in the readings from its two L-shaped detectors in Louisiana and Washington state. For the first time ever, scientists had recorded a gravitational-wave signal.

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What are Gravitational Waves?

Today, the National Science Foundation (NSF) announced the detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of ground-based observatories. But…what are gravitational waves? Let us explain:

Gravitational waves are disturbances in space-time, the very fabric of the universe, that travel at the speed of light. The waves are emitted by any mass that is changing speed or direction. The simplest example is a binary system, where a pair of stars or compact objects (like black holes) orbit their common center of mass.

We can think of gravitational effects as curvatures in space-time. Earth’s gravity is constant and produces a static curve in space-time. A gravitational wave is a curvature that moves through space-time much like a water wave moves across the surface of a lake. It is generated only when masses are speeding up, slowing down or changing direction.

Did you know Earth also gives off gravitational waves? Earth orbits the sun, which means its direction is always changing, so it does generate gravitational waves, although extremely weak and faint.

What do we learn from these waves?

Observing gravitational waves would be a huge step forward in our understanding of the evolution of the universe, and how large-scale structures, like galaxies and galaxy clusters, are formed.

Gravitational waves can travel across the universe without being impeded by intervening dust and gas. These waves could also provide information about massive objects, such as black holes, that do not themselves emit light and would be undetectable with traditional telescopes.

Just as we need both ground-based and space-based optical telescopes, we need both kinds of gravitational wave observatories to study different wavelengths. Each type complements the other.

Ground-based: For optical telescopes, Earth’s atmosphere prevents some wavelengths from reaching the ground and distorts the light that does.

Space-based: Telescopes in space have a clear, steady view. That said, telescopes on the ground can be much larger than anything ever launched into space, so they can capture more light from faint objects.

How does this relate to Einstein’s theory of relativity?

The direct detection of gravitational waves is the last major prediction of Einstein’s theory to be proven. Direct detection of these waves will allow scientists to test specific predictions of the theory under conditions that have not been observed to date, such as in very strong gravitational fields.

In everyday language, “theory” means something different than it does to scientists. For scientists, the word refers to a system of ideas that explains observations and experimental results through independent general principles. Isaac Newton’s theory of gravity has limitations we can measure by, say, long-term observations of the motion of the planet Mercury. Einstein’s relativity theory explains these and other measurements. We recognize that Newton’s theory is incomplete when we make sufficiently sensitive measurements. This is likely also true for relativity, and gravitational waves may help us understand where it becomes incomplete.

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não precisa me responder na hora, não se preocupe com isso. sei que você tem suas prioridades, eu entendo. responda-me a hora que você estiver livre, e que, não tenha que responder correndo. gosto de saber como está sendo ou como foi o seu dia. não quero que você passe o dia pensando em me responder, ou se culpando pela falta de atenção que não me deu. manda mensagem sem pressa, pode ser no fim do dia… ou eu te ligo.

Kenedy Vinicios.