Lifeboat Foundation

Dark matter is one of the greatest revelations in modern physics. Even though it hasn’t been directly detected yet, we know that it makes up around five-sixths of the total matter in the universe, binding much of it together in dramatic ways. It is this matter that stops galaxies from being torn apart as they spin.

As a new study published in the journal Physics of the Dark Universe notes, dark matter can also be destroyed. A signature of dark matter’s annihilation could potentially reveal what it was composed of in the first place, and this team of researchers from Harvard University think they’ve found one right in the heart of our own Milky Way.

Scientists are still debating what dark matter may actually be composed of, and one recent suggestion implies the particles are so dense that they are on the verge of becoming miniature black holes. Whatever they turn out to be, many astrophysicists think that these particles share a property with “ordinary” matter: they come in two flavors, matter and antimatter. When matter encounters antimatter, both are destroyed in a powerful blast that emits high-energy radiation.

Continue reading “There’s A Powerful And Mysterious Signal Coming From The Core Of The Milky Way” »

By studying the spatial distribution of gamma-ray emission in the Milky Way, astronomers believe they have identified a signature of dark matter annihilation.

We live in a dramatic epoch of astrophysics. Breakthrough discoveries like exoplanets, gravity waves from merging black holes, or cosmic acceleration seem to arrive every decade, or even more often. But perhaps no discovery was more unexpected, mysterious, and challenging to our grasp of the “known universe” than the recognition that the vast majority of matter in the universe cannot be directly seen. This matter is dubbed “dark matter,” and its nature is unknown. According to the latest results from the Planck satellite, a mere 4.9% of the universe is made of ordinary matter (that is, matter composed of atoms or their constituents). The rest is dark matter, and it has been firmly detected via its gravitational influence on stars and other normal matter. Dark energy is a separate constituent.

Understanding this ubiquitous yet mysterious substance is a prime goal of modern astrophysics. Some astronomers have speculated that dark matter might have another property besides gravity in common with ordinary matter: It might come in two flavors, matter and anti-matter, that annihilate and emit high energy radiation when coming into contact. The leading class of particles in this category are called weakly interacting massive particles (WIMPS). If dark matter annihilation does occur, the range of options for the theoretical nature of dark matter would be considerably narrowed.

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Are parallel universes real?
Right now there might be a whole other universe where instead of brown hair you have red hair, or a universe where you’re a classical pianist, not an engineer. In fact, an infinite number of versions of you may exist in an infinite number of other universes.

The idea sounds like science fiction, but multiverse theories — especially those that are actually testable — are gaining traction among physicists. Here are three of the most compelling theories:

If the universe is infinite, multiple universes probably exist.

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The black holes that kicked off the first detection of gravitational waves seem to be the right size and frequency to be long-sought primordial black holes.

Star-gobbling black holes tend to inhabit galaxies that have recently collided, suggesting that cosmic pile-ups send whole systems flying.

Another amazing female pioneer in STEM and she was a NASA chief astronomer to boot!

A former chief astronomer at NASA will discuss the evolution of the universe from the Big Bang to black holes during a lecture on Thursday, March 24.

It’s the opening of the 19th Annual Dick Smyser Community Lecture Series.

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Quantum mechanics and relativity theory are two pillars of modern physics. With their amalgamation, many novel phenomena have been identified. For example, the Unruh effect [1] is one of the most significant outcomes of the quantum field theory. This effect serves as an important tool to investigate phenomena such as thermal emission of particles from black holes and cosmological horizons [2]. It has been 40 years since the discovery of the Unruh effect, however, this effect is too weak to be observed with current technique. There have been a lot of attempts in searching for the observational evidence of the Unruh effect and in general the experimental observation is still of great challenge. To address this issue, quantum simulators [3, 4] may provide a promising approach. Quantum simulation is widely applied for simulating the quantum systems which cannot be efficiently simulated by classical computers or are not directly tractable by the current techniques in the laboratory.

The researchers, led by Prof. Jiangfeng Du from University of Science and Technology of China, reported an experimental simulation of the Unruh effect with an NMR quantum simulator [5]. The experiments were performed on a Bruker Avance III 400MHz spectrometer. The researchers used a sample of 13C, 1H and 19F nuclear spins in chloroform as the NMR quantum simulator, as shown in Figure 1(a). The simulated Unruh effect on the quantum states can be realized by the pulse sequence acting on the sample, as depicted in Figure 1(b). By the quantum simulator, they experimentally demonstrated the behavior of Unruh temperature with acceleration, which agrees nicely with the theoretical prediction, as shown in Figure 2. Furthermore, they investigated the quantum correlations quantified by quantum discord between two fermionic modes as seen by two relatively accelerated observers. It is shown for the first time that the quantum correlations can be created by the Unruh effect from the classically correlated states. This work was recently published in the Science China-Physics, Mechanics & Astronomy.

It is interesting that the Unruh effect was in Feynman’s blackboard as one of the issues to learn at the time of his death in 1988, while it was also Feynman who conceived the idea of quantum simulation in 1982. This quantum simulation of the Unruh effect will provide a promising window to explore the quantum physics of accelerated systems, which widely appear in black hole physics, cosmology and particle physics.

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“A metaphorical chip holding all the programming for our universe stores information like a quantum computer.” This is the radical insight to the foundation of our Universe developed by Mark Van Raamsdonk, a professor of theoretical physics at the University of British Columbia, that says that the world we see around us is a projection from a set of rules written in simpler, lower-dimensional physics—just as the 2D code in a computer’s memory chip creates an entire virtual 3D world. “What Mark has done is put his finger on a key ingredient of how space-time is emerging: entanglement,” says Gary Horowitz, who studies quantum gravity at the University of California Santa Barbara. Horowitz says this idea has changed how people think about quantum gravity, though it hasn’t yet been universally accepted. “You don’t come across this idea by following other ideas. It requires a strange insight,” Horowitz adds. “He is one of the stars of the younger generation.”

“We’re trying to construct a dictionary,” says Van Raamsdonk, that allows physicists to translate descriptions of our complex universe into simpler terms. If they succeed, they will have found the biggest jigsaw piece in the puzzle of a Grand Unified Theory—something that can describe all of the forces of our universe, at all scales from the atomic to the galactic. That puzzle piece is, specifically, something that can describe gravity within the framework of quantum mechanics, which governs physics on small scales. Such a unified theory is needed to explain the extreme scenarios of a black hole or the first moments of the universe.”

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