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Category: cosmology – Page 244

Recently, a research team at Osaka University has successfully demonstrated the generation of megatesla (MT)-order magnetic fields via three-dimensional particle simulations on laser-matter interaction. The strength of MT magnetic fields is 1–10 billion times stronger than geomagnetism (0.3–0.5 G), and these fields are expected to be observed only in the close vicinity of celestial bodies such as neutron stars or black holes. This result should facilitate an ambitious experiment to achieve MT-order magnetic fields in the laboratory, which is now in progress.

Since the , scientists have strived to achieve the highest magnetic fields in the laboratory. To date, the highest magnetic field observed in the laboratory is in the kilotesla (kT)-order. In 2020, Masakatsu Murakami at Osaka University proposed a novel scheme called microtube implosions (MTI) to generate ultrahigh magnetic fields on the MT-order. Irradiating a micron-sized hollow cylinder with ultraintense and generates with velocities close to the speed of light. Those hot electrons launch a cylindrically symmetric implosion of the inner wall ions towards the central axis. An applied pre-seeded of the kilotesla-order, parallel to the central axis, bends the trajectories of ions and electrons in opposite directions because of the Lorentz force. Near the target axis, those bent trajectories of ions and electrons collectively form a strong spin current that generates MT-order magnetic fields.

In this study, one of the , Didar Shokov, has extensively conducted three-dimensional simulations using the supercomputer OCTOPUS at Osaka University’s Cybermedia Center. As a result, a distinct scaling law has been found relating the performance of the generation of the magnetic fields by MTI and such external parameters as applied laser intensity, laser energy, and target size.

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IXPE will probe the physics behind some of the universe’s most dynamic objects: black holes and neutron stars.

CAPE CANAVERAL, Fla. — SpaceX successfully launched its 28th rocket of the year early Thursday morning (Dec. 9), ferrying an X-ray observatory into space for NASA.

A used Falcon 9 rocket blasted off at 1 a.m. (0600 GMT) from Pad 39A here at NASA’s Kennedy Space Center in Florida, carrying the Imaging X-ray Polarimetry Explorer (IXPE). The mission marked the fifth flight for this particular booster.

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A team of theoretical researchers have found it might be possible to detect Q-balls in gravitational waves, and their detection would answer why more matter than anti-matter to be left over after the Big Bang, reports a new study in Physical Review Letters.

The reason humans exist is because at some in the first second of the Universe’s existence, somehow more matter was produced than anti-matter. The asymmetry is so small that only one extra particle of matter was produced every time ten billion particles of anti matter were produced. The problem is that even though this asymmetry is small, current theories of physics cannot explain it. In fact, standard theories say matter and anti matter should have been produced in exactly equal quantities, but the existence of humans, Earth, and everything else in the universe proves there must be more, undiscovered physics.

Currently, a popular idea shared by researchers is that this asymmetry was produced just after inflation, a period in the early when there was a very rapid expansion. A blob of could have stretched out over the horizon to evolve and fragment in just the right way to produce this asymmetry.

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An international team of astronomers led by researchers from the Netherlands has found no trace of dark matter in the galaxy AGC 114,905, despite taking detailed measurements over a course of forty hours with state-of-the-art telescopes. They will present their findings in Monthly Notices of the Royal Astronomical Society.

When Pavel Mancera Piña (University of Groningen and ASTRON, the Netherlands) and his colleagues discovered six galaxies with little to no dark matter, they were told “measure again, you’ll see that there will be dark matter around your galaxy.” However, after forty hours of detailed observations using the Very Large Array (VLA) in New Mexico (United States), the evidence for a dark matter-free galaxy only became stronger.

The galaxy in question, AGC 114,905, is about 250 million light-years away. It is classified as an ultra-diffuse dwarf galaxy, with the name ‘dwarf galaxy’ referring to its luminosity and not to its size. The galaxy is about the size of our own Milky Way but contains a thousand times fewer stars. The prevailing idea is that all galaxies, and certainly ultra-diffuse dwarf galaxies, can only exist if they are held together by dark matter.

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If someone told you that the world’s biggest laser was in California that has something to do with space and national defence, you might imagine it was a super-weapon designed to blast enemy satellites out of the sky. But the reality is quite different. The new laser is a unique research tool for scientists, capable of creating the extreme conditions that exist inside stars and nuclear explosions.

The giant laser is located at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California, and it goes by the rather cryptic name of the National Ignition Facility (NIF). That’s because, in the context of nuclear science, “ignition” has a very specific meaning according to the Lawrence Livermore National Laboratory. It refers to the point at which a fusion reaction becomes self-sustaining – a condition that is found inside the sun and other stars, but is extremely difficult to achieve in an earthbound laboratory. Triggering nuclear fusion requires enormously high temperatures and pressures, and that’s where NIF’s giant laser comes in.

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Theoretical physicist Sean Carroll joins us to discuss whether it make sense to think of consciousness as an emergent phenomenon, and whether contemporary physics points in this direction.

We discussed Sean’s essay responding to Philip’s book ‘Galileo’s Error,’ and Philip’s counter-response essay. Both are available here: https://conscienceandconsciousness.com/2021/08/01/19-essays-on-galileos-error/

We also discussed Philip’s Scientific American article making the case that the move from the fine-tuning to the multiverse commits the ‘inverse gambler’s fallacy’: https://www.scientificamerican.com/article/our-improbable-ex…20we%20are, with%20the%20existence%20of%20life.

Finally, Keith and Philip discussed the PhilPapers 2020 survey of philosophers’ opinions on philosophical questions, which is linked to from this blog post of Philip’s: https://conscienceandconsciousness.com/2021/11/01/materialis…only-just/

Continue reading “Sean Carroll: Is Consciousness Emergent?” | >

Astronomers from the University of Texas have spotted a gigantic black hole at the heart of our galaxy’s many dwarf satellite galaxies — meaning that, in intergalactic terms, it’s just a stone’s throw away from our own Solar System.

The newly discovered black hole, dubbed Leo I, is roughly the same size as the suspected black hole at the center of the Milky Way.

It also appears to be a bit of an oddball. By measuring the gravitational pull it has on the stars surrounding it, the researchers found that it’s absolutely massive compared to the size of its host galaxy.

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Astronomers at The University of Texas at Austin’s McDonald Observatory have discovered an unusually massive black hole at the heart of one of the Milky Way ’s dwarf satellite galaxies, called Leo I. Almost as massive as the black hole in our own galaxy, the finding could redefine our understanding of how all galaxies — the building blocks of the universe — evolve. The work is published in a recent issue of The Astrophysical Journal.

The team decided to study Leo I because of its peculiarity. Unlike most dwarf galaxies orbiting the Milky Way, Leo I does not contain much dark matter. Researchers measured Leo I’s dark matter profile — that is, how the density of dark matter changes from the outer edges of the galaxy all the way into its center. They did this by measuring its gravitational pull on the stars: The faster the stars are moving, the more matter there is enclosed in their orbits. In particular, the team wanted to know whether dark matter density increases toward the galaxy’s center. They also wanted to know whether their profile measurement would match previous ones made using older telescope data combined with computer models.

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Let me back up a moment. I recently concurred with megapundit Steven Pinker that over the last two centuries we have achieved material, moral and intellectual progress, which should give us hope that we can achieve still more. I expected, and have gotten, pushback. Pessimists argue that our progress will prove to be ephemeral; that we will inevitably succumb to our own nastiness and stupidity and destroy ourselves.

Maybe, maybe not. Just for the sake of argument, let’s say that within the next century or two we solve our biggest problems, including tyranny, injustice, poverty, pandemics, climate change and war. Let’s say we create a world in which we can do pretty much anything we choose. Many will pursue pleasure, finding ever more exciting ways to enjoy themselves. Others may seek spiritual enlightenment or devote themselves to artistic expression.

No matter what our descendants choose to do, some will surely keep investigating the universe and everything in it, including us. How long can the quest for knowledge continue? Not long, I argued 25 years ago this month in The End of Science, which contends that particle physics, cosmology, neuroscience and other fields are bumping into fundamental limits. I still think I’m right, but I could be wrong. Below I describe the views of three physicists—Freeman Dyson, Roger Penrose and David Deutsch—who hold that knowledge seeking can continue for a long, long time, and possibly forever, even in the face of the heat death of the universe.

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