Gravitational waves can be lensed by massive galaxies so that they repeat, like an echo. Scientists are now readying to snare their first one and explore the cosmic secrets it holds.
The theoretical physics and paradoxes of time travel often brush up against multiverse theory and the idea of alternate universes.
Physicists haven’t yet ruled out the possibility that the universe has a complicated topology in which space loops back around on itself.
Models for how heavy elements are produced within stars have become more accurate thanks to measurements by RIKEN nuclear physicists of the probabilities that 20 neutron-rich nuclei will shed neutrons.
Stars generate energy by fusing the nuclei of light elements—first hydrogen nuclei and then progressively heavier nuclei, as the hydrogen and other lighter elements are sequentially consumed. But this process can only produce the first 26 elements up to iron.
Another process, known as rapid neutron capture, is thought to produce nuclei that are heavier than iron. As its name suggests, this process involves nuclei becoming larger by rapidly snatching up stray neutrons. It requires extremely high densities of neutrons and is thus thought to occur mainly during events such as mergers of neutron stars and supernova explosions.
A team of physicists from the University of Alabama in Huntsville and the Advanced Propulsion Laboratory at Applied Physics, in New York, has developed a model that shows it might be possible to create a subluminal warp drive.
MIT physicists and colleagues have created a five-lane superhighway for electrons that could allow ultra-efficient electronics and more. The work, reported in the May 9 issue of Science, is one of several important discoveries by the same team over the last year involving a material that is essentially a unique form of pencil lead.
This theoretical model for space-time manipulation aligns with established laws. Imagine that.
Scientists believe the environment immediately surrounding a black hole is tumultuous, featuring hot magnetized gas that spirals in a disk at tremendous speeds and temperatures. Astronomical observations show that within such a disk, mysterious flares occur up to several times a day, temporarily brightening and then fading away.
Now a team led by Caltech scientists has used telescope data and an artificial intelligence (AI) computer-vision technique to recover the first three-dimensional video showing what such flares could look like around SagittariusA* (Sgr A• the supermassive black hole at the heart of our own Milky Way galaxy.
The 3D flare structure features two bright, compact features located about 75 million kilometers (or half the distance between Earth and the sun) from the center of the black hole. It is based on data collected by the Atacama Large Millimeter Array (ALMA) in Chile over a period of 100 minutes directly after an eruption seen in Xray data on April 11, 2017.
From the article by Robin Hanson, a professor of economics who also holds degrees in physics and computer science.
So this remains my worry: our rapid rates of change in unconditional choices of cultural norms are not mostly driven by reason, but instead by a cultural evolution process that has…
I’ve been reading, thinking, and talking, trying to get clearer on what exactly are the culture problems I’m worried about, and how best to describe them. I seek descriptions not only easy for an outsider public to understand, but also for prestigious insider specialists to embrace.
