For decades, extremal black holes were considered mathematically impossible. A new proof reveals otherwise.
Category: cosmology – Page 134
Astronomers Discover Record-Breaking Twin Quasars in the Early Universe
Astronomers have identified the earliest pair of quasars, shining 900 million years post-Big Bang, revealing insights into galaxy mergers and the reionization era of the Universe.
An international team of astronomers, including members from the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), has discovered the earliest known pair of quasars using the Subaru Telescope and Gemini North telescope, both situated on Maunakea in Hawai’i. These quasars, powered by actively feeding supermassive black holes, emit intense radiation. This significant discovery will provide insights into the early evolution of the Universe.
About 400 million to 1 billion years after the Big Bang, something, possibly a combination of sources, unleashed enough radiation to strip the electrons from most of the hydrogen atoms, completely altering the nature of the Universe. Quasars are one potential source of the radiation that caused this “reionization” of the Universe. When matter falls into the supermassive black hole at the center of a galaxy, the matter heats up and releases radiation in a phenomenon known as a quasar.
Next-Gen Spectroscopy: New Tunable Laser Method Achieves Unprecedented Precision
Innovative diode laser spectroscopy provides precise monitoring of the color changes in the sweeping laser at each moment, establishing new benchmarks for frequency metrology and practical applications.
Since the laser’s debut in the 1960s, laser spectroscopy has evolved into a crucial technique for investigating the intricate structures and behaviors of atoms and molecules. Advances in laser technology have significantly expanded its potential. Laser spectroscopy primarily consists of two key types: frequency comb-based laser spectroscopy and tunable continuous-wave (CW) laser spectroscopy.
Comb-based laser spectroscopy enables extremely precise frequency measurements, with an accuracy of up to 18 digits. This remarkable precision led to a Nobel Prize in Physics in 2005 and has applications in optical clocks, gravity sensing, and the search for dark matter. Frequency combs also enable high-precision, high-speed broadband spectroscopy because they combine large bandwidth with high spectral resolution.
Something Is Wrong with Dark Energy, Physicists Say
Cosmic surveys suggest the force pulling the universe apart might not be constant after all.
Imagine sitting in the center of a firework that has just exploded. After the first flash of light and heat, sparks fly off in all directions, with some streaming together into fiery filaments and others fading quickly into cold, ashy oblivion. After a moment more, the smoke is all that remains—the echo, if you will, of the firework’s big bang.
Hopes of Big Bang Discoveries Ride on a Future Spacecraft
A possible solution to the dark matter problem.
As the early universe cooled and expanded, phase transitions might have left “bubble walls,” energetic barriers between pockets of space.
Physicists and cosmologists will have a new probe of primordial processes when Europe launches the Laser Interferometer Space Antenna (LISA) next decade.
James Webb Telescope May Have Finally Solved the Crisis in Cosmology
The “crisis in cosmology,” sparked by differing measurements of the universe’s expansion, may be nearing a resolution thanks to the James Webb Space Telescope. New data analyzed by scientists suggests that the Hubble tension might not be as severe as previously thought. This could mean our current model of the universe remains accurate.
The Debate on the Universe’s Expansion Rate
We know many things about our universe, but astronomers are still debating exactly how fast it is expanding. In fact, over the past two decades, two major ways to measure this number — known as the “Hubble constant” — have come up with different answers, leading some to wonder if there was something missing from our model of how the universe works.