Universe Today

The ekpyrotic universe is a beautiful idea that runs headlong into the data. From hand-waved singularities and assumed dark energy to the killer blow from Planck and WMAP measurements of the cosmic microwave background, here is why nature has so far voted against it.

How do you measure the mass of a dormant black hole in the early Universe? That's a question astronomers at University College London (UCL) and Carnegie scientists wanted to answer about a distant object that is invisible. So, they turned to James Webb Space Telescope (JWST) studies of the region around the black hole to find that answer.

New simulations show that interactions with a magnetic field can work to decrease the distance between still forming binary protostars. These results can help explain the characteristics of the binary star systems observed in the Milky Way. These results can also be extrapolated to binary black holes, giving insights into how super massive black holes evolve.

Meteorites are (usually) gifts from the heavens. They provide unique insights to parts of the solar system that we couldn’t access otherwise - either because it's too expensive, or because the solar system itself has evolved since it was formed. A new paper from researchers at the University of Colorado Boulder details how one particularly famous meteorite offers a window into just such a bygone age of the solar system - and the failed planet that was a part of it.

Neptune is definitely the odd one out of the gas giants. It’s tilted at a strange angle, and its moons are completely different from any other gas giant we know of. A new paper, published in Science Advances from researchers at CalTech, posits that might be because Triton, by far Neptune’s largest moon, absolutely obliterated the regular moon system it previously had, except for one particular exception - Nereid.

Unfortunately there’s more bad news to report on the clear skies front. A new paper, available in pre-print on arXiv from researchers at NASA’s Ames Research Center, reports that 73.3% of images the agency’s new SPHEREx space telescope collected between May and September of last year were contaminated by at least one artificial satellite trail. And it’s only going to get worse from here.

The ekpyrotic theory tries to beat inflation with bouncing higher-dimensional branes, no singularity, and a universe that has always existed. A tour of the prettiest version of the idea and how it claims to handle flatness, dark energy, and the entropy that doomed earlier cyclic models.

We witnessed a surprise outburst late last week, from a lesser known periodic comet. Posts flashed across message boards late last week, alerting comet watchers to a dramatic change in brightness for periodic comet 220P McNaught. Though it wasn’t on our list for bright comets to watch for in 2026, Comet 220P is now in range of binoculars or a small telescope, low to the east at dawn as it heads towards perihelion this coming weekend.

If we’re to reach another star, chemical propulsion will not get us there in any reasonable time frame. We’re going to need a different propulsion technology, and one of the most promising seems to be a solar sail. These giant reflective surfaces form the basis of many interstellar missions. Combined with giant lasers pushing them, they can be accelerated to speeds unreachable by any other current technologies. However, according to a new paper available on arXiv from Chao Shen and Jiaze Li of the Harbin Institute of Technology, once those missions start reaching a significant percentage of the speed of light they’re going to run into a drag force from the light itself.

An international team led by astronomers at the University of Sydney has uncovered the clearest evidence yet for the origin of an unusual class of cosmic signals. In doing so, they have identified a rare stellar system that is providing scientists with a natural laboratory to study extreme physics.

Inflation is awkward, possibly not even a proper theory, and it has reigned over cosmology for forty years anyway. Here is what it claims, the flatness, horizon, and monopole problems it solves, the structure-formation prediction it nailed, and the deep problems it still cannot escape.

Scientists at the SETI Institute searched for technological signals from 3I/ATLAS, the third interstellar object observed in our Solar System. Using the Allen Telescope Array (ATA) at the Hat Creek Radio Observatory in Northern California, the team scanned a wide range of radio frequencies for signs of extraterrestrial technology and found none, as expected based on other astronomical observations showing that the object exhibits natural comet-like composition and behavior. “Eventually, our own Voyager spacecraft will be extraterrestrial artifacts in other stellar systems,” said Dr. Sofia Sheikh, lead author on the paper. “Given that, it is important that we understand the natural distribution of interstellar objects so that we will be able to identify any anomalies that could one day be signs of an artificial interstellar object.” The team observed 3I/ATLAS for more than seven hours with the ATA, covering 1 to 9 gigahertz. This broad range allows scientists to search for narrowband radio signals, which are not produced by in nature and would be evidence of technology.

A look at why a cyclic, eternally repeating universe is such an appealing idea, and why the first serious attempt to build one, Richard Tolman's 1930s model of endless big bangs and big crunches, collapsed under the weight of entropy. The Big Bang keeps demanding a beginning.

Rocket scientists have always faced a trade-off in propulsion technologies. Chemical rockets can provide lots of oomph, but burn through fuel so quickly they can only do so for a few minutes. Electric propulsion, on the other hand, can run for days, but the pushing power they provide is miniscule compared to their chemical cousins. A new paper in the Journal of Propulsion and Power from researchers at MIT describes a system that might be the best of both worlds - a propulsion system that includes an electrospray thruster that uses a chemical rocket propellant, and can seamlessly switch to a chemical rocket when needed.

An international committee of experts says it has updated its rules for evaluating and revealing the detection of extraterrestrial intelligence. The revisions to the decades-old Declaration of Principles, created and maintained by the International Academy of Astronautics' SETI Committee, come just days before the release of "Disclosure Day," a movie about alien visitation directed by Steven Spielberg.

The first mission devoted to observing the Martian atmosphere and its evolution, NASA’s MAVEN (Mars Atmosphere and Volatile Evolution), has ended after more than 11 years in orbit at Mars and a decade beyond its primary, one-year mission.

Ever since the first protoplanetary disk was discovered in 1984 around the star Beta Pictoris, these objects have presented astronomers with laboratories to study the births and evolution of worlds around distant stars. A team at France's National Center for Scientific Research (CNRS) and the University of Bordeaux, made a breakthrough in understanding these planetary birthplaces when they directly observed the rotation of a protoplanetary disk around the young star AB Aurigae.

Using data from NASA’s James Webb Space Telescope, astronomers led by researchers at the University of California, Riverside have produced the most detailed map of the cosmic web ever made, tracing the network of galaxies all the way back to when the universe was one billion years old.

According to theory, all active black holes should produce winds or jets. Astronomers have long searched for wind around the Milky Way’s central supermassive black hole. New images reveal a vacant, cone-shaped region pointing to the black hole. According to new research, only a supermassive black hole could've created this region.

Stephen Hawking predicted that stars can capture primordial black holes (PBH). The PBH find their way to the stellar core, creating a Hawking star. There are two possible outcomes, both deadly for the star. Either it explodes rapidly, or it's slowly consumed by the parasitic PBH.