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.

Astronomers have developed a technique that allows them to detect cloud cycles on distant exoplanets. Using data from the James Webb Sapce Telescope (JWST), the astronomers found that mornings and evenings on the gas giant WASP-94A b have extremely different weather patterns: mornings are riddled with sand clouds, while the skies are clear in the early evenings. By isolating the clouds, researchers can more accurately measure a planet’s atmosphere and provide a clearer picture of the planet’s composition. WASP-94A b, for example, has much less oxygen and carbon than astronomers perviously calculated, making its atmosphere much more like Jupiter than they had originally thought.

New research shows how unmagnetized worlds like Mars can still deflect some of the Sun's solar wind. Unlike magnetospheres that form around planet's like Earth, this effect takes place in Mars' ionosphere. It's called the Zwan-Wolf effect, and it's not clear how deep into the atmosphere it operates.

Scientists using the Euclid space telescope found a red-dwarf brightness “gap” in the population of a globular cluster—an ancient, crowded collection of stars. A similar gap was detected by the Gaia observatory in nearby stellar populations, but it has never before been seen in a globular cluster.

It’s a familiar annual question, that we’re already hearing as we enter into June. “What are those two bright objects in the west?” They’re none other than the two brightest planets in the sky, Jupiter and Venus. Keep an eye on the dusk sky over the next week, and you’ll see the two worlds getting ever closer to each other in the west. Though this happens every year or so, an evening conjunction assures that lots of the general public will see one of the best planetary pairings of 2026.

In our final installment in the series, we'll examine all the close calls, possible candidates, and instances in which extraterrestrial signals could not be ruled out

A multi-year survey of millions of stars in the Small Magellanic Cloud shows that the dwarf galaxy is expanding rather than rotating. This is due to the influence of its larger neighbour, the Large Magellanic Cloud.

The early Universe is full of massive galaxies that stopped forming stars very early. They're called massive quenchers (MQ) and they're challenging to explain. New research shows that another type of galaxy, dusty star-forming galaxies (DSFGs) can explain why. It's all about mergers, starbursts, and AGN feedback.

Astronomers studying wind speeds on distant exoplanets have discovered weather systems driven by magnetic fields, rather than the largely hydrodynamic weather patterns observed on Earth. This discovery is among the best evidence yet for the existence of magnetic fields on exoplanets.