Space News & Blog Articles

It’s that time again! Time for another model that will finally solve the mystery of dark matter. Or not, but it’s worth a shot. Until we directly detect dark matter particles, or until some model conclusively removes dark matter from our astrophysical toolkit the best we can do is continue looking for solutions. This new work takes a look at that old theoretical chestnut, primordial black holes, but it has a few interesting twists.

Primordial black holes are hypothetical objects formed during the earliest moments of the Universe. According to the models they formed from micro-fluctuations in matter density and spacetime to become sandgrain-sized mountain-massed black holes. Although we’ve never detected primordial black holes, they have all the necessary properties of dark matter, such as not emitting light and the ability to cluster around galaxies. If they exist, they could explain most of dark matter.

The downside is that most primordial black hole candidates have been ruled out by observation. For example, to account for dark matter there would have to be so many of these gravitational pipsqueaks that they would often pass in front of a star from our vantage point. This would create a microlensing flare we should regularly observe. Several sky surveys have looked for such an event to no avail, so PBH dark matter is not a popular idea these days.

This new work takes a slightly different approach. Rather than looking at typical primordial black holes, it considers ultralight black holes. These are on the small end of possible masses and are so tiny that Hawking radiation would come into play. The rate of Hawking decay is inversely proportional to the size of a black hole, so these ultralight black holes should radiate to their end of life on a short cosmic timescale. Since we don’t have a full model of quantum gravity, we don’t know what would happen to ultralight black holes at the end, which is where this paper comes in.

As the author notes, basically there are three possible outcomes. The first is that the black hole radiates away completely. The black hole would end as a brief flash of high-energy particles. The second is that some mechanism prevents complete evaporation and the black hole reaches some kind of equilibrium state. The third option is similar to the second, but in this case, the equilibrium state causes the event horizon to disappear, leaving an exposed dense mass known as a naked singularity. The author also notes that for the latter two outcomes, the objects might have a net electric charge.

NASA has given the go-ahead for SpaceX to work out a plan to adapt its Starlink broadband internet satellites for use in a Martian communication network.

The idea is one of a dozen proposals that have won NASA funding for concept studies that could end up supporting the space agency’s strategy for bringing samples from Mars back to Earth for lab analysis. The proposals were submitted by nine companies — also including Blue Origin, Lockheed Martin, United Launch Alliance, Astrobotic, Firefly Aerospace, Impulse Space, Albedo Space and Redwire Space.

Awardees will be paid $200,000 to $300,000 for their reports, which are due in August. NASA says the studies could lead to future requests for proposals, but it’s not yet making any commitment to follow up.

“We’re in an exciting new era of space exploration, with rapid growth of commercial interest and capabilities,” Eric Ianson, director of NASA’s Mars Exploration Program, said in a news release. “Now is the right time for NASA to begin looking at how public-private partnerships could support science at Mars in the coming decades.”

For years, SpaceX executives have been talking about using Starlink satellites in Martian orbit as part of billionaire founder Elon Musk’s vision of making humanity a multiplanetary species. In 2020, SpaceX President Gwynne Shotwell told Time magazine that connectivity will be an essential part of the company’s Mars settlement plan.

The JWST is astronomers’ best tool for probing exoplanet atmospheres. Its capable instruments can dissect the light passing through a distant world’s atmosphere and determine its chemical components. Scientists are interested in everything the JWST finds, but when it finds something indicating the possibility of life it seizes everyone’s attention.

That’s what happened in September 2023, when the JWST found dimethyl sulphide (DMS) in the atmosphere of the exoplanet K2-18b.

K2-18b orbits a red dwarf star about 124 light-years away. It’s a sub-Neptune with about 2.5 times Earth’s radius and 8.6 Earth masses. The exoplanet may be a Hycean world, a temperate ocean-covered world with a large hydrogen atmosphere.

In October 2023, researchers announced the tentative detection of dimethyl sulphide in K2-18b’s atmosphere. They found it in JWST observations of the planet’s atmospheric spectrum. “The spectrum also suggests potential signs of dimethyl sulphide (DMS), which has been predicted to be an observable biomarker in Hycean worlds, motivating considerations of possible biological activity on the planet,” the researchers wrote.

The DMS caught people’s attention because it’s produced by living organisms here on Earth, mostly by marine microbes. So, finding it on an ocean world is cause for a deeper look. A team of researchers from the USA, Germany, and the UK examined the detection to see how it fits with atmospheric models.