Space and Astronomy News for the 2nd of August 2025

Not just individual rogue planets. Planets can form new planetary systems without host stars

Back in 2023, we chatted about how planets can be found wandering the Milky Way without a host star. You can read that blog post here. Astronomers theorised that there could be trillions of planets in the Milky Way that aren't part of a star system. How planets could be removed from their host star was a subject of some conjecture, including possible interactions with nearby stars or larger parts of the galaxy. 

One of the problems of finding these "rogue" stars is that don't emit light on their own, and they're not close enough to stars to cause them to wobble. They were found by watching the light from more distant stars dim as the planets pass between observer and the star. 

Now researchers have found evidence of infrared light from planets in deep interstellar space, a sign usually associated with circumstellar disks of dust from where planets are formed. Using the JWST (James Webb Space Telescope) astronomers found six possible candidates for "Solar Systems" made up of just planets.

This means that planets could possibly form into their own mini Solar System without stars. 

An illustration of a dust cloud surrounding a free floating planet. Image via: University of St Andrews

Lead author Dr Belinda Damian from the University of St Andrews said: “These discoveries show that the building blocks for forming planets can be found even around objects that are barely larger than Jupiter and drifting alone in space. This means that the formation of planetary systems is not exclusive to stars but might also work around lonely starless worlds.”

(One thing we're always asked about when talking about exoplanets is whether you'd be able to see them with your telescope. It's not something that can be done.)

Read more about this fascinating discovery here at the University of St Andrews website here.

When are humans heading back to the Moon? A bit soon than you might think

Many folks would know that the last time that humans left Earth orbit and headed to the Moon was on the Apollo 17 mission back in 1972. Since then, all human space missions have been in Earth orbit. The highest altitude achieved in recent years was the crew of Polaris Dawn at approx. 1,400km in September 2024. 

It was 54 years ago this week when the first Lunar Rover was driven on the surface of the Moon as part of the Apollo 15 mission

There's likely going to be quite a few changes in the next years, with changes to NASA priorities and staff especially. One mission that looks like it will taking place is Artemis II.

This flight will leave Earth orbit and will perform the a single orbit around the Moon before returning to Earth. It will not enter Lunar orbit. No Moon landing will be attempted until later missions.  While Artemis II might seem unexciting compared to the heady days of the Apollo program, humans leaving the Earth's orbit after such a long break marks the beginning of a more permanent presence deeper in space. 

Artemis II crew.  From left: mission specialist Christina Koch, pilot Victor Glover, commander Reid Wiseman, and mission specialist Jeremy Hansen. Image via: NASA

At this point the Artemis II mission will return humans to the Moon no later than April 2026 or about 9 months away, although there are some suggestions that the launch could be as early as February 2026.

The program is due to be cancelled after Artemis III, slated for 2027.  

Is K2-18b an ocean world?

There was a lot of interest about the announcement a few months ago that the exoplanet K2-18b harboured life. (You can read our blog article about it here. ) This was based on chemical signatures found by the JWST.  

The authors of the original research while confident in their results cautioned, that much more study would be needed. Given the significance of their claims, there has been a lot of controversy and even counter-claims by other scientists dismissing their finds of life signatures.  Some have argued that life indicating molecules were not found in the original JWST data, while others have found other, non-living pathways to the chemicals that were observed.

An illustration of K2-18b showing the planet and its host star. Image via: ESA/Hubble, M. Kornmesser

One thing researchers do seem to agree on is that further studies of K2-18 b by the JWST have confirmed that it is a Hycean world or one covered by a planet wide ocean. Such planets are considered prime targets in the search for life beyond Earth both within the Solar System or beyond.  For example, NASA's Europa Clipper is travelling to Jupiter to investigate the possibility of life in the ocean under the frozen surface of its moon, Europa. 

"This has certainly increased the chances of habitability on K2-18 b" Nikku Madhusudhan, the University of Cambridge scientists who part of the team behind the study published earlier in the year. 

"This is a very important development and further increases the chance of a Hycean environment in K2-18 b. It confirms K2-18 b to be our best chance to study a potential habitable environment beyond the solar system at the present time." he continued.

There's going to be a lot more discussion on this topic in the next years and final conclusions might have to wait until the next generations of large, Earth based telescopes come online.  

Read more here.

Cheers,

Earl White

BINTEL

2nd August 2025