Space and Astronomy News for the 19th of April 2025

Have we discovered life on an another planet?

Short answer - there's a possibility we have!

Keen BINTEL newsletter readers will remember that in the first blog entry for 2024 we chatted about what was on the horizon for that year. We mentioned that the discovery of life on another planet via the detection of biological processes in its atmosphere by the JWST (James Webb Space Telescope) could possibly happen and a number of leading figures thought this was entirely possible and would be announced soon. You can read the January 2024 post here. 

I wrapped up the blog with this as such a discovery was on the cards. Many astronomers have long thought this is how life outside the Solar System would first be found. They now have the tools (in the form of the Webb telescope) and the ever growing list of exoplanets and more detailed knowledge about them. It's long been thought that life would most likely be found on a rocky terrestrial planet like the Earth, although "ocean worlds" might also be targets to investigate. 

A few months into 2025 and it looks like such an announcement has been made!

What was found.

Astronomers from the University of Cambridge used data from Webb to detect the fingerprints of dimethyl sulfide (DMS) and/or dimethyl disulfide (DMDS).  These chemicals seem to exist in the atmosphere of the exoplanet K2-18b. This planet orbits K2-18, which is a red dwarf star some 124 light years away from Earth and is in the host star's "habitable zone" - meaning conditions on the planet might be suitable for life to exist. It's a hycean world, with a hydrogen atmosphere and likely a deep ocean.  Since its discovery in 2014, water vapour and then methane and carbon dioxide have been found in its atmosphere. You can read more about this in the NASA article from 2023 here.

These earlier results were important as they also hinted at the presence of the chemical, DMS. While they were not robust, they warranted further investigation using Webb's Mid-Infrared Instrument (MIRI) which observes through different wavelengths. Further evidence of DMS was found, along with the discovery of DMDS in K2-18b's atmosphere.

Why is the discovery of DMS and DMDS important?

Both of these chemical are found on Earth and are the results of life processes from phytoplankton and other very small aquatic lifeforms. The concentrations of DMS and DMDS in the atmosphere of K2-18b are also vastly larger than what is found on Earth and in-line and what we'd expect life on hycean planet to produce. 

Currently, we know of no purely chemical process outside of life that produces DMS and DMDS in the quantities found in the atmosphere of K2-18b. 

How confident are astronomers in this result? Does is mean life on another planet has been discovered?

Astronomers have calculated the result as being a 0.3% chance  or about one-in-three hundred of them occurring by chance. This means the results are likely but not fully confirmed. A "five sigma" confirmation of a 0.00006% confidence requires more time spent observing K2-1b with either Webb or future telescopes both in space and in the ground. 

For example, a recent study suggested the ELT (Extremely Large Telescope) which is under construction in Chile and due to start observations in 2028 could possibly confirm life on planets orbiting nearby stars through detecting chemicals in their atmospheres within hours.

An illustration of the ELT when completed. Image via Swinburne Astronomy Productions/ESO

There's still the possibility of scientists working out how DMS and DMDS can be formed and replenished in large volumes without the involvement of life processes.

It's not the announcement of the discovery of life on another world, rather that life on K2-18b is highly likely and worthy of a lot of further investigation.

The results published by the team from Cambridge University are likely to be vigorously  debated for some time to come.  

Can I see K2-18b with my telescope?

No. You won't be able to see K2-18b. Even Webb observes the planet indirectly by the way it changes how the host star, K2-18 appears.

K2-18 is a magnitude 13.8 red dwarf star in the constellation of Leo. It could be seen in very large amateur telescopes but would be extremely hard to observe or image. 

Could observers on other planets find life on Earth using this technique?

Yes. The Earth's atmosphere is full of observable carbon molecules that could be spotted from other planets as "biomarkers" for the life processes that occur here. We could also be found via our technosignatures - radio transmissions etc. 

How significant is this discovery?

There's also implications about how common life could be in the Milky Way. If life occurs only every 130 light year or so and even if we discover no more life nearby - in other words there's nothing "alive" between us here on Earth and K2-18b - that could still indicate that there might be life on over 800,000 other planets in the Milky Way.

When humanity decides that life does exist elsewhere in the Solar System or further out in the Milky Way, the results announced the team at Cambridge University on the 17th of April 2025 will always be remembered as an important milestone. 

You can read more about their research here.

A planetary alignment in the pre-dawn sky on ANZAC Day

If you're heading to the ANZAC Day dawn services next Friday,  there will be a lovely planetary alignment in the eastern sky a little while before the Sun rises. 

The view towards the east around 5.30am the ANZAC Day, 25th of April 2025 as seen from Sydney

Low in the sky as dawn approaches will be the crescent Moon, Saturn and Venus. A little below that will be hard to spot Mercury. 

Planets in the sky this weekend

This chart shows the rise and set times for planets over the next few days. You can create this chart at any time from Stellarium.

A New "Dish" for the Canberra Deep Space Communication Complex

The 70m DSS-43 at the DSCC outside of Canberra this week. 

I was fortunate to visit the Canberra Deep Space Communication Complex (sometimes called the Tidbinbilla Tracking Station) a couple of days ago on a stunning autumn day in the ACT. 

Last month this facility celebrated 60 years of being a part of NASA's Deep Space Network tracking station, helping to keep track of hundreds of missions including the Apollo Moon landings and the Voyager spacecraft. 

On the 8th of April NASA announced a "New Dish" to be built at the facility.

“Canberra has played a crucial part in tracking, communicating, and collecting data from some of the most momentous missions in space history,” said Kevin Ferguson, director of the Canberra Deep Space Communication Complex. “As the network continues to advance and grow, Canberra will continue to play a key role in supporting humanity’s exploration of the cosmos.”

You can read more about this via the NASA website here.

Has Comet C/2025 F2 (SWAN) disintegrated?

A recently discovered comet, found by several astronomers including Australian Michael Mattiazzo, seems to have brightened and then appears to be fading quickly. This is often a sign that a comet has broken up as it nears the Sun and common fate for many. 

News about this is coming in at the moment. You can get the latest here.

I hope all our BINTEL customers and friends have a safe and relaxing Easter long weekend!

Cheers,

Earl White 

BINTEL 

19th April 2024