NB: This is a speculative piece.
For 39 years images and data have been streaming across space. A small flotilla of missions to the TRAPPIST-1 system has begun transmittting. Seven small rocky worlds, all at least nominally Earthlike have drawn their share of attention over the decades. They huddle tightly around an angry little red dwarf star, somewhere in the Aquarius constellation.
Some of these planets sit within the habitable zone of TRAPPIST-1, that sweet spot where the temperature is just right: the proverbial bowl of porridge. Just right for what?
For water to exist in liquid form on the surface. And some of these worlds are very watery. Long ago the James Webb Space Telescope spotted water and indications of seasonal change on several of these worlds. Spectroscopic analysis enabled us to see these worlds with different eyes.
The missions now assigning themselves to various locales in this system show us a family of worlds possibly bearing life. TRAPPIST-1e is the prime target, but each world has a story to tell.
First approach showed us a red planet, with signs of vigorous atmospheric activity. There appears to be a purple tinge to the four large landmasses straddling this globe.
This purple haze is a striking feature of the planet. It may be due to native organisms using a photosynthetic pigment such as retinal. This protein may have been employed by early photosynthesisers on earth. Chlorophyll may have been a later card to be added to the deck.
TRAPPIST-1e appears to possess a diverse set of environments. Overall, it is a temperate world, and any life does struggle with sometimes extreme solar flare activity from TRAPPIST-1 .
Dust storms are a feature of TRAPPIST- 1e. In the above image a drone has spotted one such dust storm on the horizon as it flies over a large inland body of water. It is twilight in this image.
The TRAPPIST-1 worlds are close. The orbits of all seven planets would fit within the orbit of Mercury back home.
Traces of green can be noticed on the slopes of this extinct volcano. TRAPPIST-1 is believed to be ancient: on the order of eight to ten billion years. It’s family of seven worlds may have seen life arise more than once. This may have happened on our own world, with an enigmatic array of creatures known generically as Ediacarans appearing before the more conventional forms we see today.
The proximity of the TRAPPIST-1 planets presents an opportunity for researchers to observe lithopanspermia. The Swedish chemist Svante Arrhenius was one of the earliest scientists to suggest that life or it’s building blocks could travel from world to world, hitching a ride on moving objects such as comets or asteroids. Lithopanspermia builds on this. It’s a big idea, and observations on several of the TRAPPIST-1 worlds is showing us something we’ve only speculated on. Life travels between worlds, carried by rocks sent into space by impacts and volcanic eruptions.
Were a visitor to be admiring the sunset on, say, TRAPPIST-1d, they’d be in for a treat.
In this system, life is not restricted to one world. Here, an ecosystem interconnected by space borne life has given rise to an interplanetary ecosystem.
Next time, we visit a frozen world that may be hiding it’s own life, far beyond the habitable zone of TRAPPIST-1.
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All images: Ben Roberts