Alien plants might be closer to reality than we think, especially on planets around red dwarf stars, the most common type of star in our galaxy. These stars are smaller and cooler than our Sun, emitting dimmer and redder light.
Unlike Earth, plants on these planets would face a different light environment, which raises questions about their ability to survive. Thomas Haworth, a physicist from Queen Mary University of London, along with biologist Christopher Duffy, believes that while photosynthesis could still happen in such low-light conditions, it might look very different from the process we know on Earth.
Alien Plants Might Evolve New Colors, Survive Without Oxygen
On Earth, plants use chlorophyll to turn sunlight and carbon dioxide into energy, giving them their green color. Chlorophyll is specially adapted to absorb sunlight in the visible spectrum from blue to red light. However, red dwarf stars emit light primarily beyond 700 nanometers-redder than what plants here are used to.
For photosynthesis to work on these distant planets, plants would need more efficient systems to gather energy from dim light. Duffy and Haworth suggest that alien plants might rely on special pigments or light-capturing mechanisms that could make them purple, orange, or even red instead of green, Wired said.
There's also a possibility that alien plants might not even rely on oxygen for photosynthesis. On Earth, some microbes perform photosynthesis without oxygen, using gasses like sulfur. Purple and green sulfur bacteria, for instance, can live in environments with very little light. On alien planets, these types of organisms might form the base of ecosystems, thriving in dim, sulfur-rich waters.
To find these potential alien plants, scientists look for planets within a "habitable zone"-regions around stars that are neither too hot nor too cold for liquid water. Cassandra Hall, an astrophysicist, argues that a planet's "photosynthetic habitable zone" might be even more important. This zone is where light levels are just right to support alien photosynthesis. Hall's research points to planets like Kepler-452b and Kepler-62e, which are rocky planets orbiting within these zones.
Rocky Planets Near M-Dwarfs May Survive Radiation and Host Life
For planets orbiting M-dwarf stars, a significant challenge is the strong ultraviolet radiation emitted by these stars, which can strip away atmospheres. But recent studies suggest that some rocky planets might be able to keep a stable atmosphere, even after the harsh radiation blows away their initial one. A second, more stable atmosphere could form, allowing these planets to potentially host life.
Though we still have no direct evidence of alien plants, the possibility keeps scientists searching. According to IFLScience with advanced telescopes like the James Webb Space Telescope, researchers are exploring star systems like TRAPPIST-1, where seven Earth-sized planets orbit an M-dwarf star. These studies might one day reveal if alien plants can indeed thrive on distant worlds.
