Buzz
With the constant stream of headlines about the discovery of seven Earth-sized planets orbiting the star TRAPPIST-1, you might be thinking, “What’s all the excitement about?”
The reason: This breakthrough is considered a “critical milestone” in the quest to find extraterrestrial life in the universe, as stated by Amaury Triaud, an astronomer from the University of Cambridge. And even if this thrilling discovery leads to yet another dead end in that search, it holds immense potential for advancing the field of science.
10. Atmospheres Without Dense Hydrogen Layers
Researchers have confirmed that at least two planets orbiting TRAPPIST-1 (whose size, for comparison, would be like a golf ball if our Sun were a basketball) are not entirely covered in thick hydrogen layers, meaning they likely feature a rocky surface, similar to Earth.
While this news may not seem the most thrilling on the surface, it helps eliminate the possibility that these planets are merely massive gas balls, which would obviously make them unsuitable for life.
Gas giants are frequently found orbiting stars of this size, and the fact that these seven planets deviate from the norm leads scientists to suspect that there could be far more habitable planets than initially thought.
9. The Presence of Both Ozone and Methane
For a planet to be potentially habitable, it requires a specific combination of conditions: not too hot, not too cold, not entirely gaseous or solid. There must be a reasonably rocky terrain, abundant sunlight, an atmosphere of the proper thickness to create a temperate climate, and water that can accumulate in lakes, seas, or oceans.
Ozone in the atmosphere, a by-product of oxygen produced by photosynthetic plants, acts as an essential shield, protecting against the harmful ultraviolet (UV) radiation from the Sun.
Scientists are confident that at least three of the newly discovered planets will have both ozone and methane in their atmospheres, making them viable for supporting life.
Furthermore, the coexistence of methane and oxygen in the atmosphere of one or more of these planets would suggest an unknown life source replenishing these gases. “If you find both ozone and methane along with carbon dioxide and water, there’s only one clear explanation,” says astronomer Michael Gillon from the University of Liege in Belgium. “It is life.”
8. “M-Dwarf” Stars Have Longer Lifespans, Giving More Time for Life to Develop
TRAPPIST-1 is classified as an “M-dwarf” star. These stars are very common throughout the universe and are generally small and faint. TRAPPIST-1 is also categorized as an “ultra-cool” M-dwarf star, making it the coldest type of star possible.
M-dwarfs are well-known for consuming their nuclear fuel at a much slower rate compared to hotter, brighter stars like our Sun, allowing them to illuminate their orbiting planets for astonishingly long stretches of time, potentially even trillions of years.
(To provide some perspective, our Sun has been shining for about 4.6 billion years and is expected to burn out in another five billion years.)
This extended lifespan allows for more time for complex biological life to “evolve from pond scum,” according to Dr. Seth Shostack, an astronomer at the SETI Institute. “If you're seeking complex biology... the older, the better.”
7. New Insights Into Planet Formation Could Be Uncovered
This discovery is already a huge achievement for science, as even if the planets turn out to be incapable of supporting life, it will undoubtedly offer scientists a perfect opportunity to test a wide variety of theories.
The TRAPPIST-1 system can be compared “not only to Earth and other terrestrial planets in our solar system,” says Michael Gillon, “but also to each other.”
Because these planets are believed to have formed from the same protoplanetary disk (a rotating cloud of dense gas and dust surrounding a young star), scientists are certain that the small but significant variations in each planet’s chemical makeup and atmosphere will offer critical insights into their histories and evolutions.
This data can then be used to more effectively study the evolution of other planets, further enhancing our understanding of the universe as a whole.
6. A Sharper Insight Into Distant Worlds
This newly discovered system will likely serve as a crucial model from which data can be drawn to deepen our understanding of planets and galaxies located far beyond, particularly in our quest to find life elsewhere.
TRAPPIST-1 is the place where scientists will test their “hopes, dreams, and concerns about planets orbiting these very cold, low-mass M dwarf stars,” says Sara Seager, a planetary theorist at MIT.
In the best-case scenario, scientists will discover clear and irrefutable evidence of life. Even in the worst-case scenario, which is still promising, scientists may not be able to determine whether oxygen found on one of TRAPPIST-1’s seven planets is being produced or consumed by life forms. However, as Seager assures, that's still positive news, with the only drawback being the need for more time to pinpoint the source.
5. There Are Likely Many More Earth-Sized Planets Than We Ever Thought
While scientists have long suspected that Earth-sized planets exist throughout the universe, the discovery of the TRAPPIST-1 system has shown that these extraordinary planets are far more common than once believed.
With the TRAPPIST-1 system being discovered so close to Earth, the simple laws of probability suggest that there are likely more such systems out there than we initially thought.
It's also probable that there are more M-dwarf stars with similar characteristics throughout the universe than we had previously estimated. This opens up more opportunities for finding extraterrestrial life, and it may even mean that scientists searching for alien radio signals have been looking in the wrong spots all this time.
4. The Remarkable Success of NASA’s Spitzer Space Telescope Has Been Proven
While the majority of the credit for this groundbreaking discovery should rightfully go to the dedicated individuals who have been working on this project for months, we must also acknowledge the immense power and capability of the Spitzer Space Telescope (SST), which made this breakthrough possible.
Launched in 2003, this infrared space telescope has been unraveling some of space's most captivating mysteries for 14 years, all while orbiting the Sun.
Equipped with an Infrared Array Camera, an Infrared Spectrograph, and a Multiband Imaging Photometer, the SST is capable of capturing breathtaking images in vivid detail, including its famous image of light emitted from exoplanets—marking the first time humanity ever visually observed planets outside our solar system.
The planets within the TRAPPIST-1 system were identified by detecting subtle dips in the light from TRAPPIST-1. These light reductions occurred whenever a planet passed in front of the star, blocking some of its light from reaching the SST’s massive lens. These signals were sent back to NASA, where they were carefully analyzed to determine each planet’s size and mass.
3. Every Planet May Have Water Present
When scientists search for potential extraterrestrial life, they typically start with a fundamental question: Is there, or could there be, liquid water?
While planets like Mars and Venus are believed to have once supported liquid water, the absence of ozone and other protective layers has led many scientists to conclude that any life that might have existed would have perished long ago, unable to endure the relentless bombardment of solar and cosmic radiation.
While the presence of liquid water may be possible on all seven planets in the TRAPPIST-1 system, the likelihood of discovering water—and potentially life—is greatest on the three planets that fall within the "habitable zone", where conditions are just right—not too hot, not too cold—for water to exist in liquid form and pool into lakes, rivers, or oceans.
2. A Platform From Which To Better Understand Atmospheres
This groundbreaking discovery will not only help us learn more about other planets across the universe but will also provide valuable insights into their atmospheres.
It's important to note that these are the first Earth-sized planets ever discovered orbiting this type of star at a distance that is "just right." This makes their atmospheres a key resource for studying those of similar planets, allowing us to more effectively analyze the chemical traces—like water, methane, oxygen, and ozone—found in their atmospheres.
The TRAPPIST-1 system presents "one of the best opportunities in the next decade to study the atmospheres surrounding Earth-sized planets," says Nikole Lewis, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland.
In addition to atmospheric studies, scientists will also focus on measuring the planets' temperatures and surface pressures, key factors in assessing their potential habitability.
1. The System, 40 Light-Years Away From Earth, Is Relatively Close
The vastness of the universe undoubtedly holds numerous planets similar to those orbiting TRAPPIST-1. Yet, it's incredibly rare that we find such planets this close to our own.
40 light-years may seem like a vast distance. With current technology, traveling the 235 trillion miles from Earth would take about 44 million years. But in cosmic terms, 40 light-years is relatively nearby—allowing scientists to draw meaningful conclusions not only about our own solar system but also about planetary systems that are much harder to observe, all thanks to the data from TRAPPIST-1.
The close proximity of the TRAPPIST-1 system offers scientists a unique opportunity to explore the formation and interactions of dwarf planets, asteroids, moons, comets, and circumstellar disks in greater detail.
