I’ve always been so curious about life beyond Earth. Scientists recently discovered that there are as many as 24 planets outside of our solar system more suitable for life than Earth. They found that these planets surpass Earth in several categories, including age, warmth, wetness, and size. These factors qualify the planets to be “superhabitable” and to have optimal potential for complex extraterrestrial life.
When searching for a habitable planet, one of the most important factors to take into consideration is temperature, which goes hand-in-hand with distance from their star. Scientists have discovered several planets at extreme temperatures, including planet KELT-9b, which is so hot that its atmosphere is constantly melting or GJ 433 d, whose discoverers described it as “the coldest Neptune-like planet ever discovered”. While both of these planets are on opposite sides of the inhospitable spectrum, there are several other planets within their star’s “habitable zone”, which are not too hot or too cold for life as we know it to flourish.
Scientists have discovered over 4000 exoplanets, or planets outside our solar system so far. The main qualities researchers aim to identify in exoplanets in order to classify them as “superhabitable” include a nearby star of the right star and life span, as it took 3.5 billion years for complex life to form on Earth, and size of the planet. A larger size means more surface area for habitats, higher gravity, and a thicker atmosphere, which is beneficial for flight based organisms. Planets with these qualities in addition to being slightly warmer and wetter would be even more habitable than Earth. A larger or closer moon than Earth’s would also be considered “better”, because of benefits such as helping to stabilize its orbit and preventing life-disrupting wobbles. Taking all of these factors into consideration, the researchers came up with a list of the most ideal parameters for the perfect superhabitable planet. This planet “would be in orbit around a K dwarf star, which is a relatively small star star that’s slightly cooler than our sun […]; about 5 billion to 8 billion years old; about 10% larger than Earth; about 9 F warmer than Earth, on average; moist with an atmosphere that is 25% to 30% oxygen, with scattered land and water. [It] would also have plate tectonics or a similar geological process in order to recycle minerals and nutrients through the crust and to create diverse habitats and topography, and would have a moon between 1% and 10% of its size orbiting it at a moderate distance” (livescience.com) As we know from biology, an oxygen rich atmosphere is essential as oxygen is one of the most important building blocks of life. Our cells need oxygen to produce various proteins which in turn produce more cells. Oxygen is also vital in many of our body systems and needed for the creation of carbohydrates, nucleic acids, and lipids. Other animals and plants also require large amounts of oxygen to survive.
Out of the 24 Kepler Objects of Interest, which are unconfirmed indications of transiting planets, spotted by the Kepler telescope, two have been confirmed as exoplanets, (Kepler 1126 b and Kepler-69c), nine are orbiting around the proper type of star, 16 are within the correct age range, and five fall into the right temperature range. KOI 5715.01 was the only candidate of the 24 that fell into the correct range for each of the three categories, but the planet’s true surface temperature is unable to be determined right now because it depends on the strength of the greenhouse effect in its atmosphere. Additionally, as all of these planets are more than 100 light-years away, many of them can’t be studied properly due to lack of technology.
I personally believe that we are on the brink of making seriously ground-breaking discoveries regarding extraterrestrial life. Technology is advancing every year, and in turn we make more discoveries each year about the enigma of space. Hopefully soon we will find out if some of these planets really do have life inhabiting them.