(Image credit: NASA Hubble Space Telescope on Unsplash)
Is climate change responsible for the quality of our mid-summer thoughts? In this heat, our thoughts have turned from a caterpillar-to-butterfly transformation (see our soul-in-its-butterfly-formulation) to recent transformational scientific advances around the idea that there may be other human settlement in this universe.
While the first possible evidence of an exoplanet was noted in 1917, the first confirmation of the detection occurred only in 1992, with the number of exoplanets discovered as of 2012 was still fewer than 100 (twenty years after the first). With the launch of the Kepler planet-hunting probe in the year 2009 helping hundreds to be discovered and confirmed almost every year in the 2010s – and a “decade of exoplanets” or what some have called a “Tsunami effect” and the “ten years that transformed a discipline” – and helped by the launch of the James Webb Telescope, the number grew exponentially and today NASA tells us they have “confirmed over 5,600 exoplanets out of the billions that we believe exist”.
Exo-planets or not, the search for other life and habitable planets – whether inside the earth’s Solar System or not – gathered pace last year with the launch of European Space Agency's JUICE spacecraft on an eight-year journey through our Solar System to discover whether Jupiter's icy moons are capable of hosting extraterrestrial life in their vast, hidden oceans. Europa, Ganymede and Callisto, Jupiter’s three icy moons, were first discovered by Galileo more than 400 years ago (they are sometimes referred to as the Galilean moons though Galileo himself called them the “Medicean Stars”)!
Previous space probes have suggested that deep below their icy shells, there are huge oceans of liquid water, the main ingredient for life as we know it. That has made Ganymede and Europa prime candidates in the search for life in our celestial backyard. On top of that, Ganymede is our Solar System's largest moon and the only one that has its own magnetic field, which protects it from radiation.
Because the spacecraft lacks the power to fly straight towards Jupiter, it will have to slingshot around other planets to get a gravitational boost and is expected to arrive in Jupiter in 2031!
Outside of our solar system, the search for habitable zones amongst exoplanets have revolved around finding conditions neither too cold nor too hot to allow liquid water to exist on the planet’s surface, the so-called “Goldilocks” conditions. In 2019 two independent scientific teams found discoveries of water in the atmosphere of k2-18b, and even more interestingly, evidence of clouds - and of rain, while the exoplanet LHS 1140b is found to be a promising "super-Earth" with signs of the possible presence of an atmosphere and an ocean while also being relatively close to our solar system. And then there’s Kepler-452b which is not only Goldilocks but also of a size very similar to Earth (size also matters as a too-small planet can’t maintain an atmosphere and a too-large one will have a crushing atmosphere), hence being referred to as Earth 2.0.