The hunt for Earth-like planets came home
The new website lets anyone with a computer build an Earth-like planet with an impressive array of options to show the public how many exoplanets discovered by astronomers lauded as "Earth-like" might not look very familiar, after all.
"It is very tempting to think that an Earth-sized planet is like our habitable Earth," said Kana Ishimaru, a graduate student at the University of Arizona, to Space.com via email. "But changing one property of the planet can affect the environment significantly."
Ishimaru led the development of the website called "Earth-like," along with the Twitterbot of same name while she was still an undergraduate student at the University of Tokyo. Surfing the website, users may adjust factors like land-sea ratio and volcanism of the experimental planet, and also where it orbits in the habitable zone of its hypothetical host star.
The habitable zone is the distance within which a planet can form liquid water that remains on its surface. Small shifts in orbital position can radically reshape a would-be Earth 2.0 into just another Mars.
Making virtual worlds to understand habitability
Combining the thousands of exoplanets unveiled in the depths of space by NASA's Kepler Space Telescope and the bountiful riches many expect the Transiting Exoplanet Survey Satellite (TESS) to discover — not to mention worlds found by other instruments — many of which have showed sufficient promise to earn the term "Earth-like" from astronomers.
However, the complicated factors at play in a rocky world's evolution can easily send a proto-Earth 2.0 careening into planetary conditions that are not friendly or nice. Take Venus — a planet named after the Greek Goddess of love and sex — and at times so hot that its atmosphere melts lead.
Elizabeth Tasker — Ishimaru's advisor — had worries that distant exoplanets discovered by space telescopes and Earth-bound instruments are too-often viewed as true Earth twins; identical in their ability to support life and evolution, when in fact they are usually more likely to be inhospitable to human life.
With this worry in mind, Tasker built a website where anyone could visually analyze how minute changes in planetary conditions would drastically alter its habitability.
"Given we currently know the radius or mass [or both] for most of the Earth-sized exoplanets we've discovered, their surfaces could be wildly different from our own home world," said Tasker, in an email to Space.com.
As the hunt for Earth 2.0 carries on, it's good to withhold judgment on every successive Earth-sized exoplanet discovered because, no matter how close to another world seems to the layman, we can see how easily a rocky world can differ vastly from the pale blue dot we call home.