Scientists Have Spotted Some of the Most Earth-Like Exoplanets Yet

Friday, 29 June 2018 - 12:29PM
Astronomy
Space
Alien Life
Friday, 29 June 2018 - 12:29PM
Scientists Have Spotted Some of the Most Earth-Like Exoplanets Yet
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Image Credit: Pixabay
To get an idea of just a few of the requirements for a habitable, Earth-like planet, here's a short list: it has to orbit its star at the right distance (the 'Goldilocks' zone), the star has to be relatively stable, the planet has to be small and rocky, and there has to be a stable, resilient atmosphere to block out all the cosmic radiation. On top of this, exoplanet researchers have found that there's one more necessity: a stable planetary tilt. Luckily for scientists, two planets have identified that fit most of these requirements—Kepler-186f and Kepler-62f.

Kepler-62f used to be the most most Earth-like planet on record until 186f was discovered, but both share a common trait: the axial "tilt" of each planet doesn't change much over time. While this may seem like a relatively minor factor, it has a huge impact on the habitability of a planet—just take Mars as an example. "Mars is in the habitable zone in our solar system, but its axial tilt has been very unstable-varying from zero to 60 degrees," according to Gongjie Li, an Assistant Professor at Georgia Tech. "That instability probably contributed to the decay of the Martian atmosphere and the evaporation of surface water."

For comparison, the tilt of the Earth varies from 22.1 and 24.5 degrees. One of the factors that can influence this tilt is the gravity of other nearby planets and celestial bodies. 22.1 and 24. According to Li: "It appears that both exoplanets are very different from Mars and the Earth because they have a weaker connection with their sibling planets. We don't know whether they possess moons, but our calculations show that even without satellites, the spin axes of Kepler-186f and 62f would have remained constant over tens of millions of years."

With stable axes, Kepler-62f and Kepler-186f may be excellent hosts for life. The only problem is that both are at least 500 light-years away, and travelling to even the closest exoplanet (Proxima Centauri b) will take, oh, about 6,300 years.

For an interactive view of our solar system, take a look at the infographic below (clickable).

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