Astronomers have flagged a distant world, Kepler-442 b, as potentially more hospitable than our own planet — at least according to a new habitability rating system. Discovered by the Kepler Space Telescope, this rocky exoplanet lies some 1,200 light-years away and orbits within the habitable zone of its star. By one index, it earns a score of 0.836, slightly higher than Earth’s 0.829, suggesting a compelling target for future study.
Here’s a closer look at what this means — and what it doesn’t.
—
What is Kepler-442 b?
Kepler-442 b is a confirmed exoplanet orbiting a K-type star (designated Kepler-442) in the constellation Lyra. It was discovered through the transit method by the Kepler mission and announced in early 2015.
Some key facts:
Distance: roughly 1,196 light-years (≈ 367 parsecs) from Earth.
Size: radius about 1.34 times that of Earth.
Orbit: about 112.3 days around its star at ~0.409 AU.
Temperature: equilibrium temperature approximated at 233 K (-40 °C) though actual surface temperature could vary widely.
Because of its size and position in the habitable zone (where liquid water might exist), Kepler-442 b has been labelled one of the more promising “Earth‐like” exoplanets.
—
The habitability index: What is it?
In 2015, researchers introduced an index to compare the habitability potential of transiting exoplanets — published in the paper “Comparative Habitability of Transiting Exoplanets”.
This index takes into account several observable factors:
Whether the planet is likely rocky (rather than gaseous)
The amount of star-light (flux) the planet receives
The shape of the orbit (eccentricity) and how that affects climate stability
The planet’s albedo (reflectivity) and how that affects net energy
Other orbital/stellar properties that impact how stable and “Earth-friendly” conditions might be.
On this scale, Earth is given a baseline value of 0.829; Kepler-442 b scores 0.836. That gives the appearance of it being “more habitable than Earth” by this metric.
—
Why the score matters — and why it doesn’t
The higher score for Kepler-442 b is intriguing, but it comes with several important caveats.
Why it matters:
It means that, from what we can observe, Kepler-442 b ticks more of the boxes (rocky composition, appropriate flux, stable orbit) than some other exoplanet candidates.
It helps scientists prioritise where to focus limited observational resources (telescopes, spectroscopy, future missions) by ranking likely promising worlds.
It highlights how habitability is not simply “in the habitable zone” but depends on multiple interacting factors.
Why it doesn’t mean “move there tomorrow”:
We simply don’t know key properties of Kepler-442 b — its atmosphere composition, surface pressure, magnetic field, presence of liquid water, geology, etc. As one expert put it: “It says nothing about if the planet could be ‘inhabited’. Just because a planet is habitable doesn’t mean it is inhabited.”
The index uses observable proxies and estimates, not direct surface observations. So while it improves on older methods, it still depends on assumptions.
The distance is enormous (≈1,200 light-years) — meaning it is far beyond current human reach and detailed characterisation.
“More favourable conditions” by the index does not equal “better than Earth” in every way — Earth has biosphere, stable climate, known life, etc, which we cannot assume elsewhere.
—
What this means for the search for life
The case of Kepler-442 b illustrates how exoplanet science is moving beyond simplistic “habitable zone” labels and into more nuanced habitability metrics. It shows that we can rank worlds, compare them to Earth, and refine targets.
However, the next steps require more detailed observations:
Can we detect an atmosphere on Kepler-442 b?
What is its surface pressure and temperature range?
Is liquid water present?
Does it have a protective magnetic field and long-term climate stability?
Until those questions are addressed, the habitability index score is best viewed as a guide, not a guarantee. The authors of the index themselves caution that higher values do not equate to “more habitable” in a human sense.
—
In summary
Kepler-442 b is a rocky exoplanet about 1,200 light-years away, orbiting in its star’s habitable zone.
According to a 2015 habitability index, it scores 0.836, slightly above Earth’s 0.829.
The score reflects favourable observable factors, but does not prove the planet is inhabited or fully like Earth.
The finding helps prioritise future studies of exoplanets, but emphasises how much there is yet to learn.
As we continue to discover more worlds and refine our methods, Kepler-442 b stands out as a tantalising target. Yet our home planet remains the only confirmed world with life — and that benchmark remains humbling and inspiring.
Source:
Wikipedia – Kepler-442 b. (Information on habitability index and scores)
Newsweek – Fact Check: Did astronomers find a planet more habitable than Earth? (Explanation of index, caveats)
WIRED UK – Kepler-442 b is more habitable than Earth (Original article on habitability index)