Finding another planet outside of our solar system that can comfortably be called ‘Earth-like’ is one of those discoveries that — if confirmed — would be a major event. The complication here is that with every exoplanet that we discover through observations, determining the type of planet is hard enough, never mind figuring out whether it has an atmosphere, much less what’s in that atmosphere. This makes a recent report on LHS 1140 b rather exciting, as it strongly suggests that this super-Earth may have something close to an Earth-like atmosphere.
In the paper by [Collin Cherubim] and others in Science, the findings of helium occasionally escaping from its atmosphere have led to considerable excitement, as this time-variable atmospheric escape of helium suggests a helium-rich upper atmosphere that’s further depleted in hydrogen.
It should be noted, of course, that these assumptions are based on observations from roughly 49 light-years away, so there’s always some room for later adjustments. Even if confirmed, the star that LHS 1140b orbits is a red dwarf, with a nearly 25-day orbital period and light levels less than half of what Earth receives from the Sun. This would make the surface of LHS 1140b with its proposed oceans rather dim, even if it’s conceivably at temperatures well within the comfort range of us Earth-based mammals.
At 49 light-years distance, it’s also not close enough that — barring an FTL drive — we could do direct observations or visitations, but if these results hold, it’d be on the short list along with a number of other plausibly habitable exoplanets to check out once we build that first warp drive-powered starship.
Here on earth natural accumulations of helium are the result of radioactive decay. Maybe we shouldn’t focus our planet search on those planets that have so much of it that you can detect it from here.
No, on Earth it’s because that’s all that’s left over: the early atmosphere has lost all its helium (the hydrogen bonded, the helium just escapes).
This is a much more massive planet (5.6x Earth and 1.7x radius so about 50-60% higher surface gravity) so the helium retention time would be much longer.
And it’s not that there’s a lot of helium, but because helium escapes, it’s easier to detect since it’s over a larger area. The key isn’t the helium, it’s that there’s an atmosphere at all.
I’ve always been amazed at the pull-a-rabbit-out-of-a-hat nature of these long distance astronomical measurements. I’d dare brand it “1D astronomy,” where essentially you are trying to glean profound data from a single pixel over a long period of time.
Good point. I’ve put some effort into imagining the colonization of an “earthlike” planet, and it always seems like a stretch unless first you “terraform” before sending humans. A resource as seemingly simple as soil is complex enough to keep PhDs busy studying its mystery her at home. If you can’t do agriculture, I’d hardly call it habitable.
We’re not even able as a species to safeguard our living here and mitigate the effects of climate change so terra forming anything that is so far and such a long-term goal is clearly out of reach.
LHS 1140b is an exoplanet that has five times the mass of the Earth and 1.73 times Earth’s radius. LHS 1140b orbits a small red dwarf star every 24 days at a distance of <0.1 AU. It is also likely that the rotation of LHS 1140b is tidally locked.
LHS 1140b is NOT an “Earth-like” planet!
this tells us something about the state of the art of long distance imaging and interpretation but i’d be surprised if it tells us anything about a specific planet.
If our world was in a better place, I feel we’d be sending probes all over even if it was expected for them to take decades or centuries to teach us anything.
I’d love to see us regularly putting our state-of-the-art into work to see how much farther we can fly, how much farther we can communicate and how much faster we can do it.