🚀 Space
6,316 Exoplanets. 45 Rocky Candidates. 1 Confirmed Atmosphere. The $450,000 Question Nobody Is Asking.
A ground-based telescope in Chile confirmed the first atmosphere on a rocky habitable-zone exoplanet in 6.5 hours for roughly $10,000. Screening all 45 known rocky candidates would cost $450,000. Finding out what those atmospheres contain starts at $500,000 per planet.
Ten thousand dollars. That is roughly what it cost, in telescope time, to confirm the first atmosphere ever detected on a rocky planet in the habitable zone of another star.
On July 16, Collin Cherubim and colleagues at Harvard published a paper in Science reporting helium escaping from LHS 1140 b, a super-Earth 49 light-years away in the constellation Cetus, using the 6.5-meter Magellan Clay telescope at Las Campanas Observatory in Chile for 6.5 hours across two sessions, not the James Webb Space Telescope but a ground-based mirror in the Atacama pointed at a star so dim it radiates half a percent of the Sun's luminosity.
"This is the first time anyone has found an atmosphere on a rocky planet in the habitable zone of another star," Cherubim told USA Today.
What makes that sentence land is not the superlative but the denominator. As of July 2, the NASA Exoplanet Archive lists 6,316 confirmed exoplanets. A Cornell team catalogued 45 of those as rocky worlds in their stars' habitable zones. Of those 45, exactly one now has a confirmed atmosphere, a hit rate of 2.2 percent that raises an obvious question: what would it cost to screen the other 44?
The Screening Hierarchy
Not all questions about a planet cost the same to answer.
| Level | Question | Method | Cost / planet | Total (45 planets) |
|---|---|---|---|---|
| 1 | Does an atmosphere exist? | Ground-based helium spectroscopy (1083 nm) | ~$10,000 | ~$450,000 |
| 2 | What is it made of? | JWST transmission spectroscopy (20+ hrs) | $500K–$2M | $22–90M |
| 3 | Are there biosignatures? | ELT / HWO (hundreds of hrs) | $5–50M | Top 5–10 only |
| 4 | Is it actually habitable? | Direct imaging, next-gen missions | Unknown | Decades away |
Magellan Clay consortium time costs approximately $1,000 to $2,000 per hour, so Cherubim's 6.5-hour detection ran between $6,500 and $13,000. Multiply across all 45 rocky habitable-zone candidates: $450,000 total, less than NASA spends on a single day of JWST operations.
JWST runs at roughly $26,000 per hour in operating costs ($170 million annual budget per NASA's FY2026 request, 6,500 hours of science time per STScI Cycle 4 allocation), or $77,000 per hour on a lifecycle basis ($10 billion over 20 years). LHS 1140 b alone required at least four transit observations across two instruments (NIRISS and NIRSpec), consuming 20 to 32 hours, and that yielded only tentative evidence of a nitrogen-dominated atmosphere. Cost per planet at Level 2: $520,000 to $2.5 million.
Level 3 is where the economics collapse. Detecting biosignatures like molecular oxygen or methane requires dozens to hundreds of transits at 10 to 20 ppm signal strength, each lasting about 75 minutes and recurring every 24.74 days, meaning a hundred transits would take nearly seven years of monitoring for one planet. Only five to ten of the nearest targets are bright enough to attempt. Screening for atmospheric existence is cheap; characterizing what we find is the bottleneck nobody is funding.
What They Actually Found
LHS 1140 b is not Earth, though it nearly matches Earth's density (5.9 g/cm³ versus 5.5). Seventy percent larger in radius and 5.6 times heavier, it orbits an M4.5V red dwarf every 24.74 days, tidally locked so that one hemisphere permanently faces the star while the other stays frozen. Climate models predict a circular liquid ocean on the sunlit side ringed by ice, which is why astronomers call it the "Eyeball planet."
Cherubim's model predicted before the observation that LHS 1140 b would be a "helium world," a proposed but previously unidentified class of planet with a helium-dominated upper atmosphere and oxidizing species at lower altitudes. His observation confirmed escaping helium, and his interpretation is direct: "The new data from my study are consistent with my prediction that it's a new class of planet." Sukrit Ranjan at the University of Arizona added necessary context: "It might be habitable, but not in a conventional sense," because surface pressures on a helium world could resemble ocean floors.
The Vanishing Signal
Here is the part that should give everyone pause. Cherubim's team observed LHS 1140 b twice with identical equipment; in 2024 the metastable helium line appeared clearly, and in 2025 it vanished. An independent reanalysis confirmed the split, and nobody fully understands why. "When you make a measurement of escaping helium and then you go back and look at it months and years later, it is usually different and sometimes it isn't there," he told New Scientist. Shifting stellar activity or an asymmetric outflow tail crossing the line of sight at unpredictable intervals could explain the variability.
Natalie Allen at Johns Hopkins raised the Venus comparison at full force: "Earth and Venus are very similar in size and both have atmospheres, but Venus's surface isn't habitable." Unpublished JWST data on LHS 1140 b could determine the bulk composition, but remains unreleased.
What Comes Next
Scale transforms every number in the table above. The European Extremely Large Telescope, due around 2028, will carry a 39.3-meter mirror with (39.3 / 6.5)² = 36.5 times the Magellan Clay's collecting area, extending the helium screening horizon from about 50 light-years to roughly 300. Because volume scales as the cube of distance, the reachable M-dwarf pool expands from about 1,000 to 48,000, and at Kepler occurrence rates of 0.16 rocky habitable-zone planets per M-dwarf the target list could grow from 45 to several hundred.
Limitations
Telescope costs use estimated consortium rates ($1,000 to $2,000 per hour) that vary by institution; JWST hourly costs derive from NASA's FY2026 budget and STScI's reported science hours, with lifecycle amortization assuming 20 years. Not all 45 rocky habitable-zone planets orbit stars bright enough for current ground-based helium detection, so the $450,000 total is a theoretical upper bound. Most critically, this rests on a single positive observation not reproduced on follow-up, helium confirms only that an atmosphere exists rather than that it supports life, and M-dwarf host stars dominate the catalog because their small size makes transiting planets easier to detect, biasing the sample toward tidally locked worlds under intense ultraviolet radiation.
The Bottom Line
Forty-nine light-years away, a rocky planet slightly larger than Earth is leaking helium into space, and a recent Harvard PhD confirmed it in one night for less than a used Honda Civic. Screening every known rocky habitable-zone candidate for atmospheric existence would run $450,000, roughly what NASA spends on a single day of JWST operations, and no funded survey program has been announced.
If you have access to a 6-meter-class telescope, the Bohl et al. catalog of 45 rocky habitable-zone targets is your survey list, and 300 hours of allocation could screen the roughly thirty that are bright enough for current ground-based detection before the ELT comes online. If you work in science funding, no funded survey program has been announced, and the entire Level 1 effort costs less than administering a single JWST proposal cycle. And if you are watching the search for extraterrestrial life, track the unpublished JWST data on LHS 1140 b, which will tell us whether this helium world harbors water, carbon dioxide, or anything resembling a chemistry friendly to biology. Confirming the atmosphere cost $10,000; learning what it means will cost 50 times more.