Space & astronomy · the experiment
Deliver the cyanide intact
Comets loaded with hydrogen cyanide, an atmosphere that filters, scorching impacts and 100,000 simulated histories of the young Earth. Four questions, from beginner to expert.
1 · Count the successful deliveries
Beginner
In more than half of the 100,000 simulated histories, how many comets deliver at least 10 millimoles per litre of HCN onto dry land?
2 · Measure the gap with the lab
All the HCN delivered intact by comets, spread through one Earth ocean, would reach about 0.75 micromoles per litre. Laboratory recipes need about 10 millimoles per litre.
Intermediate
How many times too dilute would that HCN be?
3 · Explain the Martian edge
Mars receives about 5 times fewer comets than Earth. Yet, without accounting for dry land, it records 744 successful impacts, against 87 for Earth.
Expert
What explains the gap?
4 · Time the birth of life
The paper's toy model: if a successful impact is required, the expected time for life to emerge is τ_ool ≃ T_imp / (p_abio × τ_HCN). T_imp ≈ 500 million years is the length of the intense bombardment, p_abio the probability of life emerging per unit time, τ_HCN how long the HCN stays concentrated enough.
Take the most generous values: p_abio = 10³ per billion years, and τ_HCN = 10 years, the time water stays in a crater lake.
Expert
What is τ_ool?
Cyanide delivered… or not
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