Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Science. 1997 May 23;276(5316):1217-21.

The early faint sun paradox: organic shielding of ultraviolet-labile greenhouse gases

Author information

  • 1Laboratory for Planetary Studies, Cornell University, Ithaca, NY 14853-6801, USA.
  • 2Cornell U, Ithaca, NY

Abstract

Atmospheric mixing ratios of approximately 10(-5 +/- 1) for ammonia on the early Earth would have been sufficient, through the resulting greenhouse warming, to counteract the temperature effects of the faint early sun. One argument against such model atmospheres has been the short time scale for ammonia photodissociation by solar ultraviolet light. Here it is shown that ultraviolet absorption by steady-state amounts of high-altitude organic solids produced from methane photolysis may have shielded ammonia sufficiently that ammonia resupply rates were able to maintain surface temperatures above freezing.

Comment in

PMID:
11536805
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Write to the Help Desk