Cornell University | 2020 Mar 26
Cornell astronomers have created five models representing key points from our planet’s evolution, like chemical snapshots through Earth’s own geologic epochs.
They will use them as spectral templates in the hunt for Earth-like planets in distant solar systems in the approaching new era of powerful telescopes. ...
“Using our own Earth as the key, we modeled five distinct Earth epochs to provide a template for how we can characterize a potential exo-Earth – from a young, prebiotic Earth to our modern world,” she said. “The models also allow us to explore at what point in Earth’s evolution a distant observer could identify life on the universe’s ‘pale blue dots’ and other worlds like them.”
Kaltenegger and her team created atmospheric models that match the Earth of 3.9 billion years ago, a prebiotic Earth, when carbon dioxide densely cloaked the young planet. A second throwback model chemically depicts a planet free of oxygen, an anoxic Earth, going back 3.5 billion years. Three other models reveal the rise of oxygen in the atmosphere from a 0.2% concentration to modern-day levels of 21%. ...
High-Resolution Transmission Spectra of Earth through Geological Time ~ Lisa Kaltenegger, Zifan Lin, Jack Madden
- Astrophysical Journal Letters 892(1):L17 (2020 Mar 20) DOI: 10.3847/2041-8213/ab789f
- arXiv.org > astro-ph > arXiv:1912.11149 > 24 Dec 2019