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The search for signs of life on exoplanets at the interface of chemistry and planetary science.

Seager S, Bains W - Sci Adv (2015)

Bottom Line: The discovery of thousands of exoplanets in the last two decades that are so different from planets in our own solar system challenges many areas of traditional planetary science.However, ideas for how to detect signs of life in this mélange of planetary possibilities have lagged, and only in the last few years has modeling how signs of life might appear on genuinely alien worlds begun in earnest.Recent results have shown that the exciting frontier for biosignature gas ideas is not in the study of biology itself, which is inevitably rooted in Earth's geochemical and evolutionary specifics, but in the interface of chemistry and planetary physics.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. ; Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

ABSTRACT
The discovery of thousands of exoplanets in the last two decades that are so different from planets in our own solar system challenges many areas of traditional planetary science. However, ideas for how to detect signs of life in this mélange of planetary possibilities have lagged, and only in the last few years has modeling how signs of life might appear on genuinely alien worlds begun in earnest. Recent results have shown that the exciting frontier for biosignature gas ideas is not in the study of biology itself, which is inevitably rooted in Earth's geochemical and evolutionary specifics, but in the interface of chemistry and planetary physics.

No MeSH data available.


Related in: MedlinePlus

Simulated spectra of small exoplanet atmospheres.Reflected light spectra are presented in units of planet-to-star flux ratio and are of the spectral resolution anticipated for exoEarths with future space-based starlight-suppression capable telescopes. The Earth spectrum is a model developed to match Earth observations from the EPOXI mission (105), whereas the super-Earth is that model scaled by (1.5 R⊕/1 R⊕)2. The Venus spectrum is a model from the Virtual Planet Laboratory (VPL; http://depts.washington.edu/naivpl/). The Archean Earth spectrum is a model of the inhabited Earth before the rise of oxygen in its atmosphere (87). The sub-Neptune (“mini-Neptune”) model is a 2.5 R⊕ Neptune-like planet at 2 AU from a solar-twin star (R. Hu, personal communication). The spectra have been convolved to R = 70 spectral resolution and binned with two pixels per resolution element (Nyquist sampling). Figure courtesy of A. Roberge.
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Figure 2: Simulated spectra of small exoplanet atmospheres.Reflected light spectra are presented in units of planet-to-star flux ratio and are of the spectral resolution anticipated for exoEarths with future space-based starlight-suppression capable telescopes. The Earth spectrum is a model developed to match Earth observations from the EPOXI mission (105), whereas the super-Earth is that model scaled by (1.5 R⊕/1 R⊕)2. The Venus spectrum is a model from the Virtual Planet Laboratory (VPL; http://depts.washington.edu/naivpl/). The Archean Earth spectrum is a model of the inhabited Earth before the rise of oxygen in its atmosphere (87). The sub-Neptune (“mini-Neptune”) model is a 2.5 R⊕ Neptune-like planet at 2 AU from a solar-twin star (R. Hu, personal communication). The spectra have been convolved to R = 70 spectral resolution and binned with two pixels per resolution element (Nyquist sampling). Figure courtesy of A. Roberge.

Mentions: Exoplanet atmospheres are the key for life detection on a planet beyond our solar system. The premise is that life produces gases as by-products to metabolism, and that some of the gases will accumulate in a habitable planet atmosphere and in principle can be detected by spectroscopy (Fig. 2). However, we must be able to characterize exoplanet atmospheres to make any progress. Here, our understanding has advanced greatly in the last 20 years, but we are severely limited as to the underlying raw data we can collect from something as small as a shell of gas a few hundred kilometers thick around a faint planet tens of trillions or more kilometers away, where the faint planet is dwarfed by the brightness of the adjacent host star.


The search for signs of life on exoplanets at the interface of chemistry and planetary science.

Seager S, Bains W - Sci Adv (2015)

Simulated spectra of small exoplanet atmospheres.Reflected light spectra are presented in units of planet-to-star flux ratio and are of the spectral resolution anticipated for exoEarths with future space-based starlight-suppression capable telescopes. The Earth spectrum is a model developed to match Earth observations from the EPOXI mission (105), whereas the super-Earth is that model scaled by (1.5 R⊕/1 R⊕)2. The Venus spectrum is a model from the Virtual Planet Laboratory (VPL; http://depts.washington.edu/naivpl/). The Archean Earth spectrum is a model of the inhabited Earth before the rise of oxygen in its atmosphere (87). The sub-Neptune (“mini-Neptune”) model is a 2.5 R⊕ Neptune-like planet at 2 AU from a solar-twin star (R. Hu, personal communication). The spectra have been convolved to R = 70 spectral resolution and binned with two pixels per resolution element (Nyquist sampling). Figure courtesy of A. Roberge.
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Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4643826&req=5

Figure 2: Simulated spectra of small exoplanet atmospheres.Reflected light spectra are presented in units of planet-to-star flux ratio and are of the spectral resolution anticipated for exoEarths with future space-based starlight-suppression capable telescopes. The Earth spectrum is a model developed to match Earth observations from the EPOXI mission (105), whereas the super-Earth is that model scaled by (1.5 R⊕/1 R⊕)2. The Venus spectrum is a model from the Virtual Planet Laboratory (VPL; http://depts.washington.edu/naivpl/). The Archean Earth spectrum is a model of the inhabited Earth before the rise of oxygen in its atmosphere (87). The sub-Neptune (“mini-Neptune”) model is a 2.5 R⊕ Neptune-like planet at 2 AU from a solar-twin star (R. Hu, personal communication). The spectra have been convolved to R = 70 spectral resolution and binned with two pixels per resolution element (Nyquist sampling). Figure courtesy of A. Roberge.
Mentions: Exoplanet atmospheres are the key for life detection on a planet beyond our solar system. The premise is that life produces gases as by-products to metabolism, and that some of the gases will accumulate in a habitable planet atmosphere and in principle can be detected by spectroscopy (Fig. 2). However, we must be able to characterize exoplanet atmospheres to make any progress. Here, our understanding has advanced greatly in the last 20 years, but we are severely limited as to the underlying raw data we can collect from something as small as a shell of gas a few hundred kilometers thick around a faint planet tens of trillions or more kilometers away, where the faint planet is dwarfed by the brightness of the adjacent host star.

Bottom Line: The discovery of thousands of exoplanets in the last two decades that are so different from planets in our own solar system challenges many areas of traditional planetary science.However, ideas for how to detect signs of life in this mélange of planetary possibilities have lagged, and only in the last few years has modeling how signs of life might appear on genuinely alien worlds begun in earnest.Recent results have shown that the exciting frontier for biosignature gas ideas is not in the study of biology itself, which is inevitably rooted in Earth's geochemical and evolutionary specifics, but in the interface of chemistry and planetary physics.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. ; Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

ABSTRACT
The discovery of thousands of exoplanets in the last two decades that are so different from planets in our own solar system challenges many areas of traditional planetary science. However, ideas for how to detect signs of life in this mélange of planetary possibilities have lagged, and only in the last few years has modeling how signs of life might appear on genuinely alien worlds begun in earnest. Recent results have shown that the exciting frontier for biosignature gas ideas is not in the study of biology itself, which is inevitably rooted in Earth's geochemical and evolutionary specifics, but in the interface of chemistry and planetary physics.

No MeSH data available.


Related in: MedlinePlus