Skip to main content Accessibility help
×
Home
Hostname: page-component-8bbf57454-gwkvl Total loading time: 0.562 Render date: 2022-01-25T14:15:39.635Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": true, "newCiteModal": false, "newCitedByModal": true, "newEcommerce": true, "newUsageEvents": true }

15 - Atmospheric Signatures

from Part IV - Discovering Life

Published online by Cambridge University Press:  24 September 2020

Wallace Arthur
Affiliation:
National University of Ireland, Galway
Get access

Summary

Here, I look at the concept of a biosignature. The presence of certain gases in a planet’s atmosphere may represent signatures of life-forms. Oxygen is of particular interest. However, while finding a high concentration of oxygen would be suggestive of life, it would not be conclusive if abiotic means of maintenance could be envisaged. Since studies of exoplanet atmospheres are in their infancy, I start in the better-known realm of our solar system, and look at the atmospheres of planets without life, to see the extent to which these vary. Both Mars and Venus have more than 95% carbon dioxide. In contrast, the only solar-system moon to have an atmosphere – Saturn’s Titan – has more than 95% nitrogen. Mercury has virtually no atmosphere. No body in our system has a significant fraction of oxygen except Earth, with about 20%. I examine the techniques of spectroscopy and show how they allow us to see the signatures of particular gases. Then I mention some recent exoplanetary results – such as detection of atmospheric sodium. Finally, I look at proposed direct-imaging space telescopes, notably NASA’s HabEx and LUVOIR, which, if approved, will be missions of extraordinary importance.

Type
Chapter
Information
The Biological Universe
Life in the Milky Way and Beyond
, pp. 236 - 254
Publisher: Cambridge University Press
Print publication year: 2020

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Send book to Kindle

To send this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

  • Atmospheric Signatures
  • Wallace Arthur, National University of Ireland, Galway
  • Book: The Biological Universe
  • Online publication: 24 September 2020
  • Chapter DOI: https://doi.org/10.1017/9781108873154.020
Available formats
×

Send book to Dropbox

To send content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Dropbox.

  • Atmospheric Signatures
  • Wallace Arthur, National University of Ireland, Galway
  • Book: The Biological Universe
  • Online publication: 24 September 2020
  • Chapter DOI: https://doi.org/10.1017/9781108873154.020
Available formats
×

Send book to Google Drive

To send content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Google Drive.

  • Atmospheric Signatures
  • Wallace Arthur, National University of Ireland, Galway
  • Book: The Biological Universe
  • Online publication: 24 September 2020
  • Chapter DOI: https://doi.org/10.1017/9781108873154.020
Available formats
×