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Posted: July 22nd, 2015, 11:20 am
by Christopher K.
In the famous 1980 miniseries Cosmos the late Carl Sagan noted that plants existed for quite some time on Earth before animals came into being. He then hypothesized that there may be numerous planets with plant life, whereas the big intelligent things like ourselves may be "comparatively rare".

Interestingly, detection of plant life may be a lot easier than determining whether a faraway world is another animal abode. Is it possible to use spectroscopy to analyze an exoplanet's atmosphere for biosignatures?

With an April 2008 Scientific American article penned by Nancy Kiang was a sidebar mentioning different biosignatures that might be signs of life. Some mentioned were...
*oxygen with water: A little oxygen can exist on planets with no life, but a lot of oxygen would probably be produced only by photosynthesis.
*ozone: Ozone is recombined oxygen previously split by radiation.
*methane with oxygen (especially a rate that changes with seasons): Methane levels are steady on a lifeless planet, but if it fluctuates with the passing seasons, there could be life.
*nitrous oxide: This is released when plant matter decays. Only a very little nitrous oxide can be made without life (for example, during lightning strikes).

About Dr. Kiang:

Re: Biosignatures

Posted: September 23rd, 2015, 4:57 pm
by Christopher K.
Tomorrow at 3:40pm in 109 Nicholson, LSU physics professor Juhan Frank will introduce Ravi Kopparapu of the Goddard Space Flight Center. Dr. Kopparapu will present "Habitable Zones and the Occurrence of Potenial Habitable Planets in Our Galaxy". The first part of the lecture will cover his research group's contribution to the search for habitable exoplanets. The last part will give an overview of progress made so far towards finding rocky planets in the habitable zones of stars.

More information: ... arapu.html

About Ravi Kopparapu:

Re: Biosignatures

Posted: October 19th, 2015, 12:20 pm
by Christopher K.
Currently in progress is a presentation at the National Air and Space Museum entitled "Exploring Alien Atmospheres". This presentation is being broadcast live on NASA-TV1 and NASA-TV2. (It's part of the "What's New in Aerospace" series.)

Re: Biosignatures

Posted: November 17th, 2017, 12:12 pm
by Christopher K.
Currently in progress on both NASA-TVs is a live broadcast of a program at the University of Wyoming entitled "Next Steps in the Search for Habitable Worlds". Five researchers will be discussing the concept of habitability in relation to exoplanets, how a star influences a planet’s habitability, why we are focusing on Earth-like planets and the possible physical appearance of living creatures on other worlds.

This one-hour discussion will be rerun on both NASA-TVs at the following times...
*Friday 17 November = 3pm CST, 7pm CST
*Saturday 18 November = 12pm CST, 4pm CST
*Sunday 19 November = 8am CST, 1pm CST

More information: ... nasa-event