Can We Detect Signs of Life on Exoplanets Using Spectral Analysis?

  • Thread starter cph
  • Start date
In summary, the conversation discusses the potential for detecting oxygen signatures and optical flashes in our atmosphere as signs of photosynthesis and technological civilizations from afar. It also explores the effectiveness of this method compared to radio wave detection and the idea of using the Kardashev scale to search for astro-engineering products like Dyson Spheres. The conversation also mentions the challenges and possibilities of using the transit method to detect Earth-like planets and analyze their atmospheres. Overall, the conversation highlights the ongoing search for extraterrestrial life and the various methods being used to detect it.
  • #1
cph
43
0
How far away can the oxygen signature in our atmosphere be detected? Indicative of photosynthesis. How far away can optical flashes from spaceships/satellites in Moon orbit be detected? A sign of technological civilization from afar. Is this much more effective than radio wave detection?
 
Astronomy news on Phys.org
  • #2
I suppose it would depend upon the sensitivity of the instruments used by that technological civilization. Right now, I would guess our technology is better suited to detecting faint radio signals rather than oxygen signatures or optical flashes (which is why we use radio).
 
  • #3
One of the interesting ideas in ET life detection is based on the Kardashev scale - in that the more a species grows the deeper its energy requirements become. Until it is eventually hypothesized they would need the entire output of a star. The detection of a Dyson Sphere or other large body equivalent is, in my opinion, as good a method of detection as SETI.

Just my two cents worth
 
  • #4
Cosmo Novice said:
The detection of a Dyson Sphere or other large body equivalent is, in my opinion, as good a method of detection as SETI.

The search for astro-engineering products like Dyson Spheres is actually part of SETI (e.g. http://www.sciencedirect.com/science/article/pii/S0094576598000150) but currently it is as unsuccessful as the search for “intelligent” radio signals. Maybe the search programs covered the wrong temperature range. I already found publications for temperature starting from 100 K (http://iopscience.iop.org/0004-637X/698/2/2075/pdf/0004-637X_698_2_2075.pdf) but I would expect Dyson Spheres to be much colder because the degree of efficiency of the energy conversion increases with decreasing outer temperature. I already tried to perfom an own search but I wasn’t able to eliminate the Zodiacal light from the IRAS data (Does anybody know how to do that?).

I would also expect that Dyson Spheres could be detected not only by their thermal radiation but also by artificial emissions. If there are structures orbiting the sphere there would be focused transmissions for communication and power supply. If parts of these transmissions miss their target they could be detected from Earth (e.g. as optical flashes as mentioned by cph). But currently there seems to be no evidence for such signals (http://frank.harvard.edu/~howard/papers/sleague.pdf).
 
Last edited by a moderator:
  • #5
cph said:
How far away can the oxygen signature in our atmosphere be detected? Indicative of photosynthesis. How far away can optical flashes from spaceships/satellites in Moon orbit be detected? A sign of technological civilization from afar. Is this much more effective than radio wave detection?
The Earth and moon would be lost in the sun. One has to think in terms of light years.

Consider the solid angle subtended by the earth, Jupiter and Saturn. Which has the most impact on the sun's light at 1+ ly?
 
  • #6
Astronuc said:
The Earth and moon would be lost in the sun.

I'm not sure about that. Earthlike planets can be detected using the transit method. During the passage of the planet the light of its star is not only covered by the planet. A small fraction of the light will pass the planets atmosphere and might reach Earth. Then we will not only see a decrease of brightness but also additional absorption lines in the spectra of the star - carrying information about the composition of the atmosphere. Of course a successful spectral analysis will require a very high precision but this is a technical problem that might be solved in near future.
 
  • #7
DrStupid said:
I'm not sure about that. Earthlike planets can be detected using the transit method. During the passage of the planet the light of its star is not only covered by the planet. A small fraction of the light will pass the planets atmosphere and might reach Earth. Then we will not only see a decrease of brightness but also additional absorption lines in the spectra of the star - carrying information about the composition of the atmosphere. Of course a successful spectral analysis will require a very high precision but this is a technical problem that might be solved in near future.

Something like that has been done already with at least one of the so-called "hot Jupiters" that have been detected. I'm not sure spectral signals unique to various atmospheric components have been detected, though.

http://www.space.com/3673-water-extrasolar-planet-atmosphere.html
http://en.wikipedia.org/wiki/HD_209458_b
 

1. Are we detectable by other intelligent life forms in the universe?

This question is a difficult one to answer definitively, as we have no concrete evidence of other intelligent life forms in the universe. However, many scientists believe that it is highly probable that there are other intelligent civilizations out there, and that it is possible for them to detect us through various means such as radio signals or spacecraft.

2. Can we detect other intelligent life forms in the universe?

Currently, we do not have the technology or capability to detect other intelligent life forms in the universe. We have been searching for signs of extraterrestrial life through programs like SETI, but so far, we have not received any concrete evidence. However, as our technology and methods of detection continue to improve, it is possible that we may one day be able to detect other intelligent life forms.

3. How do we know if we have been detected by other intelligent life forms?

If other intelligent life forms were to detect us, it would most likely be through some form of communication or detection of our technology, such as radio waves or signals from our spacecraft. However, as mentioned before, we have not received any concrete evidence of this happening. Some scientists also believe that if other intelligent life forms were to detect us, they may choose not to make their presence known to us.

4. Are there any potential dangers in being detected by other intelligent life forms?

This is a difficult question to answer, as it largely depends on the intentions and capabilities of the other intelligent life forms. Some scientists believe that if we were to be detected by a more advanced civilization, they may see us as a threat and attempt to destroy us. Others believe that a peaceful and beneficial exchange could occur if we were to make contact with other intelligent life forms.

5. How can we increase our chances of being detected by other intelligent life forms?

There is no guaranteed way to increase our chances of being detected by other intelligent life forms. However, continuing to search for extraterrestrial life and sending out signals or messages into the universe may increase our chances. Some scientists also suggest that we should focus on developing advanced technology and improving our communication capabilities to increase our chances of being detected by other intelligent life forms.

Similar threads

How can we improve asteroid detection to prevent future impacts?
    • Astronomy and Astrophysics
Replies
2
Views
2K
Stargazing Can distance in space be measured by human systems?
    • Astronomy and Astrophysics
Replies
22
Views
2K
Can We Detect Moons Around Earth-Sized Exoplanets?
    • Astronomy and Astrophysics
Replies
5
Views
3K
How many exoplanets with an atmospheric oxygen signature would be necessary?
    • Astronomy and Astrophysics
Replies
13
Views
5K
Oxegen signature of a planet's atmosphere
    • Astronomy and Astrophysics
Replies
2
Views
2K
Is my fictional Solar System stable and realistic?
    • Sci-Fi Writing and World Building
Replies
21
Views
994
Further plausible (?) elaboration on Fermi Paradox
    • Astronomy and Astrophysics
Replies
2
Views
2K
How Can We Harness the Power of Space Elevators and Atmospheric Electricity?
    • Astronomy and Astrophysics
Replies
7
Views
2K
Writing: Input Wanted Can a Gamma-Ray Burst Affect Communication Devices?
    • Sci-Fi Writing and World Building
Replies
6
Views
638
Satellite detection of fossil fuels?
    • Earth Sciences
Replies
2
Views
4K

Hot Threads

Recent Insights

Back
Top