Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for...
-
Upload
dorothy-norman -
Category
Documents
-
view
222 -
download
0
Transcript of Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for...
![Page 1: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/1.jpg)
Jayant V. Narlikar
Inter - University Centre for Astronomy and Astrophysics
Searches for Extraterrestrial Life
![Page 2: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/2.jpg)
How big is the Cosmos?
The cosmic hierarchy has:
The Earth
![Page 3: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/3.jpg)
How big is the Cosmos?
The cosmic hierarchy has:
The Earth
The Solar System
![Page 4: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/4.jpg)
How big is the Cosmos?
The cosmic hierarchy has:
The Earth
The Solar System
The Galaxy
![Page 5: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/5.jpg)
How big is the Cosmos?
The cosmic hierarchy has:
The Earth
The Solar System
The Galaxy
Local group of Galaxies
![Page 6: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/6.jpg)
The cosmic hierarchy has:
The Earth
The Solar System
The Galaxy
Local group of Galaxies
Cluster of galaxies
How big is the Cosmos?
![Page 7: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/7.jpg)
The cosmic hierarchy has:
The Earth
The Solar System
The Galaxy
Local group of Galaxies
Cluster of galaxies
Supercluster of galaxies
How big is the Cosmos?
![Page 8: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/8.jpg)
Question:There may be around 10 21 stars in the observable universe…Is the Sun alone in hosting life on one of its planets?
Life as we know it:
DNA Cells ...evolution to more complex forms
Do the basic building blocks exist in space?
Yes!
![Page 9: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/9.jpg)
Question:There may be around 10 21 stars in the observable universe…Is the Sun alone in hosting life on one of its planets?
Life as we know it:
Do the basic building blocks exist in space?
In giant molecular clouds…
DNA Cells ...evolution to more complex forms
Yes!
![Page 10: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/10.jpg)
Millimetre wave astronomy has revealed the existence of molecules in space.
![Page 11: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/11.jpg)
Molecules in SpaceThis is a partial list to give flavour only!
![Page 12: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/12.jpg)
Thus, circumstantial evidence exists to support the idea of life beyond the Earth…
Can we estimate the number of extra-terrestrial supercivilizations in the Galaxy?
Frank Drake suggested an equation to determine the answer to this question.
![Page 13: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/13.jpg)
N= R * fs * fp * ne * fl * f i* fc * L
Drake's equation:
![Page 14: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/14.jpg)
R = Average rate of star formation (stars/year)
Drake's equation:
N= R*fs*fp*ne*fl*fi*fc*L
![Page 15: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/15.jpg)
N= R*fs*fp*ne*fl*fi*fc*L R = Average rate of star formation (stars/year)
fs = Fraction of stars that are ‘good’ suns
Drake's equation:
![Page 16: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/16.jpg)
N= R*fs*fp*ne*fl*fi*fc*L R = Average rate of star formation (stars/year)
fs = Fraction of stars that are ‘good’ suns
fp = Fraction of good stars with planetary systems
Drake's equation:
![Page 17: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/17.jpg)
N= R*fs*fp*ne*fl*fi*fc*L R = Average rate of star formation (stars/year)
fs = Fraction of stars that are ‘good’ suns
fp = Fraction of good stars with planetary systems
ne = Number planets per stars within ecoshell
Drake's equation:
![Page 18: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/18.jpg)
N= R*fs*fp*ne*fl*fi*fc*L R = Average rate of star formation (stars/year)
fs = Fraction of stars that are ‘good’ suns
fp = Fraction of good stars with planetary systems
ne = Number planets per stars within ecoshell
fl = Fraction of ne on which life develop
Drake's equation:
![Page 19: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/19.jpg)
N= R*fs*fp*ne*fl*fi*fc*L R = Average rate of star formation (stars/year)
fs = Fraction of stars that are ‘good’ suns
fp = Fraction of good stars with planetary systems
ne = Number planets per stars within ecoshell
fl = Fraction of ne on which life develop
fi = Fraction of living species that develop intelligence
Drake's equation:
![Page 20: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/20.jpg)
N= R*fs*fp*ne*fl*fi*fc*L R = Average rate of star formation (stars/year)
fs = Fraction of stars that are ‘good’ suns
fp = Fraction of good stars with planetary systems
ne = Number planets per stars within ecoshell
fl = Fraction of ne on which life develop
fi = Fraction of living species that develop intelligence
fe = Fraction of intelligent species reaching an
electromagnetic communicative phase
Drake's equation:
![Page 21: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/21.jpg)
N= R*fs*fp*ne*fl*fi*fc*L R = Average rate of star formation (stars/year)
fs = Fraction of stars that are ‘good’ suns
fp = Fraction of good stars with planetary systems
ne = Number planets per stars within ecoshell
fl = Fraction of ne on which life develop
fi = Fraction of living species that develop intelligence
fe = Fraction of intelligent species reaching an
electromagnetic communicative phase
L = Lifetime in communicative phase (years)
Drake's equation:
![Page 22: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/22.jpg)
The answer depends on estimates for the various factors made by individuals and varies between 1 and several billions! A middle opinion centres around a million or so.
N : L
![Page 23: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/23.jpg)
The Extra-Terrestrial Intelligences; How can we search for them?
By sending space-ships?
![Page 24: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/24.jpg)
The Extra-Terrestrial Intelligences; How can we search for them?
By sending space-ships? By sending unmanned probes with Information about us?
![Page 25: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/25.jpg)
The Extra-Terrestrial Intelligences; How can we search for them?
By sending space-ships? By sending unmanned probes with Information about us?
By radio messages?
![Page 26: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/26.jpg)
The Extra-Terrestrial Intelligences; How can we search for them?
By sending space-ships? By sending unmanned probes with Information about us?
By radio messages?
The last method is considered the most practical for present technology…
![Page 27: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/27.jpg)
The Extra-Terrestrial Intelligences; How can we search for them?
By sending space-ships? By sending unmanned probes with Information about us?
By radio messages?
The last method is considered the most practical for present technology…
But it demands patience!
![Page 28: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/28.jpg)
Hello, I am from Earth speaking.
Is anyone out there ?
Hello,
Greetings from Alpha-Centauri. We read you loud and clear.
8.5 years later
![Page 29: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/29.jpg)
Search for primitive life-forms: Can cells, bacteria and other micro-organisms be detected outside the Earth's atmosphere?
Hoyle-Wickramasinghe hypothesis states that comets can be carriers of micro-organisms in frozen state which they release on the Earth's atmosphere if their tails brush it.
![Page 30: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/30.jpg)
Cometary debris like meteor showers can also serve to bring the micro-organisms to the upper parts of the atmosphere.
![Page 31: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/31.jpg)
From these heights they will gradually descend. In steady state their distribution with height can be determined.
![Page 32: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/32.jpg)
Can we establish that such a population exists?
![Page 33: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/33.jpg)
ISRO-Cryosampler Experiment
TIFR-Balloon Facility used for flying a balloon to a height of 41 km.
![Page 34: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/34.jpg)
ISRO-Cryosampler Experiment
Payload consisted of cryosampler manifold with fully sterilized steel probes, each with a capacity of 0.35 litre. Pressure tolerance from 1 micro-bar to 600 bar.
Probes evacuated and cooled to liquid neon temperature to produce cryopump action with sterilized valves fitted with opening through telecommand at specified heights.
Air sucked in at 4 different height windows in two sets of samples.
![Page 35: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/35.jpg)
Analysis of the data:
Air from each probe passed in a sterile system in a laminar flow chamber, through two filters: first through 0.45m and then through 0.22m filter.
Probes were stored at –70C temperature before sample preparation.
8 filters so derived also stored at this temperature.
![Page 36: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/36.jpg)
Technique of analysis
0.45m filter is expected to have trapped microbial-size particles.
2mm2mm squares were cut from the filters and treated with special dyes.
Cationic dyes penetrate the membranes of viable cells. These give rise to fluorescent spots when illuminated by UV-light and could be identified with epifluoroscence microscope, or by a confocal scanning laser microscope…
Anionic dyes penetrate only the non-viable cells.
![Page 37: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/37.jpg)
Cataionic cyanine dye treated samples showed fuorescent spots in the form of clumps of size 0.3 – 1 m sized cells over areas measuring 5-15 microns across.
Confocal microscopy provides higher resolution pictures.
Anionic dyes showed a comparable detection rate of dead or non-viable cells.
![Page 38: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/38.jpg)
Serendipitous Discovery of Culture
Milton Wainwright from Sheffield obtained cultures from a medium in the form of Potato Dextrose Agar (PDA).
![Page 39: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/39.jpg)
Serendipitous Discovery of Culture Taking every possible precaution against contamination, cultures of the following microorganisms were grown:
(a) The coccus (spherical bacterium, often growing in clumps) 99.8% similar to the bacterium Straphylococcus pasteuri, as determined by 16S RNA analysis.
(c) A fungus identified as Engyodontium albus (Limber) d e Hoog.
(b) The bacillus (rod-like), 100% similar as determined by the above analysis to the the Bacillus simplex.
![Page 40: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/40.jpg)
These are not common contaminants, nor had they been used in the lab where these were found. No such growth was found on control membranes that were not exposed to stratospheric air.
Further confirmatory work is in progress …
If these micro-organisms are not from the Earth, then…
Have we detected extraterrestrial life?
![Page 41: Jayant V. Narlikar Inter - University Centre for Astronomy and Astrophysics Searches for Extraterrestrial Life.](https://reader035.fdocuments.net/reader035/viewer/2022062322/56649e3a5503460f94b2c600/html5/thumbnails/41.jpg)