Julian Chela-Flores The Abdus Salam ICTP, Trieste, Italia and

Julian Chela-FloresThe Abdus Salam ICTP, Trieste, Italiaand Instituto de Estudios Avanzados, Caracas, Republica Bolivariana de Venezuela

The Origins: how, when and where it all started, Accademia Nazionale dei Lincei. Centro Linceo Interdisciplinare “Beniamino Segre”, Roma, 22 May 2006

Evolution of the universe: From Astrophysics to Astrobiology

Julian Chela-FloresJulian Chela-FloresThe Abdus Salam ICTP, Trieste, Italia and

Instituto de Estudios Avanzados, Caracas,

Republica Bolivariana de Venezuela

Life habitability in Life habitability in the solar systemthe solar system

Planetary Landers and InstrumentationPlanetary Landers and InstrumentationEGU 2007,

Austria Center Vienna, Blue Level, Lecture Room 2;19 April 2007; 13.45

Testing the universality of biology on Testing the universality of biology on Europa with microprobes or landersEuropa with microprobes or landers

Plan of the talkPlan of the talk

The question of the universality ofThe question of the universality of biology. biology.

The icy and patchy surface of Europa.The icy and patchy surface of Europa.

Biogeochemistry on the surface of Europa.Biogeochemistry on the surface of Europa.

Towards the Athens Workshop and beyond the Aurora Programme.Towards the Athens Workshop and beyond the Aurora Programme.

The universality of biologyThe universality of biology

Part IPart I

International Journal of Astrobiology (2007, in press)

Is Darwinism universal?Is Darwinism universal?

contingency, contingency,

gradual action of natural selection.gradual action of natural selection.

The theory of evolution discusses the relative importance of:The theory of evolution discusses the relative importance of:

Can the outcome of evolutionary Can the outcome of evolutionary processes be predictable?processes be predictable?

To a certain extent and in certain conditions, natural To a certain extent and in certain conditions, natural selection may be stronger than chance.selection may be stronger than chance.

The ubiquity of evolutionary convergence argues against The ubiquity of evolutionary convergence argues against the view that biological diversity on Earth is unique.the view that biological diversity on Earth is unique.

Independent of historical contingency, natural selection isIndependent of historical contingency, natural selection is powerful enough to shape organisms in similar environmentspowerful enough to shape organisms in similar environments (anywhere) to similar ends.(anywhere) to similar ends.

Convergence in mammalian Convergence in mammalian evolutionevolution

Dagger-like cannines Dagger-like cannines evolved independently in: evolved independently in:

Placental catsPlacental cats (the (the extinct ‘sabre-tooth’ extinct ‘sabre-tooth’ felids), were probably felids), were probably the ancestors of the ancestors of present-day cats. present-day cats.

A group of South A group of South American American marsupialsmarsupials related to the related to the kangaroo and kangaroo and opossum, andopossum, and

marsupialmarsupial

placental catplacental cat

Convergence in biochemistryConvergence in biochemistry

Their active sites are an Their active sites are an identical identical set of 3 amino acidsset of 3 amino acids (histidine, (histidine, serine, and aspartic acid), but their serine, and aspartic acid), but their folding is different.folding is different.

Lipases are secreted by theLipases are secreted by the glands of glands of vertebratesvertebrates to catalyze fats and glycerol.to catalyze fats and glycerol.

Proteases are Proteases are housekeeping housekeeping genesgenes that are needed for the that are needed for the sustenance of all cells (sustenance of all cells (catalyzing catalyzing the digestion of proteins into its the digestion of proteins into its amino acids).amino acids).

The icy and patchy surface The icy and patchy surface of Europaof Europa

International Journal of Astrobiology (2006)

Part IIPart II

A hydrobotA hydrobot

Galileo revealed evidence for an internal oceanGalileo revealed evidence for an internal ocean Fortunately, entering the ocean is unnecessaryFortunately, entering the ocean is unnecessary

Horvath Horvath et alet al, 1997, 1997

The Europa icy surfaceThe Europa icy surface (Spectrometer data from near IR) (Spectrometer data from near IR)

and ‘patchy’and ‘patchy’

albedo per pixelalbedo per pixel

High resolutionHigh resolution albedo imagealbedo image

Distribution of Distribution of non-ice componentnon-ice component

4 km/pixel4 km/pixel McCord McCord et al,et al, Science 280 (1998), 1242Science 280 (1998), 1242

Possible sources of the stainsPossible sources of the stains

External source:External source:

Ions may be implanted from the Jovian plasma. Ions may be implanted from the Jovian plasma.

Internal source:Internal source:

Sulfur may be due to cryovolcanism, Sulfur may be due to cryovolcanism,

Could the source be biogenic?Could the source be biogenic?

One way to decide:One way to decide: Develop planetary landers.Develop planetary landers.

An array of four microprobes for EuropaAn array of four microprobes for Europa

Europa landers were included in the Cosmic Vision Report. But Europa landers were included in the Cosmic Vision Report. But landers would have to guarantee likely science return to justify the landers would have to guarantee likely science return to justify the resources to be invested.resources to be invested.

In spite of this cautious note, we should still consider landers as an In spite of this cautious note, we should still consider landers as an option in any Jupiter Exploration Programme that would eventually be option in any Jupiter Exploration Programme that would eventually be

envisaged in the future.envisaged in the future.

The Europa Microprobe The Europa Microprobe in-situin-situ Explorer Explorer (The “EMPIE study”)

The lander discussed in the Cosmic The lander discussed in the Cosmic Vision document would have a set of 4 Vision document would have a set of 4 microprobes (350 gm each). microprobes (350 gm each).

Mass constraint for the microprobes Mass constraint for the microprobes would be 1.7 kg.would be 1.7 kg.

Tirso Velasco and colleagues

Mass spectrometry for Mass spectrometry for biogeochemistrybiogeochemistry

A light MS built for the Bepi-Colombo A light MS built for the Bepi-Colombo mission to Mercury was developed. mission to Mercury was developed. (The lander has been cancelled.)(The lander has been cancelled.)

When life processes the element When life processes the element sulfur, it tends to fractionate isotopes sulfur, it tends to fractionate isotopes

differently from geology.differently from geology.

120 x 60 mm; 500 g

Biogeochemistry on Biogeochemistry on the surface of Europathe surface of Europa

International Journal Astrobiology (2006)

Part IIIPart III

The delta The delta 3434S-parameterS-parameter

CDM coincides with the CDM coincides with the average terrestrial ratio of the average terrestrial ratio of the isotopes isotopes 3232S and S and 3434S.S.

Canyon Diablo Meteorite (CDM) is a troilite (FeS), that was found in Canyon Diablo Meteorite (CDM) is a troilite (FeS), that was found in Arizona.Arizona.

Sulfate-reducing bacteriaSulfate-reducing bacteria

Sulfate-reducing bacteriaSulfate-reducing bacteria

4H4H22 + H + H22SOSO44 –» H –» H22S + 4HS + 4H22O + 39 O + 39 kilocalorieskilocalories

The HThe H22S then combines with Fe in sediments to form grains of the S then combines with Fe in sediments to form grains of the

biogenic mineral pyrite.biogenic mineral pyrite.

Iron sulphide, FeS2

Unite H with S atoms from dissolved sulfate Unite H with S atoms from dissolved sulfate ( SO( SO44-2 -2 ))

of seawater to form hydrogen sulphide Hof seawater to form hydrogen sulphide H22S :S :

The sulfur isotopes are divided The sulfur isotopes are divided between biogenic minerals and between biogenic minerals and

sulfate mineralssulfate minerals Dissolved sulfate on Dissolved sulfate on

evaporation forms evaporation forms sulfate minerals sulfate minerals depleted of depleted of 3232S by 20 S by 20 per mil.per mil.

The HThe H22S given off by S given off by

the bacteria is enriched the bacteria is enriched in in 3232S by 20 per mil.S by 20 per mil.

Sulfur ions on Earth, meteorites Sulfur ions on Earth, meteorites and Moonand Moon

Terrestrial

Meteoritic

Lunar

-40From measurements in From measurements in basins off California:basins off California:insoluble sulfide, mostly insoluble sulfide, mostly pyritepyrite

Sulfate Sulfate coexisting with coexisting with

seawaterseawater

The deltaThe delta3434S-parameterS-parameter

Where should we land?Where should we land?

DiscussionDiscussion

On Earth there are ice-locked ecosystems that can stain On Earth there are ice-locked ecosystems that can stain the icy surface without a cryovolcanic source.the icy surface without a cryovolcanic source.

It is the biology instead of the geology that does the job It is the biology instead of the geology that does the job by staining the ice.by staining the ice.

Part VIPart VI

The dry valley lakesThe dry valley lakes

A section of the icy surface of Lake HoareA section of the icy surface of Lake Hoare

Algal mat pieces on the surface of a dry-valley lake

(Parker et al, Phycologia, 1982)(Parker et al, Phycologia, 1982)

Annual escape of sulfur (kg) by the loss of algal matsAnnual escape of sulfur (kg) by the loss of algal mats

Beyond the Aurora ProgrammeBeyond the Aurora Programme

Testing the universality of biology on Europa is feasible Testing the universality of biology on Europa is feasible with microprobes or landers.with microprobes or landers.

This militates in favour of eventually considering the This militates in favour of eventually considering the extension of the extension of the Aurora ProgrammeAurora Programme to include a Europa to include a Europa landing mission.landing mission.

To sum up:To sum up:

Europa should be an Europa should be an objective of space objective of space exploration in the exploration in the foreseeable future.foreseeable future.

Europa should be an Europa should be an objective of space objective of space exploration in the exploration in the foreseeable future.foreseeable future.

Mars may not be the Mars may not be the target with the most easily target with the most easily accessible biomarkers.accessible biomarkers.

Europa should be an Europa should be an objective of space objective of space exploration in the exploration in the foreseeable future.foreseeable future.

Mars may not be the Mars may not be the target with the most easily target with the most easily accessible biomarkers.accessible biomarkers.