Interesting idea: what is the carbon composition of lava?
Is buried carbon (that gets out again through volcanic eruptions) more likely to get back into the atmosphere when it comes out of a volcano on the edge of continental margins? As compared to when it comes out of a hot spot volcano? Could increased propensity towards eruptions on the edge of continental plates mean more long-term CO2 in the atmosphere and less sequestration of carbon? When it erupts in hot spots, I would expect that it would be unlikely to get back into the atmosphere through another volcanic eruption? But the carbon on the edge of continental plates might get back into the atmosphere - simply because the carbon on the subducting plate often gets back into the magma below
Maybe this could vary based on the carbon composition of lava (how ultramafic/felsic it is). But ultramafic/felsic compositions are based off of iron/silicon content, not carbon content. But maybe ultramafic lavas have less carbon since much of it originates from hot spots deep inside the mantle, where there is comparatively less carbon (the less dense carbon would tend to rise up - at least inside the mantle).
send RAM stick full of textbooks (mathematica/matlab ISOs if possible) ==
August 4th: video conference with founder of SETI:
"search for technosignatures"
Optical SETI: Time compression. Radio SETI: Frequency compression
At Kepler, she looks at the ingress/egress of Kepler data (detect artificial transit out of higher-order moments) => Ask - what is the physical significance of these moments?
astrophysical frequencies are broadband (we might not be able to capture all these frequencies)
== ATA telescope
2*10^13 radar 1000 ly away
Allen telescope array
large N (improved sensitivity rom more dishes, larger collecting area) - small D (small dish array images a large area of sky) array
single dish FoV and spatial resolution set by D. (all of them are inversely proportional to diameter of dish)
Go into an aray: you break the degeneracy from a single fish
Antenna configuation only looks random
but the distribution of baseline pairs in configuration is Gaussian
uniform coverage in azimuthal angle. but adjusted the length of the baseline so it fits as close as possible to a Gaussian.
we do have triads (3 groups of 3 antenae) can collide but the computer doesn't let them
Why do we want to match a Gaussian profile? The F-transform of Gaussian is a Gaussian.
the Fourier transform of the locations of the antennas on the ground: gives you the PSF of the stuff in the sky. So for Nant = 42, 98, 206, 450 => what our synthesized beam looks like
350 antennas: no grating lobes - you perfectly sample the entire UV plane. So that's why you choose the locations of antennas in array
Arecibo: 7-beam field of view array. this FoV is still far less than what's covered by the roo
6-meter array (at 1.4 ghz [hydrogen frequency]) takes you to 2.5 degrees
so.. a radio camera (spectral imaging correlator) makes radio image of entire field of view: 1024 spectral channels "colors", 61,075 baselines. Aka the wideangle radio camera snapshots. With 350 antennas, you have 61,075 baselines so you sample the entire field of view
For SETI - instead of multiplying the voltages from each antenna pairwise, we add them to phase them up. then we try to pick out the direction of the sky at which we want to point.
3 phased array beams at 2 frequency bands (3 individual pixels out of the entire map)
"I can choose these directions to coincide with stars in the sky that I want to observe)
"I build spectrometers that have 100s of millions of spectral channels". we can do both correlation-mapping and beam-mapping independently on the array
Beam Plus Offset Null: blue curve (ordinary beam). then take 2D cut through it. primary beam is in center. But all telescopes have sidelobes (cover more of the sky at a lower level). but then you get a red curve (null beam) by changing the coefficients that weigh contributions from each telescope (if you do that, you get less signal from the primary direction, but slightly more in one of the lobes).
if you do that, you get a huge deep projection null - helps discriminate against interference from doing SETI searches
trying to systematically search through that galactic center survey (we intersect between 4-10 billion stars). 4-10 billion stars within 20 square degrees (this means that we look at the largest number of stars in the smallest angular volume of the galaxy).
M31 at the frequency of bright hydrogen: you see the neutral gas at the risk of the galaxy. While this map is being made...
you get a catalog of 250,000 stellar topics. do SETI search commensally
"corn-cob diagram of exoplanet candidates". illustrations of the discs of the stars. what we're seeing is little black shadows projected on the discs (these are the transits against the stars - there are 1235 of them in the first few months of observing)
takes a year to look for 1 AU transits (3-years worth of data will confirm it since we want to see 3 transits first)
54 are 'habitable' in terms of equilibrium planet at orbital distance of star. (is this including gas giants?)
radio: astrophysics vs technology (frequency compression).
low frequencies: a lot of noise from galactic synchrotron radiation
very quiet natural window: 1-10 gigahertz range: represents 9 billion frequency channels - each of which is 1 hertz wide (couldn't we try resolutions less than 1 hertz wide?)
(lose sensitivity - also - drift rates). rate of change of frequency over frequency = 10^(-9). given that value (1 hertz is not bad). but we do broaden it up at higher frequencies
we do a coherent integration (try to follow 1/10th of a hertz and follow it)
1 hz wide lasting for 1 second: looking for patterns that are represented by the straight lines (continuous wave signal that was changing its frequency over time). wh does it d that? because the earth is rotating, and the doppler shift will be different each time because of diurnal rotation (so frequency not constant with time)
DADD algorithm: the kind of computing algorithms used to find the artifact.
a signal can begin in any one of N channels. it can change its frequency up to as many as 1 bin per time sample (if you allow it to that). something that started at 1 time channel, it can add up to
a frequency channel can move to other frequency channels over time (creating degeneracies).
use log m algorithm to add up all the power along these straight lines
"Triplet Pulse Detection" - interrogate
SonATA = SETI on the ATA. they once had to build their own F-transform chips. now they've moved onto software
having moved out of the custom environment, we can look out tot he world to make the search better
SetiQuest: actively engaging the world (as opposed to passive SETI)
published code on github as open source code
also reaching out to the student/DSP community (have them help us build algorithms to find other signals)
OS developer community
citizen scientist community (adobe group)
finger to scroll through frequency vs time patterns.
crowdfunding - setistars.org (can you help us get these telescopes out of hibernation? - we met our fundraising goal) - mention that on Quora post!
they raised $202,354
Kim's comment: shifting from broadcast to cable => earth gets quieter (wow) - could that mean that longlasting civilizations get quiet?
if leakage radiation is nothing more than ours, then it gets harder to hear that.
we're then listening to backload rather than main beam
"an older technology is going to have part of its population with different bodies in "
"might be communication channels between planets that we can eavesdrop on".
local technologies are likely to be low power. someone could create a beacon (like an enormous radar system to shield against/detect incoming asteroids).
easiest to find:
In response to my question:
Watts that could be detected by optical SET.
"effective isotropic radiated power". power radiated uniformly in all directions (deduce from the signal). and yes it decays as 1/r^2
compared to aircebo
me: in response to "effective isotropic radiated power": could we put trnasmitters on moon/mars to really capture as much of that power as possible?
"early adoption of cellphones/social networking" is best to conduct global conversation on this topic". "we've done a couple of stunts to send a message, but nothing with the chance of being detected. and nothing systematically routine"
inadvertent technologies detectable?
"very low sensitivity to transient events"
archive of searches that have been done since 1960. tried to support ideals. find something out of the H1 hydrogen power line from deuterium power splitting (could be a signal of fusion).
small constrained searches vs very wide searches.
the lunar far side: very special place: never has the earth in the sky. so all of the noise (all the interference we're generating) is blocked by the body of the moon.
daedalus crater: the shielded backside of the moon is protected from radio transmission.
it costs a million and a half dollars to operate the Allen Telescope Array.
2,000,000 dollars isn't going to go very far. but it helps us get the telescopes out of hibernation.
more AC so she can run more of the compute resources.
another 3 factor of the bandwidth but it's too high/
(that's what the hibernation funding is for).
doing experiments with the USAF: demonstrate what an extraordinarily good tool the array is for tracking space debris/orbital resources (we are very close to losing parts of lower orbit to debris collisions: an exponentiation of the debris. we want to change the velocities of these pieces of debris - that whole arena is something telescopes are well-suited for.)
because we're looking at 3D visualization this summer, "are there any 3D project ideas on the science/outreach side that you might be interested in?" go to the explore-setiquest.org site. see these waterfalls we are rendering frequency vs time. the size of the dot is being used for intensity. it renders quickly but isn't necessarily the best visualization for the eye to be finding things. rendering them as mountains would be better. tipping the plane of the display down.
galaxyzoo is browser format.
back in early pulsar days: they tipped them down so that people could try to see dispersed pulse
"want things that render more quickly and enticingly against a white background"
== Chris McKay:
aftermath of phoenix lander:
In response to Martian coldness being good for preserving biological samples: oh, so heat cannot indefinitely preserve, say, the mummies of Egypt?
culture based exeriment was microbiology. now it is a small subset of it
we know that this culture-based method fails in Earth most of the time. indeed, things grow - just because there's so many organisms that there's BOUND to be one that binds to the particular culture we're using
want to focus on the GCMS: ties in with the future mission: presaging the conclusion
GCMS found: low levels of contaminants (like Freon) - was there halfway to Mars
methyl chloride at 15 ppb at 200 celsius (not seen in blank)
methylene chloride at 0.04-40 ppb at 200-500 celsius (seen in blank)
"exquisitely sensitive" - would still represent a very sophisticated capable instrument now - 40 years later. "would still love to have such an instrument on a discovery-based mission"
methyl chloride could conceivably be indigeneous to Mars.
Biemann et al 1997 reported detection of 8 contaminants (why was the paper reporting contaminants published 20 years after the experiments??)
but putting GCMS on the landers was a good thing: it *should* detect organics - the solar system is littered with organics: so it's VERY CURIOUS that we failed to detect any organics from Mars
The rovers have found meteorites on Mars.
== "major clue came with the Phoenix Mission to Mars": May 2008 to Nov 2008.
after Viking, Cospar decided that we should not sterilize spacecraft to Mars. except for special things that touched the arm below the surface.
dry heat microbial reduction. the rest of the spacecraft carried over 10,000 viable microoganisms.
the microbes in the Phoenix spacecraft are still viable (but might not be doing anything)
lower-limit of water mass fraction on Mars.
not a surprise that phoenix found ground ice (the site was chosen for its ground ice).
big surprise: perchlorate 0.5% (where most of the chlorine came from). viking detected chlorine from x-ray fluoresence (only knew the atom presence of chlorine)
orbital mapping by odyssey (mapped out chlorine. but only knew atom percent)
phoenix was first thing to measure chlorine's molecular form (we expected it to come in the form of sodium chloride). mckay didn't know about perchlorate up until the mission.
destroys organics: not bleach at room temperature (but can be bleach at 350 degrees Celsius)
perchlorate is a good candidate for making the streaks of rivers that exist on Mars today
also is edible by microorganisms. terminal electron acceptor (+7 oxidation state) ~ nitrate
totally changes our understanding of chemistry on Mars.
atacama: very low content of organics in soil
no colony-forming units (nothing that can grow in a culture sample) presence of abiotic oxidants (will consume organics irrespective of their chirality)
navarro gonzalez et al (2010).
heating and then sample. MSL will sample as it heats. Viking heated and then sampled
mix perchlorate: destroy orgnaics. but you do see methyl and methylene chlorate (we didn't expect this at all!)
we expected that perchlorate wouldn't make this peak
you can't make this peak (in methyl chlorate) unless you have BOTH chlorates AND organics in the soil
what this means:
Everything we thought we know about organics on Mars from Viking pyrolysis GCMS is likely wrong
instead of an upper limit of ppb, detection (by destruction) at ppm. (direct detection >> upper limits)
good news for future missions: organics might be high. a ppm is not high (driest parts of Atacama: a few ppm. most soils: percents, not ppm)
bad news for future missions: need non-thermal methods
(everything we did uses thermal methods). Cassini GCMS, Galileo GCMS - all first take sample and heat it up (easiest way to separate them out from the rocks)
on earth: liquid extraction (since we have hands). much simpler to do pyrolysis == ==
title of talk: organics and perchlorates at mid-latitudes
my other question: mass spectrometer.
if there is life on mars, it would have to do it with perchlorate reductants. he has gotten fixated on chloride.
next mission to Mars: Mars Science Laboratory (launch Nov. 2011). but MSL was designed before Phoenix sent its first data point.
MSL releases info that will dominate Mars for the next decade (but has cleaned out its job for the next decade)
Chosen to go to Gale Crater.
pyrolysis GCMS on upcoming MSL mission.
can watch reactions go on.
9 aliquots to do 9 samples
Sample Analysis for Mars: wash samples with 2 derivatization agents (added to sample to extract organics). 6 of first and 9 of second
sample will not be heated above 70 degrees Centigrade ==
MSL might still work. interesting question: this will easily see the spectrum of organics.
so next question: how do we tell the dif between dead microorganisms and meteoritic organic material on MSL?
Murchison carbonaceous chondrite.
the obvious thing is chirality of the orgnaics. but MSL won't do chiral separation of the organics. we want to detect alien bioorganic molecules.
warm ice at high latitde - can be liquid water when mars is at high obliquities. plnty of water for microoganisms.
immuno-assay lab on a chip. (developed by a spanish group - Parro et al.). fluorescent signal on microarray.
"perchlorate reductase" - my fav molecule
immuno-assay labs can only detect what you want them to detect (won't tell dif between two dif chiralities)
how do we detect biomolecules of an alien lifeform. "i take that as my job description".
the diversity in life we see: all morphological, not fundamental
if we find organic material, can we tell if it was ever alive? the best we can find is the frozen remains of dead micro-organisms
20 L amino acids, 5 nucleotide bases, few D sugars, etc. likely a common property of biology (and mass produced child toys) throughout the universe
diversity from combinatorial complexity of biology
but we could have a dif set of legos for a different biology.
abiotic organic chemistry. similar molecules at similar concentrations.
in biology: totally dif molecules at similar concentrations.
what if we do if we find a second genesis on Mars? (a reporter's question)
"not clever to think of it theoretically. very rarely driven by theoretical insights". - that's science
someone else's question: how do we know that we'll find anything else that's different? life on mars would prolly map on the same tree
gas chromatograph mass spectrometer:
Rubisco arrived fully born at 3.8 billion years ago: life seems to almost have come in through the same great heavy bombardment.
"do i think it's likely? it's likely enough for me to spend many of my waking life hours on working on it. even though it's not a scientific hope"
"no matter where life comes from in the phase-space of biochemistry, some biochemists (PNAS paper) say that
landscape of biochemical phase-space, only one optimum (and all paths are smooth to that optimum) - someone's argument. mckay thinks that there are lots of places in carbon-water space
== carbon-liquid methane: a lot stranger
"are perchlorates found on other bodies and other objects?" - we know that perchlorates are found at high concentrations only in atacama. but nowhere where it's the dominant form of chlorine
Mars (paper by david catling): "and maybe this is how it happens on Mars too". why is it pushed all on the other side of the oxidation table
formed on the earth by oxidation reactions.
all the chlorine has been cycled in the atmosphere - so it all ends up on the dead end.
MSL: Gale Crater: land and spend a lot of time driving (land low and then drive to the top of the crater). as it heats up the sample we should see a huge burst of oxygen as it heats up. (to analyze the clays)
N2 released by nitrate decomposition.
micro-zoo and dump it in perchlorate brine: people have been growing micro-organisms in perchlorate. perchlorate remediation at contamination sites. no one has done it under Mars-like conditions.
he literally met with john cloates at berkeley (top people in perchlorate). ground salt perchlorate as the only oxidant source. mars simulation.
john was sure it would succeed
is the perchlorate perfectly uniform across the surface?
patchy and so mobile that small levels of it will move around (so thus it's variable across the surface) = > wow that was an AMAZINGLY insightful quote!
factors of 5 variation: 5000 PPM. organics are 1 PPM. we got to see patterns of spatial variability of 5000 to 1.
Viking samples: batch heating. MSL will completely eclipse the samples done by Viking. A year from tomorrow we'll start again.
most of the work is done preparing the sample. the thing with mass spectrometry is that you have to push the sample to the analyzer. in viking it was done through an oven-like thing. in the MSL, it will be done through liquid-based extraction