Marc Kaufman is the author of two books about space: "Mars Up Close: Inside the Curiosity Mission” and “First Contact: Scientific Breakthroughs in the Search for Life Beyond Earth.” He is also an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer. While the “Many Worlds” column is supported and informed by NASA’s Astrobiology Program, any opinions expressed are the author’s alone.
To contact Marc, send an email to firstname.lastname@example.org.
I’m taking a little break alongside the Atlantic but can’t leave exoplanets et al completely behind.
Water worlds are inferred, or known, to be present and perhaps not uncommon in the galaxy. And there is reason to conclude that they may have much more water than Earth. Although 70.8% of all Earth’s surface is covered in water, H2O accounts for just some 0.05% of Earth’s mass.
Some animations and illustrations of what these aquaworlds might look like:
Depiction of a world completely covered with ocean. (NASA Kepler Mission/Dana Berry)
Artist rendering of TRAPPIST-1f in the seven-exoplanet Trappist-1 system in constellation Aquarius. The color comes from orbiting a red dwarf star. With added fisherman. (NASA)
I was moved to weigh in after reading Vice President Mike Pence’s comments last week down at the Kennedy Space Center — a speech that seemed to minimize NASA’s performance in recent years (decades?) and to propose a return to a kind of Manifest Destiny way of thinking in space.
The speech did not appear to bode well for space science, which has dominated NASA news with many years of exploration into the history and working of the cosmos and solar system, the still little-understood domain of exoplanets, the search for life beyond Earth.
Instead, the speech was very much about human space exploration, with an emphasis on “boots on the ground,” national security, and setting up colonies.
“We will beat back any disadvantage that our lack of attention has placed and America will once again lead in space,” Pence said.
“We will return our nation to the moon, we will go to Mars, and we will still go further to places that our children’s children can only imagine. We will maintain a constant presence in low-Earth orbit, and we’ll develop policies that will carry human space exploration across our solar system and ultimately into the vast expanses. As the president has said, ‘Space is,’ in his words, ‘the next great American frontier.’ And like the pioneers that came before us, we will settle that frontier with American leadership, American courage and American ingenuity.” (Transcript here.)
That a new president will have a different kind of vision for NASA than his predecessors is hardly surprising. NASA may play little or no role in a presidential election, but the agency is a kind of treasure trove of high profile possibilities for any incoming administration.
That the Trump administration wants to emphasize human space exploration is also no surprise. Other than flying up and back to construct and use the International Space Station, and then out to the Hubble Space Telescope for repairs, American astronauts have not been in space since the last Apollo mission in 1972. It should be said, however, that no other nation has sent astronauts beyond low Earth orbit, either, since then.
Where I found the speech off-base was to talk down the many extraordinary discoveries in recent decades about our planet, the solar system, the galaxy and beyond made during NASA missions and made possible by cutting-edge NASA technology and innovations.
In fact, many scientists, members of Congress and NASA followers would enthusiastically agree that the last few decades have been an absolute Golden Age in space discovery — all of it done without humans in space (except for those Hubble repairs.)
To argue for a more muscular human space program does not have to come with a diminishing of the enormous space science advances of these more recent years; missions and discoveries that brought to Americans and the world spectacular images and understandings of Mars, of Jupiter and Saturn and their potentially habitable moons, of Pluto, of hot Jupiters, super-Earths and exoplanet habitable zones, and of deep, deep space and time made more comprehensible because of NASA grand observatories.
To say that the United States has given up its “lead in space,” it seems to me, requires a worrisome dismissal of all this and much more.
Let’s start on Mars. For the past 20 years, NASA has had one or more rovers exploring the planet. In all, the agency has successfully landed seven vehicles on the planet — which is the sum total of human machinery that has ever arrived in operational shape on the surface (unless you count the Soviet Mars 3 capsule which landed in 1971 and sent back information for 14 seconds before going silent.)
One of the two rovers now on Mars — Curiosity — has established once and for all time that Mars was entirely habitable in its early life. It has drilled into the planet numerous times and has tested the samples for essential-for-life carbon organic compounds (which it found.) It also has detected clear evidence of long-ago and long-standing lakes and rivers. And it measured radiation levels at the surface over years to help determine how humans might one day survive there.
I think it’s fair to say that Curiosity has advanced an understanding of the history and current realities of Mars more than any other mission, and perhaps more than all the others combined.
Equally important, the almost two-thousand pound rover was delivered to the surface via a new landing technique called the “sky crane.” If your goal is to some day land a human on Mars, then learning how to deliver larger and larger payloads is essential because a capsule for astronauts would weigh something like 80,000 pounds.
The European Space Agency, as well as the Russians and Chinese, have tried to send landers to Mars in recent years, but with no success.
And as for Curiosity, it has been exploring Mars now for almost five years — well past its nominal mission lifetime.
NASA missions to Saturn and Jupiter have sent back images that are startling in their beauty and overflowing in their science. And they have found unexpected features that could some day lead to a discovery of extraterrestrial life in our solar system.
The most surprising discovery was at Saturn’s moon Enceladus, which turns out to be spewing water vapor into space from its south pole region. This water contains, among other important compounds, those organic building blocks of life, as well as evidence that the plumes are generated by hydrothermal heating of the ocean under the surface of the moon.
In other words, there is a global ocean on Enceladus and at the bottom of it water and hot rock are in contact and are reacting in a way that, on Earth at least, would provide an environment suitable for life. And then the moon is spitting out the water to make it quite possible to study that water vapor and whatever might be in it.
If the last decades are a guide, up-close study of these icy moons is a challenge and opportunity that the United States alone — sometimes in collaboration with European partners — has shown the ability and appetite to embrace make happen.
The plumes were investigated and even traversed by the Cassini spacecraft, which is a joint NASA-ESA mission. The primary ESA contribution was the Huygens probe that descended to Titan in 2005. To people in the space science community, these kind of collaborations — generally with European space agencies — allow for more complex missions and good international relations.
Plumes of water vapor have also been tentatively discovered identified on Jupiter’s moon, Europa. The data for the discovery came mostly from the Hubble Space Telescope, and is already a part of the previously approved NASA future. The Europa Clipper is scheduled to launch in the 2020s, to orbit the moon and intensively examine the solar system world believed most likely to contain life.
The plumes would be coming from another large global ocean under a thick shell of ice, a body of water understood to be much older and much bigger than that of Enceladus. Clearly, having some of that H2O available for exploration without going through the thick ice shell would be an enormous obstacle eraser.
A follow-up Europa lander mission has been studied and got favorable reviews from a NASA panel, but was not funded by the Trump Administration. Several follow-up Enceladus life-detection missions are currently under review.
I think one could make a strong case that the Hubble Space Telescope has been the most transformative, productive and admired piece of space technology ever made.
For more than two decades now it has been the workhorse of the astrophysics, cosmology and exoplanet communities, and has arguably produced more world-class stunning images than Picasso. In terms of exploring the cosmos and illustrating some of what’s out there, it has no competition.
There is little point to describing its specific accomplishments in terms of discovery because they are so many. Suffice it to say that a collection of published science papers using Hubble data would be very, very thick.
And because of past NASA, White House and congressional commitment to space science, the over-budget and long behind-schedule James Webb Space Telescope is now on target to launch late next year. The Webb will potentially be as revelatory as the Hubble, or even more so in terms of understanding the early era of the universe, the nature and origin of ubiquitous dark matter, and the composition of exoplanets.
Preliminary planning for the great observatory for the 2030s is underway now, and nobody knows whether funding for something as ambitious will be available.
Many of the early exoplanet discoveries were made by astrophysicists at ground-based observatories, and were made by both American, European and Canadian scientists. NASA’s Spitzer Space Telescope and others played a kind of supporting role for the agency, but that all changed with the launch of NASA’s Kepler Space Telescope.
From 2009 to today, the Kepler has identified more than 4,000 exoplanet candidates with more than 2,400 confirmed planets, many of which are rocky like Earth. Of roughly 50 near-Earth size habitable zone candidates detected by Kepler, more than 30 have been verified.
The census provided by Kepler, which looked fixedly at only one small part of the deep sky for four years until mechanical, led to the consensus conclusion that the Milky Way alone is home to billions of planets and that many of them are rocky and in the habitable zone of their host stars.
In other words, Kepler made enormous progress in defining the population of exoplanets likely to exist out there — a wild menagerie of objects very different from what might have been expected, and in systems very different as well.
Two additional NASA observatories designed to detect and study exoplanets are scheduled to launch in the next decade.
Given the number of references to our moon in Pence’s Kennedy Space Station speech — and the enormous costs of the also often referenced humans-to-Mars idea — my bet is that moon landings and perhaps a “colony” will be the Administration’s human space exploration project of choice.
I say this because it is achievable, with NASA rockets and capsules under construction and the fast-growing capabilities of commercial space competitors. We have, after all, proven that astronauts can land and survive on the moon, and a return there would be much less expensive than sending a human to Mars and back. (I’m also skeptical that such a trip to Mars will be technically feasible any time in the foreseeable future, though I know that others strongly disagree.)
As readers of Many Worlds may remember, I’m a fan of a human spaceflight project championed by former astronaut and head of NASA’s Science Directorate John Grunsfeld to assemble a huge observatory in space designed to seriously look for life around distant stars. This plan is innovative, would give NASA and astronauts an opportunity learn how to live and work in deep space, and would provide another science gem. It would indeed show American space leadership.
But here is why I think a moon colony is going to be the choice: Russia, China and the Europeans have all announced tentative plans to build moon colonies in the next decade or two. So for primarily strategic, competitive and national security reasons, it seems likely that this kind of “new frontier” is what the administration has in mind.
After all, Pence also said in his speech at the KSC that “Under President Donald Trump, American security will be as dominant in the heavens as we are here on Earth.” (An apparent reference to both NASA and the military space program, which is significantly better funded than NASA.)
Setting up an American moon colony would be very costly in dollars, time and focus, but it’s not necessarily a bad thing. Given that a pie can be sliced just so many ways, however, it’s pretty clear that a major moon colony project would end up taking a significant amount of funding away from space science missions.
Returning to the moon and even setting up a colony is not, however, an example of American leadership. Rather, it would constitute a decision for the United States and NASA to, in effect, follow the pack.
This article of mine, slightly tweaked for Many Worlds, first appeared today (July 6) in Astrobiology Magazine, www.astrobio.net
As NASA inches closer to launching new missions to the Solar System’s outer moons in search of life, scientists are renewing their focus on developing a set of universal characteristics of life that can be measured.
There is much debate about what might be considered a clear sign of life, in part, because there are so many definitions separating the animate from the inanimate.
NASA’s prospective missions to promising spots on Europa, Enceladus and Titan have their individual approaches to detecting life, but one respected voice in the field says there is a better way that’s far less prone to false positives.
Noted chemist and astrobiologist Steven Benner says life’s signature is not necessarily found in the presence of particular elements and compounds, nor in its effects on the surrounding environment, and is certainly not something visible to the naked eye (or even a sophisticated camera).
Rather, life can be viewed as a structure, a molecular backbone that Benner and his group, Foundation for Applied Molecular Evolution (FfAME), have identified as the common inheritance of all living things. Its central function is to enable what origin-of-life scientists generally see as an essential dynamic in the onset of life and its increased complexity and spread: Darwinian evolution via transfer of information, mutation and the transfer of those mutations.
“What we’re looking for is a universal molecular bio-signature, and it does exist in water,” says Benner. “You want a genetic molecule that can change physical conditions without changing physical properties — like DNA and RNA can do.”
Looking for DNA or RNA on an icy moon, or elsewhere would presuppose life like our own — and life that has already done quite a bit of evolving.
A more general approach is to find a linear polymer (a large molecule, or macromolecule, composed of many repeated subunits, of which DNA and RNA are types) with an electrical charge. That, he said, is a structure that is universal to life, and it can be detected.
As described in a recent paper that Benner’s group published in the journal Astrobiology: “the only molecular systems able to support Darwinian information are linear polymers that have a repeating backbone charge. These are called ‘polyelectrolytes.’
“These data suggest that polyelectrolytes will be the genetic molecules in all life, no matter what its origin and no matter what the direction or tempo of its natural history, as long as it lives in water.”
Through years of experimentation, Benner and others have found that electric charges in these crucial polymers, or “backbones,” of life have to repeat. If they are a mixture of positive and negative charges, then the ability to pass on changing information without the structure itself changing is lost.
And as a result, Benner says, detecting these charged, linear and repeating large molecules is potentially quite possible on Europa or Enceladus or wherever water is found. All you have to do is expose those charged and repeating molecular structures to an instrument with the opposite charge and measure the reaction.
James Green, director of NASA’s Planetary Sciences division, sees values in this approach.
“Benner’s polyelectrolyte study is fascinating to me since it provides our scientists another critical discussion point about finding life with some small number of experiments,” he says.
“Finding life is very high bar to cross; it has to metabolize, reproduce, and evolve — all of which I can’t develop an experiment to measure on another planet or moon. If it doesn’t talk or move in front of the camera we are left with developing a very challenging set of instruments that can only measure attributes. So polyelectrolytes are one more to consider.”
Benner has been describing his universal molecular bio-signature to leaders of the groups competing for New Frontiers missions, which fill the gap between smaller Discovery missions and large flagship planetary missions. It’s taken a while but due to his efforts over several years, he notes that interest seems to be growing in incorporating his findings.
In particular, Chris McKay, a prominent astrobiologist at NASA’s Ames Research Center and a member of one of the New Frontiers Enceladus proposal teams, says he thinks there is merit to Benner’s idea.
“The really interesting aspect of this suggestion is that new technologies are now available for sequencing DNA that can be generalized to read any linear molecule,” McKay writes in an email.
In other words, they can detect any polyelectrolytes.
Other teams are confident that their own kinds of life detection instruments can do the job. Morgan Cable, deputy project scientist of the Enceladus Life Finder proposal, she says her team has great confidence in its four-pronged approach. A motto of the mission on some of its written material is: “If Encedadus has life, we will find it.”
The package includes instruments like mass spectrometers able to detect large molecules associated with life; measurements of energy gradients that allow life to be nourished; detection of isotopic signatures associated with life; and identification of long carbon chains that serve as membranes to house the components of a cell.
“Not one but all four indicators have to point to life to make a potential detection,” Cable says.
NASA is winnowing down 12 proposals by late this year, so, Benner’s ideas could play a role later in the process as well. NASA’s goal is to select its next New Frontiers mission in about two years, with launch in the mid-2020s.
The Europa Clipper orbiter mission is tentatively scheduled to launch in 2022, but its companion lander has been scrubbed for now by the Trump administration.
Nonetheless, NASA put out a call last month for instruments that might one day sample the ice of Europa. Benner is once more hoping that his theory of polyelectrolytes as the key to identifying life in water or ice will be considered and embraced.
I hope you will indulge me in this foray into a very different look at the many worlds in which we live.
My father is being buried today. It is no tragedy; he lived to almost 97 and had a full life. But still…
As all of you have no doubt experienced in one way or another, there is a huge disconnect between the emotions we feel individually about a newcomer to our world or a departing elder and the arrival and departure of those we don’t know at all.
The birth of a loved child is as glorious as most anything can be. And yet it is, in the larger picture, totally banal. I found this figure: By 2011, an estimated 107,602,707,800 humans had been born since the emergence of the species.
Same with death. The death of a loved elder is a profound event. And yet it, too, is banal. One hundred billion of those born have also died.
There are a handful of exceptions to this dual reality. These births and deaths (and lives) are not viewed as banal but as historically important. You can pick your own people for that list, but I bet they will be a group of people both very good and very bad, many of them talented and all of them charismatic.
But for the rest of us, a particular birth and death are of enormous importance to very few. It’s a kind of background noise.
Why am I writing about this now?
Clearly because I’m grieving and trying to make sense of the suffering and passing of my father.
But also because that grief — and the absence of grief all around me in New York City where he lived — speaks to that weird relativity in the emotional universe. When you look closely at what reality is, the picture is very different from how things may feel inside.
This is a dichotomy I’ve had to embrace as I learn and write about the cosmos. Our human view of the world is, well, often quite lacking in perspective.
Our sense of time is another example. We humans live within a story line where a life of 97 years is a very long one. Although there are an increasing number of long-lived people — almost two million above age 90 in the United States — they remain a tiny percentage of the population.
In terms of Earth’s 4.5 million years of geological time, my father’s 96 years is less than a blip. And in astronomical time — the 13.7 billion years of the universe — they are completely inconsequential.
Our human lifetimes matter so much to us. But in the reality of time and space as they truly exist, those lives mean virtually nothing. Yet we persist in our great joys and sorrows. “All the world’s a stage and all the men and women merely players,” wrote one of those people whose name and legend does live on. “They have their exits and their entrances, and one man in his time plays many parts…” I think my father would appreciate this stepped-back approach to his passing.
He was born poor in the South Bronx and became a soldier, student, artist, professor, poet and voracious reader. His background included virtually no science study, but as I wrote more about space and life origins, he found those subjects to be increasingly interesting. (They were a welcome reprieve for me from the political discussions he was inclined to wage in a take-no-prisoners style.)
He was not a religious man, but he did enjoy thinking and reading about subjects ranging from the beginning of the cosmos to theories of quantum life. I don’t think he would ever use this word, but he sought a kind of cosmic transcendence.
This was especially so after the passing of his wife of 63 years. He was nearly crushed by his grief, but he gradually put together a life that continued with stubborn and hopefully satisfying independence for 11 years.
He told me for several years that he didn’t fear death. He didn’t want to die and went to many doctors to try to keep going. But he said he was ready to accept the end, and in his final weeks and days I came to see that he was — especially as he lost his treasured independence and endured a not inconsiderable amount of suffering.
He slowly left after a week of refusing almost all food and water. I’m told it’s a kind of animal path to dying. (No disrespect here, as we are animals, of course.) And I think such a path is no tragedy, especially given his good fortune to have had almost 97 years on Earth.
I wrote a column early in my tenure at Many Worlds about Einstein and his ideas about “cosmic religion.” In it, I wrote about that part of Einstein’s thinking that gets less attention than it seems to deserve, to me at least. And as I was thinking about my father’s passing, Einstein’s thoughts on cosmic religion came back to me.
No god, no unresolvable mysteries, no dogma. Instead the wonderful and punishing laws of nature and the cosmos, and our good fortune to have some time living in them as human beings. A kind of clear-eyed transcendence without all the religious trappings.
Thoughts of clear-eyed transcendence brought back to mind the most searing and surprising death and aftermath that I’ve witnessed. When I was a reporter at The Philadelphia Inquirer, a charming young woman and her reporter husband were finally going to have a long-desired baby. Well into the pregnancy, as I remember it, the woman starting getting very sick and was ultimately diagnosed with a fast-spreading cancer.
It was brutal, but she hung on and gave birth. And then a few days later she died.
The entire Inquirer staff came to her funeral, and her husband got up to speak. None of us knew what to expect, what someone in his place could possibly say.
But speak he did, and what he had to say was powerfully moving and instructive. Yes, he had felt despair and anger at the awful turn of events, and, yes, what faith he had was shattered.
Then he spoke as if transported about the unexpected understanding that had come to him.
The death was an absolute tragedy and hideously unfair. But out of it had come a beautiful, healthy boy. Despite the horrible twist of fate, something precious had arrived. The mother’s strength and grit had allowed a longed-for baby to survive.
And the husband ended with this reality lost in the grief: had his wife not been pregnant, she still would have died of cancer. But she would have died without a lovely child delivered to the world.
Grief and joyful transcendence. There was not a dry eye in the huge crowd and not a heart that had not been lifted.
My father’s death will effect far fewer people than the one I just described. The emotional punch of his passing has less force because he lived fully and because so many of his contemporaries are gone.
But the emotional dichotomy is still there and cries out for transcendence. Each life is so important and yet so unimportant. How do we make sense of that?
Sometimes personal affairs intervene for all of us, and they have now for your Many Worlds writer and his elderly father. But rather than remain off the radar screen, I wanted to repost this column which has a new import.
It turns out that versions of the instrument described below — a miniature gene sequencing device produced by Oxford Nanopore — have been put forward as the kind of technology that could detect life in the plume of Enceladus, or perhaps on Europa or Titan.
Major figures in the astrobiology field, including Steve Benner of the Foundation for Applied Molecular Evolution (FfAME) and Chris McKay of NASA Ames Research Center see this kind of detection of the basic polymer backbone of RNA or DNA life as a potentially significant way forward. Three different “Icy Moon” teams are vying for a NASA New Frontiers mission to Enceladus and Titan, and this kind of technology plays a role in at least one of the proposed missions.
When scientists approach the question of how life began on Earth, or elsewhere, their efforts generally involve attempts to understand how non-biological molecules bonded, became increasingly complex, and eventually reached the point where they could replicate or could use sources of energy to make things happen. Ultimately, of course, life needed both.
Researchers have been working for some time to understand this very long and winding process, and some have sought to make synthetic life out of selected components and energy. Some startling progress has been made in both of these endeavors, but many unexplained mysteries remain at the heart of the processes. And nobody is expecting the origin of life on Earth (or elsewhere) to be fully understood anytime soon.
To further complicate the picture, the history of early Earth is one of extreme heat caused by meteorite bombardment and, most important, the enormous impact some 4.5 billion years of the Mars-sized planet that became our moon. As a result, many early Earth researchers think the planet was uninhabitable until about 4 billion years ago.
Yet some argue that signs of Earth life 3.8 billion years ago have been detected in the rock record, and lifeforms were certainly present 3.5 billion years ago. Considering the painfully slow pace of early evolution — the planet, after all, supported only single-cell life for several billion years before multicellular life emerged — some
researchers are skeptical about the likelihood of DNA-based life evolving in the relatively short window between when Earth became cool enough to support life and the earliest evidence of actual life.
So what else, from a scientific as opposed to a religious perspective, might have set into motion the process that made life out of non-life?
One long considered yet generally quickly dismissed answer is getting new attention and a little more respect. It invokes panspermia, the sharing of life via meteorites from one planet to another, or delivery by comet.
In this context, the question generally raised is whether Earth might have been seeded by early Martian life (if it existed). Mars, it is becoming increasingly accepted, was probably more habitable in its early period than Earth. But panspermia inherently could go the other way as well, or possibly even between solar systems.
A team of prominent scientists at MIT and Harvard are sufficiently convinced in the plausibility of panspermia that they have spent a decade, and a fair amount of NASA and other funding, to design and produce an instrument that can be sent to Mars and potentially detect DNA or more primitive RNA.
In other words, life not only similar to that on Earth, but actually delivered long ago from Earth. It’s called the The Search for Extraterrestrial Genomes, or SETG.
Gary Ruvkun is one of those researchers, a pioneering molecular biologist at Massachusetts General Hospital and professor of genetics at Harvard Medical School.
I heard him speaking recently at a Space Sciences Board workshop on biosignatures, where he described the real (if slim) possibility that DNA or RNA-based life exists now on Mars, and the instrument that the SETG group is developing to detect it should it be there.
The logic of panspermia — or perhaps “dispermia” if between but two planets — is pretty straight-forward, though with some significant question marks. Both Earth and Mars, it is well known, were pummeled by incoming meteorites in their earlier epochs, and those impacts are known to have sufficient force to send rock from the crash site into orbit.
Mars meteorites have been found on Earth, and Earth meteorites no doubt have landed on Mars. Ruvkun said that recent work on the capacity of dormant microbes to survive the long, frigid and irradiated trip from planet to planet has been increasingly supportive.
“Earth is filled with life in every nook and cranny, and that life is wildly diverse,” he told the workshop. “So if you’re looking for life on Mars, surely the first thing to look for is life like we find on Earth. Frankly, it would be kind of stupid not to.”
The instrument being developed by the group, which is led by Ruvkun and Maria Zuber, MIT vice president for research and head of the Department of Earth, Atmospheric and Planetary Sciences. It would potentially be part of a lander or rover science package and would search DNA or RNA, using techniques based on the exploding knowledge of earthly genomics.
The job is made easier, Ruvkun said, by the fact that the basic structure of DNA is the same throughout biology. What’s more, he said, there about 400 specific genes sequences “that make up the core of biology — they’re found in everything from extremeophiles and bacteria to worms and humans.”
Those ubiquitous gene sequences, he said, were present more than 3 billion years ago in seemingly primitive lifeforms that were, in fact, not primitive at all. Rather, they had perfected some genetic pathways that were so good that they still used by most everything alive today.
And how was it that these sophisticated life processes emerged not all that long (in astronomical or geological terms) after Earth cooled enough to be habitable? “Either life developed here super-fast or it came full-on as DNA life from afar,” Ruvkun said. It’s pretty clear which option he supports.
Ruvkun said that the rest of the SETG team sees that kind of inter-planetary transfer — to Mars and from Mars — as entirely plausible, and that he takes panspermia a step forward. He thinks it’s possible, though certainly not likely nor remotely provable today, that life has been around in the cosmos for as long as 10 billion years, jumping from one solar system and planet to another. Not likely, but at idea worth entertaining.
Maria Zuber of MIT, who was the PI for the recent NASA GRAIL mission to the moon, has been part of the SETG team since near its inception, and MIT research scientist Christopher Carr is the project manager. Zuber said it was a rather low-profile effort at the start, but over the years has attracted many students and has won NASA funding three times including the currently running Maturation of Instruments for Solar System Exploration (MatISSE) grant.
“I have made my career out of doing simple experiments. if want to look for life beyond earth helps to know what you’re looking for.
“We happen to know what life on Earth is like– DNA based or possibly RNA-based as Gary is looking for as well. The point is that we know what to look for. There are so many possibilities of what life beyond Earth could be like that we might as well test the hypothesis that it, also, is DNA based. It’s a low probability result, but potentially very high value.”
DNA sequencing instruments like the one her team is developing are taken to the field regularly by thousands of researchers, including some working with with SETG. The technology has advanced so quickly that they can pick up a sample in a marsh or desert or any extreme locale and on the spot determine what DNA is present. That’s quite a change from the pain-staking sequencing done painstakingly by graduate students not that long ago.
Panspermia, Zuber acknowledged, is a rather improbable idea. But when nature is concerned, she said “I’m reticent to say anything is impossible. After all, the universe is made up of the same elements as those on Earth, and so there’s a basic commonality.”
Zuber said the instrument was not ready to compete for a spot on the 2020 mission to Mars, but she expects to have a sufficiently developed one ready to compete for a spot on the next Mars mission. Or perhaps on missions to Europa or the plumes of Enceladus.
The possibility of life skipping from planet to planet clearly fascinates both scientists and the public. You may recall the excitement in the mid 1990s over the Martian meteorite ALH84001, which NASA researchers concluded contained remnants of Martian life. (That claim has since been largely refuted.)
Of the roughly 61,000 meteorites found on Earth, only 134 were deemed to be Martian as of two years ago. But how many have sunk into oceans or lakes, or been lost in the omnipresence of life on Earth? Not surprisingly, the two spots that have yielded the most meteorites from Mars are Antarctica and the deserts of north Africa.
And when thinking of panspermia, it’s worthwhile to consider the enormous amount of money and time put into keeping Earthly microbes from inadvertently hitching a ride to Mars or other planets and moons as part of a NASA mission.
The NASA office of planetary protection has the goal of ensuring, as much as possible, that other celestial bodies don’t get contaminated with our biology. Inherent in that concern is the conclusion that our microbes could survive in deep space, could survive the scalding entry to another planet, and could possibly survive on the planet’s surface today. In other words, that panspermia (or dispermia) is in some circumstances possible.
Testing whether a spacecraft has brought Earth life to Mars is actually another role that the SETG instrument could play. If a sample tested on Mars comes back with a DNA signature result exactly like one on Earth–rather one that might have come initially from Earth and then evolved over billions of years– then scientists will know that particular bit of biology was indeed a stowaway from Earth.
Rather like how a very hardy microbe inside a meteorite might have possibly traveled long ago.
This blog is being hosted by Knowinnovation Inc. and is supported by the Lunar and Planetary Institute (LPI). LPI is operated by the Universities Space Research Association (USRA) under a cooperative agreement with NASA. The purpose of this blog is to communicate the work of the Nexus for Exoplanet Systems Science (NExSS). Any opinions, findings, and conclusions or recommendations expressed on this blog or its comments are those of the author(s) and do not necessarily reflect the views of NASA.