Meenakshi Wadhwa: Hello, my name Meenakshi Wadhwa. I’m a pro­fes­sor in the School of Earth and Space Exploration, and Director of the Center for Meteorite Studies at Arizona State University. I’d like to begin by invit­ing you to direct your atten­tion to this rock in my hand.

What do you see? It looks kin­da dark. And to me it feels quite sol­id, feels heavy. But there’s noth­ing real­ly par­tic­u­lar­ly remark­able about this rock and its appear­ance.

But here’s the thing. If this rock could only tell you where it’s been, and all the places that it’s seen, all the things that it’s wit­nessed, it could be the most extra­or­di­nary tale you’ve ever heard. Can you imag­ine peer­ing back in time almost four and a half bil­lion years ago? Back then our solar sys­tem and plan­ets, includ­ing the Earth, they did­n’t exist. All that there was in place of the solar sys­tem was a mas­sive swirling cloud of gas and dust, at the cen­ter which was a new­ly born star, the sun.

As this mas­sive gaseous disc cooled, and the very first solids began to con­dense out from that, they got quick­ly swept up into rocks that looked kind of like this one right here. And so as these rocks formed, they swept togeth­er to form larg­er and larg­er bod­ies, and even­tu­al­ly formed plan­ets like the Earth.

But this rock that I’m hold­ing right here, it escaped that fate. So lit­er­al­ly it’s a rem­nant, a left­over frag­ment from the ear­li­est stage of planet-building. It’s what we call a mete­orite. All mete­orites come from some­where else in our solar sys­tem. Most of them come from aster­oids but some come from the moon, and some come from Mars. They have trav­eled bil­lions of miles through inter­plan­e­tary space, until they final­ly fall on the Earth and can be recov­ered by us. And so it is that I hap­pen to be hold­ing here in my hand a piece of this rock that I think of as a Rosetta Stone for deci­pher­ing the ear­li­est his­to­ry of our solar sys­tem.

So my path to deci­pher­ing the sto­ries that are record­ed in mete­orites began as a lit­tle girl grow­ing up in India. I was a real­ly inquis­i­tive kid and asked lots of ques­tions. I was about eight years old, and my sci­ence teacher at school taught us about the process of res­pi­ra­tion. That we breathe in oxy­gen and let out car­bon diox­ide. And I start­ed think­ing about this, and start­ed to get kind of wor­ried that we humans were using up all this oxy­gen, putting out this car­bon diox­ide that must be build­ing up in the atmos­phere. So I real­ly got kind of wor­ried about this and I asked my moth­er, Are we gonna run out of oxy­gen? Is the world com­ing to an end?” And she just laughed and she very patient­ly explained to me the very del­i­cate bal­ance between the abun­dances of car­bon diox­ide and oxy­gen in our atmos­phere. And so I came to appre­ci­ate ear­ly the beau­ty and the del­i­cate bal­ance in the nat­ur­al world around me.

I grew up in the shad­ow of the great Himalayas and could­n’t help but feel awed and inspired by the great forces in nature that formed these tremen­dous moun­tains. I even­tu­al­ly found myself in the geol­o­gy depart­ment at Panjab University in North India. But I was one of very few women study­ing this top­ic in that depart­ment at the time. Many of my girl­friends were encour­aged by their fam­i­lies to pur­sue more tra­di­tion­al career paths, like becom­ing a nurse or a teacher. But my par­ents told me that I could do any­thing, that I could be any­thing. And while they were very very sup­port­ive of me, I was actu­al­ly afraid to tell them what I real­ly dreamed of being. And what I real­ly dreamed of being was a geol­o­gist. But not just any geol­o­gist, I want­ed to be a geol­o­gist on Mars.

I came to the United States to go to grad­u­ate school, in the Department of Earth and Planetary Sciences at Washington University in St. Louis. And at the time I was again one of very few women in my depart­ment. It was actu­al­ly my PhD advi­sor, who also hap­pened to be a woman, who got me start­ed down the path of study­ing mete­orites. She asked me if I want­ed to study these mete­orites that are thought to come from the plan­et Mars. I remem­ber see­ing these Mars rocks and think­ing to myself wow you know, these rocks real­ly look sort of famil­iar to me, like these lava rocks that we find on the Earth. And they formed on a com­plete­ly dif­fer­ent plan­et. I was total­ly hooked.

What these rocks actu­al­ly can tell us about past his­to­ry on Mars, about whether there were ancient oceans on that plan­et, and whether the atmos­phere was much thick­er in the past, these are all ques­tions that I won­dered about. And turns out that these rocks can actu­al­ly tell you all of this and a lot more.

So here’s the thing about mete­orites. They’re not some strange or obscure phe­nom­e­na. They are cen­tral to under­stand­ing the ori­gin of our home plan­et, to our very exis­tence on this plan­et, and even to our future. Many of you have prob­a­bly already heard about the great extinc­tion that hap­pened 65 mil­lion years ago, when 70% of all species on our plan­et were wiped out by a large mete­orite impact. And this is some­thing that could hap­pen to us in the future. But we can avoid that fate by gain­ing a bet­ter under­stand­ing of the chem­i­cal and struc­tur­al make­up of mete­orites. And we can devel­op strate­gies for deflect­ing them that way.

What I real­ly love about study­ing mete­orites, though, is that the infor­ma­tion that these objects tell us basi­cal­ly help us to answer some of human­i­ty’s biggest ques­tions. Are we alone in the uni­verse? Is there life else­where, in our solar sys­tem or beyond? How did our plan­ets form? How did the Earth form? And why is it that our Earth is so dif­fer­ent from oth­er plan­ets in our solar sys­tem? How did life orig­i­nate on our plan­et?

At the ASU Center for Meteorite Studies, my stu­dents and I focus on answer­ing these big ques­tions, of course. But to ini­ti­ate that process we actu­al­ly start by answer­ing small­er ques­tions which are like the pieces of a puz­zle which when we put them togeth­er can help us answer those big­ger ques­tions.

So here’s a cou­ple of inter­est­ing things that we’ve learned recent­ly from the kinds of things that we’re work­ing on in my lab­o­ra­to­ry. Using dat­ing tech­niques involv­ing radioac­tive ele­ments, we have mea­sured the age of our solar sys­tem to be 4.568 bil­lion years old. And we know this age to with­in a few hun­dred thou­sand years. That’s like look­ing at a man who’s a hun­dred years old and being able to esti­mate his age to with­in half a month. Why is it even impor­tant to know the age of our solar sys­tem to that pre­ci­sion? Well, this is the very basis, the very con­text, for under­stand­ing the time­line of evo­lu­tion of our entire solar sys­tem and the plan­ets.

The oth­er thing that we’ve learned recent­ly by study­ing the chem­i­cal make­up of mete­orites like the one that I just showed you is that our solar sys­tem began in very close prox­im­i­ty to a super­no­va, which may have trig­gered the very for­ma­tion of our solar sys­tem. And so the begin­nings of our solar sys­tem were like­ly to be very ener­getic, very vio­lent.

I’m a geol­o­gist by train­ing, and so I look for ways to answer the big ques­tions through the abun­dant rock record that we have here on Earth. In addi­tion to telling us about our own plan­et, the rocks that we find on Earth can also help us to under­stand the geo­log­ic his­to­ry of oth­er plan­ets like Mars. For exam­ple my next project, which was just fund­ed by NASA, will involve field­work in Iceland, where I’ll study rocks that are ana­logues to some types of rocks on Mars. So by study­ing these rocks on the Earth I will actu­al­ly get to be a proxy geol­o­gist on Mars, and I’ll get to under­stand how vul­can­ism on Mars has affect­ed the hydros­phere and the atmos­phere of the plan­et Mars.

Also, since the United States are now com­mit­ted to send­ing human beings to the plan­et Mars in the 2030s, these types of stud­ies, like the project that I’m going to be doing in Iceland, is going to help us to inform strate­gies for human explo­ration by astro­nauts on the sur­face of Mars. So through my research I hope to con­tin­ue to ask and to answer ques­tions that give us insights into the work­ings of our plan­et and our solar sys­tem, and pos­si­bly also oth­er planets—exoplanets, as they’re called—in oth­er solar sys­tems. However the impor­tant thing to remem­ber is that sci­ence is not about hav­ing all the answers. It’s about being able to ask bet­ter and more sophis­ti­cat­ed ques­tions. It’s only by con­stant­ly push­ing the bound­aries of our knowl­edge that we can gain a deep­er under­stand­ing of the com­plex­i­ties of our plan­et and of our solar sys­tem and even beyond our solar sys­tem.

So sci­ence is also about the abil­i­ty to ask and answer ques­tions dif­fer­ent­ly. From new per­spec­tives. And also from dif­fer­ent approach­es. And so one of the new approach­es is work­ing on a pro­pos­al to NASA to col­lect a sam­ple from the sur­face of a comet. Why do we want to exam­ine pieces of a comet, though? Well, we have mete­orites in our col­lec­tions that have quite a lot of organ­ic mate­r­i­al and water in them, but they’re invari­ably con­t­a­m­i­nat­ed because they’ve been sit­ting on the Earth and they’ve been exchang­ing with the abun­dant water and organ­ics in our envi­ron­ment. Now, the sam­ple that we would bring back from a comet would actu­al­ly not be con­t­a­m­i­nat­ed in this man­ner, and so it would pre­serve some of the most pris­tine organ­ic mate­ri­als in our solar sys­tem. So by bring­ing back a sam­ple to Earth and study­ing them in lab­o­ra­to­ries like the ones at ASU, we have the hope of under­stand­ing how life may have orig­i­nat­ed on our plan­et.

If some­one had told the 8 year-old me that I would grow up to be a geol­o­gist and would be able to do geol­o­gy on oth­er places, on oth­er plan­ets in our solar sys­tem like Mars and maybe even comets, I would’ve told them they were crazy. But by study­ing these rocks in lab­o­ra­to­ries here on Earth, in my own lab­o­ra­to­ry, and by being able to study envi­ron­ments on the Earth that are ana­logues for oth­er places in our solar sys­tem, oth­er worlds in our solar sys­tem, I’m actu­al­ly a plan­e­tary geol­o­gist in the broad­est sense of the word.

I start­ed this jour­ney as an inquis­i­tive young girl ask­ing naïve ques­tions, and the tools that I had back then were very sim­ple, too. Just a mag­ni­fy­ing glass to look at the fab­ric of rocks up close. The tools that I use now, of course, are much more sophis­ti­cat­ed. But what real­ly pro­pels my research for­ward is still the ques­tions.

As kids we are all innate­ly and vora­cious­ly curi­ous. But many of us seem to lose that spark of curios­i­ty and won­der as we get old­er and maybe more cau­tious. So let’s be unafraid to ask those big bold ques­tions, and please do the young ones in your life a favor—both boys and girls in your life. Do them a favor and indulge their curios­i­ty just like my moth­er did for me. Fuel their imag­i­na­tion by tak­ing them to a muse­um, or to sci­ence fairs. Let them know that their dreams are not far-fetched. Mine were not, and theirs cer­tain­ly are not. So let’s always plan on look­ing up in won­der at the night sky, at the mete­or show­ers, at shoot­ing stars, and keep ask­ing those ques­tions to pro­pel us for­ward in our quest for knowl­edge and under­stand­ing of the world around us. Thank you.


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