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.