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Home , Gliese 581e, Sara Seager

21 10 meters

SARA SEAGER and , Massachusetts Institute of Technology, Cambridge

We picnicked inside a fiberglass radome (a portmanteau of radar and dome), atop the tallest building in Cambridge. The Green Building, otherwise known as Building 54, houses the fields of Geology and Sciences on the lower floors and and Atmospheric Sciences on the upper floors. It was only late October, but the temperature was already below freezing, so we bundled up in fur caps and heavy jackets to endure the cold inside the dome. We sat next to a defunct radar satellite that had recently been hacked by students to bounce beams off the moon. 1 Sara requested high-protein brain food, so we made hard-boiled eggs and prepared them so that each egg was boiled for a different increment of time, which was an- notated on each of the dozen eggshells:

5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, Michael: Do you know the early astronauts like Buzz 15 min, 16 min what your kids are going to Aldrin. Buzz Aldrin can be dress up as for Halloween? alternately outspoken, rude, Sara ate a twelve-minute egg to test her theory that there is a threshold beyond obnoxious, and fun, while the which there is no effect on the egg, so boiling longer only serves to waste energy. Sara: Yes, one son is going to be current astronauts typically Buzz Aldrin, an astronaut, and appear to be more conforming (FIG. 1) the other son will be a pirate. and obedient. A pirate is kind of like the early astronauts: a Amy: Similar. radical who challenges authority.

Sara: Actually they are quite Amy: Is Buzz still alive? opposite in personality. Sara: Yes. For MIT’s 150th Amy: They are both going on anniversary in 2011, there journeys. were a number of celebratory symposia. One of the symposia Sara: Yes, agreed. Astronauts was “Earth, Air, Ocean and Space: are adventurous, most especially The Future of Exploration”

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signs of life by way of unusual off of the picture. In fact I could Michael: What is beautiful is that amounts of “” gases even argue that when we want to we will be able to observe it if we in atmospheres. think about the probability of life as a society keep aging. Eventually in the Universe we first think the light would reach us. (FIG. 2) Sara showing us our of the scale of 1021, the scale of place in the universe, a rendering our galaxy and even 1026, the Sara: If we lived for billions of what we believe our galaxy, scale of the visible universe. and billions of years we could the Milky Way, looks like. “This is One more thing I want to add is see a little further out. showing us approximately where that because we are looking for our sun is, and trying to illustrate signs of life by way of exoplanet Amy: So is that the goal of how far away we can find other atmospheric gases, we are trying astronomy, to see out that , around other . At the to understand the gas outputs far, but knowing you can’t? end of this little column, that’s how of microbial life on earth, trying far away the Kepler stars are, but to understand processes at a Sara: have many even those stars we consider too far much smaller scale than planetary different goals and most of our to see. So despite the fact that we or size, on the scale goals center around the concept have a hundred billion stars in our of 10-5. of understanding where we galaxy, and there are upwards of came from. One of our goals is 2 hundreds of billions of galaxies, we Amy: This movie was made in to know how the universe was can only really find planets close 1968, and it claimed that we born and evolved. And, we don’t to our home, right near our sun.” were looking at the edges of necessarily need to see the whole our understanding at that time. universe to move our understand- Amy: So we’ve been using How have the edges of under- ing forward. For example, right and included a panel of ten to the differing scales in Powers standing in your field changed now, outside of my window we twelve astronauts all together. of Ten to frame our conversa- from that period to now? can see the city of Boston on a Buzz certainly stole the show. tions with people; where macroscopic scale (FIG. 3). And would you place your research Sara: Well the movie went to we know that there are other Amy: Now that you’re on that continuum? 1024, and in astronomy, we’d like cities out there. We just can’t see warmed up, can you tell to go a lot further. We have the them from here but we could us about your research? Sara: Most of my research is capability for observing very, extrapolate or try to use other placed in the planetary scale, very far away. The size of the information about cities. With Sara: My research is on which is 107. Our earth has a ra- observable universe is roughly astronomy, it’s a similar concept. – planets that orbit dius of about 6,400 kilometers, so 47 billion light years or 4.4 times We still have information about stars other than our sun. We its diameter is about 107 meters. 1026 meters. We can’t see further most of the components of the know of hundreds of exoplanets What I love about exoplanets away than this because light more universe, even if we cannot see all right now and there are likely is that the research operates on than 4.4 x 1026 meters away has of the very distant components. far more than trillions of planets other scales. For instance, 1012 not had time to reach us over out there in the universe. We encompasses the of the the age of the universe. So the Returning to the changes since are trying to understand what Solar System’s four inner planets. next power of ten, 1027, is not the film was made, in the 1960s exoplanets are made of, how to Or 1013, which encompasses the observable. So, sorry you won’t exoplanets were simply specula- detect them, and how to find solar system with Pluto partially be able to do 1027. tion; people hadn’t even found

105 them yet. There were a few leads planets are twice the size of Earth planet in the so-called habitable idea, and it will be accepted. But which turned out not to be real and must have large quantities zone of its host , with a there is a line drawn, and aliens planets, so people imagined that of gas in their atmospheres, habitable moon in orbit about definitely fall on the wrong side all planetary systems were just making them more equivalent to the planet. Right now, we know of that line. Instead we are doing like our own. At the scale of a mini-Neptune than to an Earth. there are no big planets in the the real search for planets that 1013, we see an image of our solar I can give you dozens of examples Alpha Centauri sun-like star could have life; it’s our goal to system where the planets are well of anomalous exoplanets. So systems; such planets have been find so-called “habitable worlds,” sorted with the four small inner the sheer number of surprises is ruled out by observations. and when we find potentially planets and the four outer giant changing our philosophy about habitable planets, we’re going to planets. Theories were built, then, what other planets could be Michael: I’m imagining that look for signs of life on them. about planet formation based on like. This changed paradigm of Avatar must have had some There is no question that others the single example of our own the range of exoplanet types team of scientists that helped will follow and try to send or solar system. But today with is the biggest factor that has them. Have you ever been listen for radio signals. And, hundreds of known exoplanets changed since the 1960s. consulted by Hollywood? there’s also no question in my – many, many known planetary mind that in the distant future systems – we have a completely Amy: And how does that knowl- Sara: Absolutely. I really like people will try to go there, either different picture. And so now edge that there’s more out there Hollywood. At the end of the day with a robotic probe, which might we believe that for exoplanets affect culture on a larger level? Hollywood doesn’t usually take take tens to hundreds of years, anything is possible within the my advice, but I have been a ves- or alternatively to find a way for laws of physics and chemistry. Sara: What’s fascinating about sel for brainstorming in a unique humans to travel there alone. The Any kind of planet you could exoplanets is that in some ways way. The public has a huge public loves the concept of aliens, imagine is out there somewhere. popular culture is ahead of us appetite for black hole physics, and the public are our taxpayers scientists because of science time travel, , relativity, who ultimately fund our space Michael: What is an fiction, things likeStar Trek. exoplanets, and aliens. Even missions. So we want to connect example that a layperson Popular culture is already primed though the Hollywood fiction with those people, but there’s a might not imagine? for our discoveries. I would say doesn’t really match with our real- difference between people who the public loves the discoveries ity here in physics, it is wonderful like to think emotionally and Sara: A recent example is a that bring humanity one step to try and bridge that gap. people who like to use logic. We planetary system called Kepler 11. closer to finding habitable worlds. were joking around that when I Kepler 11 has six known planets, Michael: This fascination with get my satellite communications with five of those planets orbiting Amy: How do science fiction life on other planets in popular ground station in the radar dome interior to what would be akin to movies relate to scientific culture, I wonder how that gets on the roof of my building, the distance of Mercury’s orbit. planetary knowledge? talked about in certain academic we will inaugurate the ground So five planets are squeezed into circles. I found it interesting that station by sending a radio signal a location where our Solar System Sara: Well you can pick any on the seventeenth floor of this message to a planetary system has one planet. Now imagine one. Let’s pick Avatar. In terms building (The Green Building at with a known planet that has what kind of planets might the of exoplanet knowledge, Avatar MIT) the word “alien” is used. some chance of being habitable Kepler 11 planets be? Do you was ten years out of date. They (FIG. 4). think they are like Mercury, very depicted the Alpha Centauri Sara: It’s not Hollywood, but in a rocky and small? In fact they star system in the film, and strange way one great thing about Michael: What would are not. Most of the Kepler 11 they imagined a Jupiter-sized MIT is that you can have a crazy that signal be?

106 4 The ExoplanetSat nano-satellite batteries, the board that controls has three parts to it (in fact power, and many other things. ExoplanetSat is a three-unit And on the outside, there would “CubeSat”). One part is this box be deployable solar panels to here, inside of which would be a gather energy to store in pointing system (FIG. 5). The batteries. We might also have a device has no fuel or propulsion, baffle on the outside front of the so the satellite will get disturbed nano-satellite, just like you have by and other forces while one on your camera, to protect it is orbiting Earth. The pointing the camera from stray light. system inside the box would have reaction wheels to keep the Amy: So you would launch this satellite stably pointed towards a into space, and how do you target star. Now, in addition to get it back? the reaction wheel control unit, ExoplanetSat requires an Sara: We don’t get the satellite additional level of pointing back. ExoplanetSat will commu- control. The reason we want nicate to us through radio signals ExoplanetSat to point very that would reach our ground precisely is to take the best stations. And in later versions 5 images possible of the target stars, of ExoplanetSat, we plan to also over and over and over again. communicate with the equivalent Just like when you’re taking a of the satellite cellphone. picture, if you shake your camera a little, the picture becomes Amy: So it lives out there forever? blurry. The second pointing Sara: Well, that’s the question, our own terrestrial-based culture control is effectively an image Sara: Well, not exactly forever, what would the message be? might be a challenge for any stabilizer and is this little piece of but yes for about twenty years. I don’t know. I think you two alien society to interpret. hardware here: it’s only little in After that, due to atmospheric should think of something! Think size, not in dollar value! The drag, the satellite will spiral of it this way: if the aliens are Amy: Can you talk about some of second part of the ExoplanetSat down and burn up in Earth’s listening at the same frequency the tools you use in this search? nano-satellite is the camera. atmosphere. In fact, there is a rule we are transmitting on, we would Here’s the lens, and the camera for CubeSats that the lifetime have to send something clever Sara: This nano-satellite also has a special detector here, must be twenty-five years or less. enough to get their attention. demonstration model is called similar to what the camera NASA and others want to have Because what if they’re listen- “ExoplanetSat”. detector on your iPhone camera a bunch of CubeSats launch out ing? We would have to send might be. Now moving to of their standardized deployers something really cool, but it This actual model illustrates a describe the third part of the (called P-Pods) on many of the must be something universally prototype nano-satellite we are nano-satellite, in the middle rockets being launched. It’s recognized as very clever, right? building here at MIT and at our section is basically everything supposed to be a cheap way to A message that is too specific to partner institution Draper Lab. else: the flight computer, get a lot of things to space.

107 Amy: There will probably be a to see this IBM advertisement on taken off, because CubeSat nano- on other parts of Earth, done secondary commercial service the inside cover of this National satellites can be developed and by bouncing radio waves off the someday, a big magnet that goes Geographic (pointing to the inside built at the university level, where moon. It’s not used for research up and collects all this orbiting cover of the December 2009 students can actually design, anymore, the students just do this junk once it’s done being useful. National Geographic with the text, build, and integrate hardware and because it’s here and they can. “Are We Alone? Searching the software for small space satellites Sara: Well, it wouldn’t be a Heavens for another Earth” over that actually get launched. So, (FIG. 6) Extension cables pirated magnet, but you could imagine rendering of a newly discovered federal dollars support our re- up to the roof of the Green Building a future where there is a require- planet, Gliese 581e, that is - search, and they support training to power a computer that reads ment to include propulsions that retically twice the of Earth.) students and we try to combine signals received from the moon. will push small satellites into funding and training. A place lower and lower Earth orbit so It reads, “… a mandate for change like MIT has a big endowment, Amy: In terms of the life they can deorbit and eventually is a mandate for smart” followed with continued private donations. that you’re searching for, do burn up in the atmosphere. Do by a short text full of propaganda But as the economy drops, these you ever imagine what that you remember in the news, about about economic opportunity private donations go away. Right first sign of it might be? a month ago, there was a big connected to computation etc., now, my research makes no profit, satellite that was looking down at but I’m interested in the sponsor- and so we rely on funds from the Sara: I do imagine what it would earth that hadn’t worked since the ship of your research: corporate, university, the government, or pri- be. It’s extremely appealing to 1980s? It made mainstream news, federal, or taxpayer dollars? vate donations, to keep the search me, although it might not be because people were worried that for exoplanets moving forward. that exciting for everybody else a big chunk was going to hit a Sara: That’s partly why I recom- in the world. We’re looking for person, because they have no mended this magazine (pointing Amy: Can you talk about a planet that is small and rocky, control over these old satellites. to an October 2011 volume of where we are right now? and one whose atmosphere shows But I think it all burned up and The Economist with the text “Until unusual chemistry that indicates no debris at all was found. politicians actually do something Sara: We are on the roof of the a high level of probability for about the world economy … BE Green Building at MIT – the life. We always blame people for Amy: And the magazines AFRAID” over a photo of a black tallest building in Cambridge. being terra-centric, thinking of on the blanket? hole), because it had a picture We’re inside one of two domes on our own planet self-centeredly. of the galaxy, with a black hole, the roof, the larger one. But did you know the Sara: I chose a magazine from but it wasn’t about astronomy, that fills our atmosphere to Iran, which covers exoplanets, it was about the economy. And In its heyday, the World War 20 percent by volume should just to show how the whole we as scientists are tied to the II-era radio dish inside this only be present in the tiniest of world loves exoplanets. And the economy for sure. We primarily dome was used for Doppler quantities? Oxygen is actually thought of finding planets like have used taxpayer’s dollars, and radar. The dish measured created by life, by plant life, and Earth elsewhere, that has a chance NASA supports a lot of exoplanet raindrops and rain, sending photosynthetic bacteria. So we to unify us as a human species, in research. We are searching for and out radio waves that bounced like to believe that there are aliens that we all have a common inter- studying exoplanets in the interest back to help study weather. out there looking back at Earth, est that goes beyond any divisions of innovation, the intellectual and that the aliens looking at our that we have with each other. strength of the nation, and educa- Right now the dish is used by a atmosphere see all this oxygen, tion. That’s why CubeSat projects student group for moon bounce and that the aliens realize so Michael: I found it interesting like ExoplanetSat have really communications with people much oxygen shouldn’t be here;

108 by computer programs that run at best scientists, top of the field, high speeds. regardless of gender or race or any other criteria, you still come up Michael: One change in primarily with the names of white science hopefully has to do men. Things haven’t changed with women, being a woman enough. Vera and others were the in science. I’m thinking of pioneers who put up with a lot stories about Vera Rubin at the of stuff, and they made it easier Carnegie Institution for Science. for the next generation of women like me. But I’ve still had to face Amy: There is a story about Vera overt discrimination. The one at an conference thing that still upsets me is the 6 that took place at an observa- internalization of gender issues tory in the hills above San Jose, and stereotypes. I’ve actually California in the 1940s. All the thought a lot about the problem other physicists were men and of why there are so few women, and that the aliens will imagine Sara: Many of the tools used in were to stay the night upon the and sometimes I think some of there’s life on our planet Earth the research of exoplanets were hill. At the end of the first day, the simple solutions are helpful generating all of that oxygen. simply not in existence in 1968. Vera was asked to leave. She (like the timing of academic talks The best example is a space asked why she could not stay to accommodate for family sched- Michael: Are there other things telescope, such as the Hubble the night and the men told her ules; and pausing the tenure clock that would be abnormal to Space Telescope, which was put that there was not a women’s for maternity leave) but there is see in an atmosphere, besides into orbit in 1990. With Hubble bathroom; therefore, they secured a much deeper problem that is oxygen, to that extreme? (and other space telescopes) we housing for her off-site. With that not being addressed. Vera used can get above Earth’s atmosphere, she stormed to the bathrooms to complain and say that three Sara: There are many other so our observations of other and posted a handmade sign, academic generations have gone gases that we can imagine. We objects beyond Earth become ‘WOMEN” and said, “Now by, and there are not enough just don’t know, under condi- much more clear. It’s a great there is!” and stayed the night. women in the physical sciences tions that are different from question because precursor in academia to prove equality. So Earth, which gases would really technology existed, just not the Sara: Vera Rubin is one of the much more needs to be done. be the ones to look for. We’re modern technology that is most famous astronomers alive. working hard on this problem. needed. For example, space She is one of the discoverers of satellites were put up at that time, dark matter. I want you to know Michael: We talked about the but not space telescopes. that before I came to MIT, I ExoplanetSat, and this new Similarly, computers existed, but worked at Carnegie Institution for dome, which represent the not the kind with today’s Science, where I got Vera Rubin’s technology currently in use. Can computing power. My field is old job when she retired. It’s not you talk about the tools that driven by crunching large just that there are no women in your field used in the 1960s and amounts of data that we get from science, but there are very few 1970s, around the time the film space telescopes and modern successful women. If you look was made? ground-based telescopes, and also around to say, who are the very

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