The Gemini Planet Imager’s first light image of Beta Pictoris b (Processing by Christian Marois, NRC Canada)
The world’s newest and most powerful exoplanet imaging instrument, the recently-installed Gemini Planet Imager (GPI) on the 8-meter Gemini South telescope, has captured its first-light infrared image of an exoplanet: Beta Pictoris b, which orbits the star Beta Pictoris, the second-brightest star in the southern constellation Pictor. The planet is pretty obvious in the image above as a bright clump of pixels just to the lower right of the star in the middle (which is physically covered by a small opaque disk to block glare.) But that cluster of pixels is really a distant planet 63 light-years away and several times more massive — as well as 60% larger — than Jupiter!
And this is only the beginning.
GPI installed on the Gemini South 8m telescope. GPI is the boxed suite mounted beneath the platform. (Gemini Observatory)
While many exoplanets have been discovered and confirmed over the past couple of decades using various techniques, very few have actually been directly imaged. It’s extremely difficult to resolve the faint glow of a planet’s reflected light from within the brilliant glare of its star — but GPI was designed to do just that.
“Most planets that we know about to date are only known because of indirect methods that tell us a planet is there, a bit about its orbit and mass, but not much else,” said Bruce Macintosh of the Lawrence Livermore National Laboratory, who led the team that built the instrument. “With GPI we directly image planets around stars – it’s a bit like being able to dissect the system and really dive into the planet’s atmospheric makeup and characteristics.”
And GPI doesn’t just image distant Jupiter-sized exoplanets; it images them quickly.
“Even these early first-light images are almost a factor of ten better than the previous generation of instruments,” said Macintosh. ” In one minute, we were seeing planets that used to take us an hour to detect.”
Despite its large size, Beta Pictoris b is a very young planet — estimated to be less than 10 million years old (the star itself is only about 12 million.) Its presence is a testament to the ability of large planets to form rapidly and soon around newly-formed stars.
“Seeing a planet close to a star after just one minute, was a thrill, and we saw this on only the first week after the instrument was put on the telescope!” added Fredrik Rantakyro a Gemini staff scientist working on the instrument. “Imagine what it will be able to do once we tweak and completely tune its performance.”
Another of GPI’s first-light images captured light scattered by a ring of dust that surrounds the young star HR4796A , about 237 light-years away:
GPI first-light images of HR4796A. (Processing by Marshall Perrin, Space Telescope Science Institute.)
The left image shows shows normal light, including both the dust ring and the residual light from the central star scattered by turbulence in Earth’s atmosphere. The right image shows only polarized light. Leftover starlight is unpolarized and hence removed. The light from the back edge of the disk (to the right of the star) is strongly polarized as it reflects towards Earth, and thus it appears brighter than the forward-facing edge.
It’s thought that the reflective ring could be from a belt of asteroids or comets orbiting HR4796A, and possibly shaped (or “shepherded,” like the rings of Saturn) by as-yet unseen planets. GPI’s advanced capabilities allowed for the full circumference of the ring to be imaged.
The GPI integration team celebrating after obtaining first light images (Gemini Observatory)
GPI’s success in imaging previously-known systems like Beta Pictoris and HR4796A can only indicate many more exciting exoplanet discoveries to come.
“The entire exoplanet community is excited for GPI to usher in a whole new era of planet finding,” says physicist and exoplanet expert Sara Seager of the Massachusetts Institute of Technology. “Each exoplanet detection technique has its heyday. First it was the radial velocity technique (ground-based planet searches that started the whole field). Second it was the transit technique (namely Kepler). Now, it is the ‘direct imaging’ planet-finding technique’s turn to make waves.”
This year the GPI team will begin a large-scale survey, looking at 600 young stars to see what giant planets may be orbiting them.
“Some day, there will be an instrument that will look a lot like GPI, on a telescope in space. And the images and spectra that will come out of that instrument will show a little blue dot that is another Earth.”
– Bruce Macintosh, GPI team leader
The observations above were conducted last November during an “extremely trouble-free debut.” The Gemini South telescope is located near the summit of Cerro Pachon in central Chile, at an altitude of 2,722 meters.
To determine what’s in the atmosphere of an exoplanet, astronomers watch the planet pass in front of its host star and look at which wavelengths of light are transmitted and which are partially absorbed. Credit:
NASA's Goddard Space Flight Center
For the first time, astronomers have found conclusive evidence of water in the hazy atmospheres of planets orbiting other stars. Using the Hubble Space Telescope, two teams of scientists found faint but clear signatures of water in the atmospheres of five exoplanets. All five are so-called ‘hot Jupiters,’ massive worlds that orbit close to their host stars.
“To actually detect the atmosphere of an exoplanet is extraordinarily difficult. But we were able to pull out a very clear signal, and it is water,” said Drake Deming from the University of Maryland, who led a study characterizing the atmospheres of two of the five planets.
“We’re very confident that we see a water signature for multiple planets,” said Avi Mandell, a planetary scientist at NASA’s Goddard Space Flight Center, and lead author of another paper on the remaining three exoplanets. “This work really opens the door for comparing how much water is present in atmospheres on different kinds of exoplanets, for example hotter versus cooler ones.”
The five planets are all well-studied, and would not be friendly places for life as we know it — with blazing temperatures and unusual conditions. WASP-17b is an unusual planet in a retrograde orbit, and sodium had already been detected in its atmosphere.
The atmosphere of WASP-12b already has been found to hold vast amounts of carbon as well as water. WASP-19b orbits a nearby star, and has one of the shortest orbital periods of any known planetary body, about 0.7888399 days or approximately 18.932 hours. XO-1b has the distinction of being discovered by amateur astronomers
The astronomers involved in the new studies say the strengths of the water signatures in each world varied, with WASP-17b and HD209458b having the strongest signals.
Currently, studying exoplanet atmospheres can be done when the planets are passing in front of their stars. Researchers can identify the gases in a planet’s atmosphere by determining which wavelengths of the star’s light are transmitted and which are partially absorbed. Deming’s team employed a new technique with longer exposure times, which increased the sensitivity of their measurements.
In both studies, scientists used Hubble’s Wide Field Camera 3 to explore the details of absorption of light through the planets’ atmospheres. The observations were made in a range of infrared wavelengths where a pattern that signifies the presence of water would appear if water were present. The teams compared the shapes and intensities of the absorption profiles, and the consistency of the signatures gave them confidence they saw water.
“These studies, combined with other Hubble observations, are showing us that there are a surprisingly large number of systems for which the signal of water is either attenuated or completely absent,” said Heather Knutson of the California Institute of Technology, a co-author on Deming’s paper. “This suggests that cloudy or hazy atmospheres may in fact be rather common for hot Jupiters.”
Host: Fraser Cain
Guests: Thad Szabo, Scott Lewis, Ian O’Neill, Alan Boyle, Nancy Atkinson, David Dickinson, Jason Major, Matthew Francis, Nicole Gugliucci
If you’ve ever wanted to know what 3,538 exoplanets look like spinning around their stars, here you go!
This is the third and latest installment of the mesmerizing Kepler Orrery videos by Daniel Fabrycky from the Kepler science team. It shows the relative sizes of the orbits and planets in the multi-transiting planetary systems discovered by Kepler up to November 2013 (according to the Kepler site, 3,538 candidates so far.) According to Daniel “the colors simply go by order from the star (the most colorful is the 7-planet system KOI-351). The terrestrial planets of the Solar System are shown in gray.”
The "Goldilocks" zone around a star is where a planet is neither too hot nor too cold to support liquid water. Ilustration by Petigura/UC Berkeley, Howard/UH-Manoa, Marcy/UC Berkeley.
How common are planets like Earth? That’s been a question astronomers and dreamers have pondered for decades, and now, thanks to the Kepler spacecraft, they have an answer. One in five Sun-like stars in our galaxy have Earth-sized planets that could host life, according to a recent study of Kepler data.
“What this means is, when you look up at the thousands of stars in the night sky, the nearest sun-like star with an Earth-size planet in its habitable zone is probably only 12 light years away and can be seen with the naked eye. That is amazing,” said UC Berkeley graduate student Erik Petigura, who led the analysis of the Kepler and Keck Observatory data.
The Kepler telescope’s mission was to try and find small rocky planets with the potential for hosting liquid water and perhaps the ingredients needed for biology to take hold. For four years, the space telescope monitored the brightness of more than 150,000 stars, recording a measurement every 30 minutes.
Analysis by UC Berkeley and University of Hawaii astronomers shows that one in five sun-like stars have potentially habitable, Earth-size planets. (Animation by UC Berkeley/UH-Manoa/Illumina Studios)
For a recent focused study, scientists concentrated on 42,000 sun-like stars (G and K type stars), looking for periodic dimmings that occur when a planet transits — or crosses in front of — its host star. A team of scientists from the Kepler mission and the Keck telescope in Hawaii have announced that from that survey, they found 603 planets, 10 of which are Earth size and orbit in the habitable zone, where conditions permit surface liquid water.
Since there are about 200 billion stars in our galaxy, with 40 billion of them like our Sun, noted planet-hunter Geoff Marcy said that gives us about 8.8 billion Earth-size planets in the Milky Way.
But Marcy also cautioned that Earth-size planets in Earth-size orbits are not necessarily hospitable to life, even if they orbit in the habitable zone of a star where the temperature is not too hot and not too cold.
“Some may have thick atmospheres, making it so hot at the surface that DNA-like molecules would not survive. Others may have rocky surfaces that could harbor liquid water suitable for living organisms,” Marcy said. “We don’t know what range of planet types and their environments are suitable for life.”
Analysis of four years of precision measurements from Kepler shows that 22±8% of Sun-like stars have Earth-sized planets in the habitable zone. If these planets are as prevalent locally as they are in Kepler field, then the distance to the nearest one is around 12 light-years.Credit: Petigura/UC Berkeley, Howard/UH-Manoa, Marcy/UC Berkeley.
All of the potentially habitable planets found in their survey are around K stars, which are cooler and slightly smaller than the sun, Petigura said. But the team’s analysis shows that the result for K stars can be extrapolated to G stars like the sun.
The Kepler spacecraft is now crippled because of faulty gyroscopes, but scientists say had Kepler survived for an extended mission, it would have obtained enough data to directly detect a handful of Earth-size planets in the habitable zones of G-type stars.
If the stars in the Kepler field are representative of stars in the solar neighborhood, then the nearest (Earth-size) planet is expected to orbit a star that is less than 12 light-years from Earth and can be seen by the unaided eye. Future instrumentation to image and take spectra of these Earths need only observe a few dozen nearby stars to detect a sample of Earth-size planets residing in the habitable zones of their host stars.
“For NASA, this number – that every fifth star has a planet somewhat like Earth – is really important, because successor missions to Kepler will try to take an actual picture of a planet, and the size of the telescope they have to build depends on how close the nearest Earth-size planets are,” said Andrew Howard, astronomer with the Institute for Astronomy at the University of Hawaii. “An abundance of planets orbiting nearby stars simplifies such follow-up missions.”
Artist's depiction of TESS. Image Credit: TESS team.
Last week I held an interview with Dr. Sara Seager – a lead astronomer who has contributed vastly to the field of exoplanet characterization. The condensed interview may be found here. Toward the end of our interview we had a lengthy conversation regarding the future of exoplanet research. I quickly realized that this subject should be an article in itself.
The following is a list of approved missions that will continue the search for habitable worlds, with input from Dr. Seager about their potential for finding planets that might harbor life.
Transiting Exoplanet Survey Satellite (TESS)
Slated to launch in 2017, TESS will search for exoplanets by looking for faint dips in brightness as the unseen planet passes in front of its host star. With a price tag of $200 million, TESS will be the first space-based mission to scan the entire sky for exoplanets.
While the Kepler space telescope confirmed hundreds of exoplanets (with thousands of candidates yet to be confirmed) it stared 3000-light-years deep into a single patch of sky. TESS will scan hundreds of thousands of the brightest and closest stars in our galactic neighborhood.
“TESS will find many planets,” explained Seager in our interview. “The ones we’re highlighting it will find are rocky planets transiting small stars.” One of the missions goals is to find earth-like exoplanets in the habitable zone – the band around a star where water can exist in its liquid state.
The team hopes that TESS will find up to 1000 exoplanets in the first two years of searching. This will give astronomers a wealth of new worlds to study in more detail.
While the stars Kepler examined were faint and difficult to study in follow-up observations, the stars TESS will focus on are bright and close to home. These stars will be prime targets for further scrutiny with other space based telescopes.
“We plan to have a pool of planets, maybe a handful of them, that we can follow up with the James Webb Space Telescope … which will look at the atmospheres of those transiting planets, looking for signs of life,” Seager said.
ExoplanetSat
While slightly under the radar, ExoplanetSat will monitor bright stars using nano-satellites. Each nano-satellite will be capable of monitoring a single, bright, sun-like star for two years.
The current design of ExoplanetSat. The telescope is approximately the size of a loaf of bread. Image Credit: Pong et al. 2010 (SPIE 7731).
“The way that we describe this mission is not that we will find earth,” Seager said. “But if there is a transiting earth-like planet around a bright sun-like star, we will find it.”
Currently no planned mission has the capability to survey the brightest stars in the sky. TESS will observe stars of magnitude 5 through 12 – the dimmest our eyes can see and fainter.
The brightest stars are too widely spaced for a single telescope to continuously monitor. The best method is to monitor the brightest sun-like stars in a targeted star search instead.
The mission is pretty far along in terms of funding. It has already received a few million dollars and is about one million short of launching the first prototype.
After a successful demonstration the goal is to launch a fleet of nano-satellites to observe enough bright stars to find a number of interesting exoplanets. One day we may be able to look at a bright star in our night sky and know it has a planet.
Direct Imaging Missions
Disentangling a faint, barely reflective, exoplanet from its overwhelmingly bright host star in a direct image seems nearly impossible. A common analogy is looking for a firefly next to a searchlight across North America. Needless to say, very few exoplanets have been seen directly.
Because of the difficulties NASA is fostering a study and soliciting applications with a single goal in mind: create a mission that will directly image exoplanets under a price cap of one billion dollars.
Seager is working with a team that plans to utilize a star shade – “a specially shaped screen that will fly far from the telescope and block out the light from the star so precisely that we will see any planets like earth.”
The shade isn’t circular but shaped like a flower. Light waves would bend around a circle and create spots brighter than the planets themselves. The flower-like shape avoids this while blocking out the starlight – making a planet that is one ten billionth as bright as its host star visible.
The star shade and the telescope have to be aligned perfectly at 125,000 miles away. Once aligned, the system will observe a distant star, and then move to another distant star and re-align. This is technologically speaking, unchartered territory.
While this mission may not occur in full tomorrow, or even years from tomorrow, astronomers’ synapses are firing. We’re coming up with new techniques that will advance technology and find earth-like worlds.
Etc.
Above is a list of only a handful of future exoplanet missions – all at various stages in their production – with some still on the drawing board and others having received full funding and preparing for launch. With creativity and advancing technology we’ll detect a true-earth analogue in the near future.
Planetary Scientist Sara Seager. Image courtesy MIT.
Astronomers have now discovered one thousand extrasolar planets, reaching a milestone in modern astronomy. (See a recent Universe Today article on the subject.) While many have contributed to this achievement, Dr. Sara Seager of MIT has played a large role over the past two decades by contributing vastly to the field of exoplanet characterization. Her theoretical work led to the first detection of an exoplanet atmosphere.
The following is a condensed interview I held with Seager earlier this week.
What first pulled you in to the field of astronomy?
When I was 10 I got to see a really dark sky (well outside her hometown of Toronto, Canada). I stepped out in the middle of the night and I just saw so many stars. I wish you and everyone could see that. So many stars, I just couldn’t believe it.
You were working at Harvard for your PhD in the mid ‘90s when we first detected exoplanets. What was that like?
The mood was quite different. Today everybody wants to talk about it (exoplanets) and write about it. There’s a lot of hype. But back then it was very quiet.
There was a huge amount of skepticism too. People don’t like change. I want you to imagine a world where the gas giants like Jupiter and Saturn are very far from the star and the terrestrial planets like Earth, Mercury, Venus, and Mars are very close to the star. People had constructed theories on how planetary bodies form based on that one example.
So when the first planets around sun-like stars were found, they were Jupiter-mass planets, but they were several times closer to their star than Mercury is to our Sun. It offended all thoughts, theories, and paradigms … As scientists we’re supposed to be skeptical and push back on new discoveries and theories that are upsetting the system. There was huge skepticism.
An exoplanet seen from its moon (artist’s impression). Via the IAU.
How difficult was it during this time to work on exoplanets?
Many people, including my graduate student peers and faculty said, “Why are you doing this (working on exoplanet research)? This is not going to happen. And even if exoplanets are real we’re never going to be able to study their atmospheres,” which is what my PhD was on.
What pushed you through despite all the skepticism?
Ironically, I was not committed to a career in science. I didn’t feel like I needed to be involved with something that was at the 100 percent certainty level. I was free because I didn’t have a plan. I had nothing to lose by doing something I thought was really cool and exciting.
When you’re doing a PhD you’re really learning how to answer a tough question. Usually if you do a homework set in high school, or college, there’s already a known answer. But when you’re doing a PhD, if you’re asking a really hard question that has never been asked before you’re answering that question with your own tools that you’ve developed yourself.
At that time, I knew… the real thing is not just what you’re working on but it’s the tools that you’re using and the things that you’re learning. At the end of the day if you don’t stay in science you have gained a skill that most people don’t have.
Artist concept of an exoplanet. Credit: David A. Hardy. What changed then? What kept you in science after graduate school?
I had freedom and really enjoyed what I was doing.
What is your motivation for studying exoplanets? Why should we study exoplanets?
We want to know: Are we alone? We want to know if there is life beyond earth. Eventually we will have dozens to hundreds of potential earth-like planets to study in detail. We want to look at their atmospheres for signs of life by way of biosignature gases.
What do you think is the likelihood that we will discover an earth-like planet orbiting a sun-like star?
Well, it really just depends if we can rally resources and interest in doing this problem. We think we know how to find an earth-like planet around a sun-like star. But it’s a very very very hard endeavor. We think that the earths are out there. It’s just a matter of building the sophisticated space telescopes that we need.
So what are the chances? It’s really more of a political and economical question more than anything else. I think it’s inevitable that eventually we will find one.
Do you have a favorite planet?
I always like to say my favorite planet is the next planet. We have a sort of ADD (attention deficit disorder) in this field where we’re propelled and motivated forward by finding the next exciting planet. Artist’s impression of exoplanets around other stars. Credits: ESA/AOES Medialab We’ve reached a huge milestone in astronomy of detecting one thousand exoplanets. What does this milestone mean to you?
There’s a caveat here, an uncertainty. We don’t know which one is going to be number one thousand because we don’t agree on the definition of a planet. And even if we did, there’s an uncertainty in the mass and size measurements such that some objects that are called planets probably aren’t planets depending on what definition you want. Occasionally a planet is retracted.
But in general, we’re about to pass the one thousandth mark. What do I think? I think it’s phenomenal. I mean I’m so excited.
The study of exoplanets really started as a field where no one wanted to work on it. People thought it was never going to happen, they thought even if there were real planets we’d never get any measurements beyond stamp collecting – a derogatory phrase we sometimes use in astronomy for science that is not that useful. You just find discoveries and they pile up because you don’t know what to do with them.
We’ve changed the paradigm of planet formation, found exotic types of planets, and we’re right on our way to finding another Earth. So I think it couldn’t be better.
More than 1,000 exoplanets have been confirmed and cataloged (PHL @ UPR Arecibo)
It was just last week that we reported on the oh-so-close approach to 1,000 confirmed exoplanets discovered thus far, and now it’s official: the Extrasolar Planets Encyclopedia now includes more than 1,000! (1,010, to be exact.)
21 years after the first planets beyond our own Solar System were even confirmed to exist, it’s quite a milestone!
The milestone of 1,000 confirmed exoplanets was surpassed on October 22, 2013 after twenty-one years of discoveries. The long-established and well-known Extrasolar Planets Encyclopedia now lists 1,010 confirmed exoplanets.
Not all current exoplanet catalogs list the same numbers as this depends on their particular criteria. For example, the more recent NASA Exoplanet Archive lists just 919. Nevertheless, over 3,500 exoplanet candidates are waiting for confirmation.
The first confirmed exoplanets were discovered by the Arecibo Observatory in 1992. Two small planets were found around the remnants of a supernova explosion known as a pulsar. They were the surviving cores of former planets or newly formed bodies from the ashes of a dead star. This was followed by the discovery of exoplanets around sun-like stars in 1995 and the beginning of a new era of exoplanet hunting.
A “Periodic Table of Exoplanets” as listed by the Extrasolar Planets Encyclopedia (PHL)
(The first exoplanets to be confirmed were two orbiting pulsar PSR B1257+12, 1,000 light-years away. A third was found in 2007.)
Exoplanet discoveries have been full of surprises from the outset. Nobody expected exoplanets around the remnants of a dead star (i.e. PSR 1257+12), nor Jupiter-size orbiting close to their stars (i.e. 51 Pegasi). We also know today of stellar systems packed with exoplanets (i.e. Kepler-11), around binary stars (i.e. Kepler-16), and with many potentially habitable exoplanets (i.e. Gliese 667C).
“The discovery of many worlds around others stars is a great achievement of science and technology. The work of scientists and engineers from many countries were necessary to achieve this difficult milestone. However, one thousand exoplanets in two decades is still a small fraction of those expected from the billions of stars in our galaxy. The next big goal is to better understand their properties, while detecting many new ones.”
– Prof. Abel Mendéz, Associate Professor of Physics and Astrobiology, UPR Arecibo
Source: Press release by Professor Abel Méndez at the Planetary Habitability Laboratory (PHL) at Arecibo
While not illustrating the full 1,010 lineup, this is still a mesmerizing visualization by Daniel Fabrycky of 885 planetary candidates in 361 systems as found by the Kepler mission. (I for one am looking forward to the third installment!)
Of course, scientists are still hunting for the “Holy Grail” of extrasolar planets: an Earth-sized, rocky world orbiting a Sun-like star within its habitable zone. But with new discoveries and confirmations happening almost every week, it’s now only a matter of time. Read more in this recent article by Universe Today writer David Dickinson.
As far as our understanding of life in the Universe goes, right now, we’re it. But the past decade has brought discoveries of hundreds of planets orbiting other stars, some of which could potentially host life. Fellow science journalist Lee Billings has written a new book about the exciting field of searching for extrasolar planets. Five Billion Years of Solitude (read our review here) takes a look at some of the remarkable scientists and the incredible discoveries being made.
Earlier this week, we talked with Lee about the book and the future of how we might find a mirror of Earth.
Universe Today: What was the impetus behind writing this book – was there a specific event or moment where you said, ‘I want to write about astrobiology and the search for exoplanets,’ or was it a more gradual thing over time, where you were just intrigued by the whole expanding field?
Lee Billings
Lee Billings: A little bit of both. I was definitely intrigued by the expanding field of searching for exoplanets, but it came all together for me after interviewing astronomer Greg Laughlin from the University of California, Santa Cruz in 2007 for an infographic about exoplanets. Near the end of our conversation, he mentioned — rather off the cuff — that if you tracked the smallest exoplanets found year by year and graphed them out over time, the trend-line would indicate that we would find an Earth-sized exoplanet by 2011. And I thought, “Holy crap, that’s just four years away!”
I was struck by the disconnect where we could see this plain-as-day data, but the wider world didn’t realize or appreciate this. It also bothered me that we’d soon be finding potentially habitable other worlds, and yet have great difficulty actually determining if they were habitable or even inhabited. And so there was this observational disconnect too, and a lot of people who didn’t seem to care there was this disconnect.
UT: And now that finding exoplanets has made front page news, are you encouraged by how people from afar are viewing this field?
LB: Yes and no. Exoplanets have been in the news for years now. 10 to 15 years ago when astronomers like Geoff Marcy and Michel Mayor were finding the first exoplanets — honkin’ huge balls of gas orbiting close to their stars — it would make front page news. Right now, there’s kind of been ‘exoplanet fatigue,’ where every couple of days a new exoplanet is being announced and exoplanets are even less in the news now because of this overload. And it’s going to keep happening, and I feel like by 2020 finding an Earth-sized planet in the habitable zone isn’t going to make front-page news because it’s going to be happening all the time and people are getting used to it.
UT: Kind of like the Apollo program all over again, where people soon got tired of watching people walk on the Moon?
LB: Yes! Even though I feel like more people in the public are aware of exoplanets being discovered and they even think exoplanets are cool, many think that finding thousands of exoplanets is just like stamp collecting — oh, we found another planet, let’s put it in the book and isn’t that one really pretty — that’s not what this is about. It’s about finding signs of life, finding a sense of context for ourselves in the wider universe, figuring out where Earth and all life upon it fits in this greater picture. I don’t think people are attuned to that side, but are being seduced by the stamp-collecting, horse-race nature of how finding exoplanets are depicted in the media. The emphasis isn’t on what it is going to take to really go out and find out more details about these exoplanets.
Frank Drake and the Drake Equation,
UT: You had the opportunity to talk with some of the great minds of our time — of course, Frank Drake is just such an icon of SETI and the potential for finding life out there in the Universe. But I think one of the most amazing things in your book that I’d never heard of before comes in one of the first chapters where you’re talking with Frank Drake and his idea for a spacecraft that uses the Sun as a gravitational lens to be able to see distant planets incredible detail. That’s amazing!
LB: If you use the Sun as a gravitational lens as sort of an ultimate telescope is really fascinating. As Drake said in the book, you can get some mind-boggling, insane data if you used the Sun as a gravitational lens, and align that with another gravitational lens in the Alpha Centauri system and you can send a high bandwidth radio signal in between those two stars with just the power of a cell phone. In visible light, you could possibly see things on a nearby exoplanet like night-time lighting, the boundary between land and sea, clouds, and weather patterns. It just boggles the mind.
There are other techniques out there that could in theory deliver these sorts of similar observations, but there’s just kind of a technical sweetness to the notion that the stars themselves could be the ultimate telescopes that we use to explore the universe and understand our place in it. I think that’s kind of a wild, poetic and elegant idea.
UT: Wow, that is so compelling. And speaking of compelling, can you talk about Sara Seager and the time you were able to spend with her, getting to know her and her work? Her story is quite compelling not to mention heartbreaking.
LB: She’s a remarkable woman and a brilliant scientist and I feel deeply privileged and honored to be able to tell her story — and that she shared so many details of her personal story with me. Really, she’s kind of a microcosm of the field at large. She crossed over from what she originally studied — from cosmology to exoplanetolgy — and her career seems to be defined by the refusal to accept that certain things might be impossible. She is always pushing the envelope and just keeps her eyes on the prize, so to speak, of finding smaller more Earth-like planets that could be habitable and finding ways of determining what they are actually like. There’s a parallel there between her path and astronomy at large, where there is tension between parts of the professional community. A lot of astronomy is concerned with studying how the universe began and the ancient, the distant, the dead. Exoplanetology is more concerned with the nearest stars to Earth and the planets — the new, the nearby and the living. I feel like she represents that shift and embodies some of that tension.
There’s also an element of tragedy, where she suffered a significant loss with the death of her husband, and had to find a way to get through it and get stronger coming out on the other side. I see similarities between that and what has happened in the field at large where we’ve seen big federally funded plans for future, next-generation telescopes like the Terrestrial Planet Finder, be scuttled on the rocky reefs of politics — and other things. It’s complicated why that’s happened, but there’s no denying that is HAS happened. 15 years ago we were talking about launching TPS by 2014 and now here we are, almost to 2014 and the James Webb telescope isn’t even launched and its eating up all the money for everything else. And now the notion of doing these big kinds of life-finding missions have fallen by the wayside. There’s been kind of the death of a dream, and the bright future that was forecast for what was going to happen for exoplanets doesn’t seem like it’s going to be. The community has had to respond to that and rebuild from that, and there doesn’t seem to be a lot of unity on what the best path forward is.
And also, Sara Seager is walking the line between the old way of big, federally funded projects and a new private, philanthropic path that may or may not be sustainable or successful, but it’s different and trying to do science in a new way. So maybe we don’t need to rely on big government or NASA to do this. Maybe we could ask philanthropists or crowd-funding or new enterprises that could help finance the projects in going forward. She’s got her feet in both worlds and is emblematic of the field right now.
Artistic representations of the only known planets around other stars (exoplanets) with any possibility to support life as we know it. Credit: Planetary Habitability Laboratory, University of Puerto Rico, Arecibo.
UT: Yes, as you mention in the book, there is this tragic possibility that we may never find the things that these scientists are searching for — “mirror Earths, alien life, extraterrestrial intelligence, or a future beyond our lonely, isolated planet.” What do you see as the future of the search for exoplanets, in this age of funding cuts?
LB: What seems to be happening is that astronomers and planet hunters are needing to change their baselines and move their goalposts. In the past when people talked about space telescopes and finding signs of life, they were thinking of directly imaging planets around Sun-like stars and finding indications of life through studying the atmosphere and even surface features. The new way that is coming about and will likely happen in the next few decades, is an emphasis on smaller, cooler, less sun-like stars — the Red Dwarf or M-Dwarf stars. And it won’t be about directly imaging planets, but looking at transiting planets because it is easier to look at planets around lower-mass stars and at super-Earths that are easier to find and study. But these are rather alien places and we don’t know much about them, so it’s an exciting frontier.
But while transits are jackpots — in that you get all sorts of information like period, mass, radius, density and measures of the planet’s upper atmosphere — transits are very rare. If you think about the nearest thousand stars and if we are just looking for transits, that sort of search will only yield a fraction of the planets and the planetary diversity that exist. If you’re looking for life and potentially habitable planets, we really need a bigger sample and more than just transits to fill out the census of planets orbiting the stars around us.
I think missions like TESS and James Webb are going to be important, but I don’t think it will be enough. It will only leave us on the cusp of answering these bigger questions. I hope I’m wrong and that the emphasis on M-dwarfs and super-Earths and transits will be far more productive and surprising than anyone could have imagined or that there will be technology developed that are orders of magnitude cheaper, more affordable and better than these big telescopes.
But to answer the big questions more robustly in a way that is more satisfying to the public and data-hungry scientists, we’re probably going to have to make big investments, and invest the blood sweat and tears into building one of these big space telescopes. People in the astronomy community have been kicking and screaming about this because they realize the money just isn’t there.
But as someone once told me, there an economic inevitability to this in terms of how much the public can be engaged by these questions and how much they might hunger and thirst for finding other planets and life beyond our solar system. I feel like there is a strong push that could be made. I feel that the public would offer more support for these types of investments rather than for other projects, such as a a big space-based gravitational wave observatory or a big telescope devoted to studying dark energy.
Of course, we are living in this era of constrained and falling budgets, it’s going to be a really hard sell for any of these investments in astronomy, but pursuing the ancient, distant and dead instead of the new, nearby and living is probably a losing proposition, I do I wish astronomers the best of luck, but I hope they make the smart choice to prioritize the most publicly engaging science.
Artist’s impression of the transiting exoplanet HAT-P-7b. Credit: NASA/ESA
UT: You write about the competition and sometimes the disdain that competing astronomers have for each other. Is this competition good, or should there be more unity in the field?
LB: In the interest of the community at large, I’d have to say unity is better and that some people have to wait their turn or reduce their expectations. I’m biased; I’m an advocate of exoplanet missions and these investments. But this is publicly funded science and I think it’s important for the community to be unified because it’s all too easy for the bean-counters in Washington to hear the discordant cacophony coming from the various astronomer hatchlings in the nest, and that there is no consensus except they are hungry and they want more.
They need to be unified to withstand the anti-scientific trends in funding we are seeing in our federal government right now. On the other hand, competition is important. But when you are doing publicly funded science, the scientists need to do a good job of making their case of why they should be funded.
UT: What was the most memorable experience in writing this book?
LB: That’s a really hard question! One of my great privileges and joys of writing the book was having access to these scientists and their work. But one of the most memorable things was visiting California’s Lick Observatory on Mount Hamilton in 2012 for the Transit of Venus. It was the last transit of Venus in our lifetime and it was amazing to stand there and think that the last time the transit was visible from Mount Hamilton was a century before, and realize all the changes that had happened in astronomy since then. This transit happened slowly over hours and it was amazing to stand there and realize, this is the last time in your life you’re going to see it and to wonder what is going to happen in the intervening years until this event occurs again.
But Lick Observatory was an appropriate place to be since that’s where some of the first exoplanets were found. When the last Transit of Venus took place, we hadn’t walked on the Moon, there were no computers, and we’ve had all these great discoveries in astronomy. I was thinking about what the world will be like in another hundred years or so, and thinking how while that is a long time for us, in the scale of planetary time, it is nothing at all! The Sun won’t have significantly aged and Venus will likely look exactly the same in 2117 for the next transit, but I would guess the Earth will be very different then. It’s kind of indicative of this transitional era we’re in. It was a very poignant moment for me.
UT: It’s similar to how Frank Drake talked about how he and his colleagues thought that searching for radio emissions from other civilizations would be so important in the search for extraterrestrial intelligence, but realizing that Earth’s radio emissions from our technology is waning and only lasted a short period of time.
LB: Yeah, perhaps when people look back at my book in the future, they might say, ‘wow, this guy was so blinkered and stupid — he didn’t see this technologies X, Y and Z coming and didn’t see monumental discoveries A, B, and C coming.’ I kind of hope that’s actually the case, because it will mean the search for extraterrestrial life and intelligence will have surpassed my wildest dreams. However, I didn’t try to predict what was going to happen, but just wanted to capture this strange and seemingly unique moment in time in which we are poised on the threshold of these immense discoveries that could totally transform our conception of the Universe and our place in it.
UT: Talking to you today, we can obviously tell how passionate you are about this subject and you were the perfect person to write about it!
