Speaker 1: Welcome to tech Stuff, a production from iHeartRadio. Hey there,
Speaker 1: and welcome to tech Stuff. I'm your host Jonathan Strickland.
Speaker 1: I'm an executive producer with iHeartRadio and how the tech
Speaker 1: are you? It is time for a classic episode of
Speaker 1: tech Stuff. This episode is titled How the Kepler Telescope Works,
Speaker 1: and it published on June eighth, twenty sixteen, Enjoy. In
Speaker 1: May twenty sixteen, researchers with the Kepler Mission at NASA
Speaker 1: held a press conference in which they announced the largest
Speaker 1: number of exoplanets verified ever at a single event, and
Speaker 1: that was one thy two hundred and eighty four verified exoplanets. Previously,
Speaker 1: from two thousand and nine, up to that point, the
Speaker 1: mission had identified and verified nine hundred eighty four planets.
Speaker 1: So this is announcement was more than doubling the number
Speaker 1: of exoplanets verified. That's incredible. So an exoplanet, just in
Speaker 1: case you don't know, is of course a planet that
Speaker 1: is orbiting another star, not the Sun. So it's planets
Speaker 1: in other star systems, solar systems that are light years
Speaker 1: away from us. And it was a really cool thing
Speaker 1: to hear about all these different exoplanets that had just
Speaker 1: been verified. What I thought was hilarious was leading up
Speaker 1: to this announcement, you had several news outlets that were
Speaker 1: guessing what was going to happen. It was just it
Speaker 1: was just complete throw stuff against the wall and see
Speaker 1: what sticks. And there were quite a few that had
Speaker 1: guessed that NASA was going to announce that the Kepler
Speaker 1: mission had somehow discovered alien life. Now, once you hear
Speaker 1: how the Kepler telescope works and what it's meant to do,
Speaker 1: you'll understand that's really not in the purview of the
Speaker 1: Kepler telescope. It is looking for planets that could potentially
Speaker 1: support life, but it doesn't have the capacity to actually
Speaker 1: detect life on those other planets unless someone sent aliens
Speaker 1: to Earth and they started messing with the Kepler telescope,
Speaker 1: in which case you could say it discovered life, but
Speaker 1: not through its primary mission. That did not happen. As
Speaker 1: far as I know, no aliens have been messing with
Speaker 1: the Kepler telescope. So let's talk about how this telescope
Speaker 1: works and this new verification method that the research team
Speaker 1: used to identify so many exoplanets. What was it that
Speaker 1: sped up the process so dramatically as to more than
Speaker 1: double the number of confirmed exoplanets. Plus i'll talk a
Speaker 1: little bit about the new candidates for Earth like planets
Speaker 1: that might be capable of supporting life. So first, let's
Speaker 1: go way back. The Kepler Telescope is named after Johann Kepler,
Speaker 1: an astronomer of the late sixteenth and early seventeenth centuries.
Speaker 1: That's not the original name of the telescope, by the way,
Speaker 1: but more on that in a little bit. So Johann
Speaker 1: Kepler is most famous for discovering the three major laws
Speaker 1: of planetary motion, although at the time no one called
Speaker 1: them laws. It would take Newton and Newton's observations before
Speaker 1: that really started to become a thing. But law number
Speaker 1: one is that the planets move in elliptical orbits around
Speaker 1: the Sun. Law number two, the time it takes to
Speaker 1: traverse any arc of a planetary orbit is proportional to
Speaker 1: the area of the sector between the central body, for example,
Speaker 1: the Sun and the arc. So you can think of
Speaker 1: the two points along the ark, the starting point and
Speaker 1: the endpoint of the arc as your barriers on one side,
Speaker 1: the Sun being the third point in what's not exactly
Speaker 1: a triangle because you have a curve line a straight
Speaker 1: line on the arc side the area within that that
Speaker 1: is proportional to the time it takes to traverse that arc. Essentially,
Speaker 1: what that tells you is that the further out you
Speaker 1: are from a star, the slower your orbit is going
Speaker 1: to be, and the closer en you are to a star,
Speaker 1: the faster your orbit is going to be. Also, there's
Speaker 1: a relationship between the square of a planet's periodic time
Speaker 1: and the cube of the radius of its orbit, which
Speaker 1: is also known as the harmonic law. That's law number three. Now,
Speaker 1: the Kepler mission all started out with a question, which
Speaker 1: was how frequent are other Earth sized planets in our
Speaker 1: galaxy the Milky Way? How common is that? Is the
Speaker 1: Earth a strange outlier that is one in a billion
Speaker 1: or one in ten billion, or even more rare than
Speaker 1: that We had no way of knowing. Now, that particular
Speaker 1: space based telescope, the Kepler telescope, tries to answer this
Speaker 1: question by looking for planets what is called the transit method. Now,
Speaker 1: this method was proposed a few times leading up to
Speaker 1: nineteen seventy one, when Frank Rosenblatt really went strong with
Speaker 1: the idea. He suggested the transit method for detecting satellites
Speaker 1: orbiting other stars. And technically, the way this works is
Speaker 1: that you look at a star and you measure the
Speaker 1: amount of light coming to Earth from that star, and
Speaker 1: you look for any variations and that any dimming of
Speaker 1: that light. Now, if a planet were to pass between
Speaker 1: that star and the Earth, you would expect the light
Speaker 1: from that star to dim a tiny amount, and that
Speaker 1: if you were able to detect that difference, and you
Speaker 1: were able to observe that this happens regularly over the
Speaker 1: course of a given amount of time, you could come
Speaker 1: to the conclusion that what you have seen is in
Speaker 1: fact a planet passing between its host star and the Earth.
Speaker 1: This is what we call transit when we see from
Speaker 1: our perspective a planet crossing its star. Now we're looking
Speaker 1: at the planet making its progress across its star in
Speaker 1: the course of that planet's year. So if it's close
Speaker 1: to the same distance from its host star as the
Speaker 1: Earth is from the Sun, you have to wait a
Speaker 1: long time to verify that that in fact is what
Speaker 1: you saw, especially if you want to truly verify it
Speaker 1: and get a few periodic instances of that dimming, and
Speaker 1: if it has if it's a start that has multiple
Speaker 1: planets alone that same orbital plane, then that's going to
Speaker 1: cause some confusion too. But by seeing the amount of
Speaker 1: light that has been dimmed, and by detecting how long
Speaker 1: it takes this dimming to change back to normal, you
Speaker 1: can start to make some conclusion like how big the
Speaker 1: planet must be, how quickly it travels tells you a
Speaker 1: bit about its orbit. It tells you also by that orbit,
Speaker 1: how close it is to its home star. As long
Speaker 1: as you know information about the home star, then you
Speaker 1: can start to make guesses as to how hot the
Speaker 1: planet is or how cold it might be, And this
Speaker 1: is how you start to draw some conclusions about the
Speaker 1: nature of that planet. Ultimately looking for planets that are
Speaker 1: similar to size, similar to Earth size, i should say,
Speaker 1: and similar to distance from its host star as the
Speaker 1: Earth is to the Sun. The reason for that is
Speaker 1: we know that if the planet is about two times
Speaker 1: the size of Earth or smaller, it's probably going to
Speaker 1: have gravity that is amenable to life as we know it.
Speaker 1: It's going to probably be a rocky planet as opposed
Speaker 1: to a gas giant. That's also important. It's probably going
Speaker 1: to be at a temperature that will allow liquid water
Speaker 1: to be on the planet, and since life as we
Speaker 1: know it depends upon the presence of liquid water, that's
Speaker 1: what we're looking for. Keeping in mind that there is
Speaker 1: the possibility there could be life out there in the
Speaker 1: galaxy that doesn't depend upon liquid water. But we have
Speaker 1: a sample size of one planet with life on it,
Speaker 1: so we have to draw our conclusions based upon the
Speaker 1: limited information we have. So assuming that water is in
Speaker 1: fact necessary for life, we need to find other planets
Speaker 1: that could potentially have water on them. So that's kind
Speaker 1: of guiding the principles behind looking for planets through the
Speaker 1: transit method. But it's really really hard to do. Now,
Speaker 1: let's get back to Frank Rosenblatt for a second. He
Speaker 1: wasn't just famous for suggesting this astronomical approach. He wasn't
Speaker 1: known as a great dronomer. He was actually better known
Speaker 1: as a leading expert in the field of artificial intelligence,
Speaker 1: particularly in the areas of recognizing visual patterns and speech recognition.
Speaker 1: So that was his specific forte. He was really working
Speaker 1: with computers so that they could recognize visual patterns, they
Speaker 1: could recognize when what you are saying when you talk
Speaker 1: to them, and these are fields that today are really
Speaker 1: coming into their own with stuff like Google's Deep Dream,
Speaker 1: where it starts to recognize patterns even if patterns aren't
Speaker 1: really in the picture. It really enhances that and looks
Speaker 1: for patterns in the in ways that are really interesting
Speaker 1: and trippy. And speech recognition, which we're all using to
Speaker 1: some degree these days, often with the personal digital assistants
Speaker 1: that are popping up all over the place. Now here's
Speaker 1: the problem. Rosenblatz suggested approach was not practical at the
Speaker 1: time in the early seventies, the technological sophistication necessary to
Speaker 1: detect and analyze such a very tiny change in a
Speaker 1: star's brightness. If we were looking for an Earth sized
Speaker 1: planet at a distance similar to what Earth is from
Speaker 1: our sun, we're talking about a reduction of one ten
Speaker 1: thousandth the brightness of a star, and that dimming lasts
Speaker 1: between two and sixteen hours, So that's not a lot
Speaker 1: of time, and it's certainly not a big difference in brightness.
Speaker 1: You have to have a very sensitive instrument in order
Speaker 1: to be able to pick that up, and that just
Speaker 1: didn't exist in nineteen seventy one. Now, we also have
Speaker 1: to keep in mind that stars tend to be much
Speaker 1: much bigger than planets. For example, the Sun's diameter is
Speaker 1: one hundred and nine times greater than the Earth's diameter,
Speaker 1: and because of that, that's why with the distance is
Speaker 1: involved and the size is involved, it's such a tiny
Speaker 1: change in the brightness of the star. However, NASA began
Speaker 1: to explore how they might be able to use the
Speaker 1: transit method to detect exoplanets in a practical way. Back
Speaker 1: in nineteen eighty four, they were essentially laying out the
Speaker 1: requirements necessary to detect planets with a reasonable amount of confidence.
Speaker 1: A conference that they held on High precision photometry acted
Speaker 1: as the launching ground figuratively speaking, for discussions about a
Speaker 1: space based telescope designed to detect a transiting planet. The
Speaker 1: idea being that in space there would be less noise
Speaker 1: in the signal to noise ratio, you could get it
Speaker 1: outside the atmosphere. The effects of the atmosphere would not
Speaker 1: be an impediment to a space telescope, and it'd be
Speaker 1: more likely to pick up something as tiny as this
Speaker 1: change in brightness. I'll be back in just a moment
Speaker 1: to talk more about how the Kepler telescope works after
Speaker 1: this quick break, So in nineteen ninety two, NASA proposed
Speaker 1: new missions to look into the possibility of life in
Speaker 1: our galaxy, and the first concept that came up with
Speaker 1: was called the Frequency of Earth Sized Inner Planets or
Speaker 1: FREZIP FRSIP, but that proposal was rejected largely because there
Speaker 1: was doubt at the time that our technological sophistication had
Speaker 1: actually reached a level sufficient to detect any transiting planets
Speaker 1: of Earth like size. So, in other words, if we
Speaker 1: had gone forward with it, we would have built a
Speaker 1: tool that was not up to the task of actually
Speaker 1: doing what was supposed to do, and we would have
Speaker 1: wasted millions of dollars in the process, not something NASA
Speaker 1: could easily afford to do now. Two years later, in
Speaker 1: nineteen ninety four, a team proposed FREZIP again with a
Speaker 1: space based telescope in lagrange orbit, but again a committee
Speaker 1: determined the price would be similar to that of the Hubble,
Speaker 1: which was incredibly expensive and also had been a black
Speaker 1: eye on NASA because when the Hubble launched, it launched
Speaker 1: with a defect that later had to be corrected in space.
Speaker 1: A team had to be sent up to make some
Speaker 1: tweaks to the Hubble space telescope, so that it would
Speaker 1: perform more closely to what it was supposed to do
Speaker 1: because one of its mirrors was not right at any rate,
Speaker 1: they didn't want to involve a you know, or didn't
Speaker 1: want to invest in a big time project that was unproven,
Speaker 1: especially after the Hubble issue, so they rejected the proposal.
Speaker 1: By the way, in case you're wondering what a lagrange
Speaker 1: orbit is, that refers to five specific orbits around the Sun.
Speaker 1: In two of the orbits L one and L two,
Speaker 1: a spacecraft would orbit the Sun either just inside the
Speaker 1: Earth's orbit or just outside the Earth's orbit. So, in
Speaker 1: other words, if you were look top down, you would
Speaker 1: have a spacecraft that would be just inside of the
Speaker 1: Earth orbit moving at the same speed, or one just
Speaker 1: outside the Earth orbit moving at the same speed as
Speaker 1: the Earth around the Sun. And you might think, well,
Speaker 1: how is that possible? Because earlier you mentioned if you're
Speaker 1: closer in to the star, you move faster, and if
Speaker 1: you're further out from the star, you move slower. So
Speaker 1: how would a spacecraft keep up with the Earth. The
Speaker 1: answer is gravity. Earth's gravitational pull would be enough to
Speaker 1: hold the spacecraft in that orbit, that lagrange orbit, and
Speaker 1: you could do this. You might want to do this
Speaker 1: for lots of reasons. If it's on the inside of
Speaker 1: the Earth's orbit, you could do it to study the
Speaker 1: Sun as it faces Earth. If you did it outside
Speaker 1: the Earth's orbit, you could look away from the Earth
Speaker 1: out into the outer Solar System and not have the
Speaker 1: Earth in the way when you're studying those planets. There's
Speaker 1: also another one. L three Lagrange orbit is on the
Speaker 1: opposite side of the Sun from the Earth, essentially following
Speaker 1: more or less the same orbital path as the Earth.
Speaker 1: This is a great way to see the far side
Speaker 1: of the Sun while the Earth is in its normal location,
Speaker 1: So if you wanted to study the far side of
Speaker 1: the Sun you could do that and look for solar activity.
Speaker 1: Then there's L four and L five, which are sixty
Speaker 1: degrees separated either before or after the Earth's orbit. But
Speaker 1: enough about that. Those are the Lagrange orbits. The idea
Speaker 1: being that when you place something in there, it tends
Speaker 1: to be pretty stable. But NASA had determined that putting
Speaker 1: something into one of those orbits would be really expensive,
Speaker 1: so eventually they came to the conclusion that perhaps they
Speaker 1: would want to just put the Kepler telescope in an
Speaker 1: orbit around the Sun in its own orbit, not a
Speaker 1: lagrange orbit. Meanwhile, engineers started to experiment with charge coupled
Speaker 1: device sensors to see if they could be made to
Speaker 1: detect tiny changes in light, and lab experiments with CCDs
Speaker 1: proved that they were a pretty good candidate for this.
Speaker 1: So let's talk about CCDs for a second. They're designed
Speaker 1: to move an electrical charge, typically in a way that
Speaker 1: allows a device to convert the electrical charge into something else,
Speaker 1: like a digital value. And CCD image sensors are important
Speaker 1: in digital imaging, particularly for highly sensitive imaging, such as
Speaker 1: with very low levels of light. Now you can find
Speaker 1: digital cameras with CCDs, but many also use or rather
Speaker 1: instead they'll use active pixel sensors or the SMOs se
Speaker 1: moss CMOS sensors. And it used to be that there
Speaker 1: was a noticeable gap in quality that CCDs were demonstrably
Speaker 1: much higher quality than sea moss sensors. These days, that
Speaker 1: gap is much more narrow, it's not as blatant as
Speaker 1: it used to be, so we've seen the technology of
Speaker 1: one start to catch up to the technology of the other.
Speaker 1: Within the CCD you have millions of tiny light sensitive
Speaker 1: squares called photo sites, and each photo site corresponds to
Speaker 1: an individual pixel in the final image. It uses the
Speaker 1: photoelectric effect to turn photons into electrons. That's actually an oversimplification.
Speaker 1: It really uses photons to energize electrons push them into
Speaker 1: higher energy bands, and that is the key to how
Speaker 1: CCDs work. Essentially, photons raise the energy level of electrons
Speaker 1: from low energy valence bands to high energy conduction bands.
Speaker 1: And each photo site has a positively charged capacitor when
Speaker 1: the photon converts that electron when it adds that energy
Speaker 1: to an electron, the electron is then attracted to the
Speaker 1: positively charged capacitor and the number of photons that penetrated
Speaker 1: the CCD affects the voltage that this creates, and that
Speaker 1: voltage is then converted into a digital signal. The whole
Speaker 1: array is actually cooled through a series of heat pipes
Speaker 1: that run through an external radiator, so they're actually ratiing
Speaker 1: the heat directly out into space. So as this generates heat,
Speaker 1: they just vent that off into space and it keeps
Speaker 1: the whole thing cool enough for it to operate without
Speaker 1: overheating and causing any problems. Now, in nineteen ninety six,
Speaker 1: two years later. So remember this was first proposed in
Speaker 1: ninety two and rejected, ninety four, rejected, ninety six, proposed again,
Speaker 1: and at this point they started to make some changes.
Speaker 1: One of those was decided to put the telescope into
Speaker 1: a solar orbit rather than a lagrange orbit. It was
Speaker 1: also the point where they renamed the project Kepler, after
Speaker 1: the astronomer we talked about earlier. But this proposal was
Speaker 1: also rejected. This time is because no one at that
Speaker 1: point had proven that a telescope could simultaneously observe thousands
Speaker 1: of stars. One of the big selling points of the
Speaker 1: Kepler telescope is that has a very wide field of
Speaker 1: view and can keep an eye on one hundred thousand
Speaker 1: stars simultaneously. But NASA budget overseers were saying, no one's
Speaker 1: proved that you could do this yet, so researchers went
Speaker 1: to work on a prototype photometer to prove it could
Speaker 1: be done. In nineteen ninety seven, they had finished building
Speaker 1: that prototype photometer, and in nineteen ninety eight they demonstrated
Speaker 1: that it could observe six thousand stars in a single
Speaker 1: field of view and generate data that could then be
Speaker 1: analyzed the results of this project were published in a
Speaker 1: paper in nineteen ninety nine. So nineteen ninety nine, seven
Speaker 1: years after the initial proposal, it's proposed yet again, and
Speaker 1: it got rejected yet again. So why was it rejected
Speaker 1: this time, Well, it was rejected on the grounds that
Speaker 1: there was no evidence the photometer would be precise enough
Speaker 1: to find Earth sized planets that could also operate in
Speaker 1: orbit in the presence of noise. So now the argument was,
Speaker 1: all right, you've shown that it's precise enough to detect
Speaker 1: a planet, but maybe not an Earth sized one because
Speaker 1: those are particularly small. They're not the size of a
Speaker 1: gas giant, so we need to prove that, and we
Speaker 1: aren't sure that if you're in space, you will be
Speaker 1: able to differentiate a planet passing between Earth and its
Speaker 1: host star or just some random piece of space debris
Speaker 1: that happens to pass between a star and Earth. Until
Speaker 1: you can prove that, we're not giving you any monies.
Speaker 1: So the engineers built another test bed and they prove
Speaker 1: that the Kepler telescope could operate satisfactorily even within noise,
Speaker 1: that their analysis would be able to differentiate between false
Speaker 1: positives and the real thing. So two thousand rolls around
Speaker 1: and the Kepler gets proposed one more time, and this
Speaker 1: time it's selected as one of three proposals out of
Speaker 1: a total of twenty six to compete for NASA approval.
Speaker 1: So it then goes on to compete with these other
Speaker 1: two projects. And essentially this is the way NASA works.
Speaker 1: They have teams proposed different potential missions, and then they
Speaker 1: whittle that down to a group of finalists and then
Speaker 1: they say fight it out, convince us to fund your project.
Speaker 1: And sometimes only one project gets funded. And that was
Speaker 1: the case for Kepler, and in two thousand and one
Speaker 1: it won the right to be funded. It became Discovery
Speaker 1: Mission number ten. So the Kepler Telescope is a discovery
Speaker 1: spacecraft by that definition. The actual work on the mission
Speaker 1: began in two thousand and two, and that started with
Speaker 1: orders placed for the detectors for those CCDs, and the
Speaker 1: telescope was completed and lawnlaunched, and it was launched on
Speaker 1: March six, two thousand and nine, and went into space
Speaker 1: around its solar orbit. So here's some stats about the
Speaker 1: Kepler Telescope and the Kepler spacecraft. The diameter of the
Speaker 1: photometer is just shy of a meter. It's point ninety
Speaker 1: five meters in diameter, which is about three feet. The
Speaker 1: camera has a ninety five megapixel array. So your typical
Speaker 1: smartphone has an eight to maybe thirteen megapixel camera on it.
Speaker 1: This one is a ninety five megapixel camera, and it
Speaker 1: can continuously monitor the brightness of more than one hundred
Speaker 1: thousand stars simultaneously. The field of view is thirty three
Speaker 1: thousand times greater than that of the Hubble Space telescope,
Speaker 1: so it's looking at a pretty wide range of space.
Speaker 1: Keep in mind, the Milky Way Galaxy has one hundred
Speaker 1: billion stars in it, so one hundred thousand is nothing.
Speaker 1: It's it's a tiny little drop in an enormous bucket.
Speaker 1: Let's talk about the spacecraft though. The Kepler spacecraft is
Speaker 1: two point seven meters in diameter, that's about nine feet.
Speaker 1: It's four point seven meters tall, that's about fifteen point
Speaker 1: three feet, and it weighed one thousand and fifty two
Speaker 1: point four kilograms or two three hundred and twenty point
Speaker 1: one pounds at the time of launch. Why is it
Speaker 1: just the time of launch, Well, part of that weight
Speaker 1: was taken up by fuel hydrozene propellant, which it has
Speaker 1: used some of since it was launched, there was eleven
Speaker 1: point seven kilograms of fuel at that point, so that
Speaker 1: makes a difference. Also the fact that it's in space
Speaker 1: hard to weigh things. In space. You can talk about mass,
Speaker 1: but weight not as relevant. It generates electricity with one
Speaker 1: hundred and nine point eight square feet or about ten
Speaker 1: point two square meters of solar panels. Now those solar
Speaker 1: panels can provide one thousand and one one hundred watts
Speaker 1: of electrical current. The spacecraft also has a twenty amp
Speaker 1: hour lithium ion battery that's a rechargeable battery, so when
Speaker 1: it's generating excess electricity, it charges the battery and everything
Speaker 1: can continue to be powered. Once it launched, it became
Speaker 1: part of the Exoplanet Exploration Program Office, part of the
Speaker 1: Jet Propulsion Laboratory, so it's been shifted from one group
Speaker 1: in NASA to another one to actually manage the mission.
Speaker 1: So basically, the way the Kepler works, it has more
Speaker 1: than one hundred thousand stars in its view and it
Speaker 1: can detect these very tiny fluctuations in the light from
Speaker 1: those stars, and typically, up until recently, we just had
Speaker 1: to keep those stars under observation for a really long
Speaker 1: time to see if that fluctuation would repeat at regular intervals,
Speaker 1: and it wasn't just something passing between us and the star.
Speaker 1: And that was how we would go from a signal
Speaker 1: that was a potential planet to a verified planet. It
Speaker 1: also explains why, over the course of several years we
Speaker 1: were only able to verify nine hundred eighty four exoplanets,
Speaker 1: with a whole bunch of candidates that maybe are exoplanets
Speaker 1: but were not sure, so he can't call them that.
Speaker 1: But then you had this make tenth announcement of one thousand,
Speaker 1: two hundred eighty four exoplanets. So what changed? How could
Speaker 1: we potentially do that? They actually the researchers had analyzed
Speaker 1: four thousand, three hundred two potential signals these candidate planets,
Speaker 1: and out of those four thousand, three hundred two they
Speaker 1: decided that one two hundred eighty four should be verified
Speaker 1: as actual exoplanets because they had a greater than ninety
Speaker 1: nine percent certainty that they were in fact planets and
Speaker 1: not some anomaly or impostor, as they called them. This
Speaker 1: is pretty phenomenal, right, This is the fact that they
Speaker 1: could more than double them. They also had said there
Speaker 1: were another one than three hundred twenty seven signals that
Speaker 1: have a better than fifty percent chance of actually being
Speaker 1: a planet, but those would require more research and observation
Speaker 1: before NASA would go so far as to say, yeah,
Speaker 1: here are some These will also join the list of
Speaker 1: verified planets. They had a very high threshold to call
Speaker 1: a signal a planet. It had to be greater than
Speaker 1: ninety nine percent certainty. So that's pretty incredible, much higher
Speaker 1: standards than I have. I'd be cool with sixty percent
Speaker 1: now as a throwbag. The first Earth sized planet that
Speaker 1: Kepler telescope found in a potential habitable zone, also known
Speaker 1: as the Goldilucks zone was Kepler one to eight six
Speaker 1: F and the Goliluck zone that's what we think, that's
Speaker 1: the band of orbits we think would be would be
Speaker 1: amenable for life to exist, for water to exist in
Speaker 1: liquid form. The Goldilock zone is dependent upon lots of
Speaker 1: staf like the not just how close you are to
Speaker 1: the host star, but how old is that host star.
Speaker 1: You know, if it's an older star that's burned out
Speaker 1: a lot of its energy, it's a cooler star. So
Speaker 1: you have to be closer to the to the star
Speaker 1: in order to get enough energy to support life. As
Speaker 1: we know it, so it's depend upon a lot of factors.
Speaker 1: In the case of Kepler one eight six F, the
Speaker 1: host star is older than our sun, it is more red,
Speaker 1: and it's cooler. And this also means that if there
Speaker 1: is in fact life on Kepler one eight six F,
Speaker 1: it probably looks different from life on our planet. It's
Speaker 1: receiving a lot of red wavelength photons coming in, which
Speaker 1: could mean that the plants themselves might look very different.
Speaker 1: They might be big red plants all over one eight
Speaker 1: six F, or it could be a barren wasteland. We
Speaker 1: don't know. We have no way of telling yet. We
Speaker 1: can just make some guesses based upon the age of
Speaker 1: the star, the size of the star, the distance that
Speaker 1: we estimate the planet is from that star, those sort
Speaker 1: of things. Those are the kind of things that we
Speaker 1: can kind of start to draw some basic guesses around,
Speaker 1: But they're still gases until we can develop some other
Speaker 1: means of really looking at these distant planets. Got a
Speaker 1: little bit more to say about the Kepler telescope and
Speaker 1: how that sucker works, but before we do that, let's
Speaker 1: take another quick break. Now, out of all the one
Speaker 1: two hundred and eighty four planets announced by this research team.
Speaker 1: Nine of those are considered potentially habitable, meaning that they
Speaker 1: are relatively the same size as Earth or no greater
Speaker 1: than two times the size of Earth, and within their
Speaker 1: host stars Goldilocks zone. Now what's really cool is to
Speaker 1: look at how they determined this, Like what was the
Speaker 1: way that they verified these planets? And they used a
Speaker 1: probabilistic approach, meaning what is the probability that any given
Speaker 1: signal is in fact a planet. Essentially, they were looking
Speaker 1: at two main factors. How much does a single transit
Speaker 1: signal resemble what we would expect from a transiting planet,
Speaker 1: so does it look like what a planet would look
Speaker 1: like when passing in front of a star. And then also,
Speaker 1: what is the likelihood that that particular signal could have
Speaker 1: been caused by an impostor? And you take these two
Speaker 1: ideas into account and you try to figure out what
Speaker 1: is the likelihood that we have and a real legitimate
Speaker 1: hit here. One of the people associated with this mission,
Speaker 1: Timothy Morton, who's in a research scholar at Princeton University,
Speaker 1: calculate the probability that any given transit signal is actually
Speaker 1: a planet by using this and essentially you've got numbers
Speaker 1: between zero and one, and only the results that were
Speaker 1: as close to one as possible ninety nine percent better
Speaker 1: than ninety nine percent in fact, were kept and verified
Speaker 1: as a planet. Now, the big advantage of this approach
Speaker 1: is that it can be applied to many signals simultaneously.
Speaker 1: Instead of having to continuously review the data of a
Speaker 1: single signal and look for those replicable results, you could
Speaker 1: take this approach and apply it across multiple planets all
Speaker 1: at the same time and see which ones come out
Speaker 1: at greater than ninety nine percent certainty. Or, as Morton said,
Speaker 1: if you drop a few large crumbs on the floor,
Speaker 1: you can pick those up one by one, but if
Speaker 1: you spill a whole bag of tiny crumbs, you're going
Speaker 1: to need a broom. And the statistical analysis approach is
Speaker 1: their broom. So we've got out of all the different
Speaker 1: planets found about five hundred and fifty of the two
Speaker 1: hundred and eighty four that were announced on May tenth,
Speaker 1: about five hundred and fifty of them might be rocky
Speaker 1: planets like Earth, and out of those, only nine are
Speaker 1: considered to occupy the habitable zone. And you might think, well,
Speaker 1: that's a really small number nine. How many were there before?
Speaker 1: The answer was twelve, so there were a dozen discovered
Speaker 1: before this announcement. Nine more added to it, for a
Speaker 1: total of twenty one. There are several others that are
Speaker 1: possible candidates for rocky like planets that could be in
Speaker 1: the Goldilock zone, but they don't meet that criteria of
Speaker 1: ninety nine percent yet, so they have not been verified.
Speaker 1: There's just been twenty one verified planets that are of
Speaker 1: rocky most likely anyway rocky consistency and in that Goldiluck zone.
Speaker 1: So this is also we got to remember based on
Speaker 1: that assumption that liquid water is a necessary prerequisite. If
Speaker 1: it's not, then obviously we could be looking at lots
Speaker 1: of different plants that could potentially support life, might not
Speaker 1: be life that we would recognize. However, so the kepler,
Speaker 1: as awesome as it is, cannot detect all the exoplanets
Speaker 1: orbiting stars. If the planet's orbit isn't at the right
Speaker 1: angle from our perspective, From the kepler's perspective, it won't
Speaker 1: detect any dimming. In other words, if there's a planet
Speaker 1: crossing that star, but it's at an angle that does
Speaker 1: not go in front of the star from our perspective,
Speaker 1: the star doesn't dim, we don't see any change in that,
Speaker 1: and the kepler can't detect it. So how many plants
Speaker 1: are actually passing at the correct angle for Kepler to
Speaker 1: detect them well. The probability of such a thing is
Speaker 1: determined by the diameter of the star divided by the
Speaker 1: diameter of the orbit, which, for a planet the size
Speaker 1: of Earth orbiting a star similar to the Sun eventually
Speaker 1: gives you a point five percent chance of detecting that signal.
Speaker 1: Of being at the right angle to detect that signal
Speaker 1: point five percent half a percent chance of detecting the
Speaker 1: signal in the first place. Bigger plants have a better
Speaker 1: probability because they are more likely to at least pass
Speaker 1: over a star partially dependent on you know, they have
Speaker 1: fewer angles where you won't see anything at all, So
Speaker 1: a much bigger planet like something like Jupiter could be
Speaker 1: closer to a ten percent chance. So it's entirely possible,
Speaker 1: and even probable in fact, that what we have detected
Speaker 1: is just a tiny fraction of what is actually out there.
Speaker 1: Even just with the one hundred thousand or so stars
Speaker 1: we've looked at, more like one hundred and fifty thousand.
Speaker 1: But even though we've looked at one hundred and fifty
Speaker 1: thousand stars and we've detected so many of these exoplants
Speaker 1: so far, there could be a lot more that we
Speaker 1: just can't see because of the angle. And then you
Speaker 1: take into account we're looking at one hundred thousand out
Speaker 1: of one hundred billion, and the mind really starts to boggle.
Speaker 1: We realize that the frequency of planets around other stars
Speaker 1: is much greater than we anticipated, and that we even
Speaker 1: may be looking at more planets in the Milky Way
Speaker 1: than there are stars. So if you have one hundred
Speaker 1: billion stars and there's more than one hundred billion planets,
Speaker 1: you think, Wow, the odds of the chances that there
Speaker 1: is another planet within our galaxy that could potentially support
Speaker 1: life are pretty good. It may not be anywhere close
Speaker 1: to us. It may be on the other side of
Speaker 1: the Milky Way galaxy from where we are, but the
Speaker 1: chances are pretty good that there's at least some other
Speaker 1: planets within our own galaxy, let alone the universe, which
Speaker 1: is filled with billions of galaxies. And suddenly you think
Speaker 1: there's no way that we're the only life forms in
Speaker 1: the universe. That's just not statistically plausible. Is it possible? Well,
Speaker 1: I mean, technically I guess so, but it's certainly not plausible.
Speaker 1: It's more likely that there's life on lots of other planets.
Speaker 1: Whether it's evolved life that is intelligent, that's another matter.
Speaker 1: Whether it's life that is anywhere remotely close to us
Speaker 1: where we would ever have an opportunity to discover it
Speaker 1: through communication, that's highly debatable. It's quite possible that any
Speaker 1: life that's that advanced is so far away from us
Speaker 1: that we haven't had enough time to pass for any
Speaker 1: communication generated by that civilization to get to us. Because
Speaker 1: remember that stuff has to travel at the speed of light.
Speaker 1: That's as fast as you can go barring some huge
Speaker 1: change in physics, and so if you are thousands of
Speaker 1: light years away, it's going to take thousands of years
Speaker 1: from the generation of a signal for it to get
Speaker 1: to its destination. And by then the milk has gone bad,
Speaker 1: and that shopping list that the aliens gave us is
Speaker 1: not really going to do anyone any good. The party
Speaker 1: is over. But still it's really exciting to think about
Speaker 1: what the Kepler telescope has done. Now, keep in mind,
Speaker 1: this is very different from other types of telescopes. There
Speaker 1: are other ways of detecting the potential for exoplanets. One
Speaker 1: of those is to look at stars and look to
Speaker 1: see if they are moving at all, like if there's
Speaker 1: a little jiggle, which could indicate that there is a
Speaker 1: gravitational pull upon that star, and that in turn can
Speaker 1: indicate that there is a planet in orbit around the
Speaker 1: start and the planet's gravitational pull in the star is
Speaker 1: causing it to move just a little bit, and that
Speaker 1: we can detect that. That's another way of detecting at
Speaker 1: least the potential of an exoplanet in that star's orbit,
Speaker 1: but it's different obviously from the transit method. And then
Speaker 1: there are ways where we can look at planets to
Speaker 1: try and determine what are they made of, and we
Speaker 1: usually use spectroscopy for that, where we take the light
Speaker 1: reflected off of a planet and we analyze that light
Speaker 1: and we break it down into the various wavelengths, and
Speaker 1: then we start to make very educated guesses about the
Speaker 1: types of elements that are present on that particular planet.
Speaker 1: Even so, this is still largely working from very educated guesses,
Speaker 1: so educated that you could argue they are as good
Speaker 1: as fact at least in some cases, but you have
Speaker 1: to keep in mind there's still a tiny room for error.
Speaker 1: So that about wraps it up for the Kepler Telescope.
Speaker 1: It has served us well. Its primary mission is over.
Speaker 1: We will continue to look at the data from the
Speaker 1: Kepler telescope for many more years, but the actual data
Speaker 1: gathering portion of the Kepler's life is over. There are
Speaker 1: other telescopes that we're playing on launching that will continue
Speaker 1: this work. It'll either be looking for similar planets to
Speaker 1: what Kepler was looking for or different style planets. But
Speaker 1: we're just getting started, and the hope is that we
Speaker 1: will eventually be able to draw some very firm conclusions
Speaker 1: about the presence of life within our galaxy, and this
Speaker 1: could just be the first step toward that. So while
Speaker 1: a lot of those news outlets were perhaps being a
Speaker 1: bit optimistic about the announcement of the discovery of alien life,
Speaker 1: it is true that this is a step toward making
Speaker 1: such a discovery, and it may be many, many, many
Speaker 1: more decades before we're able to say, yes, we've detected
Speaker 1: the presence of life on another planet. But it's through
Speaker 1: work like the Kepler mission that we'll get there. So
Speaker 1: this is a really cool science and technology story, and
Speaker 1: I just wanted to touch on that because I love
Speaker 1: that announcement. I actually listened to it live while they
Speaker 1: were talking about and it was just really cool to
Speaker 1: hear a group of engineers and scientists talk about their
Speaker 1: life's work with such passion. I hope you enjoyed that
Speaker 1: classic episode of tech Stuff that published on June eighth,
Speaker 1: twenty sixteen, about how the Kepler telescope works. I love
Speaker 1: doing these episodes about telescopes because it's fascinating to me
Speaker 1: just how they work, how they function, and then on
Speaker 1: top of that, to learn about the incredible science that
Speaker 1: we were able to achieve thanks to these instruments. It's
Speaker 1: really inspiring stuff. If you have suggestions for topics I
Speaker 1: should cover in future episodes of tech Stuff, there are
Speaker 1: a couple of different ways that you can let me know.
Speaker 1: One is you can download the iHeartRadio app. It's free
Speaker 1: to downloads free to use. Navigate to techt Stuff by
Speaker 1: putting tech Stuff in the little search field that'll take
Speaker 1: you to our podcast page and you'll see a little
Speaker 1: microphone icon. If you click on that, you can leave
Speaker 1: a message up to thirty seconds in length. A voice
Speaker 1: message let me know what you would like. Otherwise, you
Speaker 1: can navigate on over to Twitter and you can send
Speaker 1: me a tweet. The address or handle you should use
Speaker 1: as tech STUFFHSW and I'll talk to you again really soon.
Speaker 1: Tech Stuff is an iHeartRadio production. For more podcasts from iHeartRadio,
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