Goodbye, Kepler Telescope

thousand nine. I say they retired it. They didn't have much choice in the matter. The telescope had run out of fuel and could no longer hold its orientation, which is pretty important if you are using a telescope, any kind of telescope. If you've ever used any sort of magnification and you couldn't hold it's steady, you know that it's not much use. But this mission was no failure. It was actually the conclusion of a monumentally successful scientific mission.

The Kepler team projected a nominal mission lifetime of three years, or maybe three and a half. The actual telescope was able to continue its original mission objectives for an additional year when it was first launched, and then Stuff started breaking down. But I'm getting ahead of myself. So let's start with the question what was Kepler's purpose? What was

it built to do? The simple answer is that it was built to search the galaxy for the presence of exo planets, in other words, planets outside of our own Solar system, and that included looking for Earth like planets. Scientists had very little information to go on to make conclusions about how many stars out there might have planets.

Is it common, is it infrequent? You can't really draw any other, you know, theories or or make any more hypotheses until you get more information about how frequently planets are a thing out there. And that's before you get to the question of how many planets might be similar to Earth, or, even more importantly, in our our grand scheme of things, how many of those planets might be in an orbit around their respective stars in what we would call the h Z or habitable zone. So the

habitable zone, it's pretty self explanatory. It's the region surrounding a star in which water could exist in its liquid state if it were on a planet. So there's not a single range we can give to describe the habitable zone. Right, I can't just tell you it's x many millions of miles away, And the reason for that is because there

are different kinds of stars. So to determine the habitable zone of a star, first you have to ask yourself the question, is this star old enough that any planets that might be orbiting it would have been around long enough to have time necessary for life to develop, because it would probably take billions of years, So you want to make sure that the solar system you're looking at is actually old enough for that to have been a possibility. On a similar note, the size of the star matters.

Larger stars have shorter lifespans than smaller stars. Generally speaking, that's because stars with greater mass will burn through their fuel more quickly than smaller stars. The process of fusion will be at a much greater rate for a larger star than it is for a smaller star. So if you have a really big star, it may only live to be a few million years old before it collapses

and explodes in a supernova. Now I know, a few million years it's a long time for humans, but for stars most stars, like the smaller ones, that's not long at all. A star of the size of our sun could stick around for maybe ten billion years the sun. Our sun is currently around four point six billion years old, so we got a bit. We got a minute or two before it burns out, and honestly, before it would burn out, there would be other things going on that

would be of immediate concern to us. But yeah, we got billions of years before that happens. So really, big stars are not good candidates for finding planets that might have life on them, just because they probably haven't been around long enough for life to develop. So small stars, well, that gets tricky too if the star is too small. The habitable zone overlaps a region wherein an orbiting planet

would be entitled lock with its star. So title lock means the same side of the planet would always face the star, and the opposite side would always face away from the star, So one side of the planet would always be bathed in starlight. The other side of the planet would always be dark. So the side facing the star would be too warm for liquid water or to exist. Most likely it would be it would just be too hot,

it would evaporate out and boil off. There's nothing out there to say that water is absolutely necessary for all kinds of life. We're going from a sample size of one planet that we know of that has life on it, So we're having to make a lot of assumptions here that could ultimately be wrong. But assuming water is necessary, very small stars and very big stars are not really

good candidates for planets that may support life. Now, there are a lot of different ways to classify stars, but the modern classification system is called the Morgan Keenan system and that divides stars into spectral classes, which sources stars into categories based on the spectrum of electromagnetic radiation that the star emits. Using something like a prism, you can look at this spectrum of visible light. So prisms break up visible light into the different colors that you would see.

You know, you get the visible light coming at you use a prism, and then you can actually see uh the spectrum, the full spectrum of light. And this kind of approach, you would have spectral lines interspersed through a range of colors. It would be like little black bars that would be throughout the spectrum. In eruptions in the spectrum, if you if you will, those lines indicate the abundance of certain elements and the type of element will UH you can determine what type of element is by where

on the spectrum. Those spectral lines are mostly However, the spectral lines correspond with the stars surface temperature, and the classification of stars from hottest to coolest goes like this, oh B A, F G K, M. Some people use a handy mnemonic device to remember that, like, oh be a fine guy, kiss me kind of sweet. If you think about it, oh BI and A stars typically burn out before the time we would expect it would take for life to develop on orbiting planets, So those are

your larger, hotter stars. That leaves us with F, G, K, and M stars as candidates for stars that might host planets that could potentially support life. For low mass cooler stars, the habitable zone will be closer in than if the star were larger and hotter. So, in other words, you have to have that perfect temperature or range of temperatures for water to exist in liquid form on the surface of the planet. So if a planet is too close to its star, it's possibly going to be tidally locked,

and it's also gonna be too hot. If it's too far away, it's going to be too cold. So a planet must be in orbit around its respective star in such a way that it is not in title lock. It's not too close, it's not too far, it's not too hot, it's not too cold. And for that reason a lot of people have also started calling the habitable zone the Goldilocks zone because it's just right. Okay, So we have some ideas about planets that could in theory support life if they fell into the habitable zone. It

doesn't mean that they definitely have life on them. We cannot make that determination. All we could say is, well, in theory, water could exist on that planet, and that's the best we can say. So that's one thing, But detecting planets in the first place is actually something else. Just because we could say, in theory, if a planet were to exist within this band of ranges around its star, it might be able to support life, doesn't mean we've actually found any planets, right. We have to figure out

how to do that. So we have really powerful telescopes here on Earth, but that's not really gonna cut it. Even with a telescope that has an enormous aperture several meters across, the conditions are such that we're not going to be able to directly image planets. They're just the star are too far away. The distance between us and nearby stars is enormous light years, and comparatively speaking, the distance between a planet and its host star is nothing

at all. Right, a few million miles is nothing compared to light years. So the light reflecting off a planet would also be much much, much much less bright than the light coming off of a star, like maybe a

billion times less bright. So if we're looking at a star of comparable size and brightness to our Sun, then the planet that orbits it it will end up reflecting some light off of it, but it will be a tiny fraction of the light that's coming from the Sun. So our earth based telescopes would blur this light together due to diffraction, and we wouldn't really be able to tell the difference. We wouldn't be able to distinguish the planet from the star, so direct observation with Earth based

telescopes is a non starter. However, we could look at indirect ways to observe the presence of a planet or to uh too, guess whether or not a planet is there. So stars have a gravitational poll on their planets, but planets also exert a gravitational poll on their host stars, and as planets move through their orbits around the star, they caused the star to wobble a little bit. The center of this gravitational poll is likely within the the diameter of the star itself, but it's not right at

the center of the star. So the star kind of wiggles a little bit as the planets orbit around it. So if you are able to detect this wobble, if you're able to see it, then you could uh then deduce that there's something in orbit around that star. We've used this methodology to detect binary stars that were too close together for our Earth based telescopes to differentiate between the too. We call this the astrometric method of detecting

binary stars. But planets are much smaller than stars, so the wobbles that are produced by planets are much smaller than would be produced by binary star systems AUH. It is the oldest methodology for searching for exoplanets, but for many years no one could confirm that any wobbles they were seeing actually meant there were planets in orbit around those stars. That changed in the era of space telescopes. That changed in the era of more advanced telescopes in

the nineties, but let's set that aside for now. The Kepler telescope would be powerful enough to use an alternative method to detect exo planets. This is the so called transit method, and the transit method looks for indications that a planet is moving between a star and Earth. That is, it is transitting across the face of the star from our perspective. Now, we would detect this by measure ring the amount of light coming from the star. The planet would still be too far away and too small for

us to see. It's not like we would see a tiny black dot moving across the star. But what we could do is measure exactly how much light are we receiving from that star. And if we noticed that there was a dip in the intensity of that light, it would indicate that something had passed between the star and us, that something had blocked some of that light from getting at us. A dip that happens with regularity would indicate that there is a planet in orbit around that star.

That if we're seeing every so often that little dip happened, it would tell us, all right, there's something that's orbiting the star. And every time it comes across, that's when we see the dip, and that's why there's this gap between dips. If it's regular, that is, if it were irregular, we wouldn't necessarily know what the heck is going on, unless maybe it was multiple planets that were in orbit

around the star. It would, however, require a very powerful and very precise telescope, and not only that, it would also require the planet's orbit around its star to be in an alignment so it would actually pass between the star and us. In other words, it would need to

be at the right angle. So if the orbit was at a tilt from our perspective, if it were orbiting its star, but in such a way that its pathway did not cross between us and the star, we wouldn't see any indication of it because the light woulden't dim, you know, the light would still be coming straight at us. So it requires a couple of different things for for

us to even pick it up. NASA started looking into the possibility of using the transit method to detect planets in the nineteen eighties, and one early step was a workshop at the NASA Aims Research Center in high precision photometry. Photometry is the science of the measurement of intensity of light. That's what I was talking about earlier, about measuring how much light is coming to you. That's using photometry. That

science has been around for a bit. And you know, it's obvious that not everything that emits light does so at the same intensity. Right, Some things are brighter than others, some things are dimmer than others. Light isn't just on or off. There's a magnitude associated with it. Quantifying magnitude was really tricky. I have more to say about photometry and its history in just a second, but first let's take a quick break to thank our sponsor. Okay, we're back now. One day I'm going to have to do

a full episode about photometry. The history of photometry is fascinating. It actually it dates all the way back to the ancient Greeks and Romans. But obviously, by the time we're talking about the the events that would lead into the development of the Kepler telescope, NASA was looking into something a little more sophisticated than what the ancients were capable of doing. Now, during the workshop on photometry, the group had several goals they wanted to achieve. One was determine

which astronomical problems would benefit by increased photometric precision. So we've got this technology, if we make it better, what could we use it to do? What would it be good for? Another was to get a handle on what the current level of precision was with the latest equipment, So not just what would it be good for if we made it better, but how good is it right now? Another goal was to identify any of the things that would limit the precision of photometry, so what stands in

our way of making this technology better? And finally, the last goal was to make recommendations to overcome or sidestep

any of those limitations. The workshop was considered a success, and that led to a second workshop that was held in NASA Commission to study to determine if a multi channel photometer built on silicon photo diodes would be practical, and the researchers found that such photometers were incredibly precise, but they would also have to be super cooled down to less than negative one degrees celsius or negative three

degrees fahrenheit, the temperature of liquid nitrogen. In other words, Now, since I'm gonna do an episode about photometry in the future, I'm going to skip a deep explanation of how those devices work for now. Just know that they are all about quantifying the intensity of light that is hitting them. So let's go back to our history lesson leading up to the Kepler telescope. In the early NASA officials were considering a suite of new missions for the organization to pursue.

Some of them were aimed at getting a more comprehensive understanding of our own Solar system, but some were meant to search for planets outside of our immediate neighborhood. One of those proposed missions got the name free SIP or f R E s I P, which stood for Frequency

of Earth size Inner Planets. Like all the proposed missions, the team had to outline the scientific and technical requirements to complete mission objectives, as well as how much they estimated it would cost, and a proposed schedule and management plan.

Free SIP would land on the chopping block. It would not make it through in that initial round, and in nine two there just wasn't sufficient evidence that the technical equipment would be sensitive enough to pick up the transit of a distant planet and yet also be able to

filter out noise. So what NASA HQ was saying was this is it's not that your idea doesn't have merit, it's that we cannot be certain that the equipment you would use would actually achieve the goals, and we don't want to spend millions of dollars on something that ultimately doesn't work. The scientific community still felt that the objective was worth pursuing, so in nineteen scientists organized another workshop called Astrophysical Science with a space born photometric telescope in

mountain View, California. More specifically, not just mountain View, California, this event took place at SETI Headquarters cet IS the Search for Extra Terrestrial Intelligence. Also in NASA announced the initiation of Discovery class missions. Now that's a category of missions that are supposed to be complementary to the larger missions that NASA pursus. So these are supposed to be smaller and therefore also less expensive than the bigger missions.

The Frecept team would resubmit their proposal as a Discovery class mission, but then NASA ultimately rejected that second attempt, and the reason they gave was that they felt that the mission as described would be too expensive to qualify as a Discovery class mission. In a team of scientists at the University of Geneva announced that they had discovered

an exo planet in the constellation Pegasus. This exo and it got the designation fifty one pegasie B. The team had used the so called Wobble method radial velocity method to detect this planet, and that helped fuel interest in the search for more exoplanets in the free SIP team had yet another chance to propose a flight mission, and this time they made a really big adjustment to their proposal.

Actually they made two big adjustments. It's just that one of them was perhaps more important and more key to getting approval, and that was changing the parameters of the mission. The original proposal required putting a spacecraft in a lagrange orbit. Now that's a position in space where the combined gravitational forces of two large bodies equal the centrivigal force of a body that's in that position between the two or

around the two. So the two large bodies in the case that we care about are the Earth and the Sun. So there are five lagrange points that are in that vicinity around the Sun and Earth. They have designations that go from L one up to L five, So L one lagrange orbit is at a point between Earth and the Sun. It's much closer to the Earth than the Sun because gravity depends upon mass and distance, and the Earth is much less massive than the Sun, so you need to get closer if you want to have all

that stuff kind of balance out. L two is actually located behind Earth with respect to the Sun, so in an orbit that's uh, that's further out from the Sun than Earth is. L three is actually on the opposite side of the Sun from where the Earth is. L four and L five are in effect at an orbit sixty degrees ahead and sixty degrees behind the Earth, respectively. In its orbit. Now, a satellite at L one would have an unobstructed view of the Sun, and that's why

we put the solar in Heliospheric Observatory there. A satellite at ALL two would have a view of deep space, and it would be shaded from the Sun because it would be in the shadow of Earth. That's where the

James Webb Space Telescope will eventually be. These orbits require a lot of adjustments to keep a satellite stable, otherwise they would drift out of orbit and move into a collision course with a celestial body like the Sun, for example, Moving a telescope into one of those orbits and keeping it there would have required a lot more fuel and

thus added expense to the mission. So this new proposal for what was originally called Free SIP suggested putting the telescope in a normal solar or orbit rather than on a grange orbit, and that brought the cost down significantly, and the mission also got a new name. This was the second big change, and that new name was Kepler, after Johannes Kepler, the seventeenth century German astronomer. The mission still did not get greenlit at that time, however, then

they tried again and they got turned down again. The team were told they needed to demonstrate the photometry system they had in mind would actually be sufficient to pick up the transit of a planet across its star. So they built a testing facility at the Aimes Research Center and they began running more than a hundred fifty simulations to prove that their system would actually work. In two

thousand one, NASA officials finally gave approval to Kepler. This was the fifth proposal for that mission, and it was designated as the tenth Discovery Class mission. For nearly a decade, engineers and scientists got to work building the actual telescope. I'll talk more about how it worked in just a moment, but the telescope launched on March sixth, two thousand nine.

It was on top of a three stage Delta two rocket that's what was used as the launch vehicle, and more than a month would go by once it reached its orbit before it would take the first image of a small patch of sky. It was a small patch of sky which was occupied by part of the constellation Sicknus, the Swan and Lyra or a liar, also known as the harp. There's a term for this moment when a space telescope like this sends back its first image, and

it's called first light, which I think is kind of cool. Also, it had the equivalent of a lens cap. It's a a very very large lens cap because the telescope has quite a large opening at one end, but that had to be jettisoned first before any images could be sent back. Obviously, otherwise you just get if you've ever taken a picture with a camera that still had a lens cap on, you know, what you get, you get pitch black darkness.

That same little small patch of sky. By the way, while it is a tiny, tiny portion of the overall night sky, it's home to around four and a half million stars. Kepler's job was to monitor around a hundred seventy thousand of the stars simultaneously, So its job was just to monitor the brightness of those stars and look for tiny variations in their luminosity, regular ones, periodic dips in their luminosity, which would indicate an exoplanet in transit.

On January four, the Kepler team announced that the telescope had detected five planets. They had gone through the data and they had found enough convincing data to say that in those five cases, they're certainly appeared to be planets in orbit around their respective stars, and they had exciting names like Kepler four B, Kepler five B, Kepler six B, Kepler seven B, and Kepler eight B. They fell into

a class of planets called hot jupiters. Now, these are planets that are of a similar size to Jupiter in our Solar system. That's the biggest Planet's got a diameter that's eleven times greater than Earth's. Technically you could fit about one thousand three earths inside a single jupiter. So what makes them hot, Well, it's that these planets are relatively close to their parents stars. The orbits are very short.

Compared to an Earth year, a year on one of those planets might only take three or four Earth days. So every imagine that every three or four days you've gone through an entire year. That is uh the equivalent of these planets years um. It made it easier to detect because they were big planets, so they had a big impact on the amount of light that was hitting the Kepler telescope, so you could see the indication very clearly.

And because they were so close to their parents stars, it happened so frequently that you could keep that you could actually make predictions of when you would see the next dip, and if in fact a dip occurred when you predicted it, it would be a strong support that yes, there is a very large planet that's in orbit around that star. So the telescope was very successful. It was indicating that there were bodies or in orbit around other

stars and other solar systems. It wasn't measuring the wobble is just measuring the light and it was showing that this method actually had a lot of validity to it. Now, in our next segment, I will go into a little bit about how Kepler actually worked and what else it discovered in its lifetime out in space. But first let's take a quick break to thank our sponsor. The Kepler telescope looked like a cylinder, probably about twice as tall

as your typical person, so fairly large telescope. It had solar panels along the sun facing side of the satellite, so it would generate electricity that would be used to power various parts of the telescope. It also had an angled opening. It was essentially a sunshade that would the Sun's light from interfering with the light the telescope was

trying to pick up from distant stars. You didn't want to have interference there, otherwise the sensors inside the telescope would just be registering the Sun rather than the stars it was looking for. To keep Kepler pointed at the right patch of sky, the telescope had four reaction wheels. I guess technically it still has four reaction wheels, just

there's nothing to power them anymore. Uh. These were motorized components that could cause Kepler to move in the opposite direction of the spinning of each wheel, and the wheels could spend really fast, like around a thousand to four thousand revolutions per minute. The wheels were a known point of vulnerability as well. The the group knew that the

wheels had failed on other spacecraft. After a while, but they also realized that they needed components that would help keep the budget down for Kepler, and eventually, once it got to the point where they were really worried about their reliability, it was a bit too late, so the vulnerability would become a true thorn in the side of the group in two thousand twelve. That's when one of

the four wheels failed. A second wheel would fail in two thousand thirteen, and the kepler needed at least three working wheels to maintain its orientation that way, So in two thousand thirteen, the primary mission for Kepler came to an end. The aperture on the telescope measured nearly a meter in diameter. The light detection comes from an array of forty two camera sensors, which collectively acted like a ninety five megapixel camera. Now specifically, the camera sensors were

c c d s, or charge couple devices. Each one measured fifty by twenty five millimeters in size, and each one had a resolution of twenty two hundred by one thousand, twenty four pixels. The c c d s wouldn't record information from stars below a certain lumina that would limit

the amount of data being fed back to NASA. Essentially, they were saying, you know, some of these stars are so faint that it doesn't make sense for us to track them because we're not getting enough data to be able to reliably say, oh, this represents a depth in that light. On January ten, two thousand eleven, just a bit more than a year after NASA had announced the first five planets discovered by Kepler, the agency had a new announcement, which was that the telescope had discovered the

first unquestionably rocky planet orbiting a distant star. This one became a Kepler ten B. Later that year, NASA would reveal that Kepler had found a planet that the team would designate Kepler sixteen B. This one was special, and that it was a planet in a double star system, which always makes me think of tattooing in the Star Wars series with the two sons at sunset, and at the tail end of two thousand eleven, NASA announced Kepler twenty two B. That was the first plant to be

found in the habitable zone around its respective star, and it has a diameter that's about twice the size of Earth's, so it's a bigger planet than ours is. In two thousand thirteen, after the second reaction wheel failure, the team worked had to work on coming up with a way to still use the telescope without being able to use the intended method to keep its orientation to make sure

it was pointed in the right way. Meanwhile, researchers were discovering more exoplanets as they were pouring over all the data that Kepler had gathered in its operations, and that would continue on for a couple of years. Just because the telescope wasn't in current operation didn't mean it wasn't providing really useful data for people to pursue, because they could actually go through all the stuff that already been

collected and look for more signs of it. In May two thousand fourteen, the Kepler Telescope would start a new mission called K two. In this mission. The team would rely upon sunlight, which actually does exert pressure. That's the actually the working principle behind things like solar sales, and they used the sunlight to help keep the Kepler pointed

in the right direction. Now, that would mean the telescope would have to look at around four different sections of sky every year, every three months or so, it would change its orientation just because they could not keep it pointed at the exact same patch all year round while relying upon sunlight to study it. But it did mean that the telescope could keep operating. It just wouldn't look

at the same thousand stars all year round. Instead, it was more like half a million stars in total throughout the year. But then keep in mind if you're looking at different patches of stars every three months or so. If you aren't, if it's not timed out the same way as a planet transitting its own parents star, you don't get any more data from that, right you may it may be that you look away just as something interesting happens, which is the story of my life. I

should just title my autobiography I wasn't looking. Over the years, the information from Kepler kept providing researchers with more evidence of exoplanets and other interesting phenomena. So in data suggested that a rocky planet orbiting a white dwarf star was actually being pulled apart as its solar system was kind

of dying. In two thousand sixteen, some interesting information showed odd fluctuations in a particular stars brightness, which led some people to theorize that perhaps some alien civilization had built a mega structure around that star. It was far more likely than the fluctuations were caused by a dust cloud,

but it was still a super cool thing. In the spring of twenty six NASA announced that the team had found one thousand, two hundred new exo planet's after reviewing Kepler data, And that was a huge announcement, and all of these were from that original mission of Kepler, not the K two mission. This was still from its first run. In twenty seventeen, NASA producer report that stated Kepler had detected four thousand, thirty four potential planets in its original mission,

with two thousand, three hundred thirty five planets confirmed now. Originally, the team estimated that about thirty of those planets were likely close to Earth's size and were of a rocky nature. Further examination, however, tempered our expectations a bit reduced that number somewhere down between two and twelve. In two thousand eighteen, the power of crowdsourcing in science was proven again when an Australian car mechanic discovered a planet system that had

at least four Neptune sized planets in it. He had taken the data from the K two mission and had gone through it meticulously. NASA would end up confirming his find and also the scientists who were looking into it discovered that the planet actually had a fifth or the star rather had a fifth planet in its system. So cool stuff. On April eighteen, two eighteen, the Transiting Exo Planet Survey Satellite or Tests launched into orbit. This is

Kepler's successor. It's going to be looking for planets using the transit method, much like Kepler did. On October eighteen, NASA essentially pulled the plug on Kepler. Now it could no longer operate as it run out of fuel that needed to help stabilize its position. It was too wobbly. It was just not going to provide reliable information. So it will remain in its orbit. It's safely away from Earth,

but it will be defunct. Out in space, tests, which is more powerful than Kepler was, is expected to detect perhaps more than twenty thousand new exo planets, and Kepler has given us a lot to think about. Before Kepler, we didn't really know how common exo planets were. It could be that they were really really rare. But Kepler discovered hundreds of multiplanet systems in a few small patches

of sky. So extrapolating from that information, we can estimate that there are possibly hundreds of billions of planets in our galaxy alone. Though to be fair, we don't actually know how many stars are in the Milky Way Galaxy, we can estimate it. We think it's somewhere between one

billion and four hundred billion. So even if we are being conservative we say a hundred billion, And even if we say that only a tiny fraction of the exo planets out there are earth like and in a habitable zone around the respective stars, you're still talking about hundreds of millions of planets that might possibly support life in the Milky Way galaxy. Future telescopes will give us more information about those exo planets. Visiting one, however, is going

to take a lot longer. The closest exoplanet orbiting in the habitable zone of its star is Proxima Centauri B. That's orbiting the red dwarf star Proxima Centauri. And just to be clear, Kepler did not discover Proxima B. That planet was discovered by the European Southern Observatory using the radial velocity method, you know, the good old Wobbli method. That star, however, is the closest star to our Sun, but closest is a relative term. It's still four point

two light years away. Now, that means it takes more than four years for light from that star to reach us. The spacecraft we have designed so far in the history of space travel, in in all of human history, they travel significantly slower than the speed of light. And obviously we can't get matter up to the speed of light because matter has mass, So getting to this destination would

take a really long time. However, one company called Breakthrough Initiatives has proposed a plan that would do it sort of. They plan to launch small, unmanned spacecraft that they call star chips. These tiny spacecraft would use light sales for propulsion, so light sales or solar sales use pressure from photons. Photons don't have a mass, but they do have a relativistic mass, which means they have momentum, which means when

they hit against something, they transfer momentum to it. So you can actually accelerate a spacecraft by having photons bounce off a solar sale. It does take a while to get up to a pretty fast speed, but you're under constant acceleration, so while the acceleration isn't so dramatic, you're not going like zero two, you know, point to five

the speed of light in in five seconds. It takes a long time to get up to speed, but according to the company, the StarCraft they have designed will eventually reach a top speed of about twenty that of the speed of light, so they would get to Proxima B

in around twenty years or so. Then you have to tack on another four years for the information they were sending back to get to us, So twenty four twenty five years from the time that those are launched and they start heading toward Proxima B before we would find anything out about it. But still pretty exciting, and the search for exoplants continues Kepler is done, but it has served us well. It has given us a lot more information and told us that planets are way more plentiful

than we might have hoped. Whether or not planets in the habitable zone are more plentiful, that still remains to be seen. We're gonna have to really do a careful study with using multiple lines of inquiry to make that determination. But it's really exciting stuff. I hope you guys enjoyed this episode. If you have any suggestions for me, any questions or anything like that, you can go on over to tech Stuff podcast dot com. That's the website for

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