KRIM-LP KRIM-FM 96.3 FM Payson, Online KRIM-LP KRIM-FM 96.3 FM Payson Radio internet, KRIM-LP KRIM-FM 96.3 FM Payson USA Radio Radio it's possible to glimpse the future. So, this is the Crescent Dunes Solar Facility. There are , of these mirrors. They all reflect the sun's energy up to that tower. The heat's a reservoir of molten salt, that's then used to turn water into steam, turning turbines, and generating electricity. Crescent Dunes is one of the world's largest solar power plants, but even this gigantic facility can only collect a small fraction of the sun's energy. In the future, we might build thousands more of these facilities, collecting even more of the sun's energy. The amount of energy a civilisation can harness from their star provides an indication of their technological advancement. And it's measured on what's known as the Kardashev scale. A Kardashev Type I civilisation is a civilisation that's capable of harnessing all of the energy that falls on their planet from their parent star. Human civilisation only consumes about terawatts of power. That's about th of the amount of energy that falls on our planet from our sun. But the amount of sunlight that hits the Earth is only a tiny fraction of the light that leaves the sun. Our sun's power is billion terawatts. That's million times as much energy in just one second as the entire United States consumes over the course of the year. Any civilisation capable of harnessing all the energy emitted by its star would have achieved Kardashev Type II status. But to do it would require engineering on a truly astronomical scale. A Kardashev Type II civilisation would need to build a massive network of solar collectors that would orbit their star in space. Something we call a Dyson sphere, or a Dyson structure. A Dyson structure is very much like the solar power plant here, but billions of times larger, in space, orbiting an entire star. But they needn't be a solid surface. It could be a swarm of individual solar panels, all interconnected, as long as they occluded a large fraction of the light that came from the star. To construct a Dyson sphere that enveloped the sun would require all the matter in all the planets in the solar system. And so until recently, Dyson spheres were thought to be purely theoretical. Then, in , some deeply strange observations from NASA's Kepler space telescope fell onto the desk of astronomer Tabetha Boyajian. Kepler looked at over , stars in our galaxy, and the data for this star looked nothing like any of the stars, and nothing like any other star that we know of today. For four years, the telescope scoured the Milky Way, hunting for evidence of exoplanets. Meticulously measuring the brightness of stars in search of the tell-tale dimming in light produced as a planet passes in front of them. So, this is what an exoplanet transit looks like. On the left-hand side you have the amount of light, and on the bottom you have time, and when a Jupiter-like planet transits in front of a star, you have this clean U-shaped dip in the star's light. And this dip this about %. So this is the Kepler data for KIC . And it shows four years of Kepler photometry of the star. And, as you can see, for most of the time it's pretty flat. Nothing is going on. But then in May , you had this dip that on face value, appears to look like what a transiting planet would look like. But if you take a closer look, then you actually see that the transit lasts for almost a week, compared to a planet-sized object, which would just last for a couple of hours. It was also very asymmetric in shape, meaning that, instead of having that cleanly U-shaped dip, it had this strange slope over here on the left-hand side. This seemed to indicate that whatever was crossing in front of the star was not circular like a planet. Things are pretty quiet for a couple of years, and then in March of we have this very dramatic feature where the star's brightness drops by %. And this drop is also very asymmetric. It gradually decreases in brightness for about a week and it then snaps right back up to normal in just a few days. Now, after this nothing happens again for a couple of years until February of , when you have this huge complex of dips that last almost for days.