00:01For the longest time, space seemed like a big, nearly empty place.
00:06And we were really only familiar with our home, Earth.
00:10But as we learned more, we realized there was actually a lot out there,
00:15including planets orbiting the Sun and even other stars.
00:19To get to these more distant worlds, though,
00:22it helps to start thinking of space as a bunch of nested bubbles.
00:26Our first bubble is a magnetosphere.
00:28Earth's invisible magnetic field that protects us from high-energy particles and radiation from the Sun,
00:35allowing life as we know it to develop and thrive.
00:38The next bubble, just past the Solar System, is the heliosphere,
00:44the edge of the Sun's influence, where the particles and fields of interstellar space take over.
00:50The two Voyager spacecraft have left this bubble and are our first interstellar spacecraft.
00:56It took Voyager 1 35 years, and it took Voyager 2 41 years to travel this far.
01:03The next stop is our nearest stars.
01:06The Alpha Centauri system, at just over four light-years away, is close by cosmic standards.
01:12But it would take either Voyager about 75,000 years to get there at current speeds.
01:17We clearly need to use other tools to look for worlds that far away.
01:22Enter Kepler, a space telescope that radically changed our understanding of planets outside of our solar system,
01:29also known as exoplanets.
01:32In finding thousands of new planets, Kepler showed that there are more planets in our galaxy than there are stars.
01:40But Kepler looked at only a small fraction of the sky, and many of the planets it discovered are too
01:45far away to study in much further detail.
01:48And that brings us to TESS, our newest planet hunter.
01:52The Transiting Exoplanet Survey satellite works like Kepler, and over the next two years, it will scan almost the entire
02:00sky.
02:01By looking at closer and brighter stars, TESS will find and measure the sizes of dozens of small nearby planets,
02:09best suited for detailed investigation by powerful telescopes on the ground and in space, like the future James Webb Space
02:17Telescope.
02:19And by doing that, we might finally begin to answer the question of whether Earth is alone,
02:25or whether there are worlds out there like our own, small and rocky, covered in oceans and dense clouds,
02:33or even, possibly, capable of supporting life.
02:50Thank you!
02:53The Third
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