語順訳 - ルシアン・ウォーコウィッチ: 太陽系の外にある惑星を探す

Planetary systems/ outside our own are like distant cities/ whose lights/ we can see twinkling,/ but whose streets/ we can't walk.// By studying those twinkling lights though,/ we can learn about how stars and planets interact to form/ their own ecosystem/ and make habitats/ that are amenable/ to life.//

In this image of the Tokyo skyline,/ I've hidden data/ from the newest planet-hunting space telescope/ on the block,/ the Kepler Mission.// Can you see it?// There/ we go.// This is just a tiny part of the sky/ the Kepler stares at,/ where it searches for planets/ by measuring the light/ from over 150,000 stars,/ all at once,/ every half hour,/ and very precisely.//

And what we're looking/ for is the tiny dimming of light/ that is caused by a planet passing/ in front of one of these stars/ and blocking some of that starlight/ from getting to us.// In just over two years of operations,/ we've found over 1,200 potential new planetary systems/ around other stars.// To give you/ some perspective,/ in the previous two decades of searching,/ we had only known about 400 prior/ to Kepler.//

When we see these little dips/ in the light,/ we can determine a number of things.// For one thing,/ we can determine/ that there's a planet there,/ but also how big/ that planet is/ and how far/ it is away from its parent star.// That distance is really important/ because it tells us/ how much light the planet receives overall.// And that distance/ and knowing that amount of light is important/ because it's a little/ like you/ or I/ sitting around a campfire:/ You want to be close enough/ to the campfire/ so that you're warm,/ but not so close/ that you're too toasty/ and you get burned.//

However,/ there's more/ to know about your parent star/ than just how much light you receive overall.// And I'll tell you/ why.// This is our star.// This is our Sun.// It's shown here/ in visible light.// That's the light/ that you can see with your own human eyes.// You'll notice/ that it looks pretty much/ like the iconic yellow ball --/ that Sun/ that we all draw/ when we're children.// But you'll notice something else,/ and that's/ that the face of the Sun has freckles.// These freckles are called sunspots,/ and they are just one of the manifestations of the Sun's magnetic field.// They also cause the light/ from the star/ to vary.// And we can measure this very,/ very precisely/ with Kepler/ and trace their effects.//

However,/ these are just the tip of the iceberg.// If we had UV eyes or X-ray eyes,/ we would really see the dynamic and dramatic effects of our/ Sun's magnetic activity --/ the kind of thing/ that happens on other stars/ as well.// Just think,/ even when/ it's cloudy outside,/ these kind of events are happening in the sky/ above you/ all the time.// So/ when we want to learn/ whether a planet is habitable,/ whether it might be amenable/ to life,/ we want to know not only/ how much total light/ it receives/ and how warm/ it is,/ but we want to know/ about its space weather --/ this high-energy radiation,/ the UV/ and the X-rays/ that are created by its star/ and that bathe it/ in this bath of high-energy radiation.//

And so,/ we can't really look at planets/ around other stars/ in the same kind of detail/ that we can look at planets/ in our own solar system.// I'm showing/ here/ Venus, Earth and Mars --/ three planets/ in our own solar system/ that are roughly the same size,/ but only one of which is really a good place/ to live.// But what we can do in the meantime is measure the light/ from our stars/ and learn about this relationship/ between the planets/ and their parent stars/ to suss out/ clues/ about which planets might be good places/ to look for life/ in the universe.//

Kepler won't find a planet/ around every single star/ it looks at.// But really,/ every measurement/ it makes/ is precious,/ because it's teaching us/ about the relationship/ between stars and planets,/ and how it's really/ the starlight/ that sets the stage/ for the formation of life/ in the universe.// While it's Kepler/ the telescope,/ the instrument/ that stares,/ it's we,/ life,/ who are searching.//

Thank you.//

(Applause)//