80 years ago, he made his own telescopes on the family farm. in the pluto files dr. tyson goes to a barbershop in the hometown of dr. tombaugh in streeter, illinois and finds out what he means to the town today. we re very proud of. very proud of him, what he did. and so you learned about him in high school? in elementary school? third grade, maybe. so his name comes up. and you learn he is a local guy. a streiter boy makes good. in third grade, wow. so you feel some pride? oh, you bet. always do. always here, that guy discovered pluto. walt disney named a dog after him. there you go. that s true. so how do you feel about pluto, dr. tyson? joining us now is the man who dared to move pluto, and then get a straight razor shave in
streiter, illinois. thank you for being here. happy to be here. i want to start with the basics. what is a planet? [ laughter ] is there is an agreed upon definition for what a planet is? at this moment there is a voted upon definition that doesn t have full agreement by the entire community. but planet is big enough to be round. okay. and strong enough, if you will, to have completely almost completely cleared its orbit of other debris that could change its mass over time. so in other words, the big eight well, there is the big four, jupiter, saturn, and neptune. and pluto, puny compared with these eight. so pluto is mixed with a whole group of other icy bodies in the outer solar system. the belt of comets. comets. the belt of icy bodies.