Life, the Universe, and Everything
Neil deGrasse Tyson, director of the Hayden Planetarium in New York City, talks about life, the universe, and everything
By Steven Ehrenberg
More than anything else, Tyson hopes to use the planetarium to encourage visitors to think for themselves. He talked to us about horoscopes, shadows, sundials, the future of manned space missions, and why Pluto isn't really a planet. Read on for excerpts from our interview with the independent-minded stargazing scientist.
Q: What misconceptions do people have about space?
Tyson: People come in here assuming that they'll get their horoscope. They don't know that astrology has been [disproven] for centuries, but it's a billion-dollar industry, so it's not going away soon.
I did this experiment in a college class. I found some widely read horoscope column, and I said, "Pick one at random, and put it on the wall. Is this your horoscope, or not? Type yes, no, or maybe." Eighty percent of the people thought it was their horoscope!
Some sleepless, creative person 5,000 years ago invented the constellations. If we were to make constellations today, there'd be no serpents. There'd be a cell phone and an SUV and a microwave oven and a baseball field. There would be things that are in our modern culture, expressed in the legends of the sky.
Q: What were your favorite math subjects in school?
I like thinking about pi. I like thinking about shadows of buildings. One experiment I love to do is to find the time of day when the length of your shadow is the same as your height. You can find the height of buildings that way, just by pacing their shadows out on the ground. It stays that way for 20 minutes or so.
Q: President Bush asked you to serve on a committee to send astronauts to Mars. What was that like?
Tyson: After the Columbia tragedy, many people reflected on what we were doing with humans in space. Some people realized for the first time that we had not left our planet since 1972. So if you're going to put human life at risk on that frontier, let that be one that is ever-advancing. It's not just simply driving around the block, going where hundreds have gone before. This vision was to return to the moon with humans, going on to Mars and then beyond.
I foresee a day when astronauts are the new rock stars, and it will be cool to do well in math class. It will be cool to have ambition. It will simply be really cool to be smart. Astronauts are highly educated people.
Q: It costs less to send robots into space than humans. What would we lose if we stopped sending humans to space?
Tyson: There are two answers to that. First, without the manned space program, support for NASA drops by two-thirds. Second, astronauts mean something to the dreams of the next generation. If you ask [my colleagues], "When you were a kid, what got you interested in space?" they'd say, "The manned space program."
[Most of] our society cares what other people do more than they care about what a machine does. We shouldn't be in denial of the role of the human discoverer and the capacity that has to inspire the next generation.
Q: What's the latest news about our solar system?
Tyson: The search for life on Mars and on Europa, one of the moons of Jupiter. We're about to drop a probe onto Titan, Saturn's largest moon, and Titan has an atmosphere and a surface that is the closest example that we have to Earth just before it formed life. So it's a little bit of a window.
Tyson: (laughs) We don't use the word planet anymore. It's no longer a useful word. Pluto is mostly ice. If it was where Earth is right now, it would grow a tail. Now, what kind of behavior is that for a planet? We have words for things that grow tails: comets. Pluto and comets have more in common with each other than either of them have with any of the rest of the planets.
Q: But comets don't have moons, and Pluto has a moon.
Tyson: We don't know of comets that have moons. They don't hang around long enough for us to really check this. Pluto's got a moonso do Ida and Dachtyl, which are asteroids, but we're not calling them planets just because they have moons.
If you want to call Pluto a planet, then call the other thousands of objects that we've discovered that have a similar orbit and a similar composition [planets]. There are a thousand other objects that look like Pluto. Some of them are two-thirds the size of Pluto. Then say we have a thousand planets. But that's not very useful for the word "planet," is it?
You have your gas giants, Jupiter and Saturn, and they have more in common with each other than with other planets. The same [is true] for the asteroid belt. You classify this whole system into five families: terrestrial planets, asteroid belt, gas giants, Kuiper belt, and cloud cover. And in that classification, you can now understand something about the object just based on its classification.