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Phil Plait: The secret to scientific discoveries? Making mistakes
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Phil Plait was on a Hubble Space Telescope team of astronomers who thought they may have captured the first direct photo of an exoplanet ever taken. But did the evidence actually support that? Follow along as Plait shows how science progresses -- through a robust amount of making and correcting errors. "The price of doing science is admitting when you're wrong, but the payoff is the best there is: knowledge and understanding," he says.
Phil Plait - Astronomer
Phil Plait blogs at Bad Astronomy, where he deconstructs misconceptions and explores the wonder of the universe. Full bio
Phil Plait blogs at Bad Astronomy, where he deconstructs misconceptions and explores the wonder of the universe. Full bio
Double-click the English transcript below to play the video.
00:12
Now, people have a lot
of misconceptions about science --
of misconceptions about science --
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about how it works and what it is.
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A big one is that science
is just a big old pile of facts.
is just a big old pile of facts.
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But that's not true --
that's not even the goal of science.
that's not even the goal of science.
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Science is a process.
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It's a way of thinking.
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Gathering facts is just a piece of it,
but it's not the goal.
but it's not the goal.
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The ultimate goal of science
is to understand objective reality
is to understand objective reality
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the best way we know how,
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and that's based on evidence.
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The problem here
is that people are flawed.
is that people are flawed.
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We can be fooled --
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we're really good at fooling ourselves.
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And so baked into this process
is a way of minimizing our own bias.
is a way of minimizing our own bias.
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So sort of boiled down
more than is probably useful,
more than is probably useful,
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here's how this works.
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If you want to do some science,
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what you want to do
is you want to observe something ...
is you want to observe something ...
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say, "The sky is blue. Hey, I wonder why?"
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You question it.
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The next thing you do is you come up
with an idea that may explain it:
with an idea that may explain it:
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a hypothesis.
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Well, you know what? Oceans are blue.
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Maybe the sky is reflecting
the colors from the ocean.
the colors from the ocean.
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Great, but now you have to test it
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so you predict what that might mean.
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Your prediction would be,
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"Well, if the sky is reflecting
the ocean color,
the ocean color,
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it will be bluer on the coasts
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than it will be
in the middle of the country."
in the middle of the country."
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OK, that's fair enough,
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but you've got to test that prediction
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so you get on a plane,
you leave Denver on a nice gray day,
you leave Denver on a nice gray day,
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you fly to LA, you look up
and the sky is gloriously blue.
and the sky is gloriously blue.
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Hooray, your thesis is proven.
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But is it really? No.
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You've made one observation.
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You need to think about your hypothesis,
think about how to test it
think about how to test it
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and do more than just one.
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Maybe you could go
to a different part of the country
to a different part of the country
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or a different part of the year
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and see what the weather's like then.
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01:59
Another good idea
is to talk to other people.
is to talk to other people.
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02:02
They have different ideas,
different perspectives,
different perspectives,
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and they can help you.
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This is what we call peer review.
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And in fact that will probably also
save you a lot of money and a lot of time,
save you a lot of money and a lot of time,
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flying coast-to-coast
just to check the weather.
just to check the weather.
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Now, what happens if your hypothesis
does a decent job but not a perfect job?
does a decent job but not a perfect job?
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Well, that's OK,
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because what you can do
is you can modify it a little bit
is you can modify it a little bit
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and then go through
this whole process again --
this whole process again --
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make predictions, test them --
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and as you do that over and over again,
you will hone this idea.
you will hone this idea.
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And if it gets good enough,
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it may be accepted
by the scientific community,
by the scientific community,
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at least provisionally,
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as a good explanation of what's going on,
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at least until a better idea
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or some contradictory
evidence comes along.
evidence comes along.
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Now, part of this process
is admitting when you're wrong.
is admitting when you're wrong.
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And that can be really, really hard.
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Science has its strengths and weaknesses
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and they depend on this.
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One of the strengths of science
is that it's done by people,
is that it's done by people,
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and it's proven itself
to do a really good job.
to do a really good job.
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We understand the universe
pretty well because of science.
pretty well because of science.
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One of science's weaknesses
is that it's done by people,
is that it's done by people,
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and we bring a lot of baggage
along with us when we investigate things.
along with us when we investigate things.
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We are egotistical,
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we are stubborn, we're superstitious,
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we're tribal, we're humans --
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these are all human traits
and scientists are humans.
and scientists are humans.
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And so we have to be aware of that
when we're studying science
when we're studying science
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and when we're trying
to develop our theses.
to develop our theses.
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But part of this whole thing,
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part of this scientific process,
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part of the scientific method,
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is admitting when you're wrong.
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I know, I've been there.
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Many years ago I was working
on Hubble Space Telescope,
on Hubble Space Telescope,
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and a scientist I worked with
came to me with some data,
came to me with some data,
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and he said, "I think
there may be a picture
there may be a picture
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of a planet orbiting
another star in this data."
another star in this data."
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We had not had any pictures taken
of planets orbiting other stars yet,
of planets orbiting other stars yet,
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so if this were true,
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then this would be the first one
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and we would be the ones who found it.
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That's a big deal.
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I was very excited,
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so I just dug right into this data.
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I spent a long time trying to figure out
if this thing were a planet or not.
if this thing were a planet or not.
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The problem is planets are faint
and stars are bright,
and stars are bright,
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so trying to get
the signal out of this data
the signal out of this data
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was like trying to hear a whisper
in a heavy metal concert --
in a heavy metal concert --
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it was really hard.
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I tried everything I could,
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but after a month of working on this,
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I came to a realization ...
couldn't do it.
couldn't do it.
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I had to give up.
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And I had to tell this other scientist,
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"The data's too messy.
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We can't say whether
this is a planet or not."
this is a planet or not."
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And that was hard.
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Then later on we got
follow-up observations with Hubble,
follow-up observations with Hubble,
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and it showed that it wasn't a planet.
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It was a background star
or galaxy, something like that.
or galaxy, something like that.
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Well, not to get too technical,
but that sucked.
but that sucked.
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(Laughter)
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I was really unhappy about this.
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But that's part of it.
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You have to say, "Look, you know,
we can't do this with the data we have."
we can't do this with the data we have."
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And then I had to face up to the fact
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that even the follow-up data
showed we were wrong.
showed we were wrong.
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Emotionally I was pretty unhappy.
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But if a scientist
is doing their job correctly,
is doing their job correctly,
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being wrong is not so bad
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because that means
there's still more stuff out there --
there's still more stuff out there --
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more things to figure out.
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Scientists don't love being wrong
but we love puzzles,
but we love puzzles,
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and the universe is
the biggest puzzle of them all.
the biggest puzzle of them all.
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Now having said that,
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if you have a piece and it doesn't fit
no matter how you move it,
no matter how you move it,
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jamming it in harder isn't going to help.
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There's going to be a time
when you have to let go of your idea
when you have to let go of your idea
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if you want to understand
the bigger picture.
the bigger picture.
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The price of doing science
is admitting when you're wrong,
is admitting when you're wrong,
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but the payoff is the best there is:
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knowledge and understanding.
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And I can give you a thousand
examples of this in science,
examples of this in science,
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but there's one I really like.
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It has to do with astronomy,
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and it was a question
that had been plaguing astronomers
that had been plaguing astronomers
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literally for centuries.
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When you look at the Sun,
it seems special.
it seems special.
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It is the brightest object in the sky,
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but having studied astronomy, physics,
chemistry, thermodynamics for centuries,
chemistry, thermodynamics for centuries,
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we learned something
very important about it.
very important about it.
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It's not that special.
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It's a star just like
millions of other stars.
millions of other stars.
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But that raises an interesting question.
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If the Sun is a star
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and the Sun has planets,
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do these other stars have planets?
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Well, like I said with my own failure
in the "planet" I was looking for,
in the "planet" I was looking for,
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finding them is super hard,
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but scientists tend to be
pretty clever people
pretty clever people
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and they used a lot
of different techniques
of different techniques
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and started observing stars.
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And over the decades
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they started finding some things
that were pretty interesting,
that were pretty interesting,
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right on the thin, hairy edge
of what they were able to detect.
of what they were able to detect.
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But time and again,
it was shown to be wrong.
it was shown to be wrong.
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That all changed in 1991.
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A couple of astronomers --
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Alexander Lyne --
Andrew Lyne, pardon me --
Andrew Lyne, pardon me --
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and Matthew Bailes,
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had a huge announcement.
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They had found a planet
orbiting another star.
orbiting another star.
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And not just any star, but a pulsar,
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and this is the remnant of a star
that has previously exploded.
that has previously exploded.
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It's blasting out radiation.
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This is the last place in the universe
you would expect to find a planet,
you would expect to find a planet,
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but they had very methodically
looked at this pulsar,
looked at this pulsar,
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and they detected the gravitational tug
of this planet as it orbited the pulsar.
of this planet as it orbited the pulsar.
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It looked really good.
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The first planet orbiting
another star had been found ...
another star had been found ...
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except not so much.
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(Laughter)
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After they made the announcement,
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a bunch of other astronomers
commented on it,
commented on it,
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and so they went back
and looked at their data
and looked at their data
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and realized they had made
a very embarrassing mistake.
a very embarrassing mistake.
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They had not accounted
for some very subtle characteristics
for some very subtle characteristics
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of the Earth's motion around the Sun,
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which affected how they measured
this planet going around the pulsar.
this planet going around the pulsar.
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And it turns out that when they did
account for it correctly,
account for it correctly,
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poof -- their planet disappeared.
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It wasn't real.
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So Andrew Lyne had a very formidable task.
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He had to admit this.
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So in 1992 at the American
Astronomical Society meeting,
Astronomical Society meeting,
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which is one of the largest gatherings
of astronomers on the planet,
of astronomers on the planet,
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he stood up and announced
that he had made a mistake
that he had made a mistake
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and that the planet did not exist.
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And what happened next --
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oh, I love this --
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what happened next was wonderful.
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He got an ovation.
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The astronomers weren't angry at him;
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they didn't want to chastise him.
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They praised him
for his honesty and his integrity.
for his honesty and his integrity.
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I love that!
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Scientists are people.
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(Laughter)
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And it gets better!
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(Laughter)
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Lyne steps off the podium.
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The next guy to come up
is a man named Aleksander Wolszczan
is a man named Aleksander Wolszczan
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He takes the microphone and says,
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"Yeah, so Lyne's team
didn't find a pulsar planet,
didn't find a pulsar planet,
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but my team found not just one
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but two planets
orbiting a different pulsar.
orbiting a different pulsar.
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We knew about the problem that Lyne had,
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we checked for it,
and yeah, ours are real."
and yeah, ours are real."
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And it turns out he was right.
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And in fact, a few months later,
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they found a third planet
orbiting this pulsar
orbiting this pulsar
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and it was the first
exoplanet system ever found --
exoplanet system ever found --
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what we call alien worlds -- exoplanets.
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That to me is just wonderful.
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At that point the floodgates were opened.
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In 1995 a planet was found
around a star more like the Sun,
around a star more like the Sun,
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and then we found another and another.
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This is an image of an actual planet
orbiting an actual star.
orbiting an actual star.
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We kept getting better at it.
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We started finding them by the bucketload.
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We started finding thousands of them.
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We built observatories
specifically designed to look for them.
specifically designed to look for them.
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And now we know of thousands of them.
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We even know of planetary systems.
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That is actual data, animated, showing
four planets orbiting another star.
four planets orbiting another star.
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This is incredible. Think about that.
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For all of human history,
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you could count all the known planets
in the universe on two hands --
in the universe on two hands --
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nine -- eight?
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Nine? Eight -- eight.
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(Laughter)
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Eh.
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(Laughter)
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But now we know they're everywhere.
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Every star --
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for every star you see in the sky
there could be three, five, ten planets.
there could be three, five, ten planets.
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The sky is filled with them.
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We think that planets
may outnumber stars in the galaxy.
may outnumber stars in the galaxy.
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This is a profound statement,
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and it was made because of science.
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And it wasn't made just because of science
and the observatories and the data;
and the observatories and the data;
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it was made because of the scientists
who built the observatories,
who built the observatories,
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who took the data,
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who made the mistakes and admitted them
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and then let other scientists
build on their mistakes
build on their mistakes
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so that they could do what they do
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and figure out where
our place is in the universe.
our place is in the universe.
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That is how you find the truth.
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Science is at its best
when it dares to be human.
when it dares to be human.
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Thank you.
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(Applause and cheers)
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ABOUT THE SPEAKER
Phil Plait - AstronomerPhil Plait blogs at Bad Astronomy, where he deconstructs misconceptions and explores the wonder of the universe.
Why you should listen
Phil Plait is the Bad Astronomer. Not a bad astronomer, but a blogger for Slate who debunks myths and misconceptions about astronomy -- and also writes about the beauty, wonder and importance of fundamental research.
He worked for six years on the Hubble Space Telescope, and directed public outreach for the Fermi Gamma-ray Space Telescope. He is a past president of the James Randi Educational Foundation, and was the host of Phil Plait's Bad Universe, a documentary series on the Discovery Channel.
Read more from Phil Plait in the Huffington Post's special TEDWeekends feature, "Asteroids: Getting Ready" >>
Phil Plait | Speaker | TED.com