Now, people have a lotof misconceptions about science —
about how it works and what it is.
A big one is that
science is just a big old pile of facts.
But that’s not true — that’s not even the goal of science.
Science is a process.
It’s a way of thinking.
Gathering facts is just a piece of it, but it’s not the goal.
The ultimate goal of scienceis to understand objective reality
the best way we know how, and that’s based on evidence.
问题在于 人无完人 我们有可能被愚弄
The problem here is that people are flawed,we can be fooled.
— we’re really good at fooling ourselves.
And so baked into this process is a way of minimizing our own bias.
So sort of boiled downmore than is probably useful,
here’s how this works.
If you want to do some science,
what you want to do is you want to observe something…
比如 “天空是蓝色的 我想知道为什么？”
say,”The sky is blue. Hey, I wonder why?”
You question it.
接下来 你会想到一个 可以解释该问题的想法： 一个假设
The next thing you do is you come up with an idea that may explain it: a hypothesis.
Well,you know what? Oceans are blue.
Maybe the sky is reflectingthe colors from the ocean.
Great,but now you have to test it
so you predict what that might mean.
Your prediction would be,
“ Well, if the sky is reflecting the ocean color,
it will be bluer on the coasts
than it will bein the middle of the country.”
好 这很合理 但你得验证那个预测
Ok,that’s fair enough, but you’ve got to test that prediction.
So you get on a plane,
you leave Denver on a nice gray day,
飞往洛杉矶 望向天空 天空映衬着壮丽的蔚蓝色
you fly to LA, you look up and the sky is gloriously blue.
Hooray,your thesis is proven.
But is it really?
No,you’ve made one observation.
You need to think about your hypothesis,
think about how to test it
and do more than just one.
Maybe you could goto a different part of the country
or a different part of the year and see what the weather’s like then.
Another good ideais to talk to other people.
They have different ideas,different perspectives,
and they can help you.
This is what we call peer review.
And in fact that will probably also save you a lot of money and a lot of time,
flying coast-to-coastjust to check the weather.
Now,what happens if your hypothesis does a decent job but not a perfect job?
because what you can do is
you can modify it a little bit
and then go throughthis whole process again —
make predictions, test them —
and as you do that over and over again,
you will hone this idea.
And if it gets good enough,
it may be accepted by the scientific community,
at least provisionally, as a good explanation of what’s going on,
at least until a better idea or some contradictory evidence comes along.
Now,part of this processis admitting when you’re wrong.
And that can be really, really hard.
Science has its strengths and weaknesses
and they depend on this.
One of the strengths of science is that it’s done by people,
and it’s proven itselfto do a really good job.
We understand the universepretty well because of science.
One of science’s weaknessesis that it’s done by people,
and we bring a lot of baggage along with us when we investigate things.
We are egotistical, we are stubborn, we’re superstitious,
we’re tribal, we’re humans —
these are all human traitsand scientists are humans.
And so we have to be aware of that when we’re studying science
and when we’re tryingto develop our theses.
But part of this whole thing,
part of this scientific process, part of the scientific method,
is admitting when you’re wrong.
I know, I’ve been there.
Many years ago I was workingon Hubble Space Telescope,
and a scientist I worked
with came to me with some data,
and he said,”I think there may be a picture of a planet orbiting another star in this data.”
We had not had any pictures taken of planets orbiting other stars yet,
so if this were true,
then this would be the first one and we would be the ones who found it.
That’s a big deal.
I was very excited, so I just dug right into this data.
I spent a long time trying to figure out
if this thing were a planet or not.
The problem is planets are faintand stars are bright,
so trying to getthe signal out of this data
was like trying to hear a whisper in a heavy metal concert —
it was really hard.
I tried everything I could,
but after a month of working on this,
I came to a realization…couldn’t do it.
I had to give up.
And I had to tell this other scientist,
“The data’s too messy.
We can’t say whetherthis is a planet or not.”
And that was hard.
Then later on we gotfollow-up observations with Hubble,
and it showed that it wasn’t a planet.
It was a background staror galaxy, something like that.
Well,not to get too technical,but that sucked.
I was really unhappy about this.
But that’s part of it.
You have to say,” Look, you know,
we can’t do this with the data we have.”
And then I had to face up to the fact
that even the follow-up data showed we were wrong.
Emotionally I was pretty unhappy.
But if a scientistis doing their job correctly,
being wrong is not so bad
because that meansthere’s still more stuff out there —
more things to figure out.
Scientists don’t love being wrongbut we love puzzles,
and the universe isthe biggest puzzle of them all.
Now having said that,
if you have a piece and it doesn’t fit no matter how you move it,
jamming it in harder isn’t going to help.
There’s going to be a time
when you have to let go of your idea
if you want to understandthe bigger picture.
The price of doing scienceis admitting when you’re wrong,
but the payoff is the best there is:
knowledge and understanding.
And I can give you a thousand examples of this science
but there’s one I really like.
It has to do with astronomy,
and it was a question that had been plaguing astronomers literally for centuries.
When you look at the Sun,it seems special.
It is the brightest object in the sky,
但经天文学 物理学 化学 热力学几个世纪的研究后
but having studied astronomy, physics,chemistry, thermodynamics for centuries,
we learned somethingvery important about it.
It’s not that special.
It’s a star just likemillions of other stars.
But that raises an interesting question.
If the Sun is a star and the Sun has planets,
do these other stars have planets? Well,
like I said with my own failurein the”planet” I was looking for,
finding them is super hard,
but scientists tend to be pretty clever people
and they used a lotof different techniques
and started observing stars.
And over the decades they started finding some things that were pretty interesting,
right on the thin, hairy edge of what they were able to detect.
But time and again,it was shown to be wrong.
That all changed in 1991.
几位天文学家 — 亚历山大•莱恩
A couple of astronomers — Alexander Lyne —
Andrew Lyne, pardon me —
and Matthew Bailes, had a huge announcement.
They had found a planetorbiting another star.
And not just any star, but a pulsar,
and this is the remnant of a star that has previously exploded.
It’s blasting out radiation.
This is the last place
in the universe you would expect to find a planet,
but they had very methodicallylooked at this pulsar,
and they detected the gravitational tug of this planet as it orbited the pulsar.
It looked really good.
The first planet orbitinganother star had been found…
except not so much.
After they made the announcement,
a bunch of other astronomers commented on it,
and so they went backand looked at their data
and realized they had madea very embarrassing mistake.
They had not accountedfor some very subtle characteristics
of the Earth’s motion around the Sun,
which affected how they measuredthis planet going around the pulsar,
and it turns out that when they did account for it correctly,
poof — their planet disappeared.
It wasn’t real.
So Andrew Lyne had a very formidable task.
He had to admit this.
So in 1992 at the AmericanAstronomical Society meeting,
which is one of the largest gatherings
of astronomers on the planet,
he stood up and announcedthat he had made a mistake
and that the planet did not exist.
And what happened next — oh,
I love this — what happened next was wonderful.
He got an ovation.
The astronomers weren’t angry at him;
they didn’t want to chastise him.
They praised himfor his honesty and his integrity.
I love that!
Scientists are people.
And it gets better!
Lyne steps off the podium.
The next guy to come up
is a man named Aleksander Wolszczan
He takes the microphone and says, “Yeah,
so Lyne’s teamdidn’t find a pulsar planet,
but my team found not just one
but two planetsorbiting a different pulsar.
We knew about the problem that Lyne had,
we checked for it,and yeah, ours are real.”
And it turns out he was right.
And in fact, a few months later,
they found a third planet orbiting this pulsar,
and it was the firstexoplanet system ever found —
我们称之为外星世界 —— 系外行星
what we call alien worlds — exoplanets.
That to me is just wonderful.
At that point the floodgates were opened.
In 1995 a planet was found around a star more like the Sun,
and then we found another and another.
This is an image of an actual planet orbiting an actual star.
We kept getting better at it.
We started finding them by the bucketload.
We started finding thousands of them.
We built observatoriesspecifically designed to look for them.
And now we know of thousands of them.
We even know of planetary systems.
That is actual data, animated,
showing four planets orbiting another star.
This is incredible. Think about that.
For all of human history,
you could count all the known planets
in the universe on two hands —
nine — eight? Nine?
Eight — eight.
But now we know they’re everywhere.
Every star —
你在空中看到的每颗恒星 都有3 5 10 颗行星环绕
for every star you see in the sky there could be three, five, ten planets.
The sky is filled with them.
We think that planetsmay outnumber stars in the galaxy.
This is a profound statement,
and it was made because of science.
And it wasn’t made just because
of science and the observatories and the data;
it was made because of the scientistswho built the observatories,
who took the data,
who made the mistakes and admitted them and then let other scientists build on their mistakes
so that they could do what they do
and figure out where our place is in the universe.
That is how you find the truth.
Science is at its bestwhen it dares to be human.