This week, a UK-based startup owned by Google
called DeepMind unveiled the latest version
its board-game-playing artificial intelligence program.
And if any human has to face it,
they’re better off throwing in the towel.
Because this AI has defeated everything
that came before it.
You might’ve heard about AlphaGo before.
The first iteration made headlines two years ago
when it beat a professional Go player.
Then, six months later,
it bested one of the top players in the world,
Lee Sedol, 4 games to 1.
But this version has done something even more amazing,
it’s learned to be the best all on its own,
with no human supervision.
In case you’re not up on ancient Chinese board games,
Go is played with black and white stones.
You try to capture the other person’s stones
and grab as much territory as possible to earn points.
The rules are simple, but the game is complex
because it’s played on a 19 by 19 board,
so there are a lot of ways each match can play out.
In fact, there are more possibilities than
the number of atoms in the known universe.
So it’s pretty hard to calculate
what the next best move will be
from all those options.
And that’s why Go has become the game
to beat among the AI crowd.
If a computer can master such a challenging game,
that’s a sign that its learning algorithms
could be put to use on other complex problems.
So this new version, called AlphaGo Zero,
is a pretty big deal.
It works because of reinforcement learning.
Basically, it plays games against itself,
learning more each time.
Previous versions of Alpha Go
used reinforcement learning too.
But first, engineers trained them ahead of time
with move combinations from thousands
of human-played games.
AlphaGo Zero starts from scratch.
When the program starts,
the neural network it uses to select moves and predict the winner
is a blank slate.
This network is just a function that spits out values,
but it has a fancy name because
it’s modeled after the human brain.
At first, the neural network is really dumb.
But over time, it improves a lot.
In fact, just sparring against itself
works way better than training with human data.
Within 76 hours of letting Zero do its thing,
it won 100 out of a 100 against the version
of AlphaGo that beat Lee Sedol.
In a matter of days,
AlphaGo Zero played 4.9 million games,
essentially collected thousands of years of Go knowledge,
and hit upon new strategies that
humans haven’t thought up yet.
而且 与前几代相比 AlphaGo Zero耗费
As a bonus, Zero also takes less computational power
than previous iterations,
and works off a single machine,
rather than being spread out over many.
For many AI fanatics,
this AlphaGo is a real milestone.
Since we don’t need to feed it a bunch of Go knowledge
for it to play games real well,
theoretically we can use the same learning algorithms
to do other things.
Like, modeling protein folding to discover new drugs
and designing new materials.
So stayed tuned as scientists start using AlphaGo
like superhuman programs to fly past old limits
and solve some of our trickiest problems.
With hopefully no robot uprising.
That is, unless volcanoes get us first.
Or rather, we do ourselves in,
with a little help from volcanoes.
Earlier this week,
historians and climate scientists at Yale University published a
hypothesis after combing through thousands of years of data.
They think that volcanoes may have led to
some of ancient Egypt’s most violent revolts,
and ultimately, the final dynasty’s downfall.
But it’s not because of a bunch of deadly lava.
Instead, the idea is that volcanoes can change weather patterns,
specifically the amount of rainfall in the Ethiopian highlands,
which affects how much the Nile River will flood
during the monsoon season.
Now, we usually think of flooding as a bad thing.
But back before the Nile was dammed,
annual flooding was the main way farmers watered their crops.
No flooding meant famine.
Now volcanoes disrupt the climate
because they spew out sulfurous gasses
which can react to form other compounds called aerosols
that hang out in the atmosphere for as long as a year or two.
The tiny particles reflect the sun’s light,
meaning temperatures fall.
Those lower temps can lead to less precipitation,
and can also change wind patterns
that will also decrease rainfall,
especially for northern monsoon regions like Egypt.
The research team noticed that
rainfall in northern Africa fell
after five volcanic eruptions
in the 20th century,
so they wondered if that had happened before.
To find out, climatologists looked at volcanic deposits in ice cores
to get a timeline of those events.
Historians then mapped those dates with
measurements from the Islamic Nilometer,
which was basically a well the Egyptians used
to tell how much water they would get from the river each summer
The Nilometer got its start in the 600s,
so for earlier than that, historians also scoured
ancient writings for mentions of the floods.
They found that flood heights were much lower
around the time of eruptions,
suggesting volcanoes did have an impact on Nile.
Then the team then looked to see
whether there were any ripple effects on Egyptian society.
And they found a strong correlation between
the number of revolts and whether a volcano had recently erupted.
Priestly decrees also went up in years with eruptions,
and the Egyptians were more likely
to end war campaigns against their rivals, the Seleucid Empire.
The idea is that with less flooding,
粮食减产 国家资源减少 不堪战争重负
there was less food, fewer resources to wage battles,
and everyday people were more upset with the government.
We’ll never really know what happened back then,
but by 30 BCE, the last Egyptian dynasty
was overtaken by the Romans.
And these scholars think a series of badly timed volcanoes
may have played a part.
The climate effects of volcanoes
haven’t necessarily ended, either.
Today, around 70 percent of people live in areas
where monsoons help grow crops.
So beyond any immediate devastation,
it’s important to keep in mind that volcanoes could
trigger droughts that would impact billions of us.
Thanks for watching this episode of SciShow News!
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