This course is designed for anyone who is interested in learning more about modern astronomy. We will help you get up to date on the most recent astronomical discoveries while also providing support at an introductory level for those who have no background in science.
2. Discovery
Loading...
Do curso por University of Arizona
Astronomia: Explorando oTempo e Espaço
927 classificações
Na lição
Science and History
Science combines logic and evidence to increase our understanding of the natural world, including remote and inaccessible regions of space and time.
Conheça os instrutores
Chris ImpeyDistinguished Professor
Astronomy
One of the excited things about science is discovery.
The fact that many important things about astronomy were never predicted
by a theory or anticipated by astronomers before they made the observations.
We never predicted the existence of dark energy or dark matter or black holes.
But we've observed these things, and
we've observed extraordinary things in the universe that were
based on surprises to people looking at the world in new ways.
As a metaphor and
an analogy for discovery in nature, let's look at sequences of cards,
regular playing cards with the face cards taken out, so just the numbered cards.
It's a toy model but
it meaningfully captures some of the essence of how science works.
You're going to see four different sequences of cards.
And the goal in this little game is to decide what is
the rule that governs how these cards were laid down.
What is the pattern in nature, in this case,
the pattern in a numbered series of cards of four different suits.
That describes what's going on.
The first example is obvious.
Don't need any explanation from me.
It's just a numbered sequence of the same suit.
The rule is obvious.
The second pattern is a little more interesting.
It's an alternating red and black sequence.
But, notice here that some information is important.
The alternating red and black sequence and some information is irrelevant, the actual
numbers of the cards or the difference between the two red and two black suits.
This is a lesson that in nature and in science is not obvious what the most
important information is when we seek a pattern and don't yet understand it.
But now, look at the third and fourth patterns and
see if you can decide, before I give away the answer,
what is the rule that governs how these cards were laid down?
You can see it's a little subtle.
There too appear to be sequences and
patterns embedded in that layering of cards.
But it's not obvious.
By trying to imagine the rule, you're doing what a scientist does.
You're developing a hypothesis and testing it against nature.
In this case, a sequence of cards.
And you're using a small sequence of the data to see if your
prediction matches what comes later.
Immediately, you're testing a feature of science where we have to understand how
much data is needed to test the hypothesis.
We're also seeing another aspect of science where possibly more than
one hypothesis can explain the same set of data.
Looking at those last two sequences of cards, C and
D, it's quite possible that more than one simply stated rule governs the sequences.
This is partly why astronomers argue about theories.
Sometimes it's not obvious what the best theory is, or
there's not a unique theory at all.
The rule, or rather I should say, one rule that governs sequence c is when you play
successive cards you're either matching the color or the number of the card.
That's a very simple rule stated in only a few words.
But notice how subtle a pattern of cards it makes.
A rule that describes the fourth card sequence is that a red card is placed on
top of an even numbered card, and a black card is placed on an odd numbered card.
Again, it's a very simple rule stated in only a few words, and
it produces a surprisingly subtle pattern of cards in sequence.
When you stare at these sequences cold, without any idea of what's going on,
you can see how difficult it is to elicit the rule, or
the underlying law of nature, if you like, that describes these sequences.
So this is just a cartoon example, but
it does illustrate many of the features of the scientific method.
The Periodic Table is an excellent example of patterns in nature and
how science works.
The first notion of a Periodic Table came from the Greek philosopher,
Empedocles, almost 2500 years ago.
Empedocles came up with the idea that everything in nature,
all the material substances of the earth, and the atmosphere, and even of
human beings were made of four essential elements, earth, air, fire and water.
And the combinations of those four fundamental elements produced
the diversity of the material world.
It's an extraordinary idea, but it's the basis of modern chemistry.
Flash forward almost 2,000 years and we have Mendeleev, doing simple experiments
and drawing the skeleton of the modern periodic table where the associations and
the properties of similar elements eventually gives us the idea that
those elements have physical underpinnings.
It's not until the modern atomic theory that we truly understand the periodic
table but the patterns in nature.
The similarities between reactive elements and metals and
noble gases is a basis of understanding how the atom works.
The idea of discovery leads to a debate that's going on for many centuries.
The distinction between what is invented in science and
what is discovered is science a product of the human mind and imagination or
is it purely the discovery of things that exist in nature that we and
maybe other creatures elsewhere in the universe can understand?
This is an interesting debate, and artists and scientists have
often found themselves intriguingly on opposite sides of the debate.
We might imagine that like Newton, we are dissecting the rainbow,
that science is pure analysis turning white light into it's component colors,
and Newton was the one who put it all together in the theory of light.
So the standard view of science is that it is reductionist, that it
takes complex observed phenomena and then reduces them to their simplest elements.
But science also involves synthesis and that synthesis is
an important part about how we understand nature and build scientifical theories.
As an example from the artistic side, consider Michelangelo who wrote poetry and
sonnets and we know as a scientist and an engineer.
We might imagine that an artist is imposing their will on a canvas or
a lump of marble or clay imposing a vision of what they
might imagine that to be and creating it from scratch.
But that's not how Michelangelo saw it.
He talked about roaming around the Northern Italian towns where
the marble was quarried, Carrara.
And he would scramble over the hillside looking for a piece on the hillside where
he saw something hidden in the rock that he could liberate through his talon.
That's an unusual view of art, that there's something in nature,
in the lump of marble that he is liberating or seeing for the first time.
It's more of a scientific idea.
And I think, a true and nuanced view of both science and
art shows that the truth is more complicated.
That there is synthesis and analysis and dissection and
re-compiling into a whole that occurs in both the fields of human endeavor.
Discovery is an important and exciting part of science.
Many of the things we understand about the universe were not predicted by any theory.
They were completely unanticipated.
So scientists must always be alert to patterns in nature, to something new and
surprising that might lead them to a deeper understanding of the universe.
This is as true in art as in science.
The whole idea of whether things are discovered or
invented and are products of the human mind,
is in the interesting philosophical debate that's never been resolved.
Explore nosso catálogo
Registre-se gratuitamente e obtenha recomendações, atualizações e ofertas personalizadas.
O Coursera proporciona acesso universal à melhor educação do mundo fazendo parcerias com as melhores universidades e organizações para oferecer cursos on-line.
© 2018 Coursera Inc. Todos os direitos reservados.
