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This activity,
Anyone Out There?,
is a variation on the Drake equation,
a famous thought experiment that attempts to estimate
how many other intelligent civilizations
might be in our galaxy right now.
It's important to emphasize that we don't know the right answer
this exercise simply allows your visitors to examine the question.
It's a great way to get a large group engaged in thinking about the
possibility of other intelligent civilizations.
You'll be using this tally sheet,
as your audience makes guesses
you will keep a tally for them to see,
we'll show you how.
On the back
are presenters cues for each question, they're talking points that can prompt
you if you're not sure what to say,
and help you keep the conversation on track.
There's also a lot more background information in the activity write up.
This exercise encourages discussion and lets imaginations run wild.
These will likely create more questions than answers.
Let the group do most of the talking and step in gently if you've identified any
major misunderstandings.
You can also incorporate other activities from this toolkit to explore
some of the questions,
especially
the earth timeline.
How many of you think we're the only intelligent life in our galaxy?
What do you think the chances are that we could find another alien civilization?
Scientists are wondering the same thing,
let's take a look at some of the ways that science is thinking about aliens.
Now here I have six cards,
pass those out there's about twenty of you so divide into groups of three and
four and each take a card
and go ahead and look at the question on your card and then discuss it
together for a minute.
Reassure your audience that there are no right or wrong answers to these
questions
all are just our best guess.
Don't be afraid to say
I don't know,
astrobiology is cutting-edge science and not even the experts know most of the
answers.
There are hundreds of billions of stars in the milky way,
let's estimate that there are four hundred billion stars.
That means were starting with
four hundred billion potential locations for life,
that's a lot of places to look.
Where's group number one?
Could you read your question and give us your best guess?
Woman: Out of all the stars in the milky way how many have at least one planet?
well we think maybe about half. Okay great,
that seems like a reasonable guess so half of four
is two
that makes two hundred billion places that may potentially host life.
Wow let's if we can narrow that down a little bit.
Who has question number two?
Say group number two estimates that one in a hundred planets have the right
environment to support life
look on the back of your cue sheet
at the bottom it tells you that for a chance of one in a hundred I should
cross off
two zeros
starting from the end of the string like this.
If the third group thinks that life actually develops
on one in a thousand planets where there's liquid water
then I cross off three more zeros
as it prompts me to do on the back of the sheet
and so on.
When you finish all six of the cards
you'll have a number left
no matter if your group predicts we're alone or one of many
this can be a profound thought.
In the activity write up you'll find suggestions for ways to wrap up the
activity depending on the
answer that you get.
Let's say in this case they got twenty.
Wow, this group predicts twenty intelligent civilizations in our galaxy right now
you know we could do this exercise again and again and get a different answer
each time,
this isn't necessarily the right answer it's just our prediction after making
many guesses
but it is an exciting thought.
If there are twenty other civilizations in our galaxy we might actually be able
to communicate with another civilization.
Here is an illustration of our milky way galaxy
the sun is right here.
With a few exceptions we're only able to detect stars
with planets
out to a distance of a few thousand light years.
That's an area
about
this big
that's actually really far
but it's also only a small part of our galaxy.
If we heard from another civilization
a thousand light years away we would first have to figure out what they
were saying
and then how to respond
and then come up with the technology to send the signal back.
Now none of those are simple tasks.
What do you think the real problem would be?
Woman: It would take a really long time for them to get that message!
Yeah, if they were still there to receive a message it would take at least two
thousand years to get a response.
That's a long time to wait for an invitation to a party
and of course traveling there is unthinkable with our current technology
so we'd send a message back.
What message would you send back
if you heard from an alien civilization?