Card
Games for the Whole Family - with a Cosmic Twist
The
Family ASTRO Cosmic
Decoders Card Set (a take-home
activity for families) consists of a deck of 72 cards featuring
beautiful color images of cosmic objects and some well-known telescopes.
These can be used to play four different fun astronomical games.
The cards are also available for purchase to anyone through the
Society’s AstroShop.
Topics:
The
Games
Frequently
Asked Questions about the Cards and the Games
More
Information and Web Links for the Images Depicted on the Cards:
The
Games
- Build
A Galaxy: In this game, the aim is to be the first to build your own galaxy
— to add the right kinds of star clusters and nebulae to
your Galaxy Builder Card! Be sure to try "Version 2,"
where players can only win by cooperating with another member
of the family to form an alliance of linked galaxies.
- Telescope Trouble: In this game you’ll uncover new
"Deep Space Objects" and compare their characteristics
to the last object played. The aim is to be the first one to get
rid of all their cards. Sometimes players will do this by making
a direct match, but sometimes they will need to go one "Size
Category" bigger. And watch out, opponents can play Telescope
Cards that spell trouble!
- Distance Derby: In this game, you win cards by paying attention
to how far away from Earth the Deep Space Objects are. The goal
is to add as many cards as possible to your own "observing
list" of Deep Space Objects. To collect a card, you must
have a card in your hand whose distance is between two other object
cards already in the "distance chain."
- Galactic Gobble: This game is similar to War, where
players turn over cards simultaneously and the player with the
largest Size Category object wins the hand. In other words, just
as in real life collisions (at least among galaxies), the larger
object "gobbles up" smaller ones.
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Frequently
Asked Questions about the Cards and the Games
The
Cards
Q:
How Can I Obtain Additional Copies of Cosmic Decoders?
A:
Cosmic Decoders is available for purchase by anyone through
the Society's AstroShop.
Q:
How and Why Did You Pick the 52 Images of Deep
Space Objects and 12 Telescopes that are Depicted on the Cards?
What Makes Them So Special?
A:
To begin with, we wanted our card games to have four "suits" (like
a standard deck of cards), so our images had to come in four categories.
Once we agreed on the four categories of Deep
Space Objects that would best help players learn about the variety
of objects in space (and lend themselves to the best pictures),
we then set about narrowing down our choices by looking over the
many "galleries" of astronomy pictures now on the web.
If you want to see some of the major galleries we looked at, click
here.
Once
we got to that point, we confess that picking the images was not
(pardon the expression) an exact science. We first assembled a series
of pretty images that demonstrated the science points we wanted
the cards to make. (Our gallery search had yielded over a hundred
such images from the world's biggest telescopes!) For our final
group of 52 Deep Space Object images, we simply picked pictures
we and our test audiences liked best. Different people could have
picked many different objects. We apologize, therefore, if we left
out any of your favorites.
Overall,
we wanted the pictures to show some visually arresting examples
of each type of object. So, for example, among star
death nebulae, we wanted to show a nice variety of both planetary
nebulae (the "death shrouds" of smaller stars) and supernova
remnants (what remains after the explosion of larger stars).
Among galaxies, we
wanted to show different shapes (spiral,
elliptical, and colliding
galaxies) and different sizes (from giant to dwarf galaxies).
In addition, we wanted to show images from several of the most important
telescopes, both on the ground and in space. So, in addition to
the Hubble Space
Telescope images, you will also see pictures from the European
Southern Observatories Very
Large Telescope, the Chandra
X-ray Observatory, and many other major telescopes around the
world.
For
the 12 telescope
cards, we wanted to show a range of telescopes at the forefront
of astronomy research, and at the same time, include some that captured
the images of Deep
Space Objects we chose. Some of these telescopes are on high
mountaintops on the Earth, while others orbit our planet in space.
Also, we wanted to show telescopes that gather more than just visible
light, the light our eyes can see. So the cards show several
instruments for collecting "radio static" from space (or radio
waves), x-rays, and infra-red rays (or heat rays).
See the Learn More About
Telescopes section for more information about telescopes that
collect invisible types of light.
Q:
Where Can I Find More Pictures Like These?
A:
If you want to see some of the major galleries we looked at, click
here.
Q:
Are the colors on the pictures real?
A.
The answer to this question is not simple, and depends on the instruments
with which the image was taken. A few of the pictures in our card
set show cosmic objects as seen not with visible light, but other
kinds of waves (radio waves or x-rays) that our eyes cannot see.
In these cases, the colors are added as a kind of code - colors
could show different types (energies) of x-rays, for example, or
they could show where radio waves are stronger or weaker in the
sky. It is best to read the detailed captions on the web that go
with each image to see what the colors mean. To find these captions,
go to our section "More
Information and Web Links for the Images Depicted on the Cards,"
and for each card, click on the link provided under "Where on the
Web is the Image?"
The
majority of the images on our cards are taken with telescopes and
cameras that record visible light. So you may ask, are those
colors real? We don't mean to sound like lawyers, but that depends
on what you mean by "real."
When
astronomers take pictures of astronomical objects, they don't do
it with a simple camera - like the ones we use for home snapshots.
The process is a bit more complicated and usually involves several
exposures that are later combined to make the image that is published.
Often each exposure is taken using a filter to highlight
a specific type of feature in the object we are interested in. A
filter selects one narrow set of colors and keeps all others out.
Different colors can tell us about different processes going on
in nebulae, star clusters, or galaxies.
For
example, hydrogen gas, when excited, glows in a pinkish red color.
Clouds of excited hydrogen often mark star-forming regions in galaxies.
So to highlight such regions, one exposure of a galaxy might be
taken with a particular red filter that only lets through the hydrogen
color. Another excited gas (oxygen, say) may glow in a different
color, so a different filter is used to highlight those regions
rich in excited oxygen. Astronomers may combine several single-color
images taken with different filters and produce an image that looks
"full color." Thus, not all colors in the object may be present
in such an image, but only those highlighted by the filters chosen
for the individual exposures.
In
other cases, all the filters being used might let pass various shades
of red. Then, to distinguish the results from different filters
more clearly, astronomers may choose to artificially change one
or two of the red images to a green or a blue. This helps clarify
what is happening in the object, but now takes us even further from
what you might consider "true color."
Again,
we recommend reading the detailed captions
for each image by following the "Where on the Web is the Image?"
links if you want to know what colors are being captured and how
and why the image may have been enhanced or changed.
For
a nice graphic description of how the Hubble Space Telescope team
creates their color images, visit their web site at: http://hubblesite.org/sci.d.tech/behind_the_pictures/
Q:
Since there are no 1-hour photo developing machines in space,
how are images taken with telescopes in orbit?
A:
Telescopes like the Hubble
Space Telescope don't use cameras with film. Instead, images
are recorded on sensitive electronic detectors, devices similar
to (but better than) what is now used in home camcorders and digital
cameras. They are called CCD's - charge coupled devices. They convert
each pixel (picture element) of light in an image into a flow of
charge (or current or electricity). The amount of electricity at
each spot tells you how much light hit the detector. And unlike
undeveloped film, the results can be "beamed" back to Earth. Plus
these devices are much more sensitive than film ever was, and thus
can record much lower levels of light - something that is very important
for astronomy where objects are so far away, they look very dim
even in large telescopes.
Q:
How Do Astronomers Know How Far Away or How Big the Objects on
the Cards Are?
A:
Measuring distances to objects out in space is one of the most challenging
parts of modern astronomy. After all, you can't just send a graduate
student out there with a tape measure. Most of the objects astronomers
are interested in are, in fact, so far away that we may never be
able to visit them. Nevertheless, if we want to figure out how big
they are, how much energy they give off, or what groups of objects
they are part of, we first need to know how far away they are located.
One
way to measure distances is to look at relatively nearby objects
in space from opposite sides of the Earth's orbit. (In the same
way, surveyors can measure distances across a wide river, by sighting
from two different locations along the river's bank.) One nice bonus
we get from living on Earth is a free trip around the Sun every
year. This means that the Earth's position in its orbit in the spring
is roughly twice the distance between the Earth and the Sun, or
186 million miles from its position in the fall. So in those two
seasons we see the universe from two different vantage points some
186 million miles apart.
To
understand how this method works, note that you get a slightly different
perspective on the world from your right and left eyes. Try holding
up a finger in front of your face and then close one eye and then
the other several times in a row. What do you see? Note that each
time you close an eye the finger "shifts" relative to the background.
The closer the finger (or cosmic object) is to you, the greater
the shift. (Try it! Starting with your finger at arm's length,
repeat the experiment above, but this time slowly move your finger
closer and closer to your face as you close and open each eye.)
In the same way, we see nearby objects in space shift (very slightly)
from the Earth's fall and spring vantage points. By measuring this
so-called shift, or "parallax," we can determine the object's distance.
However, this method only works for objects that are not too
far away. It gets astronomers "started," so to speak, in measuring
cosmic distances, but is actually not directly useful for most of
the Deep Space Objects
on our cards.
Another
way astronomers try to measure distances is by searching for "standard
candles" (or standard bulbs in modern terms) among cosmic
objects. Standard bulbs are bright objects of a known luminosity
(i.e., "built-in" brightness). Imagine you are in a dark auditorium
or arena and are trying to get yourself oriented. Luckily, someone
has installed some light bulbs around this giant space, and the
staff turns a few of them on. If all the bulbs are 100-watt
bulbs, say, then they will all look the same if you see them from
close up. But the further you get from a source of light (like a
bulb), the dimmer it will look. (Distance, after all, makes all
lights look dimmer.)
This
means that if a bulb looks bright to you, it must be nearby. If
a bulb looks very dim, it must be way on the other side of the auditorium.
But being able to judge the distance of a bulb from how it bright
it looks can only work if ALL the bulbs are the same. If some bulbs
are 10 watts, others 100 watts, others 250 watts (and you don't
know which is which), then how bright a bulb looks will depend not
only on distance but also on which "built-in" wattage bulb it is.
Stars
and galaxies in the universe are (alas) not standard bulbs. They
come in a wide range of built-in brightnesses and so how bright
they look from Earth is not a clear indication of their distances.
Astronomers have spent the last century trying to identify objects
out there that are (more or less) standard bulbs. For example, a
certain type of exploding star (called a Type Ia supernova)
generally has the same brightness. The brightest elliptical
galaxy in a cluster of galaxies is often roughly the same built-in
brightness. When we observe such an object, how bright it looks
to us will give us an indication of its distance.
Another
type of star is also a big help in finding distances. "Variable
stars" are stars whose light output changes with time - they get
a little brighter, then a little dimmer, and then brighter again.
(The most commonly used variable stars like this are called "cepheids,"
after the constellation in which the first one was discovered back
in 1784.) These slight but regular changes in the star's brightness
can take less than a day, several days, and, in some cases, several
weeks.
It
turns out that the built-in brightness (the "usual" brightness)
of such a star is related to how long the variations take. The shorter
the time to vary, the less bright the star. (This is not obvious,
but had to be figured out from information about many such stars.)
Measurements of the time for one cycle of getting brighter or dimmer
for a variable star can then be used to tell astronomers how bright
the star really is. It's as if the flashing rate of a twinkling
bulb on a Christmas tree were related to its wattage. Slow flashing
bulbs are high-wattage, but fast flashers are low wattage. Measuring
the time for flashing (which is easy to do), tells us the wattage
(which is hard to know from far away.) This is not generally true
for flashing bulbs in store windows, but IS true for variable stars.
You can essentially read off the "wattage" of the star from how
long it takes to vary. Once we have the built-in brightness of a
variable star, we are in good shape. Comparing how bright the star
really is and how bright it looks from Earth helps to tell us its
distance.
Because
many star clusters
and galaxies have
such variable stars in them, we have used these "flashing" stars
to measure distances to many objects in our galaxy and in other
nearby galaxies. But this technique requires astronomers to be able
to make out one individual star within a galaxy - something that
gets harder and harder to do as the galaxy is farther away and begins
to look like a smudge of light even in large telescopes. Luckily,
we have other methods of establishing distances to far away galaxies
(that are a bit technical beyond the scope of this brief web page.)
In
such ways, astronomers have been able to determine how far away
stars, nebulae, star
clusters, and galaxies
throughout the universe are and have been able to show how things
are organized on the largest of scales.
For
a somewhat more technical introduction to how astronomers measure
distances, see the UCLA web site, The ABC's of Distances:
http://www.astro.ucla.edu/~wright/distance.htm
Q:
Can I really see the star cluster M92 without a telescope? Isn't
M13 the visible globular in Hercules?
A:
Yes, M13 is the more famous of the globular clusters found in this
constellation. But M92
is visible to the naked eye too; although not from the city, because
of all the "interference" from city lights that shine directly or
reflect their light into the skies. Astronomers call this light
pollution. It's one of the main reasons that observatories are in
such remote mountaintop locations. But if you are out camping, say
in the Tetons, or if you simply live in a more rural setting with
no bright lights shining into the sky, look at Hercules again. If
M13 is along his right thigh, M92 is under his left foot. (Note:
Both can be found using binoculars if they are not visible with
the unaided eye.) So even though many sky watchers know M13, we
thought the little beauty that is M92 deserved some notoriety as
well. Click here
for more information about M92.
Q:
I Have a Question about One of the Objects Pictured on Your Cards.
How Can I Get More Information?
A:
Click here to
be taken to the sections that provide information links for each
of the images depicted on the cards. Many other questions about
the Deep Space Objects
or telescopes on our
cards will be answered by following those links.
Q:
I Have a Question about Something Else in Astronomy. Where on
the Web Can I Ask an Astronomer a Question (or a Dozen Questions)?
A:
Click here to go
to our general web resources page, where there is a list of "Ask
an Astronomer" web sites.
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The
Games
Q:
What Other Games has the Family
ASTRO Team Produced?
A:
To date, four Family ASTRO take-home
activities have been produced. Click
here to view them all. In addition, all our Family ASTRO kits
and games are available for purchase to anyone through the Society's
AstroShop.
Q:
In Build a Galaxy,
what happens if the first card turned over from the deck is a Telescope
Card?
A:
In both Build a
Galaxy and Telescope
Trouble, if the first card turned up is a Telescope
Card, put it back in the middle of the deck and turn over a
new card to start the discard pile. (See page 12, item #3 in your
Cosmic Decoders Manual.)
If
you have a question about the Cosmic Decoders Card Set that
is not listed here, or about Cosmic Decoding in general, please
contact us at astro {at} astrosociety.org.
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