NASA's astrophoto challenge lets you
make your own space image using real
astronomy data this time featuring
incredible views of interacting galaxies
but before you get started let's find
out more about what we're seeing in
these remarkable
images when you look up at the sky on a
dark night you can see countless stars
and every one of them is part of the
hundreds of billions of stars in the
Milky Way our home Galaxy but if you
take a telescope and peer between and
Beyond those Stars you will see Tiny
glowing balls and swirling discs these
are other galaxies far beyond our Milky
Way each of them is a collection of
stars gas and dust pulled together by
gravity usually we find galaxies in
groups and when they're close together
sometimes we can see them in interacting
with one
another interacting galaxies are
galaxies that are close enough to feel
each other's gravitational pole so
gravity pulls on each Galaxy Stars gas
and dust you know causing their visible
shapes to change and then depending on
how strong this pole is it can stretch
galaxies out compress gas to form new
stars or even tear them apart so rather
than galaxies living in in complete
isolation interactions can have a
profound effect on the structure and
future evolution of the Galaxy while
interacting galaxies can get twisted and
stretched into countless varieties there
are some that take on a ringlike shape
there is a special kind of Galaxy which
we call collisional ring galaxies which
are we believe are formed in a rather
unique way in which you have a rotating
Milky Way Type Galaxy and a SW small
spidal Galaxy falls down through the
center of the larger rotating Galaxy
driving a ring out through the disc and
so the same process happens when you
drop a pebble in water for example so
the water that was there moves outward
and forms this nearly perfect ring and
so these galaxies are really rare
because the ring doesn't last forever
maybe a few hundred million years or so
which sounds like a long time but it
really isn't it's just 1% of the time uh
that has been around so finding them is
actually pretty cool and really
rare ring galaxies you know they're
already very rare but the cartv is even
more interesting both visually and
science wise because if you look at it
it's basically a textbook example of
what happens after a major Collision um
it has an outer ring which like as in
the case of a cartwheel would be the
outer part of the wheel and it has an
inner sort of Hub which is actually
composed of at least one or possibly two
rings then you have these faint spokes
of gas and dust that are connecting both
the inner and the outer ring and then
you see these two nearby galaxies one of
which looks like it could have been the
Galaxy that pushed through it in the
first place each of the cartwheel Galaxy
data sets you can use comes from a
different part of the spectrum and each
tells us a different part of its story
as revealed by a NASA telescope so image
of the cartwheel invisible light shows
um very much the stars in the galaxy in
particular the extremely bright and very
blue stars in the outer ring and the
reddish glow from the inner ring and the
Very faint spokes infrared observations
help us pierce the dust and reveal the
warm gas in the Rings particularly in
the outer ring where we see a lot of
very intense start formation occurring
if you look at the cartwheel in x-rays
you see a lot of very bright points and
it's even hard to tell that they're
forming part of the segment of the Ring
we call them Ultra luminous x-ray sauces
but it's very rare to see so many of
them in one Galaxy in fact the cartwheel
is almost unique in having so many this
UV image is highlighting the youngest
and hottest stars that are concentrated
in the outer range so these stars were
directly for formed from the gas
compressing um during the Collision so
you have this really this burst of young
hot star
formation my favorite thing about the
cartwheel Galaxy is that such a major
Collision you know it may have
completely reshaped the Galaxy but it
also allowed for so many new stars to
form that simply wouldn't have formed
without it the Galaxy like took like
this very dramatic event you know and it
turned it into something very new and
beautiful I.E the new Star formation
that we
so I think it's like very oddly
inspiring you know a story of resilience
because you know something can crash
straight through you and disrupt
everything and yet you can still pick up
the pieces and rebuild exactly what the
cartwheel
did Galaxy interactions aren't limited
to remote parts of the universe close to
home our neighbor Andromeda galaxy shows
signs of having interacted with one of
its own Galactic satellites so the
Andromeda Galaxy
is um The Milky Way's nearest large spal
Galaxy and it's about 2.5 million light
years away so it's really almost in our
backyard compared with for example the
cartwheel and one very obvious
difference between the Milky Way and
andrometer is that Andromeda does not
have obvious strong spiral structure
it's dominated by an inner bright car
and a faint outter disc so one of the
things you'll notice about the visible
image is that in addition to the bright
car and the overall disc you also see uh
faint dark features like almost like a
dark ring where there's we believe
there's dust that's absorbing some of
the visible light here we have a short
infrared wavelength image of Andromeda
and so here we are seeing the Starlight
from the older stars in Andromeda you
can also see the companions again so you
can see m110 to the upper right and you
can also see M32 just under the center
the long infrared rings that we're
seeing right here in this image um is
piercing through the very dusty clouds
and allowing us to see the actual inner
structure of andromeda's disc and when
you look at it it doesn't look like
continuous spiral arms like you would
expect for a regular spiral galaxy
instead we can see that the matter is
organized into these very distinct Rings
kind of like the cartwheel Galaxy so
what I love about Andromeda which this
large nearby companion Galaxy is that
you can see it very clearly with the
naked eye on a dark night you're only
really seeing the very central part of
Andromeda but what's amazing about it is
that it's heading towards us at about
300 km/s which is about 670,000
mph at its present rate if it's falling
directly toward ODS as and most of the
models think that it more or less is
it's going to collide with the Milky way
in about 2.5 billion years from now now
that seems like a long time away but
imagine that the Earth is only 4.5
billion years old a lot of people think
it's going to be like very violent and
it's going to hurt like all the stars
and stuff like that but actually like
the stars don't experience too much when
galaxies are colliding they just kind of
like Get drifted around a little bit and
it's like we wouldn't really experience
too much it wouldn't be a super violent
process like a lot of people think it
would be because there's a lot of space
in between stars and so they're not
going to be colliding with one another
the Milky Way will cease to exist as a
band across the sky all the stars will
be scattered around will'll end up
merging with the Andromeda it should be
it's a very exciting and dramatic
thought but far into the future whether
you choose to make an image of the
cartwheel or Andromeda galaxy you'll
have a snapshot of a moment in Cosmic
time showing how their appearances have
been altered by their neighbors
understanding merging and colliding
galaxies and the way they evolve over
time is sort of central to the human
quest of answering you know why are we
here and where did we come from just
like people galaxies grow and evolve
through their interactions with others
and so this teaches us not only about
the incredible forces of gravity but
also about how change you know even when
it's disruptive like in the case of the
cartv Galaxy can lead to growth in
something entirely new
there are countless ways to mix and
match these data sets and we encourage
you to submit your Creations to the
astrophoto challenge website your work
might even be featured as a standout
entry try NASA's astrop photo challenge
yourself we want to see the pictures
that you've made tell us about the
colors you've chosen share your images
with us and tell us about your creative
decisions were your choices scientific
artistic or both