Exploring Deep Space-Galaxies! - My NSTA
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SCOPE ON THE SKIES
Exploring Deep Space—
Galaxies!
BY BOB RIDDLE
W
e all know that our so- column we are going to explore ingly large, it is not large from
lar system is part of a the universe of galaxies by going the perspective of the scale of the
much, much larger col- deep—deep as in “Deep Space.” known universe. For me, Deep
lection of hundreds of millions What is Deep Space? Deep Space Space is beyond our solar system,
of stars that are mixed with dust, is mostly described as the region even beyond the edges of our gal-
gases, and stuff we do not know of the space beyond the Earth– axy. It is the rest of the universe,
much about into a spiral shape we Moon system. Quite frankly, that seen and unseen, that our galaxy,
call the Milky Way Galaxy. This is a lot of space, but it seems to the Milky Way, is a part of. And
is a huge shape at approximately suggest Deep Space is within the our galaxy is not alone, as the
100,000 light years in diameter, solar system. Think bigger. Even Milky Way belongs to the Local
but there are other galaxies whose though the solar system, from our Group (see Figure 1) of galaxies
size dwarfs our galaxy, and there perspective in the inner solar sys- that we share with our portion of
are even dwarf galaxies. So, in this tem “looking outward,” is seem- the universe, which in turn is part
of a cluster of groups of galaxies,
| FIGURE 1: Local group and nearest galaxies. and so on.
Imagine a place where nearly
all of the points of light are not
stars, but individual galaxies. In
the Hubble Deep Field Image of
a region of the sky, thousands of
galaxies were revealed showing
a variety of shapes, sizes, and
interactions (see Figure 2). An
interesting and appropriate state-
ment about galaxies is that when
we see a galaxy and determine
its distance, we know that we see
it not as it is today but as it once
WIKIMEDIA COMMONS
was. Students will learn that dis-
tance in light years is the same as
the time it took for that light to
reach the Earth. For example, the
light we see from a galaxy that
January/February 2022 59is 10,000,000 light years distant
took 10,000,000 years to reach | FIGURE 2: Hubble deep field image.
the Earth. We would have to wait
another 10,000,000 years to see
today’s light from that galaxy!
Like someone has said more than
once: You can’t imagine the mag-
nitude of the situation.
A good way to start with your
students on a journey outward
would be by watching some short
videos that will set the stage for
exploring Deep Space and give
them a sense of the known and
estimated size and age of the
universe. Begin with an old clas-
sic, the original “Powers of Ten”
(see Videos section in Online Re-
sources), a short video that starts
WWW.NASA.GOV
with a couple having a picnic
outlined with a square that is one
meter wide. As the video pro-
gresses at 10-second intervals,
the view zooms outward at in-
creasing size that is 10 times far- of Ten” titled “Scales of the Uni- plore galaxies, both of which are
ther and 10 times wider than the verse in Powers of Ten” (see Vid- based on real images and data.
previous view—for example, 10 eos section in Online Resources) Using an image from the Great
meters (101 meters), 100 meters produced in 1996 by IMAX and Observatories Origins Deep Sur-
(102 meters), 1,000 meters (103 me- narrated by Morgan Freeman. vey (GOODS; see Online Resourc-
ters), one light year (1016 meters), This cosmic journey is based on es), the video “Ultra-Deep Field:
and so on—until arriving at the the same idea, except that a circle Looking Out into Space, Look-
farthest known distant celestial is used rather than a square and ing Back into Time” (see Videos
objects at 100,000,000 light years the video takes us outward to a section in Online Resources) in a
(1024 meters). The process is then circle 10,000,000,000 light years few minutes takes a 3-D journey
reversed, but instead of stopping wide (1026 meters). Then like its through the vastness of space
at the one square meter, the view video predecessor, it takes us in- looking at the many varieties of
decreases in size at intervals of ward, but this time the images galaxies, while the shorter video
negative powers of ten. This time zoom inward on a drop of wa- “Hubble: Galaxies across Space
the view stops at the smallest size, ter, each time 10 times smaller, and Time” (see Videos section in
0.00001 angstroms wide (10-15 but also ending at the realm of Online Resources), produced by
meters), of objects known at the quarks, 10-15 meters. IMAX, shows how the appear-
time—quarks. Keep in mind that To help students understand ance of galaxies differ as distance
this video was based on what was and visualize the range of galax- increases. Nearby galaxies are
known or suspected in 1977. ies in terms of shape, size, age, more completely formed and bet-
There is a relatively more and distance, you can show stu- ter developed in terms of their
modern version of the “Powers dents two short videos that ex- spiral shape than more distant
60SCOPE ON THE SKIES
galaxies, or as this video describes as Peculiar Galaxies. This could “browse” the universe using the
them, they are more “disheveled.” be a pair of galaxies in the process Explore Our Universe Skymap
Remember, we see galaxies as they of merging with distorted shapes, (see Online Resources) to start
once were, not as they are, so well- or a galaxy appearance distorted their galaxy search.
developed and relatively closer through a process called gravita- Another option could be taking
spiral-shaped galaxies, for exam- tional microlensing (see Online part in a Citizen Science Project
ple, are younger than the more dis- Resources). Whatever galaxy a stu- or NASA Challenge event. Most
tant disheveled-appearing older dent chooses, the student should recently, during the summer of
galaxies. As spiral galaxies age, be encouraged to learn more about 2021, NASA hosted the annual As-
they go through changes in their how that galaxy came to look as trophoto Challenges, offering two
structure and appearance due to we see it now and what it may look different directions for students to
a variety of causes, including the like in the future. follow as they studied the spiral
merger and interaction with an- galaxy M-87. One option was the
other galaxy, the growth of a black Finding images MicroObservatory Challenge, and
hole, or even a merger of black There are many opportunities for the other was the NASA Data Chal-
holes (see Image Archive: Galaxies students to learn more about gal- lenge. Although those challenges
in Online Resources). Keep this in axies that include requesting im- have ended, students can still visit
mind, as students may select gal- ages from a remotely controlled the website to explore the entries
axies based on their shape. The telescope and examining images submitted by student participants
shapes students may be attracted of our universe taken by both or to try the challenges themselves.
to besides the face-on spiral galax- land- and orbital-based large ap- Information and links to the chal-
ies are possibly those referred to erture telescopes. Students could lenges are on the Observing with
Visible planets
Mercury moves into the morning skies and starts becoming visible over the eastern horizon toward the
end of January.
Venus starts becoming visible over the eastern horizon toward the end of January and gradually
becomes more visible and brighter as each day passes.
Mars is visible as a morning planet above the eastern horizon during January and February. Watch it
pass by the reddish star Antares, the heart of Scorpius the Scorpion, the first week of January.
Dwarf planet Ceres has an apparent magnitude that may be bright enough to be seen in binoculars. To
find this closest Dwarf Planet, look above the southern horizon mid-evening for the stars of the open
cluster, the Pleiades and the Hyades. Ceres is approximately midway between the two star clusters.
Jupiter is visible over the south to southwest horizon at sunset until the latter half of January but is
setting lower each day. Watch for Jupiter to reappear in the morning skies later during the spring.
Saturn is too close to the Sun to be seen, but it will start to reappear in the morning skies toward the
end of Feburary.
January/February 2022 61NASA website home page (see atlas of the sky that is connected by the Sloan telescope. The Euro-
Online Resources). Students may to several databases of astronomi- pean Southern Observatory (ESO)
also make their own image re- cal imagery and data. The Aladin maintains an Image Archive that
quests of galaxies as well as any Lite home page opens with a col- includes some spectacular images
visible planet, our Moon, and the or view of the region around the of galaxies and clusters of galax-
Sun. Then using the online image “belt stars” and the Horsehead ies (see Image Archive: Galaxies
processing, they can analyze those Nebula taken by the Deep Sky in Online Resources). If looking
pictures. (Note: an e-mail address Survey 2 (DSS2; see Figure 3). Us- at online pictures of galaxies and
is required to receive the images.) ing that view or an object select- other deep sky objects piques
Online sources for images ed by the student, you can cycle your students’ interest, there may
taken by land- and orbital-based through several telescope surveys be an observatory nearby for real
telescopes vary in how they oper- that show the object in different sky observing (see Observatories:
ate, but all have images taken in wavelengths including visible USA and Observatories: Globe in
a variety of wavelengths, offering light, X-ray, hydrogen alpha, and Online Resources).
a chance to view different details infrared. With most objects the Have a stack of unused CDs
in an image. Students can explore difference in detail is striking. laying around? If you do, check
how objects differ when viewed Other online sources of im- out Universe of Galaxies (see
through different wavelengths agery and data include the Sloan Online Resources) to see how to
at the NASA Explore Light inter- Digital Sky Survey/Sky Server put those CDs to a good use in
active web page (see Online Re- (SDSS) where students can search an activity that models the rela-
sources). for objects by the object’s ID or tive distances between the Milky
Of the many options for obtain- by location. A quick way to ac- Way Galaxy and other galaxies.
ing images of celestial objects, the cess images taken by the SDSS Galaxies are made up of many
Aladin Lite online or download- telescope is by clicking on the Fa- things, chief of which are the stars
able program is one of the easi- mous Places link. This will pres- that come together gravitation-
est to use. This is an interactive ent a graphical list of objects seen ally. Students can learn about the
| FIGURE 3: Home page for the Aladin Lite program.
62SCOPE ON THE SKIES
lifecycle of stars by taking part in the Earth. Students could use this
an online star party with Infinis- astronomy program to search for James Webb Space
cope’s interactive Star Party (see objects like a galaxy, or just see Telescope
Online Resources). what is visible on a given eve- As of this writing, the launch of
Regardless of the online source ning. Additionally, the program the James Webb Space Telescope
used, a good practice for students has a feature called NoctuaSky, (JWST; see Online Resources) is
is to keep a log of their observa- which allows users to keep a re- scheduled for December 22, 2021,
tions; either the online or mobile cord or log of their efforts. (Note: and once in orbit will be readied
version of Stellarium (see Online Use of the log requires creating a for operation after a few weeks
Resources) would be a good start- user account.) Once an object has of system checks. The JWST will
ing point. Stellarium is a plane- been located, the student could not so much replace the Hubble
tarium-type program capable of then use that information to find Space Telescope (HST; see On-
showing the night or day sky and their object at one of the websites line Resources) as add on to what
most celestial objects for one’s offering images in different wave- the aging HST is capable of, plus
home location or other places on lengths. doing much more. At the JWST
January
01 Moon at perigee: 222,474 Star Cluster 12 Venus—Mars conjunction
miles (358,037 km) 20 Moon near Regulus 13 Moon near Pollux
02 New Moon 23 Venus at perihelion 14 Moon near Beehive Open
03 Quadrantid meteor shower Mercury at inferior conjunc- Star Cluster
Moon—Mercury conjunction tion 15 Galileo Day
04 Earth at perihelion: 0.98333 24 Moon near Spica 16 Full Moon
AU (91,406,234 miles; 25 Last quarter Moon Moon near Regulus
147,104,074 km) 27 Moon at descending node Mercury at greatest elonga-
Moon—Saturn conjunction Moon near Antares tion: 26.3°W
05 Moon—Jupiter conjunction 29 Moon near Mars 20 Moon near Spica
07 Mercury at greatest elonga- 30 Moon at perigee: 225,091 23 Moon at descending node
tion: 19.2°E miles (362,250 km) Last quarter Moon
08 Venus at inferior conjunc- 31 New Moon Moon near Antares
tion
24 Autumnal Equinox on Mars
09 First quarter Moon
25 Parker Solar Probe at 11th
12 Moon at ascending node February perihelion
Mercury—Saturn conjunction 02 Moon near Jupiter 26 Moon at perigee: 228,532
14 Moon at apogee: 252,156 04 Saturn in conjunction with miles (367,787 km)
miles (405,806 km) Sun 27 Moon near Mars
15 Mercury at perihelion 08 First quarter Moon 28 Moon near Mercury
Moon near Pollux 09 Moon at ascending node 28 Mercury at aphelion
Full Moon 10 Moon at apogee: 251,591 Moon near Saturn
18 Moon near Beehive Open miles (404,897 km)
January/February 2022 63SCOPE ON THE SKIES
website, there is an interactive Riddle. November 2017. OGOUUniverseGalaxiesMetric.pdf
resource where students can see NASA Explore Light—www.nasa.gov/ Webb vs. Hubble Telescope—www.
content/explore-light jwst.nasa.gov/content/about/
how the two orbiting telescopes
Observatories: Globe—www.go- comparisonWebbVsHubble.html
compare. • astronomy.com/observatories.htm What Did Hubble See on Your
Observatories: USA—www.visittheusa. Birthday?—www.nasa.gov/content/
ONLINE RESOURCES com/experience/closer- goddard/what-did-hubble-see-on-
“A Candle in Space”—Science Scope. look-cosmos-must-visit-us- your-birthday
Scope on the Skies. Bob Riddle. observatories WorldWide Telescope—
October 2017. Observing Log—stellarium-web.org/p/ worldwidetelescope.org/home/
Aladin Lite—aladin.u-strasbg.fr/aladin. observations
gml Observing with NASA:
Color the Universe—imagine.gsfc.nasa. MicroObservatory—mo-www.cfa. Videos
gov/features/coloring_pages/ harvard.edu/OWN/index.html Deep Field: The Impossible Magnitude
Explore Our Universe Skymap—www. Sloan Digital Sky Survey/Sky Server— of our Universe—deepfieldfilm.com/
nasa.gov/content/explore-our- cas.sdss.org/dr7/en/tools/places/ Hubble: Galaxies Across Space and
universe-skymap Star Party—infiniscope.org/ Time—bit.ly/3wNyFoc
Galaxify—writing.galaxyzoo.org/ Stellarium Observation Log—stellarium- Original Powers of Ten—youtu.
GOODS: The Great Observatories Origins web.org/p/observations be/0fKBhvDjuy0
Deep Survey—www.stsci.edu/ Using WWT in the Classroom— Scales of the Universe in Powers of
science/goods/ worldwidetelescope.org/use/ Ten—youtu.be/44cv416bKP4
Gravitational Microlensing Animation— educators/ Ultra Deep Field: Looking Out into
svs.gsfc.nasa.gov/20242 Universe of Galaxies activity— Space, Looking Back into Time—
How Big is Our Universe?—lweb.cfa. nightsky.jpl.nasa.gov/docs/ youtu.be/yfWYXY85mBk
harvard.edu/seuforum/howfar/
HowBigUniverse.pdf
Hubble Deep Field Image—www.nasa.
gov/pdf/283957main_Hubble_Deep_
Field_Lithograph.pdf For students
Hubble Space Telescope—hubblesite.
org/ 1. Check out an e-book from the Hubble Digital E-Book Library to
Hubble Telescope E-Books—www.nasa. learn more about galaxies, the universe, and the Hubble Space
gov/content/goddard/hubble-e- Telescope.
books
Image Archive: Galaxies—www.eso.org/ 2. Go to the Observe with NASA MicroObservatory (OWN) website
public/images/archive/category/ and request images of galaxies. Use the online image processor
galaxies/
to analyze your images.
“Imaging the Night Sky”—Science
Scope. Scope on the Skies. Bob
3. Use the Aladin website to find images of a galaxy you are
Riddle. February 2014.
Imagine the Universe Coloring Pages— interested in. What structures or parts of the galaxy are seen
imagine.gsfc.nasa.gov/features/ or not seen with different wavelengths? With which wavelength
coloring_pages/ does your galaxy look the best? Any idea why?
James Webb Space Telescope—www.
jwst.nasa.gov/ 3. Galaxify your own message using galaxy shapes at the My Galaxy
Local Group of Galaxies—www.messier. website (see Online Resources) or the Hubble website to find out
seds.org/more/local.html what the Hubble Space Telescope saw on your birthday.
“Measuring the universe”—Science
Scope. Scope on the Skies. Bob
Bob Riddle (bob-riddle@currentsky.com) is a science educator in Lee’s Summit, Missouri. Visit his astronomy website at https://
currentsky.com.
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