Latest / Kidcast Daily / Ep384: Galaxies closest to us

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Ep384: Galaxies closest to us · Kidcast Daily

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  Spin the wheel, let's take a ride.
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  Sports and science bursting from inside a world of wonder.
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  Open wide. Come on kids, let's amplify kid
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  cats. Daily starts your day, Fun and
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  laughter come your way. Sports and Trinia games galore.
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  Welcome back to Kick Ass Daily. Get ready to learn something
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  awesome today. Whether it's sports records,
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  science, discoveries, history, mysteries, or wild trivia.
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  Today we are exploring galaxies that are closest to us and what
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  makes them special. We will keep things simple, use
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  real facts, and take a friendly tour through our cosmic
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  neighborhood. So let's get on with today's
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  episode. First, what is a Galaxy?
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  A Galaxy is a huge collection of stars, gas, dust, and invisible
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  matter called dark matter, all held together by gravity.
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  Our home Galaxy is the Milky Way.
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  It is shaped like a disc with spiral arms and a central bulge,
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  and our sun is one of its hundreds of billions of stars.
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  If you imagine the Milky Way as a community, then the galaxies
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  closest to us are like nearby towns that astronomers can study
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  in detail. Astronomers measure Galaxy
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  distances in light years. One light year is how far light
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  travels in one year, which is almost 10 trillion kilometers.
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  That is a big number, but it helps us talk about space in a
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  clear way. When we say a Galaxy is 160,000
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  light years away, we mean the light we see from it left
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  160,000 years ago and has been traveling through space to reach
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  our eyes and telescopes. The closest galaxies to the
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  Milky Way are not giant spirals. They are mostly small companion
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  galaxies that travel around the Milky Way in paths called
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  orbits. Many are called dwarf galaxies
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  because they have far fewer stars than the Milky Way.
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  One of the nearest is the Sagittarius Dwarf Spheroidal
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  Galaxy, sitting about 70,000 light years from Earth.
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  It is faint and stretched out, and astronomers mapped it by
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  tracking the motions of its stars.
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  There are many other tiny satellites as well, such as the
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  Ursa Minor Dwarf and the Draco Dwarf, each a few 100,000 light
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  years away. Two of our most famous neighbors
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  are the Large Magellanic Cloud and the Small Magellanic Cloud.
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  The Large Magellanic Cloud, often shortened to LMC, is about
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  160,000 light years away. The Small Magellanic Cloud, or
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  SMC, is about 200,000 light years away.
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  These two are irregular galaxies, which means they do
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  not have the neat spiral shape of the Milky Way.
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  They are busy with star formation, and their gas and
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  dust make great laboratories for studying how stars are born.
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  These clouds are bright enough that people without telescopes
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  can see them from certain places on Earth.
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  Did you know the LMC and SMC were recorded by navigators
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  traveling in the Southern Hemisphere centuries ago because
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  they helped sailors recognize the night sky?
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  Did you know the LMC is the site of a famous supernova observed
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  in 1987, which helped scientists learn about the life cycle of
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  stars? Beyond our closest companions,
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  we have the big neighbor everyone hears about, the
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  Andromeda Galaxy, also called M31.
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  It is about 2.5 million light years away.
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  Andromeda is a spiral Galaxy, large like the Milky Way, and it
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  contains hundreds of billions of stars.
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  Astronomers study Andromeda to compare it with our own Galaxy
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  because it is similar in structure.
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  Another important neighbor is the Triangulum Galaxy or M33 at
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  about 2.7 million light years away.
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  Triangulum is smaller than Andromeda and the Milky Way, but
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  it has well defined spiral arms and active star forming regions.
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  Together, the Milky Way, Andromeda and Triangulum anchor
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  a cluster of more than 50 galaxies known as the Local
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  Group. Here is a yes or no question.
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  Can you see the Andromeda Galaxy with your unaided eyes from a
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  very dark location with no city lights?
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  Yes, from a dark sight, people can spot it as a faint elongated
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  patch in the sky, especially during autumn in the northern
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  hemisphere. Here is a trivia question for
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  you. In which constellation is the
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  Andromeda Galaxy located in the sky?
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  It is in the constellation Andromeda, which is how it got
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  its common name. Let's talk about how scientists
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  learn these distances. One method uses special stars
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  called Cepheid variables. These stars brighten and dim in
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  a regular pattern, and the pattern tells astronomers how
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  bright the star truly is. By comparing the true brightness
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  to what we see from Earth, scientists can figure out how
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  far away the star and the Galaxy it lives in must be.
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  This method helped confirm that Andromeda is far outside the
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  Milky Way and is its own separate Galaxy.
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  Here is another trivia question. What is the nickname of the
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  giant star forming region in the Large Magellanic Cloud that
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  astronomers love to study? It is called the Tarantula
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  Nebula, and it contains some of the most massive newborn star
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  clusters known. Did you know the Triangulum
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  Galaxy likely has a disk of hydrogen gas that extends
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  farther than its visible stars, making it useful for mapping how
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  Galaxy matter is spread out? Did you know Andromeda has a
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  bright central bulge where stars are packed more closely than in
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  its spiral arms? Now, a few words about how these
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  neighbors move. Galaxies are not still.
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  They move through space under the pull of gravity.
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  Measurements show that the Milky Way and Andromeda are moving
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  toward each other. This motion will likely bring
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  them together in about 4 to 5 billion years, and over time
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  they will form a single, larger Galaxy.
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  Stars and galaxies are very far apart from one another, so this
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  kind of event does not mean stars will crash into each
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  other. Instead, their paths will shift
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  as gravity changes the overall shape of the combined system
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  over a very long time. Here is a yes or no question.
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  Do astronomers use a unit called a kiloparsec or KPC as a
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  standard way to describe Galaxy scale distances?
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  Yes. One kiloparsec is about 3260
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  light years and it is handy for mapping Galaxy structures like
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  spiral arms and Halos. Our nearby galaxies also help us
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  test our tools. Telescopes on mountains and in
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  space capture images across different kinds of light, such
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  as visible light, infrared, and X-rays.
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  The Magellanic Clouds are close enough that even medium sized
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  telescopes can pick out individual star clusters and
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  clouds of gas. Andromeda and Triangulum fit
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  nicely into wide field images that show their spiral patterns.
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  Here is another yes or no question.
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  Are the Magellanic Clouds easy to see for most of North America
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  and Europe? No.
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  They are mainly visible from the southern hemisphere and near the
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  equator. People in places like Chile,
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  Australia, South Africa and New Zealand often have good views
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  when the skies are clear. Did you know the Small
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  Magellanic Cloud has an extended stream of gas called the
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  Magellanic Stream trailing behind it and the LMC?
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  This stream helps scientists learn how galaxies share gas
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  with their surroundings. Did you know that tiny, ultra
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  faint dwarf galaxies around the Milky Way can contain only a few
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  thousand stars, which is less than a small town's population
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  if every person counted as one star?
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  Time for one more trivia question.
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  Which historic telescope helped Edwin Hubble find Cepheid
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  variable stars in Andromeda, proving it was a separate
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  Galaxy? The 100 inch Hooker telescope at
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  Mount Wilson Observatory in California.
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  Those observations in the 1920s changed our view of the
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  universe. As we wrap up, let's review what
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  we learned. A Galaxy is a vast system of
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  stars, gas, dust, and dark matter held together by gravity.
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  The Milky Way is our home Galaxy.
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  The closest galaxies to us are mostly small dwarf galaxies,
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  including the Sagittarius Dwarf Spheroidal and several others
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  that orbit the Milky Way at 10s to hundreds of thousands of
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  light years away. 2 standout neighbors are the Large
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  Magellanic Cloud at about 160,000 light years and the
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  Small Magellanic Cloud at about 200,000 light years.
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  Both are irregular galaxies and rich in Star forming regions
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  just beyond them. The Andromeda Galaxy lies about
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  2.5 million light years away and the Triangulum Galaxy is about
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  2.7 million light years away. These together with many dwarf
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  galaxies form our local group. We also learned that Andromeda
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  can be seen without a telescope from dark places.
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  It sits in the constellation Andromeda, and the Tarantula
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  Nebula is a famous star forming site in the LMC.
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  Astronomers use tools like Cepheid variable stars,
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  Lightyear and killoparsec distance units, and powerful
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  telescopes to measure and map these galaxies.
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  Finally, we discovered that our galactic neighbors are moving,
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  and in the far future, the Milky Way and Andromeda are expected
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  to come together to form a larger Galaxy.
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  Thanks for listening and exploring nearby galaxies today.
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  Keep looking up on clear nights, and if you ever travel to the
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  southern hemisphere, try spotting the Magellanic Clouds.
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  There is always more to learn in our cosmic neighborhood, and
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  every new fact is a step toward understanding how the universe
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  is put together. And beyond breakfast, feeling
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  fine, adventures waiting. Don't be late.
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  Today's the day we celebrate. Kid Cast Daily starts your day.