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The Snow Moon & The Pale Blue Dot: A Cosmic Perspective · Star Trails: From Backyard Astronomy to Cosmic Wonder

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  Howdy Stargazers and welcome to this episode of Star Trails.
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  I'm Drew and I'll be your guide to the night sky for the week starting February 9th through
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  the 15th.
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  This week we're rolling back the clock to 1990 when Voyager 1 looked back and captured
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  its final series of images, an poignant family portrait of our solar system.
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  Also in last week's episode we examined the scale of time as it relates to the vast age
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  of our universe.
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  This week we're bringing the nearly unimaginable size of our universe into perspective.
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  But first let's start with what you can see from your backyard this week.
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  So grab a comfortable spot under the night sky and let's get started.
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  Tonight the moon will be in its waxing gibbous phase, about 90% illuminated.
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  This phase continues until the full moon on February 12th, known as the snow moon.
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  We'll end the week in a waning gibbous phase.
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  The snow moon is the traditional name for the full moon that occurs in February.
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  The name originates from Native American Anglo-Saxon and European folklore, recognizing February
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  as the month with the heaviest snowfall in the Northern Hemisphere.
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  In many regions February is the coldest and harshest time of the year making the snow
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  moon a fitting title for this celestial event.
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  Interestingly this moon took on some unique names in other cultures.
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  It's been called the Hunger Moon by many Native American tribes, particularly the Algonquin,
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  because harsh winter conditions made hunting difficult.
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  For similar reasons it's also known as the Bony Moon or Little Famine Moon in some indigenous
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  cultures.
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  Some tribes such as the Cree call it the Bear Moon because February marks the time when
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  bear cubs are typically born in their dens.
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  While this moon will wash out dimmer objects this week, the planets are still putting on
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  a show.
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  Venus shines brilliantly in the western sky after sunset.
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  It will reach its peak brightness on the 16th making it a stunning evening star throughout
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  our week.
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  Mars is visible in the evening sky and will have a close encounter with the moon tonight.
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  Look towards the east after sunset to witness this conjunction near the twin stars of Gemini,
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  Caster and Pollux.
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  Jupiter continues dominating the early evening sky.
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  It can be seen high overhead after sunset and it's visible until the early morning.
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  Saturn is still visible in the western sky after sunset, but it's gradually descending
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  towards the horizon.
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  It will become more difficult to observe in the coming weeks.
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  I always like to make note of some of the lesser known constellations.
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  We've covered winter favorites like Gemini and Orion extensively in recent episodes.
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  So this week I thought we'd look at two whimsical constellations, Camelopartilus and Montserros.
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  Camelopartilus, the giraffe, is a large but faint constellation that sprawls across the
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  northern sky.
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  Despite its size, it has no particularly bright stars making it difficult to spot with the
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  naked eye.
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  Its name comes from the Latin words for camel and leopard as ancient observers thought giraffes
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  resembled a mix of these two animals.
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  This constellation is home to NGC 2403, a spiral galaxy that resembles a miniature version
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  of the Andromeda galaxy.
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  This galaxy is around 8 million light years away and is visible in small telescopes.
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  Binocular observers may want to track down Kimball's Cascade, a string of stars forming
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  a diagonal line.
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  Across the sky we find Montserros, the unicorn, a dim but fascinating constellation located
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  between Orion, Canis Major and Gemini.
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  It was first documented in the 17th century and lacks bright stars, making it challenging
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  to locate without a star chart.
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  This constellation is home to the Rosette Nebula.
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  This massive region of ionized hydrogen gas is home to a young open cluster of stars.
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  It's best seen with astrophotography or in large telescopes, but a faint glow can sometimes
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  be seen through binoculars.
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  This region also contains the Christmas tree cluster, an open star cluster shaped like a
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  holiday tree.
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  Also, be on the lookout for Beta monoceratis, a triple star system that can be resolved in
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  a small telescope.
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  Although the bright moon this week may hamper observations, these two constellations offer
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  up some nice targets when skies are darker.
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  Do you remember where you were on February 14th, 1990?
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  I was a freshman in high school.
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  Maybe some of you weren't born yet.
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  On that date, Voyager 1 took a family photo of our solar system.
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  While some folks were celebrating Valentine's Day, for those who look up to the cosmos,
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  that day marked something truly extraordinary.
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  Humanity captured an image that changed how we see ourselves.
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  The image is a mosaic of our solar system.
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  One frame in particular would go on to become iconic, the pale blue dot.
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  From a distance of about 3.7 billion miles, Earth appeared as a tiny speck, less than
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  a pixel in size, suspended in a beam of scattered sunlight.
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  It showed how small and fragile our planet looked, just a faint dot adrift in the vast
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  cosmic ocean.
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  The idea for the image was proposed by Carl Sagan, who believed this portrait of our solar
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  system could be a profound reminder of our place in the cosmos.
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  In his now famous words, Sagan described Earth as a mode of dust suspended in a sunbeam,
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  reminding us that everything we've ever known, all of human history, every triumph and tragedy,
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  has unfolded on that tiny dot.
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  Consider again that dot.
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  That's here.
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  That's home.
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  That's us.
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  Everyone it, everyone you love, everyone you know, everyone you ever heard of, every human
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  being, whoever was, lived out their lives on a mode of dust suspended in a sunbeam.
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  As Voyager 1 prepared to leave the solar system, NASA engineers sent a command to the spacecraft
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  to turn its camera around and take one last look back, capturing six of the solar system's
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  planets.
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  Uranus, Earth, Jupiter, Saturn, Uranus and Neptune.
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  Mercury was too close to the sun to be seen and Mars didn't make the cut due to unfavorable
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  lighting conditions.
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  The sun itself had to be carefully managed in the image to avoid damaging Voyager's sensitive
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  camera.
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  This resulted in an unintended consequence.
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  Earth appeared an array of scattered sunlight, a cosmic coincidence that gives the photo
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  an almost spiritual quality.
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  Earth is tiny in this mosaic, barely larger than a tenth of a pixel in the rendering.
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  From a distance of 3.7 billion miles, Voyager's camera had to use a narrow angle lens and
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  extreme precision to even spot Earth in the void.
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  The photo was taken with three color filters, blue, green and violet.
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  These were combined to create the final image.
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  The result wasn't about vibrant detail, it was about perspective.
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  Earth's faint presence emphasized just how vast and dark space truly is.
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  The full family portrait also holds symbolic weight.
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  It's the only time in history that we've captured an image of the solar system in this
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  way.
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  By 1990, Voyager 1, now years past its mission to study Jupiter and Saturn, was speeding
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  out of the solar system at nearly 40,000 miles per hour.
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  And this was its final look back before its camera was permanently turned off to conserve
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  power.
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  While the pale blue dot is the most famous image from the mosaic, each frame tells a
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  story.
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  Saturn, for instance, appeared as a soft golden orb surrounded by its majestic rings.
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  Jupiter, with its immense size, dominated its frame.
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  And Neptune and Uranus, captured as faint, icy blue dots, hinted at the mysteries of
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  the outer planets.
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  Today, Voyager 1 is the farthest human-made object from Earth, carrying its golden record
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  as a message for any intelligent life it might encounter.
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  And yet, its most powerful legacy might be that small image of Earth.
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  With that, let's take a journey from our tiny corner of the solar system to the edge
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  of the observable universe, and learn more about scale and the vastness of our galaxy
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  and the universe itself.
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  Before we start, let's talk about why scale is important.
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  Imagine the sun is the size of a grapefruit.
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  If that's the case, how far away do you think Earth would be?
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  At this scale, Earth would be a tiny grain of sand about 50 feet away.
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  That's the length of a school bus.
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  And Neptune, the farthest planet from the sun, would be a marble 1500 feet away, a little
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  more than a quarter of a mile.
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  This analogy shows just how much empty space there is in our solar system.
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  And believe it or not, this is just the beginning of the story.
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  The universe is so vast that even astronomers struggle to wrap their heads around it.
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  So let's start small and work our way up.
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  Let's begin close to home.
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  Our solar system.
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  At the center is the sun, a star so massive that it makes up 99.8% of the solar system's
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  total mass.
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  It's about 864,000 miles across.
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  That's so big you could fit 1.3 million Earths inside of it.
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  The Earth orbits the sun at an average distance of 93 million miles.
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  We call this distance one astronomical unit, or AU.
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  But here's where it gets wild.
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  Neptune, the farthest planet from the sun, is 30 AU away.
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  That's 2.8 billion miles.
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  And here's another way to think about it.
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  Light from the sun takes 8 minutes to reach Earth, but it takes more than 4 hours to reach
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  Neptune.
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  That means when you look at Neptune through a telescope, you're seeing it as it was
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  4 hours ago.
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  And that's just within our solar system.
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  Now let's zoom out a bit.
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  The nearest star to our sun is Proxima Centauri, part of the Alpha Centauri system.
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  It's 4.24 light years away.
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  That's 25 trillion miles.
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  To put that in perspective, if the sun were a grapefruit in New York City, Proxima Centauri
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  would be another grapefruit in Los Angeles.
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  That's how much empty space there is between stars.
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  And Proxima Centauri is just our next door neighbor.
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  For a galaxy, the Milky Way contains 100 to 400 billion stars, and it's about 100,000
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  light years across.
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  Our solar system is located in one of the Milky Way's spiral arms, about 27,000 light
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  years from the galactic center.
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  If the Milky Way were the size of a football field, our solar system would be a tiny speck
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  on the 10-yard line.
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  Of course, the Milky Way is just one galaxy among billions.
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  Our nearest galactic neighbor is the Andromeda Galaxy, which is 2.5 million light years away.
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  That means the light we see from Andromeda today left around the time early humans were
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  first walking the Earth.
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  Andromeda is part of a small group of galaxies called the Local Group, which includes about
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  54 galaxies.
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  But even the Local Group is just a tiny part of a much larger structure called the Virgo
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  Supercluster, which contains more than 100 galaxy groups and spans 110 million light years.
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  And here's the kicker.
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  The Virgo Supercluster is just one of countless superclusters in the universe.
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  These superclusters form a vast cosmic web, with galaxies strung along filaments like pearls
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  on a necklace.
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  The scale is almost impossible to comprehend.
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  Now, let's zoom out even further to the observable universe.
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  This is the part of the universe we can see from Earth, and it's about 93 billion light
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  years across.
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  Scientists think the universe is around 13.8 billion years old, so how can the universe
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  beat 93 billion light years across?
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  Just because the universe is expanding, space itself is stretching, carrying galaxies along
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  with it.
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  So the light from distant galaxies has traveled much farther than we might expect.
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  The observable universe contains an estimated 2 trillion galaxies, each with billions or
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  even trillions of stars.
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  If the observable universe were the size of Earth, the Milky Way would be the size of
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  a postage stamp.
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  Here's something else to ponder.
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  When astronomers look at the most distant galaxies, they're seeing them as they were
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  billions of years ago, not long after the Big Bang.
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  One of the most humbling images in astronomy is the Hubble Deep Field.
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  In 1995, the Hubble Space Telescope pointed at a tiny, seemingly empty patch of sky, about
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  the size of a grain of sand held at arm's length.
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  What it revealed was astonishing—thousands of galaxies, each containing billions of stars.
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  And that's in just one tiny corner of the sky.
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  But even with modern tools like Hubble and the James Webb Space Telescope, the true scale
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  of the universe is almost beyond comprehension.
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  And that's part of what makes astronomy so awe-inspiring.
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  The fact that we can observe, measure, and even begin to understand the scale of the universe
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  is a testament to human curiosity and ingenuity.
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  And it helps connect us in a very real way to the rest of the cosmos.
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  If you found this episode useful, let me know and feel free to send in your questions and
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  observations.
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  The easiest way to do that is by visiting our website, startrails.show.
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  This is also a great way to share the show with friends.
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  Until next time, keep looking up and exploring the night sky.
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  Clear skies, everyone.