Latest / Star Trails: From Backyard Astronomy to Cosmic Wonder / A Star in Someone Else’s Sky

Transcript

A Star in Someone Else’s Sky · Star Trails: From Backyard Astronomy to Cosmic Wonder

• 0:07
  Howdy Star Gazers and welcome to this episode
• 0:10
  of Star Trails. Drew here and I'll be your guide
• 0:14
  to the night sky for the week starting July the
• 0:17
  13th through the 19th. This week we welcome darker
• 0:21
  skies, the return of Jupiter, and the first traces
• 0:24
  of the Perseid meteor shower. Later in the show,
• 0:28
  we turn the telescope around and examine how
• 0:31
  the earth looks from different areas of our solar
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  system. Whether you're tuning in from the backyard,
• 0:37
  the balcony, or just your imagination, I'm glad
• 0:40
  you're here. So find a cozy spot, let your eyes
• 0:43
  adjust, and let's see what the sky holds for
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  us this week. Let's start with the moon. We're
• 0:51
  coming off the full buck moon, which reached
• 0:54
  its peak on July the 10th. Hopefully, some of
• 0:57
  you managed to catch this big moon as it stayed
• 1:00
  fairly low to the horizon. Sadly, we had thunderstorms
• 1:04
  here, so it wasn't visible. The moon will spin
• 1:07
  the early part of this week in its waning gibbous
• 1:10
  phase, gradually shrinking in brightness each
• 1:13
  night. By Thursday, it reaches the last quarter
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  phase, with about half the moon illuminated.
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  Through a scope or binoculars, you'll see shadows
• 1:23
  stretching across the surface. highlighting craters
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  and mountain ranges near the terminator line.
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  By the end of the week, the moon will be entering
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  a waning crescent phase. That means darker skies
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  for tracking down faint galaxies, star clusters,
• 1:39
  and nebula. Now onto the planets. In the evening
• 1:44
  sky, you'll still be able to spot Mars glowing
• 1:47
  with its characteristic reddish hue. It's faint
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  this time of the year, but still visible just
• 1:53
  after sunset, low in the western sky. Mercury
• 1:57
  is also hanging around after sunset, especially
• 2:00
  early in the week, but it's hugging the horizon,
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  so you'll need a clear flat view and some luck
• 2:07
  with twilight timing. The best planetary viewing
• 2:11
  is for early risers. Venus remains dazzling in
• 2:15
  the morning sky. This week it's shining as bright
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  as ever, almost like a headlight, and gliding
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  near the famous Hyades and Pleiades star clusters
• 2:25
  in the constellation Taurus. This alignment creates
• 2:29
  a beautiful cosmic scene through binoculars or
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  a small telescope. Saturn rises in the late evening
• 2:36
  and climbs higher into the southern sky before
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  dawn. It's slowly moving closer to opposition
• 2:42
  later this summer, so the ringed planet is looking
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  especially good. Look for its golden glow near
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  the constellation Aquarius. Uranus is up too,
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  hovering close to the Pleiades and Taurus, not
• 2:56
  far from Venus. Neptune is nearby, a little east
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  of Saturn. You can catch both Saturn and Neptune
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  about a degree apart this week, roughly the width
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  of the full moon. As always, you'll need a good
• 3:11
  scope or binoculars to see Uranus and Neptune.
• 3:16
  And finally, Jupiter is slowly creeping back
• 3:18
  into the morning sky. It's faint right now, but
• 3:22
  you might catch it above the eastern horizon
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  before sunrise by the weekend. Our constellations
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  and deep sky treasures are much the same as previous
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  weeks. Overhead, the Summer Triangle, made up
• 3:35
  of the bright stars Vega, Deneb, and Altair,
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  is dominating the sky after dark. In Lyra, try
• 3:43
  spotting the famous Ring Nebula, also known as
• 3:46
  M57. You'll need a telescope to see its donut
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  -like shape, but it's well worth the effort.
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  Over in Cygnus, the Swan, check out the dumbbell
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  nebula M27. This is a planetary nebula visible
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  even through binoculars under dark skies. And
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  if you've got a scope and a good Oxygen 3 filter,
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  swing over to the Veil Nebula, a supernova remnant
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  that stretches like wisps of smoke across the
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  sky. Draco coils high in the north, and if you
• 4:20
  have a telescope, see if you can spot the tiny
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  but fascinating Cat's Eye Nebula. Looking lower
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  toward the southern horizon, Scorpius and Sagittarius
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  are rich with targets. Scorpius hosts the bright
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  red supergiant Antares, and Sagittarius, the
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  teapot, is packed with nebula and star clouds
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  along the heart of the Milky Way. In that area,
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  check out the lagoon nebula M8, the wild duck
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  cluster M11, and the butterfly cluster. The Milky
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  Way's core is glowing this time of year, so take
• 4:57
  your time scanning through this star -rich region.
• 5:01
  And here's a heads up, the Perseid meteor shower
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  begins this week. While it won't peak until mid
• 5:07
  -August, the first few meteors may begin to streak
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  across the sky by July 17th. With the moon waning
• 5:15
  and rising later each night, early morning hours
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  this week offer a growing window of dark skies.
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  If you're between midnight and dawn, you just
• 5:24
  might catch an early Perseid or two. And if you're
• 5:28
  observing Saturn this week, keep an eye out for
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  Titan, its largest moon. A Titan shadow transit
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  is predicted for the early hours of July the
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  18th. This transit is visible in backyard telescopes.
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  I'll include a link in the show notes with additional
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  information on this phenomenon, upcoming transits,
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  and how to catch them. Each week we peer out
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  into the cosmos describing the planets and constellations
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  that grace our sky. We chart the orbits of worlds,
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  track their brightness, and note how their appearance
• 6:09
  changes with the seasons. We talk about how bright
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  Venus is and the red glow of Mars. We're always
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  describing what these distant places look like
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  from here on Earth. But what if we flip that
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  around? What if instead we asked, what does Earth
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  look like from other planets? How do we appear
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  in someone else's sky? Let's take a little journey,
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  not outward, but inward, and look at ourselves
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  through distant eyes. To begin, we head over
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  to our nearest neighbor, Venus. If you could
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  stand on the surface of Venus and somehow peer
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  through the thick sulfuric clouds, you'd see
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  Earth as a brilliant bluish star, never far from
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  the Sun. Just as Venus plays the role of Morning
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  Star or Evening Star for us, we play that same
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  role for them. Always close to the Sun, always
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  confined to the twilight sky. At its brightest,
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  Earth would gleam at magnitude negative 4 .1,
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  nearly as bright as Venus looks from Earth. With
• 7:20
  a nice telescope on Venus, you'd see the Moon
• 7:23
  as a dot alongside Earth. From Venus, Earth would
• 7:28
  show slight phases, waxing and waning, shifting
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  from gibbous to full and back again. You'd never
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  see Earth as a crescent from Venus. It's too
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  far out for that. Now, from Earth, we never see
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  the outer planets in phases, so why would we
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  see Earth in phases from Venus? It has to do
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  with the Earth -Venus -Sun angle, which can become
• 7:52
  quite significant depending on where the planets
• 7:54
  are in their respective orbits. At greatest elongation,
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  when Earth is at the maximum angle away from
• 8:01
  the Sun in the Venusian sky, Earth appears not
• 8:05
  directly opposite the Sun, but offset. So only
• 8:09
  part of its dayside is visible, rendering Earth
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  as a bright gibbous disk. When it's directly
• 8:16
  behind the Sun at superior conjunction, Earth
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  is fully illuminated and looks full from Venus.
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  And Earth has been seen from even closer to the
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  Sun. In 2005, NASA's MESSENGER probe en route
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  to Mercury turned its camera outward and photographed
• 8:35
  Earth from 66 million miles away. We appeared
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  as a bright star, outshining everything else
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  in the field. Now let's journey out to Mars.
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  From the red planet, Earth appears smaller and
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  dimmer. To Martian eyes, Earth would be a bright
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  speck, rarely far from the Sun. A telescopic
• 8:57
  view of Earth has been recorded from Mars, and
• 9:00
  it's a stunning image. In 2007, NASA's Mars Reconnaissance
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  Orbiter turned its camera back toward us and
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  captured the Earth and the Moon floating side
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  by side in space, both in half -phase. You can
• 9:16
  actually see detail, not just light, but texture,
• 9:19
  weather systems, and the oceans. That's from
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  127 million miles away. Now, let's go even farther
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  out, to the orbit of Saturn. In 2013, the Cassini
• 9:33
  spacecraft took a moment from its study of the
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  ringed giant to look homeward. There, just below
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  Saturn's vast rings, was a tiny point of light.
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  That point was us. The photo was titled The Day
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  the Earth Smiled. For the first time, people
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  on Earth were invited to look up and wave, while
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  a camera out in the Saturnian system captured
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  our image. From nearly a billion miles away,
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  Earth was just a pixel, a flicker of sunlight
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  reflecting off oceans, ice, clouds, and continents,
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  all flattened into one shining speck. And that
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  image echoes another. Back in 1990, the Voyager
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  1 spacecraft, now past Neptune, was instructed
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  to turn around and take one final photo of its
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  home planet. What it captured became one of the
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  most iconic images in human history. We talked
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  about that image back on episode 51 earlier this
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  year. Of course, this is the famous pale blue
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  dot image where Earth, less than a pixel in size,
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  is caught in a ray of sunlight. It was Carl Sagan
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  who gave the photo its name and its voice. Consider
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  again that dot. That's here. That's home. That's
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  us. On it, everyone you love, everyone you know,
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  everyone you ever heard of. Every human being,
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  whoever was, lived out their lives. That image
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  wasn't just a picture. It was a mirror, a chance
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  to see ourselves not as giants, but as fragile,
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  temporary, and rare. From out there, we're not
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  the center of the universe. We're not even especially
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  noticeable. We're just another point of light
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  among billions, brighter than some, fainter than
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  others. It's a useful shift in perspective. Looking
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  back at Earth reminds us that astronomy isn't
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  only about the distant and the unfamiliar. Sometimes
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  it's about remembering where we are in all of
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  this, how we fit into the grand map of the solar
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  system, and the quiet role we play in someone
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  else's sky. If the stars spoke to you this week
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  or if a question's been on your mind, I'd love
• 12:00
  to hear it. Visit our website starrtrails .show
• 12:04
  where you can contact me and explore past episodes.
• 12:09
  Be sure to follow us on Blue Sky and YouTube.
• 12:12
  Links are in the show notes. Until we meet again
• 12:15
  beneath the stars, clear skies everyone.