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Tempus Fugit: Time in Space and Sky · Star Trails: From Backyard Astronomy to Cosmic Wonder

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  Howdy stargazers and welcome to Star Trails.
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  I'm Drew and I'll be your guide to the night
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  sky for the week of August the 31st to September
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  6th. This is a week when the moon climbs from
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  half -lit to nearly full, brightening each evening,
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  and the outer planets take center stage. We'll
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  also wander through a few oft -ignored constellations
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  that hold some real treasures for small scopes
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  and binoculars. Later in the show, we take a
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  look at time from the watches worn on space missions,
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  Martian days, and the time -warping science behind
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  GPS satellites. Whether you're tuning in from
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  the backyard, the balcony, or just your imagination,
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  I'm glad you're here. So find a cozy spot, let
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  your eyes adjust, and let's see what the sky
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  holds for us this week. We start with our nearest
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  neighbor. The moon reached first quarter in the
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  early hours of Sunday morning and now it's waxing
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  steadily through gibbous all week. By Saturday,
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  it's a brilliant lantern nearly full with the
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  official full moon arriving on Sunday the 7th.
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  So your deep sky hunting windows shrink quickly.
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  Favor the first half of the week if you want
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  darker skies after midnight. Farther away, Saturn
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  is a best bet right now. It's glowing in Pisces
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  all evening, a bright golden ember. The rings
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  are still at their thinnest in decades, edge
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  -on and knife -like, but still a thrill in any
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  telescope. Saturn reaches opposition later this
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  month, so it will only get better. Neptune, also
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  in Pisces, is nearby for late -night telescopic
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  hunters. and Uranus comes up after midnight in
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  Taurus. Mars is a low ember in the western twilight,
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  hard to spot but technically present. Meanwhile,
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  the mornings belong to Venus and Jupiter. Venus
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  continues as the dazzling morning star while
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  Jupiter rises earlier each night and sits near
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  Gemini's bright twins, Castor and Pollux. A fine
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  pairing to greet the dawn. If you're out in the
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  early hours Monday morning, keep an eye on Auriga
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  for the Aurigad meteor shower. It's usually faint,
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  but has a history of surprise outbursts. And
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  in the same part of the sky, Comet Lemmon C2025A6
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  is sliding near Gemini. It's faint now, more
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  a telescopic quarry, but worth noting as it brightens
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  toward October. The brighter moon pushes us towards
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  star clusters, doubles, and brighter objects
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  that punch through moonlight. In Delphinus, the
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  little diamond -shaped dolphin high in the southeast,
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  you'll find two globular clusters, NGC 6934,
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  a compact grainy ball, and NGC 7006, a distant
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  halo globular so far away it appears as a mere
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  smudge in the eyepiece. Slide westward to Sagitta,
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  the tiny arrow pointing between Aquila and Volpecula.
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  Here you'll find M71, a cluster that sits right
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  on the border between open and globular, granular,
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  loosely packed, and striking at medium power.
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  Up in Volpecula, telescopes reveal NGC 6940,
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  a lush field of faint suns. In Scutum, the wild
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  duck cluster M11 is one of the sky's finest open
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  clusters with stars packed like glitter. And
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  for a challenge, hunt nearby for IC1295, a delicate
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  planetary nebula that responds beautifully to
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  an O3 filter. Faint little Equelius, the little
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  horse near Delphinus, offers a fine double star,
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  Epsilon Equilii, a classic seeing test. And in
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  Lacerda, the lizard crawling high overhead later
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  at night, NGC 7243 sprawls as a pleasing scattered
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  open cluster. The Milky Way still arcs bright
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  through the south in early evening, but the moon's
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  glow will wash it out more and more as the week
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  goes on. Take advantage of the first few nights
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  after midnight for darker glimpses, then shift
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  your focus to planets, clusters, and lunar landscapes
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  once the moon dominates. Next week brings the
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  full moon and elsewhere in the world a total
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  lunar eclipse, but it's not visible here in the
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  Americas. You may have heard the Latin expression
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  tempus fugit, which simply means time flies.
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  We're going to examine that in a very literal
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  way as we explore watches in space, atomic clocks,
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  and how time passes on other planets. That's
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  coming up after the break. Stay with us. Welcome
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  back! Let's take a break from the sky and talk
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  about something we can't escape, no matter what
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  planet we're on. Time. Here on Earth, time feels
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  fixed. The sun rises, the sun sets, and our clocks
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  keep a steady rhythm. But once you leave Earth,
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  or even just start thinking like an interplanetary
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  explorer, time starts to slip and bend in ways
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  that are both subtle and profound. Let's start
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  with Mars. A Martian day, or what scientists
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  call a Sol, lasts 24 hours, 39 minutes, and 35
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  seconds. Only about 40 minutes longer than an
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  Earth day, but enough to wreak havoc on human
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  schedules. Whenever NASA sends a rover, like
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  Spirit, Opportunity, Curiosity, or Perseverance,
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  the mission team shifts to Mars time. Their schedules
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  drift by 40 minutes each day, so within a couple
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  of weeks, scientists are working the night shift,
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  then the day shift, then back again. It's a jet
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  lag without ever leaving Pasadena. Families of
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  engineers even reported being pulled into this
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  Martian rhythm, living in a haze of perpetual
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  time zone changes. It's known as Martian insomnia.
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  The engineers at JPL actually commissioned Mars
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  watches. They look like ordinary chronographs,
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  but the second hand ticks just a little slower,
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  stretching the day to match a soul. It's one
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  of the few times in history people have worn
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  a watch calibrated to another planet. And that
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  brings me to a portion of the show I call Watches
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  in Space! First off, I'm a geek when it comes
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  to watches in general. Watches worn by astronauts
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  are a niche interest of mine, one that peaked
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  a few years ago when I saw in person the Omega
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  Speedmaster worn by astronaut Charles Duke. I
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  once had the opportunity to meet shuttle astronaut
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  Clayton Anderson, and I spent most of that time
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  talking to him about ham radio on the ISS and,
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  of course, his Omega X -33 watch. The tradition
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  of timekeeping in space runs deep. Early in human
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  space exploration, NASA selected the Omega Speedmaster
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  Chronograph, a fully mechanical hand -wound watch.
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  Mechanical watches can't crash or short out in
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  a vacuum or when exposed to radiation. Additionally,
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  the Speedmaster has an acrylic crystal, that's
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  the glass over the dial, which is shatter -resistant,
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  unlike the sapphire crystals that are often used
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  in luxury timepieces. In old mission photos,
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  you can see astronauts wearing the Speedmaster
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  strapped over the wrist of their spacesuit during
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  Gemini, EVAs, and on moonwalks. My favorite image
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  of the Speedmaster was taken on Apollo 11, being
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  worn by Buzz Aldrin inside the command module.
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  Once on the lunar surface, Neil Armstrong actually
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  left his watch in the lunar module as a backup
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  timer, so it was Aldrin's that became the first
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  watch on the moon. If you've seen the film Apollo
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  13, you might remember when a crucial course
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  correction burn was timed by the stopwatch hand
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  on the Speedmaster, or Speedy, as it's affectionately
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  known in watch nerd circles. Omega has embraced
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  this history and still produces the original
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  Moonwatch to this day. They include a NASA -style
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  nylon strap you can attach for real astronaut
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  authenticity, along with the engraving First
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  Watch on the Moon on the case back. If you have
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  7 grand or so burning a hole in your pocket,
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  it can be yours. Or you can buy the plastic look
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  -alike Moon Swatch for about $270. This one is
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  a special edition from Omega's parent company,
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  The Swatch Group. If you grew up in the 80s,
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  you might remember the swatch watch, those colorful
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  plastic timepieces that were all the rage, along
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  with neon colors on everything, parachute pants,
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  jelly bracelets, and trapper keepers. The Omega
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  isn't the only moon watch. Bulova makes a version
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  inspired by watches worn on the Apollo 15 mission,
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  although it eschews the mechanical innards for
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  a super -accurate, high -beat quartz movement.
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  NASA isn't as picky about watches nowadays. Crews
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  have worn zens, fortices, and even digital watches.
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  Today, astronauts often bring their personal
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  watches like Garmin's and Apple watches. But
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  the core idea is the same. You need reliable
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  timekeeping when every maneuver, every engine
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  burn, and every oxygen check is a lie for death.
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  And there's just something kind of cool about
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  knowing that something as everyday and ordinary
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  as a wristwatch can be used as a tool for space
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  exploration. But what happens when you need extreme
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  precision? Right now your phone's navigation
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  app depends on clocks in space, the atomic clocks
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  onboard GPS satellites. Each satellite carries
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  multiple clocks tuned to within billionths of
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  a second. The system works by measuring how long
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  it takes signals to reach your device. Even the
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  tiniest error in timing would put you miles off
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  course. And here's where relativity sneaks in.
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  Einstein showed us that time doesn't tick the
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  same everywhere. If you move very fast, your
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  clock slows down compared to someone standing
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  still. That's special relativity. If you climb
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  higher out of a planet's gravity, your clock
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  actually ticks faster, and that's general relativity.
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  GPS satellites are in both situations at once.
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  They're zipping around Earth at nearly 9 ,000
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  miles per hour, which makes their clocks run
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  a little slow. But they're also about 12 ,500
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  miles above Earth's surface in weaker gravity,
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  which makes their clocks run a little fast. Add
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  the two effects together, and the fast wins.
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  Their clocks tick about 38 microseconds ahead
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  each day compared to clocks on Earth. That sounds
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  tiny, but if engineers didn't correct for it,
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  your location on Google Maps would drift by several
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  miles in a matter of hours. In other words, without
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  taking relativity into account, we'd all be lost.
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  So, whether it's engineers struggling to live
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  on Martian time, astronauts strapping speed masters
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  to their sleeves, or atomic clocks whispering
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  to your smartphone, space reminds us that time
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  is not universal. It's a local rhythm, tied to
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  gravity, velocity, and the turning of worlds.
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  Here on Earth, we march to a 24 -hour beat. On
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  Mars, the tempo slows by 40 minutes. In orbit,
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  atomic clocks tick just differently enough to
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  keep us humble. Time is not some absolute metronome
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  in the background of the universe. It's pliable
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  and contextual. And as we push farther into space,
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  we'll discover just how many ways we can bend
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  it, stretch it, and live by it. If the stars
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  spoke to you this week or if a question's been
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  on your mind, I'd love to hear it. Visit our
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  website, StarTrails .Show, where you can contact
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  me and explore past episodes. Be sure to follow
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  us on Blue Sky and YouTube. Links are in the
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  show notes. Until we meet again beneath the stars,
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  clear skies, everyone.