Howdy Star Gazers and welcome to Star Trails.
I'm Drew and I'll be your guide to the night
sky for the week of October the 12th to the 18th.
This week we're moving deeper into autumn and
the sky is shifting gears. Longer nights, crisp
air, and the fading moon are about to make for
some excellent observing conditions. Also, we
continue our march toward Halloween with another
eerie observation. This week we journey into
the house of a thousand mirrors to examine one
of my favorite topics, the weird world of gravitational
lensing. Whether you're tuning in from the backyard,
the balcony, or just your imagination, I'm glad
you're here. So find a cozy spot, let your eyes
adjust, and let's see what the sky holds for
us this week. The week begins with a waning gibbous
moon just past full. On Monday the moon reaches
last quarter and thins into a waning crescent
rising later each night. That means the second
half of the week will bring darker skies in the
late evening perfect for galaxies, nebula and
faint star clusters. The planetary lineup is
solid this week. Saturn takes the spotlight right
after dusk. It's hanging in Aquarius, high enough
for steady views by mid -evening. It passed opposition
back in September, so it's still bright and its
moon Titan is easy to spot even in a modest telescope.
Neptune is over in Pisces, best seen around midnight.
Look for it as a tiny bluish dot in binoculars.
Uranus rises later in the evening in Aries, steadily
climbing toward its November opposition. Under
suburban skies, it's easy to catch with binoculars
and shows a small greenish disk in a telescope.
Jupiter doesn't make its entrance until the early
morning hours, but when it does, it dominates
the sky. It's rising earlier each night and will
reach opposition in January. So this is the beginning
of its best observing season. And don't miss
Venus now reemerging as a brilliant morning star
in the pre -dawn sky. By week's end, you'll see
it low in the east with a delicate crescent moon
nearby. An excellent photo opportunity if you
have a clear horizon. Mars and Mercury are low
and tricky this week. Mars is fading into the
twilight. and Mercury will become more visible
later in the month. The Orionid meteor shower,
made of dust from Halley's Comet, is ramping
up. The official peak is on October 21st, but
during our week, early Orionids are already visible.
For your best chance, head out after midnight,
face east, and watch as Orion climbs higher in
the sky. Late in the week, the dimming moon will
make it easier to spot them. Constellations of
autumn are rising. We mentioned the great square
of Pegasus last week, and how to locate the Andromeda
galaxy. If you revisit that same area, look for
M33, the Triangulum galaxy, a faint but rewarding
catch. And while you're in Pegasus, don't miss
M15, a bright, compact globular cluster that
looks great even under moderate light pollution.
Overhead at dusk, Cygnus is still well placed,
its Milky Way lanes glowing faintly in darker
skies. A telescope with a nebula filter can reveal
the Veil Nebula or the North America Nebula,
especially during the moon -free later part of
the week. Down south near Saturn, swing your
scope to M2 in Aquarius, a fine globular cluster,
and the Helix Nebula, a ghostly planetary nebula
that really pops with an O3 or UHC filter. And
if you're up late or early, you'll see Taurus
rising in the east. The Hyades and Pleiades star
clusters sparkle in the pre -dawn sky, signaling
that winter constellations are on their way.
And don't forget to check NASA's Spot the Station
app for ISS flyovers. A bright pass can add a
little unexpected excitement to your observing
session. In a moment, we'll step into a place
where light bends, time folds, and a single galaxy
can appear a dozen times over. We'll explore
the House of a Thousand Mirrors, where gravity
itself builds a cosmic funhouse. That's coming
up after the break. Stay with us. Welcome back.
Imagine drifting alone through intergalactic
space, no stars, no planets, no sound, just the
faint cold light of distant galaxies. Then there
it is, a single quasar, bright and sharp, and
another, and another, and another. The same object
repeated again and again, hanging in the void
like reflections in a hallway of mirrors. What
you're seeing isn't a trick of your eyes. It
isn't a glitch in your telescope. It's the universe
itself bending light into impossible shapes.
Welcome to what I call the cosmic version of
the house of a thousand mirrors. This strange
funhouse is built by gravity, more specifically
gravitational lensing, one of the most breathtaking
predictions of Einstein's general theory of relativity.
Einstein showed that massive objects, stars,
galaxies, star clusters, don't just sit in space,
they curve space -time itself. Light, always
following the straightest possible path, bends
along those curves like a car following a winding
mountain road. Picture a glass marble placed
on a stretched rubber sheet. Roll a bead of light
nearby and it veers off course. Now, scale that
up to a galaxy weighing trillions of suns. The
result is a natural lens, an effect that can
resemble a funhouse mirror. There are different
kinds of gravitational lensing. Strong lensing
is the funhouse variety, the one that splits
a single object into multiple distinct images.
These are the mirrors you can actually see. Weak
lensing is subtle, like a warped reflection in
an old window. Astronomers use it statistically
to map the invisible skeleton of the universe.
And micro -lensing happens when stars briefly
magnify distant objects like flickering lanterns
in the dark. But for our purposes tonight, it's
strong lensing that turns the universe into something
eerie. A place where a single object can appear
dozens of times, scattered across the sky like
a shattered reflection. One of the most famous
examples is the Einstein Cross, a quasar billions
of light years away, whose light is split into
four identical points arranged neatly around
a foreground galaxy. It looks like a cosmic emblem.
Then there's Abell 1689, a massive galaxy cluster
that bends light so dramatically it produces
arcs, rings, and multiple mirror images of galaxies
hiding far behind it. If you've ever seen those
long ghostly arcs and Hubble images, that's Abell
1689 at work. Perhaps the most astonishing example
is Max J1149. In 2014, astronomers witnessed
the explosion of a distant supernova named Refsdal.
Then, a year later, they saw it again. The light
had traveled through different routes in the
warped space -time of a galaxy cluster. One path
was shorter, one was longer. It was the same
explosion appearing twice. This is time itself,
folded by gravity. In an actual hall of mirrors,
light bounces from surface to surface, arriving
at your eyes at different moments. Gravitational
lensing works in a similar way, but the mirrors
aren't made of glass. They're made of space -time.
Light from a distant quasar might arrive at Earth
by multiple routes, some taking longer than others.
It's kind of like watching the same film twice,
but from different theater seats. This cosmic
rerun is eerie, but it's also incredibly useful
to astronomers. By carefully measuring the time
delays between these mirror images, astronomers
can calculate the expansion rate of the universe.
That's the Hubble constant. And interestingly,
these lensing -based measurements don't quite
match other methods, hinting at something strange
about our cosmos. Gravitational lensing also
has another use. It reveals the distribution
of dark matter, the invisible mass that shapes
the universe. It helps us discover galaxies too
distant and faint to detect otherwise. The lens
acts like a magnifying glass, boosting their
light. The James Webb Space Telescope is already
peering through these natural telescopes to find
some of the earliest galaxies after the Big Bang.
For backyard astronomers, strong lensing is challenging
to spot directly, but not impossible. With a
large enough telescope under dark skies, the
arcs of able clusters can be teased out. More
accessible, though, are the iconic images captured
by Hubble and the James Webb. The Einstein cross,
the frontier fields, the incredible deep field
mosaics are all freely available online. The
next time you look at one, take a moment to ponder.
Every arc, every ghostly streak is the distorted
light of a galaxy billions of years old, seen
through another galaxy's gravity. You're looking
into a cosmic mirror maze built by mass itself.
These lenses in space replay the past and reveal
the secrets hidden at the edge of time. If the
stars spoke to you this week or if a question's
been on your mind, I'd love to hear it. Visit
our website StarTrails .Show where you can contact
me and explore past episodes. Be sure to follow
us on Blue Sky and YouTube. Links are in the
show notes. Until we meet again beneath the stars,
clear skies everyone.