Howdy Star Gazers and welcome to this episode
of Star Trails. My name is Drew and I'll be your
guide to the night sky for the week of March
the 1st through the 7th. Believe it or not, this
is our 100th episode and over the past few months
we've traveled far. We've talked about stars
that will outlive our species. We've wandered
through globular clusters and nebula. We've stood
at the edge of galaxies and contemplated black
holes. but this month we're coming home. Every
object we'll discuss in March is right here in
our own solar system, not light years away. These
are worlds we can see with our own eyes, and
more than that, these are worlds we have visited.
Later in the show, we'll check in with this week's
sky, which features the only total lunar eclipse
of the year, and we'll take a quick look at electric
cars in space. Whether you're tuning in from
the backyard or the balcony, I'm glad you're
here. So grab a comfortable spot under the night
sky and let's get started. This month we're taking
a closer look at our solar system. We'll start
with the inner planets and move outward. Later
in the month we'll explore some of the wildest
moons of our system, venture into the mysterious
area beyond the outer planets, and we'll take
a special detour over to Pluto, the planet that
went on trial and lost. What I love about this
month's series is that humanity has orbited,
landed on, driven across, drifted into, and photographed
every planet we'll talk about this month. That's
stunning if you stop and think about it. So this
week we begin with the inner planets, Mercury,
Venus, Earth, and Mars. Four rocky worlds with
very different outcomes. Mercury is often overlooked.
It's tiny, it hugs the Sun, it never strays far
from the horizon, and it's notoriously difficult
to observe. But Mercury played a pivotal role
in one of the greatest scientific revolutions
in history. For decades in the 19th century,
astronomers noticed something odd about Mercury's
orbit. The point of closest approach to the Sun,
its perihelion, slowly shifted over time in a
way that Newton's laws couldn't fully explain.
The discrepancy was small, just 43 arc seconds
per century. Some astronomers proposed that an
unseen planet inside Mercury's orbit was tugging
on it gravitationally. They even gave this hypothetical
world a name, Vulcan. Searches were conducted,
observations were claimed, Vulcan sightings were
reported near the Sun's glare during eclipses,
but Vulcan didn't exist. Instead, in 1915 Albert
Einstein showed that Mercury's strange orbital
precession wasn't caused by an invisible planet.
It was caused by the curvature of space -time
itself. According to general relativity, massive
objects like the Sun warp the fabric of space
-time. Mercury, being so close to the Sun, moves
through that warped geometry. Its orbit isn't
simply a Newtonian ellipse, it's an ellipse slowly
turning within curved space -time. Mercury helped
prove that gravity isn't just a force, but rather
geometry. That's an extraordinary legacy for
a little planet most people struggle to find
in the twilight. But Mercury is weird in other
ways too. A year on Mercury, that's the time
it takes to orbit the sun, is 88 Earth days.
But a single solar day, from one sunrise to the
next, lasts 176 Earth days. If you stood on Mercury's
surface, you would watch the sun rise, pause,
reverse direction slightly, then continue its
path across the sky. The planet's 3 to 2 spin
orbit resonance creates one of the strangest
day -night cycles in the solar system. And despite
being the closest planet to the Sun, Mercury
has water ice. Not oceans, of course, but water
ice trapped in permanently shadowed craters near
its poles, where sunlight never reaches. So the
hottest world in the solar system harbors ice
in eternal darkness. As for exploration, Mercury
has only been visited by a handful of spacecraft.
NASA's Mariner 10 flew by in the 1970s. Decades
later, the MESSENGER mission orbited Mercury
from 2011 to 2015, mapping its surface in detail
and confirming the presence of that polar ice.
From Mercury, we venture out to Earth's twin,
Venus. Well, maybe it's more of a fraternal twin
than identical. Venus is nearly the same size
and mass as Earth. It's a rocky world wrapped
in clouds. For much of the 20th century, science
fiction writers imagined steaming jungles beneath
those clouds, swamps, oceans, maybe even life.
Instead, Venus turned out to be something far
more unsettling. It's a runaway greenhouse world.
Its thick atmosphere is composed mostly of carbon
dioxide. with surface pressures about 90 times
that of Earth. That's like being nearly a mile
underwater. The surface temperature hovers around
900 degrees Fahrenheit, and that's hot enough
to melt lead. As for those clouds, well, they're
made of sulfuric acid. Venus has a weird orbital
quirk in that it rotates backwards. While most
planets spin in the same direction they orbit
the Sun, Venus spins retrograde. That means on
Venus the Sun rises in the West and sets in the
East. Also, it rotates extremely slowly. A single
rotation of Venus takes about 243 Earth days.
That's longer than its year, which is about 225
Earth days. If you stood on its surface, ignoring
the fact that you'd be crushed and incinerated
almost instantly, you would experience one of
the strangest celestial rhythms imaginable. And
we've been there. The Soviet Union's Venera program
achieved one of the most remarkable feats in
planetary exploration. In the 1970s and early
80s, several Venera landers successfully reached
the surface of Venus. They transmitted data,
and in some cases images, before succumbing quickly
to the heat and pressure. The images they returned
are eerie. A flat, rock -strewn landscape beneath
a yellowish sky. The light filtered and distorted
by thick atmosphere. A suffocating alien stillness.
More recently, orbiters like NASA's Magellan
mission mapped Venus using radar. since visible
light can't penetrate the cloud deck. Radar revealed
a world shaped by volcanism, vast lava plains,
pancake domes, massive shield volcanoes. We're
still not entirely sure if Venus is volcanically
active today, but there have been hints. Sulfur
dioxide fluctuations, possible thermal anomalies.
Venus may still be reshaping itself beneath those
clouds. Scientists see Venus as a cautionary
tale for Earth. Two rocky planets born from the
same solar nebula, similar in size and composition,
and yet they diverged dramatically. One became
a world of oceans and life, the other became
a greenhouse gas furnace wrapped in acid clouds.
And yet, in our twilight sky, Venus remains the
brightest planet of all. Serene and beautiful
from a distance. Now we arrive at a planet we
think we know very well, Earth. But let's do
something unusual. Let's imagine we're not standing
on it. Let's imagine we're alien astronomers
observing this small blue world from dozens of
light years away. What would we see? First, we'd
notice the color. Earth is strikingly blue because
liquid water covers about 70 % of the surface.
That water absorbs red wavelengths and scatters
blue back into space. To a distant observer,
Earth's spectrum would show strong signatures
of water vapor in the atmosphere. That alone
would be interesting. But then the alien spectroscopist
would notice something even stranger. Oxygen.
Earth's atmosphere contains about 21 % molecular
oxygen, which is highly reactive. It doesn't
like to remain free in an atmosphere for long.
It bonds, oxidizes, and disappears into rocks.
For an atmosphere to maintain that much free
oxygen, something must be replenishing it continuously.
From a purely chemical perspective, Earth's atmosphere
is in disequilibrium. An alien observer might
detect methane alongside oxygen. Those two gases
should rapidly react and cancel each other out,
yet on Earth both persist. Of course, here on
Earth we know the explanation is biology. Photosynthesis
splits water molecules and releases oxygen as
waste. Microbes, plants, forests, and plankton
are all quietly altering the chemistry of an
entire planet. Then there's the reflectivity
problem. As Earth rotates, its brightness changes.
Oceans reflect differently than continents. Cloud
cover shifts. Seasonal variations alter albedo.
Ice caps grow and shrink. An alien observer tracking
the light curve might infer continents, weather
systems, polar ice caps. They'd even detect our
moon. Earth's unusually large moon stabilizes
the planet's axial tilt. That stabilizes climate
over long periods. From afar, the gravitational
dance between Earth and Moon would reveal itself
in subtle wobbles. And then there are the unnatural
signatures. Over the past century, Earth has
begun leaking radio signals into space, television
broadcasts, radar pulses, communications. a faint
expanding shell of electromagnetic noise roughly
100 light years in radius. And Earth has begun
sending objects away from itself. We've placed
satellites in orbit. We've sent probes to other
planets. We've launched spacecraft that have
exited the solar system entirely. And while an
alien astronomer wouldn't know about our culture,
our music, literature, or lifestyles, They'd
still see spectral lines, and if they're conducting
their own search for extraterrestrial intelligence,
maybe they'd hear our radio waves. The alien
observers would certainly notice our moon. Among
the inner planets, Earth is the only one with
a truly large, gravitationally significant moon.
Mars has two small, irregular moons, Phobos and
Deimos, which are likely captured asteroids.
But Earth's moon is enormous relative to its
planet. It's about one -quarter the diameter
of Earth and more than 1 % of Earth's mass. That
might not sound like much, but in planetary terms,
it's huge. In fact, some astronomers even describe
the Earth -Moon system as a double planet. The
barycenter, the shared center of mass around
which both Earth and the moon orbit, doesn't
sit at the exact center of Earth. It lies about
1700 kilometers beneath Earth's surface. Earth
itself wobbles around this point as the moon
orbits. Earth itself also does something subtle
but important. It spins once every 24 hours.
That rapid rotation helps generate a magnetic
field through the motion of molten iron at its
core. That magnetic field shields the atmosphere
from the solar wind, preventing it from being
stripped away over billions of years. And that
brings us to Mars, the red planet that wasn't
as lucky as Earth in regards to its atmosphere.
From a distance, Mars looks almost like Earth.
It has polar caps, seasons, a 24 .6 hour day,
remarkably close to our own. A tilted axis produces
familiar rhythms of spring, summer, autumn, and
winter. Mars is a world that seems to have started
with potential. We see ancient river valleys
carved into its surface. Delta formations where
sediment once fanned outward into standing bodies
of water. Minerals that form only in the presence
of liquid water. Billions of years ago, Mars
almost certainly had flowing water on its surface.
It had a thicker atmosphere, a warmer climate,
and then something changed. Mars is only about
half the diameter of Earth. Smaller planets cool
faster. As its interior cooled, Mars likely lost
the dynamo effect that once generated a global
magnetic field. Without that magnetic shield,
the solar wind gradually stripped away much of
its atmosphere. The water didn't simply vanish,
some escaped to space, some froze underground,
and some remains locked in polar ice. What we're
left with today is a thin, cold atmosphere, less
than 1 % the pressure of Earth's, and a landscape
sculpted by wind and dust. Mars may be the most
explored inner planet after Earth. NASA's Spirit
and Opportunity rovers, solar -powered explorers,
lasted far beyond their expected lifetimes. Opportunity
operated for nearly 15 years. Curiosity and perseverance,
nuclear -powered rovers, continue to traverse
ancient lake beds and deltas, drilling into rocks
that may preserve chemical traces of past habitability.
We've flown a helicopter, ingenuity, in the thin
Martian air. That alone sounds like science fiction.
We haven't sent humans to Mars, but we're trying
to, and maybe one day we will. There's one more
reason Mars continues to grip our imagination,
the possibility that it once hosted life. We
know that early Mars had liquid water, and for
a period billions of years ago, Mars was likely
warmer and wetter. On Earth, life appears very
early in our geological record. almost as soon
as conditions allowed it. So scientists ask a
simple question. If life arose quickly here,
could it have arisen there? We haven't found
proof, but we found hints. In 1996, a meteorite
from Mars known as ALH84001 made headlines around
the world. Scientists announced that it contained
tiny structures resembling fossilized microbes.
along with chemical signatures suggestive of
biological activity. For a brief moment it seemed
possible that we had found evidence of past Martian
life. But over the following years further analysis
showed that those structures could be explained
by non -biological processes. The consensus today
is that the meteorite does not provide convincing
evidence of life. Since then, rovers have detected
organic molecules in Martian rocks. But organic
chemistry is not the same thing as biology. Methane
has also been detected in trace amounts in the
Martian atmosphere. Intriguing, but still inconclusive.
All four of these worlds formed from the same
protoplanetary disk four and a half billion years
ago. Same star, similar materials. But over billions
of years, tiny differences compounded. The inner
solar system is not a random assortment of rocks.
It's a long running experiment in planetary evolution.
Four test cases, one sun, and four very different
outcomes. If you want to understand how fragile
habitability is, you don't need to travel light
years away. You only need to look next door.
After a quick break, we'll be back with this
week's Night Sky Report and more. Stay with us.
Welcome back. I hope you don't mind if I take
a moment to meander and maybe nerd out a bit.
The last time I bought a car was almost 15 years
ago, and the hot tech of that era was built -in
GPS navigation, backup cameras, and Bluetooth.
These are things we just expect a new car to
have nowadays. My little economy hatchback had
none of that, although I did pack a few amateur
radio transceivers into it, earning it the nickname
The Hamster among my friends. Just as the universe
is fumbling toward entropy, so is my old car.
With many systems failing, I finally had to retire
it last week. In the 15 years since the hamster
rolled off the assembly line, a lot has changed.
In 2011, there were maybe three consumer electric
cars, and only society's elite or extreme early
adopters drove them. Now they're everywhere,
and charging points are peppered throughout cities
and along highways. Electric is just another
choice in the sea of automobiles. In recent years,
they've become surprisingly affordable, particularly
in the used market, where they currently represent
some of the best value in the industry. So I
decided my next ride would be powered by electrons,
and I've been in full -on geek mode ever since.
For my new car, I chose a color similar to Neil
Armstrong's Marina Blue Corvette Stingray, and
yes, that was absolutely on purpose. My new hatchback
on steroids is fun to drive, but because a large
part of the car is a high -voltage battery, you
can also do some very practical things with it,
like power equipment. Imagine being at a dark
sky site with your imaging rig plugged straight
into your electric car. Maybe it gets cold, so
you plug in a small space heater. Maybe you get
sleepy, so you power up a coffee maker. Meanwhile,
a laptop hums quietly, guiding a telescope that's
tracking a galaxy millions of light years away.
No marine batteries, power inverters, or noisy
generators. Just stored energy in silence. This
is my Observatory on Wheels. And it dawned on
me that electric cars have been part of space
travel for more than half a century. The first
vehicles humans ever drove on another world were
electric. During the Apollo missions beginning
with Apollo 15 in 1971, astronauts unfolded the
lunar roving vehicle from the side of the lunar
module like some kind of cosmic origami. It ran
on non -rechargeable silver -zinc -potassium
-hydroxide batteries with four independent electric
motors, one in each wheel. Top speed? 8 miles
per hour. In this case, electricity was required
because it couldn't have burned fuel even if
it wanted to. There's no oxygen on the moon.
Lunar astronauts logged nearly 60 miles on the
lunar surface with their rovers. They collected
samples, explored craters, and dramatically increased
the scientific return of the missions. And when
they left, they parked the rovers there. There
are still three electric vehicles sitting quietly
on the moon. Then there are the Mars rovers,
which we've already mentioned earlier in this
episode. While they weren't made to carry humans,
they are, in every meaningful way, electric cars
operating on a different planet. And, of course,
there's the slightly absurd case of the Tesla
Roadster launched into space in 2018, during
the first flight of SpaceX's Falcon Heavy rocket.
Instead of a dummy payload, they bolted a production
electric sports car to the upper stage and sent
it into orbit around the sun. On the dashboard,
a sign read, don't panic, a nod to writer Douglas
Adams. David Bowie's Space Oddity blasted through
the speakers on a loop into the soundless vacuum
of the cosmos. There's a mannequin in a space
suit in the driver's seat, nicknamed Starman,
and the roadster is still orbiting the sun to
this day. You can track its location on websites
like Heavens Above, and it may wander the inner
solar system for millions of years. That means
the first production car to leave Earth was electric.
EVs may or may not be the future depending on
who you ask, but the truth is they were humanity's
first off -world transportation dating back to
the Apollo era. And so here I am driving what
feels like a spaceship on pavement during a week
when the moon takes center stage. So let's get
into it. This month kicks off with a headline
event, a total lunar eclipse. The moon begins
the week waxing toward full. By the night of
March 2, into the early hours of March 3, it
reaches full moon, traditionally known as the
worm moon, named for the time of year when the
ground softens and life begins to stir beneath
the surface. But this year that full moon won't
stay bright for long. In the early morning hours
of March 3, the earth will move directly between
the sun and the moon, casting its shadow across
the lunar surface. This is a total lunar eclipse,
and it's the only one in 2026 visible to much
of North America and the Pacific region. A lunar
eclipse unfolds gradually. First, the moon slips
into the Earth's penumbra, a subtle shading that
many observers won't even notice. Then comes
the umbra, the darker central shadow, and you'll
begin to see a distinct bite taken from the lunar
disk. Over the course of a couple hours, that
bite grows until the moon is fully engulfed.
Totality lasts just under an hour, about 58 minutes.
Instead of disappearing, the moon turns coppery
red. This effect is caused by a sunlight passing
through Earth's atmosphere, where it gets filtered
and bent. Blue light scatters away, while the
longer red wavelengths continue on, curving into
Earth's shadow and softly illuminating the moon.
The exact shade of red can vary. If Earth's atmosphere
is especially dusty, perhaps from volcanic eruptions
or heavy pollution, the moon can appear darker,
even brick red. On a particularly clear year,
it may glow more orange or copper. You won't
need a telescope. In fact, lunar eclipses are
best enjoyed with your own eyes. Binoculars can
enhance the color contrast, but this is a naked
eye event. Once this eclipse passes, we won't
see another total lunar eclipse in North America
until late 2028 or early 2029. So if skies are
clear, this is one to check out. You'll want
to use an app like Stellarium to track where
the eclipse occurs in your area. Here in the
southeast U .S., where I'm located, the eclipse
begins around 5 a .m. on the morning of the 3rd.
Very low on the western horizon, so it's going
to be a tough one for some of us to spot. Now
while the moon steals the spotlight this week,
the planets are still putting on their quiet
show. Jupiter shines brightly in the evening
sky, still positioned among the stars of Gemini.
It's one of the brightest objects overhead after
sunset, outshining nearby stars Castor and Pollux.
Low in the western twilight, Mercury lingers,
but it's a fleeting target. Around March 7th,
it reaches inferior conjunction, passing between
Earth and the Sun, which means it will be extremely
difficult to see by week's end. Catch it early
in the week if you have a very clear western
horizon. Venus also glows in the dusk. Near the
end of the week it draws close to Neptune in
a conjunction, though Neptune itself will require
binoculars and very steady skies to glimpse.
I'd plan to get into the next two chapters of
Night Watch in this episode, but let's hold off
on that discussion until next week. We'll be
discussing the outer planets in the next episode,
so the chapter about the planets should fit nicely
into our discussion. That's going to do it for
this week. If you found this episode interesting,
please share it with a friend who might enjoy
it. The easiest way to do that is by sending
folks to our website, StarTrails .Show. And if
you want to support the show, use the link on
the site to buy me a coffee. That really helps.
Be sure to follow Star Trails on Blue Sky and
YouTube. Links are in the show notes. Until we
meet again beneath the stars, clear skies everyone.