Speaker 1: Welcome to Astronomy Daily.
Speaker 2: I'm excited to bring you another fascinating day of space
and astronomy news. There's quite a bit to cover today,
from orbital drama to seasonal changes on the Red planet.
We'll start with a concerning development in Earth orbit, where
a retired military weather satellite has broken up into dozens
of pieces, adding to a pattern of similar incidents with
these particular spacecraft. Then we'll look ahead to SpaceX's upcoming
Bandwagon two mission, which will carry an impressive array of
thirty different payloads into orbit, including an advanced.
Speaker 1: Radar satellite for South Korea.
Speaker 2: We'll also take a journey to Mars, where NASA's Mars
Reconnaissance Orbiter has been capturing some incredible seasonal phenomena. Unlike
Earth's gentle seasonal transitions, Mars experiences some remarkably explosive changes
during its spring thaw, and I can't wait to tell
you all about them. Plus, we've got to look at
a new theory about that mysterious dark energy, and we'll
revisit an age old debate with some new research.
Speaker 1: So let's get started.
Speaker 2: In a concerning development, the US Space Force has reported
that a defunct military weather satellite experienced what they're calling
a low velocity fragmentation event on December eighteenth. The incident
occurred at an altitude of about eight hundred and forty kilometers,
creating more than fifty pieces of trackable debris, according to
radar observations from commercial space monitoring company Leo Labs. The
satellite in question, known as DMSP five D two F fourteen,
was launched back in nineteen ninety seven as part of
the Defense Meteorological Satellite Program. After serving its purpose for
over two decades, it was retired in twenty twenty, but
remained in its Sun synchronous orbit. Weighing about seven hundred
and fifty kilograms, this spacecraft is now the latest in
a series of similar satellites to meet this unfortunate fate.
What's particularly concerning is that this isn't an isolated incident.
Several other satellites from the same family have experienced similar
breaks make ups over the years. In October twenty sixteen,
the F twelve satellite broke apart, following the fragmentation of
F thirteen. In February twenty fifteen, going back even further,
the F eleven spacecraft created fifty six pieces of tracked
debris when it broke up in two thousand four. The
root cause appears to be a known design flaw in
these satellites battery assemblies that makes them vulnerable to explosion.
This issue isn't limited to military satellites either. Similar civilian
weather satellites operated by Noah have suffered the same fate,
with Noah sixteen breaking up in twenty fifteen and Noah
seventeen following suit in twenty twenty one. Most troubling is
that these breakups occurred despite attempts to prevent them through
a process called passivation, where satellites are prepared for decommissioning
by draining their batteries and venting fuel tanks.
Speaker 1: Industry experts note.
Speaker 2: That this process may not be fully effective on older
satellites that were designed before modern orbital debris mitigation practices
were established. Next up, SpaceX is gearing up for an
exciting ride share mission from Vandenberg Space for Space in California.
The Bandwagon two mission, scheduled for a three thirty four
am Pacific launch on December twenty first, will carry an
impressive array of thirty different payloads to orbit the Star
of this mission is a sophisticated radar satellite for South Korea,
capable of seeing through clouds and darkness to capture detailed
images of Earth. This spacecraft is part of South Korea's
four hundred and twenty five project, a constellation of military
Earth observation satellites that combines both optical and radar imaging capabilities.
Among the other fascinating payloads are two satellites from Ice
that will join their radar imaging constellation, and a trio
of satellites from Hawkeye three hundred and sixty that will
work together to pinpoint radio frequency transmissions from orbit. Two
compact weather satellites from tomorrow dot Io will collect valuable
atmospheric data, while LIZZISATI will test out new imaging and
computing technologies in space. The mission will use Falcon nine
booster B one THY seventy one, making its twenty first flight.
After sending its passengers on their way, the booster will
return to land at landing Zone four, right next to
its launch pad. The second stage will perform a carefully
choreographed series of burns to deploy the satellites at two
different altitudes, most at five hundred and ten kilometers and
the South Korean satellite at five hundred and seventy kilometers.
This launch represents SpaceX's one hundred thirty first Falcon mission
of the year, marking an incredibly busy period for the company.
It's also their second dedicated ride share mission to a
mid inclination orbit, specifically chosen to keep these satellites positioned
over more populated areas of our planet rather than following
the polar orbits typically used for Earth observation missions. After deployment,
these satellites will begin their diverse missions from Earth imaging
and weather monitoring, to testing new space technologies and providing
communications serve vises. Together, they represent a remarkable snapshot of
the increasing variety and capability of small satellites being launched today.
Ever thought about the concept of seasons on other planets.
While we're celebrating the approaching new year here on Earth,
Mars has already completed its journey around the Sun, marking
the end of its six hundred and eighty seven Earth
Day year this past November. But unlike Earth's northern winter
wonderland or southern hemispheres summer, Mars is experiencing a spectacular
spring awakening that's far more dramatic than anything we see
here at home. Instead of gentle snow melt and trickling streams,
Mars puts on an explosive show. The red planet's thin
atmosphere means ice doesn't gradually melt into liquid. It transforms
directly into gas in a process called sublimation. This creates
some truly remarkable phenomena that NASA's Mars Reconnaissance orbiter has
been tracking for nearly two decades. One of the most
dramatic events are the frost avalanche. Imagine witnessing a massive
chunk of carbon dioxide frost wider than a house, breaking
free and tumbling down Martian cliffs. The orbiter's high resolution
cameras actually captured one of these spectacular events, showing a
sixty six foot wide block of dry ice in freefall.
But that's just the beginning. As spring temperatures rise, pressurized
carbon dioxide gas builds up beneath the surface ice until
it literally explodes upward, creating powerful geysers that blast dark
fans of sand and dust into the Martian sky. These
explosive jets leave behind distinctive patterns in the soil that
when viewed from orbit, look remarkably like giant spider legs
etched into the surface. Perhaps most impressive is the planet's
northern ice cap, a structure as large as Texas that
features enormous spiral troughs carved by powerful seasonal winds. Some
of these troughs stretch as long as California, dwarfing similar
features found in Antarctica. As the spring thaw begins, these
channels become super highways for warm wind gusts that gain
speed and heat as they race downhill. These same winds
are constantly reshaping Mars's landscape, particularly its sand dunes. During winter,
carbon dioxide frost locks these dunes in place, but once
spring arrives and the frost sublimates, they begin their slow
migration across the Martian surface. It's a seasonal dance that's
been ongoing for eons, sculpting and reshaping the face of
our neighboring planet. What makes this even more fascinating is
that each Martian spring is unique, with subtle variations in
temperature and timing creating different patterns of sublimation and surface activity.
It's a reminder that Mars, despite its apparent desolation, is
a dynamically changing world with its own distinctive seasonal rhythm. Now,
let's dive into a topic that's been puzzling scientists for
decades dark energy. For years, the term dark energy has
been used to describe the mysterious force believed to drive
the accelerated expansion of our universe. It's thought to make
up about two thirds of the universe's total mass energy content. However,
recent research from the University of Canterbury in christ Church,
New Zealand challenges this long standing concept. Led by Professor
David Wiltshire, the team analyzed supernova light curves with enhanced precision.
Their findings suggest that the universe's expansion isn't uniform, but
rather lumpy, varying in different regions. This challenges the conventional
lambda cold dark matter model, which relies on dark energy
to explain the universe's accelerating expansion. The researchers propose an alternative,
the timescape model. This model considers that gravity affects time,
causing clocks and regions with different gravitational strengths to tick
at varying rates. For instance, a clock in the emptiness
of space would run faster than one within a galaxy.
These time differences could lead to the perception of an
accelerating universe without invoking dark energy. Professor Wiltshire explains our
findings show that we do not need dark energy to
explain why the universe appears to expand at an accelerating rate.
He suggests that what we've been interpreting as dark energy
might actually be variations in the kinetic energy of expansion
influenced by the universe's lumpy structure. This perspective also offers
insights into the Hubble tension, the discrepancy between the current
expansion rate of the universe and predictions based on early
universe observations. By accounting for regional variations and expansion, the
Timescape model could bridge this gap. While these findings are compelling,
they don't entirely dismiss the existence of dark energy. Instead,
they encourage a reevaluation of our cosmological models and highlight
the importance of considering the universe's complex structure in our calculations.
As we continue to explore these cosmic mysteries, each discovery
brings us closer to understanding the true nature of our universe.
It's a thrilling reminder of how much there is yet
to learn. Finally, today, let's revisit a classic debate, what
really caused the extinction of the dinosaurs. For decades, scientists
have pondered whether massive volcanic eruptions or a catastrophic meteorite
impact led to the dinosaur's demise. Recent research from utrect
University and the University of Manchester sheds new light on
this mystery. The study focuses on the Deccan Traps in India,
where colossal volcanic eruptions occurred around sixty six million years ago.
These eruptions released vast amounts of sulfur and carbon dioxide,
potentially altering the global climate. By analyzing fossil molecules from
ancient peats in the United States, scientists reconstructed air temperatures
during this period. They discovered that a significant volcanic eruption
about thirty thousand years before the meteorite impact caused a
global cooling of approximately five degrees celsius. However, temperatures rebounded
twenty thousand years before the impact, likely due to volcanic
CO two emissions. This timeline suggests that while these volcanic
events had drastic consequences, for life on Earth. Their climatic
effects had dissipated thousands of years before the chi Salub
meteorite struck. Therefore, the meteorite impact remains the primary culprit
behind the mass extinction event that wiped out the dinosaurs.
Lauren O'Connor of Utrecht University notes these volcanic eruptions and
associated CO two and sulfur releases would have had drastic
consequences for life on Earth, but these events occurred millennia
before the meteorite impact and probably played only a small
part in the extinction of dinosaurs. This research underscores the
catastrophic impact of the Chisalub meteorite, which unleashed wildfires, earthquakes, tsunamis,
and an impact winter that blocked sunlight and devastated ecosystems.
Understanding these events helps us piece together Earth's complex history
and the factors that have shaped life on our planet.
It's a fascinating reminder of the dynamic forces at play
over geological timescales, and that wraps up today's fascinating journey
through space, from Earth orbiting satellite breakups to SpaceX's ambitious
ride share mission and the dramatic spring spectacle unfolding on Mars.
I'm Anna and I hope you've enjoyed this episode of
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Speaker 1: And TikTok.
Speaker 2: We'd love to hear your thoughts on today's stories and
engage with you about all things space. Thank you for
spending time with us today exploring the wonders of space.
Until next time, keep looking up and stay curious about
our cosmic neighborhood.
Speaker 1: Sunny Day Star is so.
Speaker 2: Star is Star