Chapter 1: What mysterious structures are astronomers discovering in space?
Our planet is haunted. Now you might think that is an odd thing to claim for an astronomy channel. But there have been whispers among astronomers that something is out there. Ghostly spectres lurking in our orbital path. entities that have eluded scientific detection for decades, drifting in perfect balance between cosmic forces.
Some claim to have captured faint images of these ethereal silhouettes, looming up to nine times wider than Earth itself. Yet others have searched the same regions of space and found Nothing at all. For over six decades, astronomers have debated their existence. Are these mysterious entities merely elaborate optical illusions? Or something truly extraordinary hiding in plain sight?
What celestial phenomenon could simultaneously be so large, yet remain so elusive? Is the Moon truly Earth's only companion in our journey around the Sun? I'm Alex McColgan and you're watching Astrum. Today we're investigating one of astronomy's most enduring mysteries, the controversial Ghost Moons, that may be silently accompanying our planet through the cosmos.
This ghost story begins in 1961, when Polish astronomer Kazimierz Kordylewski first spotted two diffuse patches of sky that kind of looked like clouds through a telescope, which were located suspiciously near the stable L4 and L5 Lagrange points of our Earth-Moon system. In case you aren't familiar with Lagrange points, let me quickly explain.
Lagrange points are positions in space where the gravitational forces of two large bodies are balanced by the centripetal force required for a smaller object to move with them. This creates a sort of gravitational equilibrium that allows the smaller objects to maintain a position relative to the two larger bodies.
Lagrange points were named after the Italian-French astronomer and mathematician Joseph-Louis Lagrange. after he published a prize-winning paper about this phenomenon in 1772. While we're going to be talking about the Lagrange points present in our Earth-Moon system in this video, similar points exist for other two-body systems, such as between the Earth and the Sun, or Jupiter and the Sun.
In any two-body system, there are five spots where gravitational forces and orbital motion create these Lagrange points, and they're labelled L1 through L5. Three of these, L1, L2 and L3, are considered unstable.
Small objects may be temporarily captured near these points, like the NASA ESA satellite SOHO at L1, or the James Webb Space Telescope at L2, but they have to make corrections to their altitude and course every 23 days to avoid drifting out of position.
Objects in these unstable equilibrium points are balancing on a metaphorical knife's edge, and any slight push from the solar wind, radiation, or the moon's gravity will tip the balance. But L4 and L5, these positions are stable. Unlike the other Lagrange points, these each make equilateral triangles with the Earth and moon, and are resistant to gravitational perturbations.
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Chapter 2: What are the Ghost Moons and how were they first identified?
Observing these dust clouds has tested the limits of our observational abilities, and as our technology and science improves, so can our understanding of KDCs. We should aim to build up more observation data of the L4 KDC, as this feature is historically underrepresented compared to the cloud at L5.
We could also re-survey the clouds using methods like radar to see if technological improvements can yield different results compared to the negative detections of the past, as this would further establish the presence of these elusive features, and fend off any lingering skeptics.
But now that they've been broadly accepted by the scientific community, future research can begin to explore how KDCs are replenished over time, their potential impact on space weather, and their influence on satellite operations. Whether KDCs exist continuously, or appear and disappear over time, at least now we know that something really is out there, and we can study them with the right focus.
These ghostly dust clouds continue to haunt our skies, reminding us that even the faintest, spooky traces of cosmic apparitions can hint at something palpable, and is worth investigating. When 15 supernovae go off close together, both in time and proximity, it makes quite a bang.
It should be of no surprise that such a violent event should fundamentally transform the region of space around where it occurred. Interstellar dust was swept aside from the forces of those concurrent blasts, creating a monumental void of low-density matter, and a shockwave that continues to hurtle across the galaxy to this day at a rate of 6km a second.
In its wake, plasma, reaching 1 million degrees Celsius in temperature, This simultaneous Swiss cheesing and heating up of the interstellar medium is what is now called a hot bubble, and represents both the end of stars and their beginning. But this is not some distant structure that lurks in a far away corner of the universe. Our solar system isn't even heading right towards it.
We're in it, charging for its point of origin head first. Welcome to our local hot bubble. What scientists now realize is the local environment that exists around our solar system. It is a neighborhood we are still exploring, but its nature is becoming clearer and clearer. So what do we know about the local hot bubble? How did it form? And what more is there to be discovered?
I'm Alex McColgan and you're watching Astrum. Join me today as we walk in the aftermath of exploding stars and discuss how scientists even determined we were in the heart of a cataclysm to begin with. The local hot bubble was not always something we knew about.
First identified in the 1970s from observations of low-energy X-ray emissions that were detected over the entire sky, the local hot bubble was hypothesized to be a large cavity in the interstellar medium, called a superbubble, filled with tenuous, million-degree, low-density gas.
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Chapter 3: How do Lagrange points contribute to the mystery of Kordalevsky dust clouds?
Because of this, when we find a deposit that contains these elements, scientists can compare the amounts of iron-60, cobalt-60 and nickel-60, like an elemental clock, to reveal when that material was deposited on our planet. And luckily for us, international research teams have found several such deposits over the last couple of decades.
In 2016, iron-60 deposits were found in deep-sea cross samples taken from the Pacific, Indian, and Atlantic oceans, indicating two distinct spikes in the radioactive debris that pointed to several supernova events in the not-so-distant past, and not too far from our solar system, just 326 light-years away.
The sample showed a spike of iron-60 between 3.2 and 1.7 million years ago, and another spike between 6.5 and 8.7 million years ago.
Nuclear physicist Anton Walner, who led one of these research teams studying the deposits, said that the fact that the more recent debris was spread across 1.5 million years suggests that there were a series of supernovae that occurred one after another in close succession.
Astrophysicist Dieter Breitschwert, who led a second team of scientists, identified a likely source of these supernova explosions, which would have occurred 196 to 423 light years from the Sun. These supernovae that created our local hot bubble may have been part of an ageing star cluster, whose surviving members are now associated with the Scorpius-Centaurus stellar group.
Using the IN60 deposits, the team was able to trace the signals of two supernovae, one that happened 1.5 million years ago and the other 2.3 million years ago, as the result of the deaths of stars that were 8.8 times and 9.2 times the mass of our Sun, respectively. In fact, our LHB is still growing today, albeit much more slowly than when the supernova exploded millions of years ago.
The speed of expansion has plateaued at about 6 km per second now, according to astrophysicist Catherine Zucker. In 2022, Zucker authored a groundbreaking paper that reconstructed the evolution of our galactic neighbourhood, tracing the chain of events that created our local hot bubble and led to the formation of all the young stars we see nearby today.
From there, they made an incredible discovery. Using data from the European Space Agency's Gaia telescope, Zucker and her team were able to construct a 3D spacetime map, showing that within 500 light years of our planet, all of the young stars and star-forming regions reside on the surface of our local hot bubble.
With these 3D positions, and the 3D motions of the stellar clusters, they traced back 20 million years of star formation history near our local hot bubble. The implications were clear, that all of the well-known star-forming regions near our solar system had formed along the outer edge of the local bubble as it swept up gas during its expansion.
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Chapter 4: What evidence supports the existence of Kordalevsky dust clouds?
We observe the expansion of the universe, and observe the filamentary structures. But the universe is an impossibly large place. We can only see so far, only live so long. Plus, our technology is limited. We have theories which try and explain what we see, but I really wouldn't be surprised to see these theories change as more data becomes accessible. Some may ask, what's the point then?
However, I for one am hugely grateful for the bright minds working on this, as discovering our place in the universe is so fascinating. I'm glad humans have an insatiable need to explore and understand everything around them. This innate sense of wonder and curiosity is what drives the evolution of mankind, and I am excited to witness it. A massive thank you to our Astronauts on Patreon.
This video had no sponsors, but it was still made possible thanks to the hundreds of members we have there. Link is in the description to join our growing community. Patreon is where Astrum truly takes shape, a place for people who love space, who want to see these videos keep improving and reaching more curious minds.
Chapter 5: How did NASA's observations impact the understanding of Kordalevsky dust clouds?
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