The Buzzing Milky Way: Stars on the Move#

You know, from down here, the night sky looks all quiet and tidy. But up there? Stars are actually zooming through our Milky Way galaxy like crazy, moving at hundreds of thousands of kilometers per hour. They aren’t stuck in neat shapes; they’re constantly getting new neighbors.

Now, good news first: space is HUGE. This means stars in our galaxy are super unlikely to actually crash into us. Phew!

Bad news though? They don’t need to hit anything directly to make things really, really rough for us here on Earth. And guess what? There are already stars starting to get pretty close.

Understanding the Danger: It’s All About Gravity#

To figure out how a star passing by could mess things up for us, we gotta talk about gravity.

See, gravity is this force that pulls every single bit of matter towards every other bit of matter in the whole universe. Yeah, even an atom a million light years away is pulling on you right now, and you’re pulling back.

Luckily, this force gets weaker the further away things are. It also depends on how much stuff (or mass) something has. So, things that are close by AND really massive are way better at winning this cosmic tug-of-war. They’re more “attractive.”

Because of this, really massive things basically decide what smaller things do around them.

Look at our Sun. It makes up a whopping 99.75% of all the mass in our solar system. That’s why it’s in charge, shaping the paths and orbits of absolutely everything else around it.

Our Solar System: A Hard-Won Balance#

Billions of years back, right after the Sun was born, our solar system was a total mess. It was chaotic and dangerous. The planets were just starting to form from tons of little pieces smashing into each other all the time.

But over incredibly long stretches of time (eons, they call ‘em), things settled down. A stable balance appeared.

Today, most planets, asteroids, and other bits have found safe, predictable paths they stick to. We’ve got:

• The inner planets (like Earth!)
• The outer planets (the gas and ice giants)
• The asteroid belt
• The Kuiper Belt
• And way, way out at the edge, the Oort Cloud. This is like a giant, icy sphere of comets just hanging out in “cold storage,” orbiting super slowly.

Why We Don’t Want Visitors: Disturbing the Peace#

The main thing is, we really, really don’t want this nice, stable balance to get messed up.

If another star came too close to us, its gravity would start yanking and pulling on everything in our solar system. Imagine a spoiled toddler just trashing a perfectly organized room – that’s kind of what a passing star’s gravity does to the planets, asteroids, and comets in their neat orbits.

Not Just Imaginary: Past Encounters#

This isn’t just some made-up sci-fi worry.

About 70,000 years ago, a system of two stars – a red dwarf and a brown dwarf (brown dwarfs are kind of like failed stars) – actually passed through our Oort Cloud.

They definitely stirred things up out there. It’s even possible this encounter sent a dangerous flood of asteroids hurtling our way. We might not see those guys for a long time though – it could take up to 2 million years for those specific visitors from the Oort Cloud to finally reach the inner solar system where we live.

A Bigger Concern: Glaive 710#

There’s an even more significant issue coming up, though.

It’s a star named Gliese 710. It’s a red dwarf, roughly half the mass of our Sun. And right now, it’s headed towards our solar system.

In about a million years, it’s predicted to pass right through the Oort Cloud. When it’s closest, it will actually become the brightest star you can see in the night sky!

A close pass like this would play out over hundreds of thousands of years. It would seriously disrupt the orbits of millions of objects hanging out in the Oort Cloud.

If we’re unlucky, this could kick off a new period of stuff hitting planets, maybe like when the solar system was young. The night sky could fill up with comets and asteroids raining down into the inner solar system. The really big ones? Yeah, they could cause massive extinction events, like the one that got the dinosaurs. Definitely not good for the stock market, or anything else really.

What About a Really Close Flyby?#

Now, it could get much, much worse than just Oort Cloud disruption.

The galaxy is a busy place, and stars get close to each other pretty often. So, it’s possible a star could come much closer to us. Not just a pass through the Oort Cloud, but flying directly through the inner solar system.

This would be very, very bad news.

While the chance of another star actually colliding with our Sun is incredibly, astronomically unlikely, that’s not the main thing we worry about.

If another star were to pass by, say, as close as the Earth is from the Sun right now? That could easily just eject Earth right out of the solar system.

The odds of something like that happening are estimated to be about 1 in 100,000 over the next 5 billion years. It’s small, sure, but not like, ridiculously impossible. As we talked about in another video, there seem to be billions of rogue planets drifting through the galaxy, and this is one way they get made!

If Earth Gets Kicked Out: The Long Farewell#

So, let’s imagine this worst-case scenario happens with an average red dwarf star. What would happen to Earth?

• The Star Arrives: As the star enters our solar system, you’d see a small, orange-ish dot appear in the sky. Over months, it would get bigger and bigger. Eventually, you’d even be able to see it during the daytime. It would grow much bigger and brighter than the Moon – way too bright to look at directly. The night sky would glow with this eerie red light.
• The Star Departs, The Sun Fades: After a few months, the star would start shrinking in the sky as it moves away. But then… the Sun would start shrinking too. Over a few years, the Sun would slowly look smaller and smaller in the sky. With less sunlight, warmth and light would start fading everywhere on Earth.
• The Final Winter: As the days turn dark, humanity’s final winter would begin.
  • The polar ice caps would start growing and spreading out.
  • Plants would shrivel and die.
  • Forests would freeze solid.
  • Animals would die off in huge numbers.
• Deep Freeze: As Earth drifts past where Mars orbits, the average temperature on the surface would have plummeted to around -50°C. From space, Earth would start looking like an icy moon, its usual blue and green colors turning into the pale gray-white of death.
• Civilization Collapse: Global infrastructure would break down. People would huddle indoors, burning anything they could find for warmth, counting the days until they ran out of food, which can no longer grow outside. Anyone living on the surface would essentially be on borrowed time.
• Even Colder: By the time Earth reaches the orbit of Jupiter, surface temperatures would sink to -150°C. That’s even colder than the coldest temperatures ever recorded in Antarctica. Needless to say, by this point, almost everyone would be gone.
• The Water Cycle Stops: Without sunlight providing energy to evaporate water, clouds wouldn’t form anymore, and the water cycle would just stop. The polar ice caps would eventually meet at the equator. The oceans would freeze over with a thick layer of ice.
• Under the Ice: As more and more of Earth’s internal heat escapes, more water would freeze onto the bottom of that ocean ice sheet. The salt left behind in the remaining deep ocean water would become highly concentrated, likely poisoning most animals that might have survived down there. However, around places called hydrothermal vents on the ocean floor, some extreme communities of life that live off chemicals might be able to adapt.
• Deep Life Survives? Deep below the surface, some bacteria might not even notice much of this change, as they’re still kept warm by the natural breakdown of radioactive elements in Earth’s core.
• Atmosphere Freezes: As Earth reaches the orbits of Pluto and the Kuiper Belt, the Sun would still be the brightest star you could see, but it would just be one star among many. Other stars would now be visible even during the day. The temperature on Earth would be barely 40°C above absolute zero (that’s incredibly cold, around -233°C!). This is below the freezing temperature of the gases that make up our atmosphere.
• Atmospheric Snow: A weird, sad show unfolds as the atmosphere itself turns into nitrogen and then oxygen “snow” over a few years. This frozen atmosphere gets deposited into an icy sheet about 10 meters thick all over the planet’s surface, leaving only a thin whisper of gas behind. The frozen bodies of plants and animals would be buried beneath this layer.
• A Rogue Planet: Finally, as Earth leaves the solar system, it becomes a rogue planet, just drifting alone through the dark, lifeless, and empty space.

Is There Any Hope?#

Weirdly enough, yes, there is hope in this grim scenario.

Humanity wouldn’t be completely surprised by this potential extinction event. We’d see it coming thousands of years beforehand. There’s not much we could do to stop a star, but we could prepare.

Most of us would likely die, yes. But perhaps a few million people could survive. How? In massive, artificial complexes built underground, powered by energy sources like geothermal energy (heat from the Earth’s core) and nuclear energy. Maybe even fusion power, if we figure that out. We might even learn to use the vast amounts of ice surrounding us for power.

Here, inside these havens, humanity might be able to survive for hundreds of thousands of years.

At some point, future generations would get used to these strange circumstances. They might watch documentaries (or whatever they have) in disbelief about the time when humans had their own star and could actually walk around on the surface of Earth outside.

And eventually, they might decide it’s time to look for another home.

If Earth, now a rogue planet, happened to drift close enough to another star that had a planet with habitable conditions, we could potentially try to start over there.

Space travel, oddly, would become much easier without an atmosphere to punch through. So, it’s not crazy to think that the last survivors might leave Earth behind and try their luck on a new planet orbiting a new star.

Maybe, just maybe, thousands of years from now, the descendants of humanity will tell legends about Earth’s ancient past. Stories about our lost home – a mysterious, icy planet drifting alone and empty through the dark emptiness of space.

The Quartz Kazal Lab#

Alright, let’s switch gears for a sec. Welcome to the Quartz Kazal Lab! Time for some stellar experiments.

• First, let’s add some more mass to this protostar… More… A bit more… Wow! We’ve just created a blue giant! That’s a star with 10 times the mass of our Sun!
• Now, let’s fast-forward a couple of million years… And look! A supernova! Just breathtaking.
• And look what it leaves behind… a black hole! Fascinating stuff.

Now, time to write down our findings. Gotta be careful to keep that sparkle just right.

It’s Duck’s final inspection time! This part’s always a bit nerve-wracking, that duck has incredibly high standards.

Luckily for us, our work here is scientifically accurate, gives you a good overview of how some big space processes work, and it’s a real stunner to look at.

Duck approves!

Looks like it’s ready to share with the world… as a poster! It’s a very special piece of Quartz Kazal you can actually take home and touch.

You can get this very special poster, plus lots of other sciencey and spacey things we’ve created with love and care, from our shop.

Just so you know, every single Quartz Kazal product you buy directly helps fund the time we get to spend working on making these videos for you. Thank you so, so much for being a part of our story and for making this whole channel possible.