SPACE is a deadly place – and we’re all living at its mercy on a little blue rock.
Thankfully we know that asteroid 2024 YR4 won’t be crashing into us after all, but that’s not the only space threat we need to worry about.
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In fact there are several ways that the horrors of space could cause an on-Earth cataclysm.
They’re all tremendously unlikely, if that helps you sleep any better.
Unseen asteroid
We’re in the clear from asteroid 2024 YR4 – but that’s not to say an asteroid won’t ever wipe out humanity.
In fact, Nasa is tracking hundreds of asteroids set to swing close to Earth. They could be nudged by another bit of debris that makes them collide with Earth.
And some of these asteroids are hundreds of feet wide, enough to cause global chaos.
Nasa also maintains a list of asteroids that could hit Earth one day, even if the chance is only minute.
Thanks to clever mathematics, Nasa can track asteroid orbits decades into the future.
But there’s a big problem with all of this: Nasa can only track asteroids that it can see.
Space is massive and there may be far-off asteroids that might be on their way to us – but they’re simply too distant to spot.
And other asteroids are made difficult to detect because they’re hidden by the glare of the Sun. These unseen rocks can’t easily be identified and tracked.
If a massive asteroid hit Earth, it could transform the planet into an unlivable hellscape. So keep your fingers tightly crossed.
“The good news is we know where most of the really big asteroids are that get closest to the Earth, and we’ve found more than 90 percent of these big asteroids,” Nasa says. Reassuring.
Rogue planet
Of course an asteroid isn’t the only thing that could crash into Earth. Sorry.
It’s also possible that a rogue planet could collide with our home – wiping us out with tremendous force.
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There are a couple of ways that this could happen.
One option is something called a rogue planet, which is exactly what you probably think it is.
It’s a planet that isn’t tied to the gravity of a star, and is effectively “floating free” across space. Terrifying.
They’re not exactly “rare” either. Our own galaxy – the Milky Way – is estimated to have trillions of rogue planets.
Astronomers do a lot of work to try to track down these planets, but it’s very hard to find them all.
The dinosaur-destroying asteroid is believed to have been about nine miles wide.
By contrast, a planet could be thousands of miles wide. It would instantly end all life on Earth.
There’s also a chance that a non-rogue planet could hit Earth too.
What's the difference between an asteroid, meteor and comet?
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Here's what you need to know...
- Asteroid: An asteroid is a small rocky body that orbits the Sun. Most are found in the asteroid belt (between Mars and Jupiter) but they can be found anywhere (including in a path that can impact Earth)
- Meteoroid: When two asteroids hit each other, the small chunks that break off are called meteoroids
- Meteor: If a meteoroid enters the Earth’s atmosphere, it begins to vapourise and then becomes a meteor. On Earth, it’ll look like a streak of light in the sky, because the rock is burning up
- Meteorite: If a meteoroid doesn’t vapourise completely and survives the trip through Earth’s atmosphere, it can land on the Earth. At that point, it becomes a meteorite
- Comet: Like asteroids, a comet orbits the Sun. However rather than being made mostly of rock, a comet contains lots of ice and gas, which can result in amazing tails forming behind them (thanks to the ice and dust vapourising)
Picture Credit: Getty Images – Getty
A planet’s orbit could become unstable due to gravitational forces, or another collision may knock it out of its usual movement.
Scientists have previously thought that Mercury could one day become unstable and crash into Earth, but the chances of that happening are extremely low.
In the long distant future, the Milky Way is expected to collide with our space neighbour, the Andromeda galaxy.
That could see Earth smashing into other planets, if it did happen. Of course, galaxies are mostly just empty space – so it’s not a definite doomsday.
But don’t worry, that’s four billion years away anyway. So unless technology gets very good, we’ll all be long-dead. That should cheer you up.
Gamma-Ray Burst
This is the really horrible one.
At least with an asteroid, you think we have a fighting chance. We could pull a Bruce Willis in Armageddon, maybe. It’s a fair game.
A nearby gamma-ray burst could kill us all. And they can move at close to the speed of light, so oblivion would strike very quickly.
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They’re short but extremely powerful burst of energy, unimaginably more powerful than our own Sun.
And if one was close enough – from within our own galaxy – then it could damage Earth’s protective layers, allowing dangerous UV radiation to reach the surface.
If it was extremely close and powerful, it could be devastating.
“A nearby gamma-ray burst could sterilise Earth,” the European Southern Observatory warns.
“These bursts of energy are so powerful that they can briefly outshine the rest of the Universe. Fortunately, the chance of one occurring nearby is slim.”
Thankfully astronomers think that the chances of a gamma-ray burst wiping out all life in the near future is so small that it’s not even worth worrying about.
The Sun itself
No, not us. We’re too busy writing articles. The one up in the sky.
The Sun will definitely destroy Earth one day. We already know this.
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Earth will no longer be habitable in about a billion years.
It’ll evaporate our oceans, and reduce the amount of carbon dioxide in the atmosphere to the point where plant life can’t exist.
And in about seven to eight billion years, the Sun will likely expand to the point that it engulfs Earth, destroying it completely.
In the meantime, we just have to hope that there isn’t a strange increase or decrease in the power that the Sun puts out, which could affect our ability to live on Earth.
Hopefully by the time any of this stuff actually happens, we’ll be living on other, safer planets. All aboard the next Elon Musk shuttle…