In 2005, we landed a probe on the surface of Titan, which is one of Saturn’s Moons.
Just think of what this involves, for a moment.
Saturn is almost a billion miles away. When you look at it in the sky, it’s an orange dot of light.
And somewhere around that dot of light, is a SMALLER dot of light orbiting around it, that we can’t even see with the naked eye.
Now, imagine firing a gun at 10 times the speed of a bullet, almost 7 years in advance, to try to hit that moving dot around the dot. Because that’s basically what they did when they launched the Huygens space probe.
Only imagine firing the gun from the surface of a rotating sphere (Earth), which itself moves around the sun. So does Saturn, at a different speed. And Titan moves around Saturn.
Yet NASA managed to compute the right trajectories, and apply the right braking with retro-rockets, so that the probe not only achieved a soft landing on Titan, but managed to send back pictures.
When our grandparents were born, computers didn’t’ even exist, and rockets couldn’t even travel more than a few miles, let alone go into space.
That’s pretty amazing, when you think about it.
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The coldest temperature in the deepest nether-regions of intergalactic space is about 3 degrees Kelvin (-270C).
That’s three degrees above absolute zero (which is as cold as anything can ever get).
But why 3 deg K? Why doesn’t it get colder than that?
Because the 3 degrees is the fossil remnant of the Big Bang: the huge explosion that was believed to have created the Universe at the Beginning of Time.
The fireball from the Big Bang was intensely hot at first. But over billions of years, the Universe expanded, and everything cooled off, to the point of where we are today.
But there’s still that remaining 3K of heat left over, that’s present throughout the entire fabric of the Universe. This is what’s know as “background radiation“.
Though in the laboratory, we’ve managed to get temperatures colder than this, approaching Absolute Zero to within 0.0000000001 of a degree.
So basically, here on earth, we puny humans, with our tiny, insignificant experiments, have created what is the coldest known temperature in the entire Universe.
Not bad, eh? …for hairless apes who only learned to write 6000 years ago!
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By the way, it’s impossible to reach Absolute Zero, exactly. You can come close to it, but you’ll never quite get there.
It’s not like we eventually can, if we develop technology and design a better way to freeze things.
Nope. It’s just impossible.
The Laws of Thermodynamics imply that at Absolute Zero, all atoms stop vibrating. There is zero motion, all particles are in fixed positions.
This violates the Heisenberg Uncertainty Princicple. The laws of Quantum Mechanics do not allow us to simultaneously know where a particle is and how fast it’s moving (or not moving).
If it sounds complicated, it IS. I wont’ bore you with all the details.
But just remember, that Absolute Zero is impossible.
Because that’s just the way the Laws of the Universe work.
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It’s fasciniating the way things are quantized at the sub-atomic level, where events take place in discrete steps.
Take electrons orbiting around an atomic nucleus, for example.
Say an electron absorbs some energy. This might kick it up to the next higher orbit around the atom. If this electron loses energy, it would drop back down to the lower orbit from where it came.
But the thing is… the electron can only jump from one orbit to the other. It’s Either-Or. There is no going in-between the orbits.
That would be like the equivalent of someone trying to push you up hill in a wagon.
Imagine if the wagon could only be in two places: at the top, or at the bottom. There would be no such thing as half-way up the hill, or 7/8th up the hill, etc…
Fortunately, things dont’ work this way in our everyday life.
On the human scale, any quantum effects are so incredibly tiny that everything appears to take place smoothly and continuously.
The Deep Friar 