re: nevermind

They are just using big words to explain it. Pretty much saying if you have two stillshots in time of a sandwich, one when it was hot and one when it was cold, and you know nobody moved or touched the sandwich, that the cold sandwich exists after the hot sandwich.

However, if the sandwich is in a microwave (open system) you can no longer know this was certainty.

It's just a way to say "hey, this is what time actually is"

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Intelligent extraterrestrial life is another matter. If you look at Earth, of all the billions of species that have existed, only one has found it advantageous to evolve self-awareness and intelligence. It's simply not an evolutionarily advantageous trait.

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This is wrong on so many levels.

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Laws of Thermodynamics make heat death an inevitable end of the universe.

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Glad I could bring some entertainment to your life.

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Entropy is the only quantity in the physical sciences (apart from certain rare interactions in particle physics; see below) that requires a particular direction for time, sometimes called an arrow of time. As one goes "forward" in time, the second law of thermodynamics says, the entropy of an isolated system will increase. Hence, from one perspective, entropy measurement is a way of distinguishing the past from the future. However in thermodynamic systems that are not closed, entropy can decrease with time: many systems, including living systems, reduce local entropy at the expense of an environmental increase, resulting in a net increase in entropy. Examples of such systems and phenomena include the formation of certain crystals, the workings of a refrigerator and living organisms.

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This is almost completely plagiarized from Steven Hawking's A Brief History of Time.

Wanna really get your mind blown, start reading about imaginary time and antiparticles. Imaginary time (like imaginary numbers which result from the square root of negative numbers) is absolutely a real thing that can be mathematically proven and in conjunction with antiparticles can result in negative entropy.

I've only ever utilized entropy as a quantification of the irreversibilities present in a system, which is useful for finding how much usable energy is lost by running a complete cycle of whatever it is you are doing.

You could say it is a measurement of order, I just wanted to explain it in terms if useful energy because that's one of entropies most useful characteristics in terms of the practical world. If you know the entropy generated in a process you can easily find how much usable energy was expended, or how much closer your system is to complete equilibrium if it is isolated.

Getting in this one late.

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Not quite. I'm sure you've heard "energy cannot be created or destroyed", the First Law of Thermodynamics. We know energy can change into a variety of different forms (and we know cool facts like matter is simply a form of energy, and can be transformed between a form of energy with mass or without mass, and we know how much of this energy from that famous equation E = mc^2)

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This is correct. Matter can be transformed into energy, which we know how to do. Energy can be transformed into matter, which we'll get a handle on with findings concerning the Higgs Boson.

As long as there is matter, there is potential for energy. And vise versa.

The universe will always have some form of energy. Despite everything 'moving away from each other' there are still collisions on a regular basis. Will it get to a point when the energy/matter is so distant, that it is rendered ineffective? Maybe.

Until we get a better handle on dark matter and dark energy, we can't say with any certainty what the death of the universe will look like.

As for aliens...yep, they exist. The real question is, will we ever discover a way to travel long distances in space (or find shortcuts) that allow us to interact with them.