Big questions in science are the biggest questions we currently face. The existence of nothing, the origins of the universe, religious interference, quantum mechanics, physics, and sometimes philosophy, are a few of the topics that are open for discussion. We want to find out what happened at the beginning, was there something before our beginning, the multiverse perhaps? We are improving our understanding of what is happening now, what has already happened, and what is likely to happen in the future. Philosophy in this case gets a simple honorable mention due to its lack of progress, but still recognized as the "forefathers" of modern scientific theories. And finally, the gasping for air position of religion, which is the easiest argument to refute, will suffer that fate once again.
In the most practical and obvious application of quantum mechanics, advancements have led to your phones, your computers, and your cars. But in the deeper, more scientific realms of quantum mechanics, it shows the existence of "dark energy" that makes up the majority of the universe, but we still don't know what it is. Scientists measure the action of dark energy on the universe, but the particle has yet to be discovered. It is the stuff in which planets, stars, moons, and so on float around, then influenced by their gravitational pull on each other. It has been humorously described as to be like molasses, in which you see air bubbles moving around in all directions. Quantum mechanics also explains black holes, which have a strong gravitational force that no light can escape, and apparently have space travel properties, but that is beyond what I can describe. I refer you to Stephen Hawking's book, "A Brief History of Time" to become truly educated on the subject.
As far as quantum mechanics have come, and are still progressing, astrophysics is competing with its own great mystery, the beginning of the universe. As far as physicists know, our universe came from nothing. The "Big Bang" happened, things were exploding in every direction, and all the rest, but was there a state before the beginning of the universe? What does nothing mean, and how could a universe come out of nothing? The most honest answer a physicist can give to these questions is "I don't know," but they do know what is likely to have happened. "Not knowing is great because it means there's something else to learn," says astrophysicist Lawrence Krauss of the Origins Project at Arizona State University. This doesn't mean that astrophysicists are stumped, they have "reverse engineered" the universe to its earliest moments, fractions of fraction of fractions of nanoseconds after the Big Bang. We know what happened when it started, but how did it start?
The conversation of what "nothing" actual means or is has been lead by astrophysics, but it is the subject most interfered with by philosophy and religion (along with evolution). Philosophy says that the word "nothing" is as far as nothing goes, the word describes what is not. The universe cannot arise spontaneously out of what is not. Physicists say that the philosopher's definition is old fashioned and does not properly take into account the latest data and experiments. Science says that what philosophers have previously described as nothing is actually something, that is has properties, yet is simultaneously nothing at all. We know now that matter and anti matter have the ability to spontaneously collide, their collision would create a large mass of energy, leading to what could be considered a universe. But while they can do this, their existence together does not dictate this activity, rather it is more probable that such a thing wouldn't happen. Matter and antimatter also have the ability to, by description, cancel each other out, at which point nothing exists. Both of these possibilities exist simultaneously. And finally, religion says god was always there and created the universe. My question is, how do you know that? Because you want it to be true, you were raised to believe it, or is it simple faith? The existence of god runs you into nothing but an infinite regression, was there something before god, then what was before that...? And so on religion goes to falling away from serious discussion.
My conclusion so far is that the definition of "nothing" is beyond human comprehension, we just don't have the cognitive abilities to even ask the correct questions, but that is a pessimistic view I admit. I see neuroscience and neurophysiology as essential tools to solving these mysteries. They don't look at the issue, they look at what is happening that let's the issue be addressed in the first place. Our brains are sophisticated organs, there is no doubt, and they seem to have a unique ability ask themselves questions beyond their own comprehension. The brain thinks there is an answer to a specific question, often unaware that it is far beyond its ability to answer. The neurologically and physiologically strong position to have on modern science is that its answers are reasonable, and the other candidates are irrational and full of coincidence. There is a clash between empirical, testable evidence (science) and certainties based solely on psychology and thought processes(philosophy, religion). The question is, which do you trust?