Question

What is matter made of? ... Why is gravity so weird? ... Why does time seem to flow only in one direction? ... Where did all the antimatter go? ... What happens in the gray zone between solid and liquid? ... Can we find a unified theory of physics? ... How did life evolve from nonliving matter?

Answer 1

Answer:

A definition of "matter" more fine-scale than the atoms and molecules definition is: matter is made up of what atoms and molecules are made of, meaning anything made of positively charged protons, neutral neutrons, and negatively charged electrons

Answer 2

ago are now taught in freshman physics classes (the composition of stars is one good example).

Newton would be stunned to see enormous experiments like the Large Hadron Collider (LHC) in Switzerland — and possibly perturbed to learn that his theory of gravity had been superseded by one dreamed up by some fellow named Einstein. Quantum mechanics would probably strike him as bizarre, though today’s scientists feel the same way.

But once he was up to speed, Newton would no doubt applaud what modern physics has achieved — from the discovery of the nature of light in the 19th Century to determining the structure of the atom in the 20th Century to last year’s discovery of gravitational waves. And yet physicists today are the first to admit they don’t have all the answers. “There are basic facts about the universe that we’re ignorant of,” says Dr. Daniel Whiteson, a University of California physicist and the co-author of the new book "We Have No Idea: A Guide to the Unknown Universe."

What follows is a brief tour through seven of the biggest unsolved problems in physics. (If you’re wondering why head-scratchers like dark matter and dark energy aren’t on the list, it’s because they were in our earlier story on the Five Biggest Questions about the Universe.)

1. What is matter made of?

We know matter is made up atoms, and atoms are made up of protons, neutrons, and electrons. And we know that protons and neutrons are made up of smaller particles known as quarks. Would probing deeper uncover particles even more fundamental? We don't know for sure.

We do have something called the Standard Model of particle physics, which is very good at explaining the interactions between subatomic particles. The Standard Model has also been used to predict the existence of previously unknown particles. The last particle to be found this way was the Higgs boson, which LHC researchers discovered in 2012.

But there’s a hitch.

“The Standard Model doesn’t explain everything,” says Dr. Don Lincoln, a particle physicist at Fermi National Accelerator Laboratory (Fermilab) near Chicago. “It doesn’t explain why the Higgs boson exists. It doesn’t explain in detail why the Higgs boson has the mass that it does.” In fact, the Higgs turned out to be a heck of a lot less massive than predicted — theory had held that it would be about “a quadrillion times heavier than it is,” says Lincoln.