Some of the greatest mysteries of the cosmos have been resolved by physicists. But work still needs to be done.
1. WHAT IS MATTER MADE UP OF ?
We are aware that matter is formed of atoms, and that protons, neutrons, and electrons make up each atom. We also know that quarks, which are smaller particles, make up protons and neutrons. Would going further reveal even more fundamental particles? We are unsure for sure.
The Standard Model of particle physics, which is what we do have, is extraordinarily effective at explaining the interactions between subatomic particles. The existence of previously unidentified particles has also been predicted using the Standard Model. The Higgs boson was the last particle to be identified in this manner; it was found by LHC physicists in 2012.
Dr. Don Lincoln, a particle physicist at Fermi National Accelerator Laboratory (Fermilab) close to Chicago, claims that “The Standard Model doesn’t explain everything.” It doesn’t explain the existence of the Higgs boson. It doesn’t go into great length to explain why the Higgs boson is as massive as it is. The Higgs was really much less massive than expected; according to Lincoln, theory anticipated that it would be around “a quadrillion times heavier than it is.”
There are still unanswered questions. Although it is well known that atoms are electrically neutral because the protons’ positive charge is balanced by the electrons’ negative charge, Lincoln answers, “Nobody knows,” when asked why this is the case.
2. WHY GRAVITY IS SO WEIRD?
Gravity is the most familiar force since it maintains our feet on the earth. Additionally, gravity is mathematically described in Einstein’s theory of general relativity as a “warping” of space. But compared to the other three forces known to science, gravity is a trillion trillion trillion times less (electromagnetism and the two kinds of nuclear forces that operate over tiny distances).
One speculative option is that there are additional hidden dimensions to the three we can currently see in space, possibly “curled up” in a way that prevents us from seeing them. Why gravity looks so faint to us might be explained if these extra dimensions are real and if gravity can “leak” into them.
According to Whiteson, it’s possible that gravity is just as powerful as these other forces but that it quickly loses strength as it spills into these other invisible dimensions. However, there has been no success so far. Some physicists had hoped that experiments at the LHC would provide a hint of these extra dimensions.
3.WHY DOES IT SEEM TO FLOW IN ONLY ONE DIRECTION?
Physicists have thought of space and time as forming a four-dimensional structure known as “spacetime” since Einstein. However, space differs from time in fundamental ways. We have complete freedom to move around in space. We’re stuck when it comes to time. We get older rather than younger. And we can recall the past but not the future. Unlike space, time appears to have a preferred direction, which physicists refer to as the “arrow of time.” According to some physicists, the second rule of thermodynamics might hold the key. A physical system’s entropy, or essentially the degree of disorder, is said to increase through time, and physicists believe that this increase is what gives time its direction. (For instance, a shattered teacup has more entropy than an intact one; likewise, smashed teacups always appear after intact ones, never before.)Even though entropy is now higher than it was earlier, why was it low in the first place? When the Big Bang created the cosmos 14 billion years ago, was its entropy abnormally low?Sean Carroll of Caltech is one scientist who believes it to be the final piece in the jigsaw. He says, “I can explain the rest of it if you can tell me why the early cosmos had a low entropy. Entropy isn’t the complete picture, according to Whiteson. The most fundamental question, he claims, is “why is time so distinct from space?” (Recent computer simulations appear to demonstrate how the asymmetry of time might result from the fundamental physical laws, but the work is debatable and the nature of time itself continues to be the subject of fervent discussion.)
4. HOW DID ALL THE ANTI-MATTER DISAPPEAR?
In fiction, antimatter may be more well-known than it is in reality. The warp drive that propels the U.S.S. Enterprise at faster-than-light velocities in the original Star Trek is powered by an interaction between antimatter and conventional matter. Contrary to popular belief, antimatter exists in the actual world. We are aware that an identical particle with the opposite electrical charge can exist for every particle of conventional matter. For instance, an antiproton is a proton with a negative charge. The positively charged positron, on the other hand, is the antiparticle to the negatively charged electron. In the lab, physicists have produced antimatter. However, they produce an equivalent amount of matter when they do. That implies that matter and antimatter must have been produced in equal amounts during the Big Bang. However, the majority of everything we perceive in the world, from the ground beneath our feet to the farthest galaxies, is composed of common material. What is occurring? Why does matter predominate over antimatter? Our best hypothesis is that there was a very slight excess of matter compared to antimatter at the Big Bang. For every 10 billion antimatter particles, there had to be 10 billion and one matter particles, according to Lincoln, who theorizes that this ratio must have existed early in the universe’s existence, right after the Big Bang. “And the one was left after matter and antimatter destroyed the other 10 billion. The bulk that makes up each of us is that tiny “one.”But why was there ever a little surplus of matter over antimatter? Lincoln says, “We truly don’t get that. It’s strange, If the original proportions of matter and antimatter had been the same, they would have utterly destroyed one another in a flash of energy. Lincoln claims that “we wouldn’t exist” in that scenario. When the Deep Underground Neutrino Experiment (DUNE) begins data collection in 2026, some solutions might become apparent. A beam of neutrinos, which are small, almost massless particles, will be analyzed by DUNE after it is shot from Fermilab to the Sanford Underground Research Facility in South Dakota, some 800 miles away. In order to determine whether neutrinos and antineutrinos act similarly, the beam will contain both particles. If they do, it may be possible to deduce something about nature’s matter-antimatter asymmetry.
5.WHAT TRANSPIRES BETWEEN A SOLID AND A LIQUID IN THE TRANSLATIONAL STATE?
We know a lot about solids and liquids. The behavior of some materials, however, is unpredictable because they behave both like a liquid and a solid. For instance, sand. A single grain of sand is as heavy as a boulder, but a million may move down a funnel almost as easily as water. Highway traffic can act similarly, moving freely until it is slowed down at a bottleneck.Therefore, a deeper comprehension of this “gray zone” may have significant practical implications. According to Dr. Kerstin Nordstrom, a physicist at Mount Holyoke College, “People have been questioning, under what conditions does the entire system jam up or clog.” What are the essential factors to prevent clogging? Strangely enough, when certain circumstances are met, a blockage in the flow of traffic might actually ease traffic congestion. It’s quite illogical, she claims.
6. CAN WE DEVELOP AN ALL-ENCOMPASSING THEORY OF PHYSICS?
These days, general relativity, the theory of gravity proposed by Albert Einstein, and quantum mechanics serve as the two overarching frameworks for virtually all physical phenomena. From golf balls to galaxies, the former is effective at explaining motion. Even in its own sphere, the world of atoms and subatomic particles, quantum mechanics is astounding. The problem is that the two theories have quite different descriptions of our environment. While spacetime is fluid in general relativity, it is fixed in quantum mechanics, where events take place. What would the structure be of a quantum theory of curved space-time? Carroll says, “We don’t know.” We have no idea of what we are attempting to quantify. Even so, attempts have continued. String theory has been hailed as the best hope for a unified explanation of physics for many years. It depicts matter as being composed of minute vibrating strings or loops of energy. However, other scientists favor loop quantum gravity, which postulates that space is composed of minuscule loops.Each strategy has had some degree of success; methods created by string theorists in particular are proving helpful for solving some challenging physics issues. However, experimental verification of either string theory or loop quantum gravity is lacking. For the time being, we are still without the long-sought “theory of everything.”
7. HOW DID LIFE BEGIN IN THE ABSENCE OF LIVING THINGS?
Earth was lifeless for its first half-billion years. Life then began to flourish and has done so ever since. However, how did life begin? Before biological evolution, simple inorganic molecules are thought to have undergone chemical evolution, interacting to create more complex organic compounds, most likely in the oceans. But what was the first catalyst for this process? Dr. Jeremy England, an MIT physicist, recently proposed a theory that seeks to explain the genesis of life in terms of basic physics. According to this theory, increasing entropy must eventually lead to life. According to England in 2014, if the idea is accurate, the emergence of life “should be as unsurprising as rocks tumbling downhill.”The concept is quite speculative. However, recent computer simulations might be supporting it. The simulations demonstrate that typical chemical interactions, such as those that would have occurred often on a freshly formed Earth, can produce highly structured molecules, which appear to be an essential first step on the way to the development of living things.Why is studying physics so challenging for physicists? Any living thing is, in the words of physics, “far from equilibrium.” When a system is in equilibrium, there is no energy flow and each component is essentially identical to every other component. (A rock or a box of gas would serve as examples.) The reverse is true in life. For instance, a plant takes in sunlight, uses it to create complex sugar molecules, and then releases heat back into the environment.According to Stephen Morris, a physicist at the University of Toronto, comprehending these intricate systems “is the big unsolved challenge in physics.” How do we handle these out-of-equilibrium systems that self-organize into incredible, intricate entities like life?