The universe is a big place, but it is made up of small pieces.The· Periodic table Contains elements such as oxygen, carbon Stars, cats, and other components that make up coffee. But since the turn of the 20th century, scientists have been thinking and discovering smaller and smaller elementary particles. atom It fills the universe. So which of these elementary particles is the smallest? And on the contrary, which is the largest?
Don Lincoln, a senior scientist at the Fermi National Accelerator Laboratory (Fermilab) near Chicago, is one of the scientists trying to answer this question. At Fermilab, scientists use particle accelerators to grind individual particles and examine the debris (or potential new elementary particles) that emerge. According to Lincoln, there are two ways to measure particle size: by looking at the mass and by measuring the physical size, such as calculating the diameter of a ball.
Relation: What is the weight of an atom?
When it comes to mass, answering these questions is relatively easy.The smallest non-zero mass particle we know is Neutrino, Lincoln said. However, he pointed out that the instruments used to calculate the mass of elementary particles are not sensitive enough to accurately measure the mass of neutrinos.
“Neutrinos are particles, like ghosts in the subatomic world,” Lincoln said. Neutrinos have a very weak interaction with matter and are the second most abundant particles after photons (which behave more like waves than real particles). In fact, trillions of neutrinos pass through you at this moment. Neutrinos are light in weight and move at speeds close to the speed of light.
The nucleus is composed of neutrons, protons, and electrons. The protons and neutrons themselves are about one-tenth the size of the nucleus as a whole, Lincoln said. Although the electron mass is almost zero, it actually weighs 500,000 times as much as a neutrino (accurate measurement is impossible even at this point).
According to Lincoln, physicists use electron volt (eV) to measure the mass of subatomic particles. Technically, the unit is eV / c ^ 2, where c is the speed of light. One electron volt is equivalent to about 1.6×10 ^ -19 joules. To simplify things, physicists use a set of units with a speed of light of 1. Then, to calculate the mass of elementary particles, use: Albert Einstein The famous equation E = mc ^ 2 for obtaining mass (m) in kilograms.
According to Lincoln, the electron weighs 511,000 electron volts, which is equivalent to 9.11 x 10 ^ -31 kilograms. For comparison, he said, a typical proton in the nucleus of a typical atom weighs 938 million electron volts, or 1.67 x 10 ^ -27 kg.
Conversely, according to Lincoln, the largest elementary particle we know (in terms of mass) is a particle called a top quark, which measures a whopping 172.5 billion electron volts. Quarks are another basic particle that, as far as we know, cannot be broken down further. Scientists have discovered six types of quarks: up, down, strange, charm, bottom, and top. Up quarks and down quarks make up protons and neutrons, which weigh 3 million electron volts and 5 million electron volts, respectively. In comparison, top quarks weigh 57,500 times more than up quarks.
It’s difficult to answer physical size questions. We know the physical size of some particles, but not the smallest. Some of the “small” particles that people hear in their daily lives, such as viral particles, are actually quite large.
Lincoln provided this sense of scale. Typical virus particles are about 250-400 nanometers (nanometers are one billionth of a meter, or 10 ^ -9 m), and typical nuclei are about 10 ^ -14 m (next). 0.00000000000001). m). In other words, the nucleus is as small as a virus for a virus.
Currently, the smallest physical size that scientists can measure with a particle accelerator is 1/2000 of a proton, or 5 x 10 ^ -20m. So far, scientists have been able to determine that quarks are smaller, but not how much.
Originally published in Live Science.
What is the smallest particle in the universe? (How about the biggest one?)
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