what happens when a particle of matter meets its corresponding antiparticle of antimatter?

# what happens when a particle of matter meets its corresponding antiparticle of antimatter?

S
9.9k points
What happens when a proton collides with an antiproton?They convert into two photons.
What is the current temperature of the universe?a few degrees
Which of the following does not provide strong evidence for the Big Bang theory?observations of the amount of hydrogen in the universe
Which of these options is the best explanation for why the night sky is dark?The universe is not infinite in space
What is the earliest time in the universe that we can directly observe?a few hundred thousand years after the Big Bang
How do we determine the conditions that existed in the very early universe?We work backward from current conditions to calculate what temperatures and densities must have been when the observable universe was much smaller in size.
What was the significance of the end of the era of nucleosynthesis, when the universe was about 5 minutes old?The basic chemical composition of the universe had been determined.
According to the Big Bang theory, why do we live in a universe that is made of almost entirely of matter rather than antimatter?During the first 0.001 second after the Big Bang, particles and antiparticles were made in almost but not perfectly equal numbers. Everything annihilated except the very slight excess of matter particles.
Which of the following is not an observed characteristic of the cosmic microwave background?It contains prominent spectral lines of hydrogen, the primary chemical ingredient of the universe.
In principle, if we could see all the way to the cosmological horizon we could see the Big Bang taking place. However, our view is blocked for times prior to about 380,000 years after the Big Bang. Why?Before that time, the gas in the universe was dense and ionized and therefore did not allow light to travel freely.
If observations had shown that the cosmic microwave background was perfectly smooth (rather than having very slight variations in temperature), then we would have no way to account for ________.how galaxies came to exist
In stars, helium can sometimes be fused into carbon and heavier elements (in their final stages of life). Why didn't the same fusion processes produce carbon and heavier elements in the early universe?By the time stable helium nuclei had formed, the temperature and density had already dropped too low for helium fusion to occur
Which of the following is not consistent with observations of the cosmic microwave background?The universe is at least 20 billion years old.
Based on observations of the cosmic microwave background, the overall composition of the universe is ________.4% ordinary (baryonic) matter, 23% non-ordinary (nonbaryonic) dark matter, 73% dark energy
The Big Bang theory seems to explain how elements were formed during the first few minutes after the Big Bang. Which hypothetical observation below (these are not real observations) would call our current theory into question?The discovery of a galaxy with a helium abundance of only 10% by mass
What happens when a particle of matter meets its corresponding antiparticle of antimatter?The combined mass of the two particles is completely transformed into energy (photons).
Which of the following statements correctly summarizes the events in the early universe according to the Big Bang theory?The universe began with the forces unified. During the first fraction of a second, the forces separated and there was a brief but important episode of inflation. Subatomic particles of both matter and antimatter then began to appear from the energy present in the universe. Most of the particles annihilated to make photons, but some became protons, neutrons, electrons, and neutrinos. The protons and neutrons underwent some fusion during the first three minutes, thereby determining the basic chemical composition of the universe.
Which statement about the cosmic microwave background is not true?It is the result of a mixture of radiation from many independent sources, such as stars and galaxies.
The Big Bang theory is supported by two major lines of evidence that alternative models have not successfully explained. What are they?(1) The theory predicts the existence of and the specific characteristics of the observed cosmic microwave background; (2) the theory correctly predicts the observed overall chemical composition of the universe.
Olbers' paradox is an apparently simple question, but its resolution suggests that the universe is finite in age. What is the question?Why is the sky dark at night?
Which of the following statements cannot be tested by science today?Prior to the Planck time, our universe sprouted from another universe.
What kinds of atomic nuclei formed during the nucleosynthesis era?hydrogen, helium and trace amounts of lithium, beryllium, and boron
Why is the nucleosynthesis era so important in determining the chemical composition of the universe?except for a small amount of elements heavier than helium produced later by stars, the chemical composition of the universe is the same now as at the end of the nucleosynthesis era.
Why did the era of nuclei end when the universe was about 380,000 years old?The universe had expanded and cooled enough for stable, neutral atoms to form
Evidence that the cosmic background radiation is the remnant of a Big Bang comes from predicting characteristics of remnant radiation from the Big Bang theory and comparing these predictions with observations. Four of the five statements below are real. Which one is fictitious?The cosmic background radiation is expected to contain redshifted emission lines from hydrogen and helium, and it does.
Which of the following statements about the cosmic background radiation is not true?It is the result of a mixture of radiation from many independent sources, such as stars and galaxies that formed within the first billion years of the Big Bang.
Why does the Big Bang theory predict that the cosmic background radiation should have a perfect thermal radiation spectrum?The background radiation came from the heat of the universe, with a peak corresponding to the temperature of the universe.
Why do we expect the cosmic background radiation to be almost, but not quite, the same in all directions?The overall structure of the universe is very uniform, but the universe must have contained some regions of higher density in order for galaxies to form.
Helium originates frommostly from the Big Bang with a small contribution from stellar nucleosynthesis.
What are the two key observational facts that led to widespread acceptance of the Big Bang model?the cosmic background radiation and the helium content of the universe
What happens when matter collides with anti-matter?The two particles destroy each other, and create photons.
Which of the following hypothetical observations, if true, would disprove a prediction of the Big Bang theory? The discovery ofa galaxy with 10% helium abundance.
what happens
studybud

Surround your text in *italics* or **bold**, to write a math equation use, for example, $x^2+2x+1=0$ or $$\beta^2-1=0$$

Use LaTeX to type formulas and markdown to format text. See example.