Where did the most abundant elements in the Universe come from?

Where did the most abundant elements in the Universe come from?

Gamma rays produced protons, helium, and carbon nuclei in the big bang; nuclear fusion in stars produced all other elements.

Gamma rays produced protons and neutrons in the big bang; protons and neutrons formed helium during the next few minutes; fusion in stars produced all other elements.

Gamma rays produced protons and all the other elements in the big bang.

Gamma rays produced protons and helium in the big bang; fusion during the first three minutes produced oxygen; stars produced the all other elements.

Why does astronomers say that our galaxy has a supermassive black hole in its core?

Long wavelength observations show gas clouds orbiting at high speed, the only credible mechanism that explains this behavior is a supermassive blackhole.

We can view conditions in other galaxies, and all of them exhibit behavior that we can only explain with a supermassive blackhole.

Emissions at galactic center include energetic lightray bursts, and the known mechanism for this kind of energy is from a supermassive blackhole.

Stars are orbiting with speeds so high that only a supermassive blackhole can cause the observed speeds.

Why do metal-poor stars in our galaxy tend to have large elliptical orbits outside the disk?

Because metals, with higher gravitational attraction, tend to stabilize stellar orbits.

Because of a possible past interaction between our galaxy and a neighboring galaxy changed the circular orbits of these early stars into elliptical orbits.

They don't have this tendency. The metal-poor stars exhibit well-organized orbits around galactic center, with nearly circular orbits.

Because these stars formed before the spiral shape formed, when the galaxy was a larger, more diffuse cloud, with no well-defined concentration of mass near the center.

Which of the following is NOT evidence implying the existence of large quantities of dark matter?

The motions of galaxies are too rapid to be due only to the luminous matter in those clusters.

Gravitational lensing, by rich galaxy clusters, of light from distant quasars implies massive amounts of dark matter in these clusters.

The speed of stars and gas in the outer reaches of spiral galaxies is far too high to be accounted for only by the luminous material in those galaxies.

The observed deceleration of the universal expansion in the distant past can only be explained if there is far more dark matter than luminous matter in the Universe.

In the most modern cartographical sense, what is the purpose of the constellation boundaries?

They are the outlining of primitive mythical figures in the sky that result from "connecting the dots."

They are just old folklore of animals, and other things like monsters.

They are groups of stars and planets and events associated with the seasons.

They are organizational mapping. The dividing and naming of the sky's regions in large sections.

Which of these statements regarding the stimulation of star birth is the most nonsensical claim.

Interactions or mergers of galaxies compress gas/dust clouds and stimulate star formation.

In the early Universe star formation was more rapid than now because of the overall crowded conditions.

In spiral galaxies, stars form rapidly after gas/dust clouds leave the spiral arms and become less compressed.

Exploding stars in regions of gas/dust clouds can stimulate star formation.

What is a total solar eclipse?

An eclipse where the shadow of the Earth falls on the Moon.

An eclipse where the shadow of the Earth falls on the Sun.

An eclipse where the intervening Moon appears the same size or larger than the Sun.

An eclipse where the intervening Sun appears smaller than the Moon.