week 9

Which of the following is NOT a product of the first step in the p-p chain of nuclear fusion?

a form of helium

Astronomers have found that the level of the Sun's activity varies over the centuries. How did they come to realize that this is from:

all of the evidence listed was collected

Astronomers first detected the presence of a wind of particles coming from the Sun by

by noting the wind's effects on the tails of comets

Which part of the Sun's atmosphere has the lowest density (number of atoms per unit volume)?

cornoa

Which part of the Sun's atmosphere is the hottest?

corona

The ten million tons of particles that escape the Sun each year in the form of the solar wind get out mainly through regions called

coronal holes

What happens to the positron created during the p-p chain of nuclear reactions inside the Sun?

it quickly collides with an electron and turns into gamma-ray energy

Today we realize that the source of energy for the Sun is a process called

nuclear fusion

The Sun is an enormous ball of gas. Left to itself, a ball of so many atoms should collapse under its own tremendous gravity. Why is our Sun not collapsing?

nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced

The material inside the Sun is in the form of a

plasma

The antimatter version of an electron is called a

positron

Which of the following is NOT one of the fundamental particles that we find inside atoms?

positrons

What mechanisms do astronomers believe is responsible for making the Sun's outer atmosphere so much hotter than its photosphere?

the Sun's magnetic field interacting with the charged particles that make up the atmosphere

A friend (who does not have the new awareness which you have gained from this course) suggests that the mechanism that keeps the Sun shining as brightly as it does is the burning of coal. You brilliantly challenge his theory! Your challenge comes in several related steps; which of the following is one of those steps?

the dating of radioactive rocks show that the Earth and thus the Sun are billions of years old

The Sun's photosphere is

the part of the Sun from which the light comes that we see when we look at the Sun with our eyes