Supernovas are among the most energetic events in the universe and res

Supernovas are among the most energetic events in the universe and result in the complete disruption of stars at the end of their lives. Originally, the distinction between Type I and Type II supernovas was based solely on the presence or absence of hydrogen atoms (hydrogen lines). Supernovas without hydrogen lines were called Type I, while those with hydrogen lines were Type II. Subsequent analysis of many of these events revealed that this empirical classification schema instead reflected two different mechanisms for the supernova explosion.

Type I supernovas happen in binary stars — two stars that orbit closely each other — when one of the two binary stars is a small, dense, white dwarf star. If the companion star ranges too close to the white dwarf that it is orbiting, the white dwarf’s gravitational pull will draw matter from the other star. When the white dwarf acquires enough matter to become at least 1.4 times as big as the Sun, it collapses and explodes in a supernova.

Type II supernovas occur when a star, much more massive than the Sun, ends its life. When such a star begins burning out, the core of the star quickly collapses releasing amazing energy in the form of neutrinos, a kind of particle smaller than even an atom. Electromagnetic radiation — energy that is electric and magnetic — causes the star to explode in a supernova. Whereas Type I supernovas typically destroy their parent stars, Type II explosions usually leave behind the stellar core.

The classification schema regarding the mechanism for supernova explosions helps to more succinctly answer the question: Is the Sun in danger of becoming a supernova? Neither does our Sun have a companion star orbiting it nor does our Sun have the mass necessary to become a supernova. Furthermore, it will be another billion years until the Sun runs out of fuel and swells into a red giant star before going into a white dwarf form.

How is this passage organized?
A)A single phenomenon is introduced and two overlapping classification schemas are contrasted.
B)An original theory is mentioned before being overturned as a result of new findings.
C)Two complementary mechanisms for describing a single phenomenon are discussed and a conclusion is offered.
D)A new classification schema is described and an example of how it works is provided.
E)Two different classification systems are outlined and a question posed to help reconcile both.


It can be inferred from the passage that
A)Classifying a Type I or Type II event based on the presence or absence of hydrogen is not necessarily incompatible with a classification schema based on the mechanism
by which these two events explode.
B) A dense white dwarf’s gravitational pull on its companion star causes the companion star to collapse and explode as a supernova.
C) Before a star such as the Sun can become a red giant, it must first become a white dwarf.
D) In a Type II supernova, energy and electromagnetic radiation causes a star to collapse and explode.
E) Supernovas are rare events in our universe.


Which of the following best summarizes the author’s answer to the question: Is the Sun in danger of becoming a supernova?
A) The Sun is too large to have a white dwarf as a partner and lacks the physical size required to become a red giant.
B) Even if the Sun were paired with a white dwarf, the Sun does not have the mass necessary to create sufficient electromagnetic radiation.
C) The Sun is not a white dwarf with a companion star orbiting it, nor does it have the size to qualify as a Type II supernova.
D) Without a white dwarf orbiting the Sun, the Sun has no obvious way to increase its size to become a Type II supernova.
E) The Sun will inevitably become a supernova once it passes from a red giant to white dwarf but not for at least a billion years.


According to the passage, which statement or statements below are true?
I. The energy created from a Type II explosion is greater than the energy created by a Type I explosion.
II. The sun is not a binary star.
III.Both Type I and Type II supernovas result in the complete destruction of the exploding star.
A) I only
B) II only
C) I and III only
D) II and III only
E) I, II, and III

Supernovas are among the most energetic events in the universe and result in the complete disruption of stars at the end of their lives. Originally, the distinction between Type I and Type II supernovas was based solely on the presence or absence of hydrogen atoms (hydrogen lines). Supernovas without hydrogen lines were called Type I, while those with hydrogen lines were Type II. Subsequent analysis of many of these events revealed that this empirical classification schema instead reflected two different mechanisms for the supernova explosion.

Type I supernovas happen in binary stars — two stars that orbit closely each other — when one of the two binary stars is a small, dense, white dwarf star. If the companion star ranges too close to the white dwarf that it is orbiting, the white dwarf’s gravitational pull will draw matter from the other star. When the white dwarf acquires enough matter to become at least 1.4 times as big as the Sun, it collapses and explodes in a supernova.

Type II supernovas occur when a star, much more massive than the Sun, ends its life. When such a star begins burning out, the core of the star quickly collapses releasing amazing energy in the form of neutrinos, a kind of particle smaller than even an atom. Electromagnetic radiation — energy that is electric and magnetic — causes the star to explode in a supernova. Whereas Type I supernovas typically destroy their parent stars, Type II explosions usually leave behind the stellar core.

The classification schema regarding the mechanism for supernova explosions helps to more succinctly answer the question: Is the Sun in danger of becoming a supernova? Neither does our Sun have a companion star orbiting it nor does our Sun have the mass necessary to become a supernova. Furthermore, it will be another billion years until the Sun runs out of fuel and swells into a red giant star before going into a white dwarf form.

How is this passage organized?
A)A single phenomenon is introduced and two overlapping classification schemas are contrasted.
B)An original theory is mentioned before being overturned as a result of new findings.
C)Two complementary mechanisms for describing a single phenomenon are discussed and a conclusion is offered.
D)A new classification schema is described and an example of how it works is provided.
E)Two different classification systems are outlined and a question posed to help reconcile both.



It can be inferred from the passage that
A)Classifying a Type I or Type II event based on the presence or absence of hydrogen is not necessarily incompatible with a classification schema based on the mechanism
by which these two events explode.
B) A dense white dwarf’s gravitational pull on its companion star causes the companion star to collapse and explode as a supernova.
C) Before a star such as the Sun can become a red giant, it must first become a white dwarf.
D) In a Type II supernova, energy and electromagnetic radiation causes a star to collapse and explode.
E) Supernovas are rare events in our universe.



Which of the following best summarizes the author’s answer to the question: Is the Sun in danger of becoming a supernova?
A) The Sun is too large to have a white dwarf as a partner and lacks the physical size required to become a red giant.
B) Even if the Sun were paired with a white dwarf, the Sun does not have the mass necessary to create sufficient electromagnetic radiation.
C) The Sun is not a white dwarf with a companion star orbiting it, nor does it have the size to qualify as a Type II supernova.
D) Without a white dwarf orbiting the Sun, the Sun has no obvious way to increase its size to become a Type II supernova.
E) The Sun will inevitably become a supernova once it passes from a red giant to white dwarf but not for at least a billion years.



According to the passage, which statement or statements below are true?
I. The energy created from a Type II explosion is greater than the energy created by a Type I explosion.
II. The sun is not a binary star.
III.Both Type I and Type II supernovas result in the complete destruction of the exploding star.
A) I only
B) II only
C) I and III only
D) II and III only
E) I, II, and III