If the core thats left after a supernova is big ie

If the core that's left after a supernova is big (i.e. greater than 3 solar masses), then it will become a _________
_______.
Black hole. A black hole is the most compact object imaginable--hypothetically so compact and having so much
gravitational force that nothing can escape it--not even light. Note that very rarely, the supernova is so strong
that neither a neutron star nor a black hole is formed--essentially the entire core is destroyed.
A black hole consists of two parts--at the center would be a singularity and "surface" of the black hole would be
the ________ ________.
Detailed Explanation:
Event horizon. As you learned previously, a singularity is an infinitesimally small point with infinite density,
exerting infinitely strong gravitational force.
Astronomers call all elements heavier than hydrogen and helium ___________.
:
Metals. Therefore, when we refer to the metallicity of an object, we are talking about what percentage of it is
composed of heavier elements--elements other than Hydrogen and Helium.
The metallicity of a star may correlate with its ______.
xplanation:
Age. As you recall, based on the Big Bang theory, the early universe should have been composed entirely of
Hydrogen and Helium. The heavier elements would have been produced later in the first stars and distributed
through their supernovas.
The Population system of classifying stars is based on its metallicity. Population III stars are the __________,
with the lowest metallicity.
Oldest. Astronomers break down stars into three categories: Population I, II, and III, with Population III being
the oldest. A population III star has no metallicity--it would be one of the first stars formed after the Big Bang,
composed entirely of Hydrogen and Helium. Population III stars are actually hypothetical--none have ever been
observed.

The oldest stars that have been found in the universe are Population ____ stars.
Explanation:
II. As indicated in the previous question, a Population III star has never been found. Population II stars have
very low metal content, but even the oldest Population II star has at least a little bit of metal (around 0.1%).
Population II stars tend to be found in globular clusters and in the halos of galaxies. They are less luminous and
cooler than Population I stars.
The youngest stars are the Population I stars, and these tend to be found in _______ clusters.
:
Open. Open clusters are young, and therefore consist of the young Population I stars. Population I stars have the
highest metallic content. Based on what you learned about the Big Bang, how stars our formed, and supernovas,
this makes sense.
The earliest stars would have been formed entirely of hydrogen and helium. When they blew up in supernovas,
they would have created and left behind heavier elements--metals. New stars that formed in these clouds of gas
from the aftermath of the supernova would have higher metallic content, and when they explode, they would
leave behind an even richer cloud of gas for subsequently born stars.