https://www.ck12.org/book/ck-12-middle-school-earth-science-concepts/section/23.8/
Read & Answer the questions at the end
Neutron Stars and Black Holes
How dense can you get?
A neutron star has about 500,000 times Earth's mass. It is the size of Brooklyn, New
York. These objects have an immense amount of gravity, but not as much as a black
hole!
Neutron Stars
After a supernova explosion, the star's core is left over. This material is extremely
dense. What happens next depends on the core's mass. The core might be less than
about four times the mass of the sun. In this case, the star will become a neutron star. A
neutron star (Figure below) is made almost entirely of neutrons. A neutron star has
more mass than the sun; yet, it is only a few kilometers in diameter.
A pulsar is a rotating neutron star that emits radiation in pulses. A pulsar can only be
seen when the beam is pointing toward Earth. Pictured below is a nebular that looks like
https://www.ck12.org/book/ck-12-middle-school-earth-science-concepts/section/23.8/
a cosmic hand (Figure below). There is a bright swirl of gas in the wrist of the hand. A
very tiny but bright neutron star is in the center of that swirl.
A pulsar sits in the center of this nebula.
Black Holes
The core remaining after a supernova could be more than about five times the mass of
the sun. In this case, the core collapses to become a black hole. Black holes are
unimaginably dense. Not even light can escape their gravity (Figure below)! This is why
they are black. We can't see black holes.
How can we know something exists if radiation can't escape it? A black hole affects the
objects around it. It affects them with its gravity. Some radiation may leak out around the
edges of a black hole. A black hole isn't a hole at all. It is the tremendously dense core
of a supermassive star.
Answer:
1. What are the characteristics of a neutron star?
High density, strong gravitational force and formed during the death of a massive star.
2. What are the characteristics of a black hole?
https://www.ck12.org/book/ck-12-middle-school-earth-science-concepts/section/23.8/
It has strong gravitational fields that not even light can escape from.
They are invisible because they don’t emit or reflect light.
They have different sizes.
3. How do scientists know that black holes exist?
By observing their gravitational effects on the surrounding matter and light.
4. Describe how a star forms a neutron star or a black hole and why it would form one or
the other.
When a massive star exhausts its nuclear fuel, it collapses under its own gravity,
potentially forming either a neutron star or a black hole, depending on the star's initial
mass and the density of the remnant core
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