Sun and Stars Test

The Sun is very hot plasma. Why doesn't the plasma just expand into space and the Sun fly apart?

the Sun has a lot of mass, so the gravity holds it together

The Sun has a lot of mass. Why doesn't it all collapse to a single point at the center?

the plasma of the Sun is hot and wants to expand, and this pressure balances gravity

The energy to heat the Sun comes from the core, where

small atoms are fused into larger ones in nuclear fusion

Fusion converts hydrogen in the core to helium. What happens to the helium generated in the core?

it stays in the core

What is the surface of the Sun like?

it’s not solid, it’s just where the plasma is thin enough that light can escape into space

The part of the star where the plasma keeps thinning above the photosphere

atmosphere

The interior part of a star where fusion doesn’t occur and where the composition stays the same since the star was formed

envelope

The overall electric charge of the Sun

neutral

The part of the star where energy is generated

core

The surface of a star, where the plasma is thin enough that light can escape freely into space

photosphere

The process where small nuclei are merged to form a heavier element, which can release energy

fusion

Sunspots are dark because they…

are cooler than surrounding material

If you see a sunspot, you know…

there must be a strong, tangled, magnetic field poking through the Sun's surface

The Sun sends a powerful CME toward the Earth. Which of these could be side-effects of the resulting geomagnetic storm?

more people would see aurora (northern and southern lights) at night, satellite orbits might degrade, some areas would lose power and some satellites might short circuit

When in the sunspot cycle do we have the best chance of seeing the aurora as far south as Toledo?

middle

On Earth we are used to solid land, liquid water, and gaseous atmosphere. We saw jovian planets had gas atmospheres and liquid interiors. The hydrogen and helium in the Sun exist in what state?

plasma, since they are so hot that their electrons are ripped off 

very high mass star

black hole

low mass star

white dwarf

high mass star

neutron star

A pulsar is a

neutron star that is spinning very quickly and emitting radiation

Neutron stars and black holes can have a few times the mass of the Sun and are about the size of

a city like Toledo 

Think about what kinds of stars create which stellar corpses and how common those stars are. If you look at a really old collection of stars, where there has been enough time for a star of any mass to die, what kind of corpse would you expect to see more of?

white dwarfs 

supergiant

high mass star

red giant

low mass star

What are stars mostly made of?

hydrogen and helium 

These extremely luminous stars are among the largest ever observed and represent the very short-lived old age phase of high mass stars.

supergiant

These luminous stars represent the short-lived old age phase of low mass stars. When our Sun hits this phase, it could become large enough to engulf the Earth.

red giant

These objects are too low mass to initiate stable hydrogen fusion and cool as they age

brown dwarf

This represent the longest phase of a star's life, when it is stable and burning hydrogen

main sequence

A high mass star has a lot more hydrogen as fuel than a low mass star; why does a high mass star have a much shorter lifespan?

a high mass star's core is hotter, so it goes through its fuel much faster than a low mass star 

Which generates more energy in old age, low or high mass stars?

high mass stars, fusion is running faster and there are more types of fusion 

In old age why can a more massive star fuse heavier elements (like carbon, oxygen, and silicon), while a low mass star might only be able to fuse hydrogen and helium?In old age why can a more massive star fuse heavier elements (like carbon, oxygen, and silicon), while a low mass star might only be able to fuse hydrogen and helium?

 it has more mass, which crushes the core to higher pressure and temperature 

Why do stars get larger in old age?  

different types of fusion generate more energy which makes the star expand 

What is a planetary nebula?

the gas cloud thrown off a low mass star when it dies

If I could change the mass of a star, which of these would also change?

temperature, color, lifetime, fusion reaction rate, and size

Consider a star with the same mass as the Sun. Why will the star be much larger in the red giant phase than during the main sequence phase?

 in the red giant phase fusion reactions are generating more energy than on the main sequence, which inflates the envelope more 

Why is the surface of a giant star redder than when it was a main sequence star?

the surface is farther from the core and is therefore cooler 

thing that would eventually ignite fusion and become our Sun

protostar

process by which planets move around in the disk

plantary migration

disk-shaped cloud from which our sun and the planets would eventually form

protoplanetary disk

original gas clump from which solar system formed

nebula

What happened to the molecules of the "ices" (water, methane, ammonia) present inside the frost line?

they existed as a gas

Jovian planets grew larger and faster than terrestrials because Jovians formed _____, where there were solid particles of ice, rock, and metal --- rather than just rock & metal

farther from the Sun than the frost line 

What event cleared out the gas from the protoplanetary disk?

the Sun became a star and its solar wind blew away the gas

what heats the sun?

light elements fusing into heavier elements

where does fusion occur in the sun?

only in the core

what are sunspots

patches of plasma on the sun that are cooler because strong magnentic fields are poking out

when is the sun most active in the sunspot cycle?

middle

the sun is a very hot plasma. why doesn’t the plasma just expand into space and the sun fly apart?

the sun’s strong magnetic fields trap the plasma and holds it together

why is the core of the sun so hot?

gravity pushes inwards and the pressure heats the core

what is the difference between solar flare and coronal mass ejection?

solar flare is when light is released and plasma stays on the sun and CME is when a plasma ball is thrown off the sun