1
Q
What is a NEBULA?
A
A large cloud of gas and dust in space where stars form
Nebulae are usually located in the spiral arms of a galaxy.
2
Q
What triggers star birth?
A
Density compressional waves that squeeze together gas and dust
This process occurs in nebulae.
3
Q
What is a PROTOSTAR?
A
A star that forms when temperatures reach about 15 million degrees, allowing nuclear fusion to begin
H = He + energy
This process involves hydrogen fusing into helium and energy.
4
Q
What defines a MAIN SEQUENCE STAR?
A
Stellar equilibrium between outward pressure from fusion and inward pressure from gravity
Stars spend the majority of their life as a main sequence star until equilibrium is disturbed.
Stars spend most of their life in this phase.
5
Q
What happens when hydrogen is depleted in a star’s core?
A
First, the core collapses, helium fuses into heavier elements such as carbon and oxygen,
Then the shell of hydrogen around the core ignites, and the outer layers expand, cool, and turn reddish in color. Finally, the star becomes a RED GIANT
Red giants are about 10 times larger in diameter than our sun.
6
Q
What are SUPERGIANTS?
A
Stars that develop several shells of fusion, forming heavier elements like iron
Similar to a red giant.
Can be several hundred times larger than the sun.
Supergiants can be several hundred times larger than our sun.
7
Q
What forms after a star’s outer layers lift off?
A
A PLANETARY NEBULA
A tiny white hot stellar core remains, known as a WHITE DWARF.
8
Q
What is a SUPERNOVA?
A
The explosion of a star when iron accumulates in the core to the point that equilibrium is disturbed. The core then collapses and the outer part explodes.
Can outshine an entire galaxy of stars.
This explosion can outshine an entire galaxy of stars.
9
Q
What is a NEUTRON STAR?
A
A star formed when protons and electrons pack together after a supernova.
They are incredibly dense. A sugar cube sized lump would weigh 100 million tons.
They are incredibly dense; a sugar-cube sized lump weighs 100 million tons.
10
Q
What are black holes?
A
Objects formed from the core collapse of very massive stars, with infinite density. An object so dense that nothing can escape its gravity, not even light.
Nothing can escape their gravity, not even light.
11
Q
Fill in the blank: A star’s core collapses and forms a _______ after a supernova.
A
NEUTRON STAR
This is the last resort to prevent collapse through neutron degeneracy pressure.
12
Q
What is the role of electron degeneracy pressure in a WHITE DWARF?
A
It prevents further collapse of the stellar core
This occurs after the outer layers have expanded away.
13
Q
What occurs during the stellar evolution process?
A
- Nebula forms
- Protostar develops
- Main sequence star stabilizes
- Red giant phase
- Supernova explosion
- Neutron star or black hole forms
This diagram illustrates the life cycle of stars.
14
Q
What is gravitational heating?
A
the process by which gravitational potential energy (potential energy due to gravity) is converted into thermal energy (heat) as gas and dust collapse inward to form or maintain a star.
15
Q
What are high mass stars?
A
Highest
temperature (surface temp. ~
35,000 degrees C) so they shine
blue/white in color, last 10-100
million years
16
Q
What are middle mass stars?
A
Mid temp
(surface temp. ~ 6000 degrees C),
shine yellow/white, last about
10 billion years (our sun)
17
Q
What are low mass stars?
A
Lowest temp.
(surface temp. ~ 3500C),
shine red, last ~100 billion to
trillions of years (longest!)
18
Q
How many times larger, in diameter, is a red giant than the sun?
A
10 times
19
Q
What is a white dwarf?
A
A small, hot stellar core remaining after a star has exhausted its nuclear fuel.
20
Q
A
21
Q
What is the nearest star to Earth?
A
the sun
The sun is a giant ball of gas.
22
Q
What is the diameter of the sun?
A
864,950 miles
The sun has a mass of about 1.99 million, trillion, trillion tons.
23
Q
What percentage of the solar system’s mass does the sun account for?
A
99.9%
The sun’s gravity keeps the planets in orbit.
24
Q
What are the two main components of the sun?
A
- 73% hydrogen
- 25% helium
These components make up the sun’s composition.
25
What are **sunspots**?
Dark spots on the surface of the sun
| Sunspots effect the climate on earth.
## Footnote
They are cooler areas with strong magnetism and change in 11-year cycles.
26
What are **prominences**?
Huge arches of glowing gases above sunspots
## Footnote
They are a feature of the sun.
27
What are **solar flares**?
Sudden eruptions in the sunpsot regions releasing energy and plasma, where the hydrogen gas explodes out into space
## Footnote
They result in a solar wind with charged particles reaching Earth.
28
Where does **nuclear fusion** occur in the sun?
the core
## Footnote
The core is the hottest part of the sun, reaching about 15 million degrees Celsius.
29
What is the temperature of the **core** of the sun?
about 15 million degrees Celsius
## Footnote
This extreme temperature allows hydrogen atoms to fuse into helium.
30
How long will the **hydrogen fuel** in the sun's core last?
10 billion years
## Footnote
The sun is currently about 5 billion years old.
31
What is the temperature range of the **radiation zone**?
about 2 million degrees Celsius
## Footnote
Energy is transferred from atom to atom in waves in this zone.
32
What is the temperature range of the **convection zone**?
roughly 1 million degrees Celsius
## Footnote
Energy is transferred through convection currents in this zone, as warm gases rise, and cooler gases sink.
33
What is the **photosphere**?
The surface of the sun
| Photo means light, so it is where light is made.
## Footnote
It is where light is made and has a temperature of 5000-6000 degrees Celsius.
34
What does **chromosphere** mean?
colored sphere
| Chromo means color
## Footnote
It is the inner layer of the sun’s atmosphere, visible during an eclipse.
35
What is the temperature range of the **chromosphere**?
10,000 - 30,000 degrees Celsius
## Footnote
This layer appears pinkish during an eclipse.
36
What does **corona** mean?
crown
| Appears as a white halo around the sun.
## Footnote
The corona is the outer layer of the sun’s atmosphere, visible during a solar eclipse.
37
What is the temperature of the **corona**?
1,500,000 degrees Celsius
38
What process allows hydrogen atoms to fuse and form helium?
Nuclear fusion occurs when extreme temperatures and velocities enable hydrogen atoms to combine into helium, releasing vast amounts of energy in the form of light and heat.
## Footnote
The mass of the resulting helium atom is less than the combined mass of the two hydrogen atoms, leading to the conversion of the missing mass into energy (E = mc²).
39
What model of the Universe did the **ancient Greeks**, including Aristotle, develop around 350 B.C.?
**Geocentric**
## Footnote
This model placed the Earth at the center of the Universe, orbited by the sun, moon, and planets.
40
In what year did **Copernicus** publish the **heliocentric** theory?
1514
| helio means sun
## Footnote
The heliocentric theory declared that the Earth revolves around the sun.
41
Who used a telescope in 1609 to provide evidence supporting the **heliocentric** view?
Galileo
## Footnote
His observations helped validate Copernicus's theory.
42
What is the **imaginary line** that passes through Earth’s center and poles called?
**Axis**
## Footnote
Earth's rotation occurs around this axis.
43
What is the term for Earth's spinning on its axis?
**Rotation**
## Footnote
This causes day and night.
44
How long does it take Earth to complete one **rotation** on its axis?
About **24 hours**
## Footnote
This duration defines a full day.
45
What is the movement of one object around another called?
**Revolution**
## Footnote
Earth's revolution around the sun takes approximately 365 ¼ days.
46
What phenomenon occurs every 4th year due to Earth's **revolution**?
**Leap year**
## Footnote
An extra day is added to February.
47
What angle is Earth tilted at as it moves around the sun?
**23.5 degrees**
## Footnote
This tilt is responsible for the changing seasons.
48
What occurs when Earth's tilt is neither towards nor away from the sun?
**Equinoxes**
| Equi means equal, nox means night
## Footnote
This results in equal day and night.
49
What are the two types of tides caused by the gravitational pulls of the sun and moon?
* High tide- when ocean levels rise
* Low tide- when ocean levels drop
## Footnote
There are typically 2 high and 2 low tides each day.
50
What is a **Spring Tide**?
Much higher tide due to the moon and sun pulling together
## Footnote
Occurs during full and new moons.
51
What is a **Neap Tide**?
Not as high tide when the moon and sun are at right angles
## Footnote
Occurs during the 1st and 3rd quarter moons.
52
What is the **sidereal period** of the Moon?
27.322 days
## Footnote
This is the time the Moon takes to complete one full revolution around the Earth.
53
What is the **synodic period** of the Moon?
29.531 days
## Footnote
This is the time required for the Moon to return to the same position relative to the Sun.
54
What phase of the moon occurs during a **solar eclipse**?
**New moon**
## Footnote
The moon passes between the sun and the Earth.
55
What is the area of total shadow during a lunar eclipse called?
**Umbra**
## Footnote
The penumbra is the area of partial shadow.
56
What phase of the moon occurs during a **lunar eclipse**?
**Full moon**
## Footnote
The Earth passes between the moon and the sun.
57
True or false: **Solar eclipses** occur more frequently than lunar eclipses.
TRUE
## Footnote
Solar eclipses usually occur about 2-5 times per year.
58
What causes the **rise and fall** in sea level known as tides?
Gravitational pulls of the **sun** and **moon**
## Footnote
The moon has a greater influence on tides.
59
What is the term for the **period** when the moon is illuminated and increasing in size?
**Waxing**
## Footnote
This includes phases like waxing crescent and waxing gibbous.
60
What is the term for the **period** when the moon is illuminated and decreasing in size?
**Waning**
## Footnote
This includes phases like waning crescent and waning gibbous.
61
What season is it if the earth is tilted toward the sun?
Summer
62
What season is it if the earth is tilted away from the sun?
winter
63
Why don’t we see a solar and lunar eclipse each month when the sun-earth-moon are properly aligned?
The moon’s orbit is inclined 5° to the Earth’s. In order for an eclipse to occur the Earth, Sun, and moon must line up on the same plane, with the moon passing through the ecliptic.
64
What time does a full moon rise and set?
rise: 6pm
set: 6am
65
What time does a waning gibbous moon rise and set?
rise: 9pm
set: 9am
66
What time does a 3rd quarter moon rise and set?
rise: midnight
set: noon
67
What time does a waning crescent moon rise and set?
rise: 3 am
set: 3 pm
68
What time does a new moon rise and set?
rise: 6 am
set: 6 pm
69
What time does a waxing crescent moon rise and set?
rise: 9 am
set: 9 pm
70
What time does a 1st quarter moon rise and set?
rise: noon
set: midnight
71
What is the **angular size** of an object?
The angle it makes from the viewer’s location
## Footnote
Measured in degrees (°), arcminutes (‘), and arcseconds (‘’).
72
What is **stellar parallax**?
The apparent shift in position of distant stars due to Earth's orbit
Measured 6 months apart, so that the earth is on the opposite side of the sun.
## Footnote
Used to measure distances to stars.
73
Who proposed that the **Earth orbited the sun** in the 16th century?
Nicolaus Copernicus
## Footnote
His theory was not measurable at the time due to technology limitations.
74
What was the first trigonometric stellar parallax measured by Wilhelm Bessel?
61Cygni with a parallax of 0.29 seconds of arc
## Footnote
This measurement was announced in 1838.
75
What is the parallax of **Alpha Centauri**?
0.76 arc seconds
## Footnote
It is the star nearest to Earth.
76
What is the **radius of Earth’s orbit** around the sun?
1.496 x 10^8 km
| This is 1 AU
## Footnote
This value is used for distance calculations.
77
What is the conversion factor for **1 light year (LY)** in kilometers?
9.48 x 10^12 km
## Footnote
This is essential for converting distances from km to light years.
78
How many arcseconds are in an arcminute?
60
79
How many arcminutes are in a degree?
60
80
Who was **Tycho Brahe**?
Danish nobleman and astronomer (1546-1601)
## Footnote
Had an observatory funded by the King of Denmark and built many new instruments.
81
What did **Johannes Kepler** use Tycho Brahe's data to determine?
* Mars has an elliptical orbit
* Develop his three laws of planetary motion
* Create detailed charts for calculating planetary positions
## Footnote
Kepler was Brahe’s assistant in Prague (1571-1630).
82
What is **Kepler’s 1st Law**?
The orbit of each planet is an ellipse with the Sun at one focus
## Footnote
This law defines the shape of planetary orbits.
83
What does **Kepler’s 2nd Law** state?
As a planet moves around its orbit, it sweeps out equal areas in equal times
## Footnote
This law describes the speed of a planet in its orbit.
84
What is the formula for **Kepler’s 3rd Law**?
T² = R³
| T is the orbital period in years, and R is the average distance from the
## Footnote
This implies that the more distant planet moves at slower speeds.
85
What is the orbital period (T) for Earth, which is 1 astronomical unit (AU) from the Sun?
1 year
## Footnote
This is a direct application of Kepler's 3rd Law.
86
Calculate T for **Mercury** with R = 0.387 AU.
T = 88 days
## Footnote
This calculation uses Kepler's 3rd Law.
87
Calculate T for **Neptune** with R = 30 AU.
T = 164.3 years
## Footnote
This calculation uses Kepler's 3rd Law.
88
Who was **Isaac Newton**?
British scientist (1642-1727)
## Footnote
Changed our understanding of motion and gravity and invented calculus.
89
What is the **Universal Law of Gravitation**?
* Every mass attracts every other mass through gravity
* Attraction is proportional to the product of their masses
* Attraction decreases with the square of the distance
## Footnote
This law explains the force of gravity between two objects.
90
What does Newton’s form of **Kepler’s 3rd Law** help to solve for?
The mass of a large body with an object orbiting it
## Footnote
It involves the mass of the body, orbital radius, and orbital time.
91
What is the **Gravitational constant (G)**?
6.67 x 10⁻¹¹ Nm²/kg²
## Footnote
This constant is used in the Universal Law of Gravitation.
92
What is the **largest body** in our solar system?
The Sun
## Footnote
It contains approximately 99% of the total solar system mass.
93
What is the **density** of the Sun's core compared to water?
150 times that of water
## Footnote
This high density is due to the extreme pressure and temperature.
94
What is the **visible surface** of the Sun called?
Photosphere
## Footnote
Light from the Sun is free to radiate into space from this layer.
95
What occurs in the **chromosphere** of the Sun?
Large solar flares
## Footnote
These flares are sudden outbursts of energy caused by magnetic field activity.
96
What is the **corona** of the Sun?
A very thin and hot layer
## Footnote
It is only visible during a total solar eclipse.
97
What are **sunspots**?
Dark, planet-sized regions on the Sun
## Footnote
They are cooler than the surrounding surface and can impact Earth's climate.
98
What do **solar winds** consist of?
* Subatomic particles of hydrogen
* Protons
* Electrons
## Footnote
These particles stream outward at high speeds and interact with Earth's magnetic field.
99
How many **terrestrial worlds** are there?
Five
## Footnote
The terrestrial worlds include Mercury, Venus, Earth, the Moon, and Mars.
100
What is the **radius** of Mercury?
2,439 km
## Footnote
Mercury is 0.39 AU from the Sun.
101
What is the **atmosphere** of Venus primarily composed of?
Carbon dioxide
## Footnote
This creates a pressure 90 times greater than that on Earth.
102
What is the **average temperature** on Mars?
-55 °C
## Footnote
Surface temperatures can vary significantly on Mars.
103
What is the **orbit distance** of the Moon from Earth?
384,400 km
## Footnote
The Moon is the second brightest object in our sky.
104
What type of eclipse occurs when the Moon passes between the Earth and the Sun?
Solar eclipse
## Footnote
This can only happen during the New Moon phase.
105
What is the **radius** of Jupiter?
71,492 km
## Footnote
Jupiter is 5.20 AU from the Sun.
106
What is the **average density** of Saturn compared to water?
Less than that of tap water
## Footnote
Saturn has numerous rings made of ice particles.
107
What gives Uranus its **blue color**?
Condensed methane gas
## Footnote
This is due to the colder temperatures in its atmosphere.
108
What are **comets** primarily composed of?
* Ice
* Dust
## Footnote
They develop tails when entering the inner solar system.
109
What are the two main regions where comets orbit the Sun?
* Kuiper Belt
* Oort Cloud
## Footnote
The Kuiper Belt extends about 100 AU into space.
110
What is the asteroid belt?
Asteroids are chunks of rock and metal orbiting the Sun (mostly between Mars and Jupiter). These are likely rocks and debris that never formed into planets. Asteroids are also known as minor planets and range in size from Ceres, about 1000 km in diameter, down to pebbles. Much of what we know about asteroids comes from studying meteorites.
111
What are the Jovian worlds (planets)?
Jupiter, Saturn, Uranus and Neptune- the 4 furthest planets from the sun
| Jovian means Jupiter, so it is the planets like Jupiter that are further
112
What is Jupiter made of?
Core made of hydrogen compounds, rocks, and minerals that are mixed together under incredibly high temperature and pressure.
Atmosphere is made of hydrogen (75%) and helium (24%) gas.
113
What creates the banding patterns and the Great Red Spot on Jupiter?
Jupiter has circulation cells that create banding patterns and a continual high-pressure storm known as the Great Red Spot.
## Footnote
The Great Red Spot is a massive storm that has been ongoing for at least 350 years.
114
What is the atmosphere of Saturn like?
Saturn has an atmosphere similar to Jupiter's, characterized by stronger winds and a banding pattern created by circulation cells.
## Footnote
Saturn is also known for its numerous rings, up to 100,000, made primarily of ice particles.
115
What is the color of Uranus and why?
Uranus appears blue due to condensed methane gas in its atmosphere, which absorbs red light.
## Footnote
The planet's unique tilt may have resulted from a collision with another planet-sized body early in the solar system's history.
116
What is the atmosphere of **Neptune**?
Similar to **Uranus**, with a small core and an atmosphere of hydrogen, helium, and **methane**, which gives it a blue color. Neptune has massive wind storms, with winds reaching up to 2000 km/h.
117
What are the two main regions where comets orbit the Sun?
The two main regions where comets orbit the Sun are the Kuiper Belt and the Oort Cloud.
## Footnote
The Kuiper Belt extends about 100 AU from the Sun, while the Oort Cloud is a spherical region that may extend halfway to the nearest stars.
118
What does the **HR diagram** show?
Relationships and differences between stars
## Footnote
It displays stars of different ages and stages simultaneously.
119
What two characteristics of stars are indicated by the **position of each dot** on the HR diagram?
* Luminosity
* Temperature
## Footnote
Each star is represented by a dot on the diagram.
120
On the HR diagram, the star’s **luminosity** is plotted on which axis?
y-axis
## Footnote
Luminosity indicates the amount of energy a star radiates.
121
What does a **luminosity** of 1 indicate?
As bright as the sun
## Footnote
Luminosity values can be compared to the sun as a reference.
122
What does a **luminosity** of 0.1 indicate?
1/10th as bright as the sun
## Footnote
This shows how the brightness of a star compares to the sun.
123
How is the **temperature** of a star’s surface plotted on the HR diagram?
x-axis
## Footnote
Temperature can be labeled in Kelvin or degrees Celsius.
124
In the HR diagram, where are the **hotter temperatures** located?
On the left
## Footnote
Cooler temperatures are on the right.
125
What does a star in the **upper left corner** of the HR diagram indicate?
Hot and bright
## Footnote
This position reflects high temperature and luminosity.
126
What does a star in the **upper right corner** of the HR diagram indicate?
Cool and bright
## Footnote
This position shows a star that is cooler but still luminous.
127
Where does the **Sun** rest on the HR diagram?
Approximately in the middle
## Footnote
The Sun is used as a comparison point for other stars.
128
What does a star in the **lower left corner** of the HR diagram indicate?
Hot and dim
## Footnote
This position reflects high temperature but low luminosity.
129
What does a star in the **lower right corner** of the HR diagram indicate?
Cool and dim
## Footnote
This position shows a star that is both cooler and less luminous.
130
131
Who was **Hipparchus** and what is he known for?
Greek astronomer known for compiling the first comprehensive star catalog
## Footnote
He classified over 1000 stars into six magnitude classes according to their brightness.
132
What is the **apparent magnitude** of a star?
The brightness we perceive on Earth
## Footnote
Hipparchus measured the apparent magnitude of stars.
133
What does a **1st magnitude star** signify in terms of brightness compared to a **6th magnitude star**?
1st magnitude stars are 100 times brighter than 6th magnitude stars
## Footnote
Each increase in magnitude corresponds to a decrease of 2.512 in brightness.
134
What is the **absolute magnitude** (M) of a star?
The apparent magnitude (m) of a star if it were located at 10 parsecs from Earth.
| Absolute magnitude is about measuring each star from the same distance.
## Footnote
Absolute magnitude is used to determine if a star is intrinsically bright.
135
What is the absolute magnitude of the **Sun**?
4.77
## Footnote
This value helps in comparing the intrinsic brightness of stars.
136
True or false: A low apparent magnitude star always implies it is intrinsically bright.
FALSE
## Footnote
A star could be low in apparent magnitude simply because it is located far from Earth.
137
What is the apparent magnitude of **Deneb** and its absolute magnitude?
Apparent magnitude: 1.25; Absolute magnitude: -7
## Footnote
Deneb is 60,000 times brighter than the Sun and located about 1400 light years away.
138
What is the brightest star's magnitude value?
Negative magnitudes
## Footnote
For example, the Sun has a magnitude of -26.5.
139
What is the faintest star visible from Earth with telescopes?
Approximately 25
## Footnote
This indicates the limit of visibility for faint stars.
Honors Physical Science
flashcards
Decks in class (1)
# Cards
