ASTRO (Science) EXAM 5 FINAL EXAM
QUESTIONS CORRECTLY ANSWERED.
The total lifetime of the Sun is close to 10 billion years. Estimate the
lifetime of a star twice as massive as the Sun, and explain why it is likely
or unlikely for complex, multi-cellular life to be able to evolve on a planet
in the habitable zone around that star
A star that is twice as massive as the sun will have a lifetime that is about 2
billion years (1.7bil). Since Large stars live fast and die young, planets that
surround this star would not have a long enough to foster life before the
planet would explode and therefor complex organisms would not be able to
develop because the sun is so large and because it is far hotter and more
luminous and the habitable zone would be farther away from the sun. It also
took 4.5 billion years for life to develop on planet Earth, so it would not be
enough time.
- more mass -> more luminous
- L = M^4
lifetime of a star: M/L; M/M^4; 1/M^3
Our universe is approximately 13.7 _________ years old.
billion
One of the nearest stars is Alpha Centauri, whose distance is 4.4 light-
years. The time it takes light to travel from Alpha Centauri to us is
4.4 years
The time it takes light to cross Neptune's orbit is closest to which of the
following?
a night's sleep
Light-hour is a measure of __________
distance
,If an event were to take place on the Sun, how long would it take for the
light it generates to reach us?
8 minutes
If you were to specify your address in the universe, listing your
membership from the smallest to largest physical structures, it would be
Earth, Solar System, Milky Way, Local Group, Laniakea Supercluster, the
universe.
A scientific theory can be shown to be wrong if
scientists gather new data that contradict its predictions
a theory is
- a hypothesis that has withstood many attempts to falsify it
- tied to know physical laws
- able to make testable predictions
the cosmological principle states that
the universe looks the same everywhere as long as you look on large enough
scales
If you have a stuffy nose, a fever, chills, and body aches and a doctor
treats you for the flu rather than four separate diseases that account for
each of your symptoms, this is an application of
Occam's razor
one of the central assumptions in astronomy is that the physical laws of
nature
are the same everywhere in the universe
Because of _____________, we can conclude that gravity works the same
way on Earth as it does on Mars.
the cosmological principle
scientific notation is used in astronomy primarily because it allows us to
,write very large and very small number in a convenient way
the number 123,000 written in scientfic notation
1.23 x 10^5
Declination is a measure of a star's location relative to
celestial equator
Right ascension is a measure of a star's location on the celestial sphere
that is most closely similar to which measurement of location on Earth?
longitude
If the star Polaris has an altitude of 35°, then we know that
our latitude is +35°
The direction directly overhead of an observer defines his or her
zenith
The apparent path of the Sun across the celestial sphere over the course of
a year is called the
ecliptic
At a latitude of +50°, how far above the horizon is the north celestial pole
located?
50°
at what latitude is the north celestial pole at your horizon?
0°
The meridian is defined as an imaginary circle on the sky on which lie the
zenith and the north and south celestial poles
If you go out at exactly 9 P.M. each evening over the course of 1 month,
the position of a given star will move westward by tens of degrees. What
causes this motion?
, the revolution of Earth around the Sun
The ecliptic is defined by the motion of _________ in the sky.
the Sun
When the northern hemisphere experiences fall, the southern hemisphere
experiences
spring
If Earth's axis were tilted by 5° instead of its actual tilt, how would the
seasons be different than they are currently?
winters would be warmer
For a person who lives at a latitude of +40°, when is the Sun directly
overhead at noon?
never
Earth is closest to the Sun when the Northern Hemisphere experiences
winter
You and a friend go outside to view the stars at midnight tonight. Six
months later, you go outside to find the stars in exactly the same position
in the sky as when you and your friend viewed them. What time is it?
Assume you can see the stars at any time, day or night.
noon
Choose the latitude on Earth this star trail picture was most likely taken at:
+5 degrees (near the equator)
If it is wintertime right now and it is just after the winter solstice, how does
the height of the Sun at noon change over the next several months?
increases
How would the number of hours of sunlight and the height of the Sun in
the sky at noon change (if at all) over the course of the year for locations
on the equator?
QUESTIONS CORRECTLY ANSWERED.
The total lifetime of the Sun is close to 10 billion years. Estimate the
lifetime of a star twice as massive as the Sun, and explain why it is likely
or unlikely for complex, multi-cellular life to be able to evolve on a planet
in the habitable zone around that star
A star that is twice as massive as the sun will have a lifetime that is about 2
billion years (1.7bil). Since Large stars live fast and die young, planets that
surround this star would not have a long enough to foster life before the
planet would explode and therefor complex organisms would not be able to
develop because the sun is so large and because it is far hotter and more
luminous and the habitable zone would be farther away from the sun. It also
took 4.5 billion years for life to develop on planet Earth, so it would not be
enough time.
- more mass -> more luminous
- L = M^4
lifetime of a star: M/L; M/M^4; 1/M^3
Our universe is approximately 13.7 _________ years old.
billion
One of the nearest stars is Alpha Centauri, whose distance is 4.4 light-
years. The time it takes light to travel from Alpha Centauri to us is
4.4 years
The time it takes light to cross Neptune's orbit is closest to which of the
following?
a night's sleep
Light-hour is a measure of __________
distance
,If an event were to take place on the Sun, how long would it take for the
light it generates to reach us?
8 minutes
If you were to specify your address in the universe, listing your
membership from the smallest to largest physical structures, it would be
Earth, Solar System, Milky Way, Local Group, Laniakea Supercluster, the
universe.
A scientific theory can be shown to be wrong if
scientists gather new data that contradict its predictions
a theory is
- a hypothesis that has withstood many attempts to falsify it
- tied to know physical laws
- able to make testable predictions
the cosmological principle states that
the universe looks the same everywhere as long as you look on large enough
scales
If you have a stuffy nose, a fever, chills, and body aches and a doctor
treats you for the flu rather than four separate diseases that account for
each of your symptoms, this is an application of
Occam's razor
one of the central assumptions in astronomy is that the physical laws of
nature
are the same everywhere in the universe
Because of _____________, we can conclude that gravity works the same
way on Earth as it does on Mars.
the cosmological principle
scientific notation is used in astronomy primarily because it allows us to
,write very large and very small number in a convenient way
the number 123,000 written in scientfic notation
1.23 x 10^5
Declination is a measure of a star's location relative to
celestial equator
Right ascension is a measure of a star's location on the celestial sphere
that is most closely similar to which measurement of location on Earth?
longitude
If the star Polaris has an altitude of 35°, then we know that
our latitude is +35°
The direction directly overhead of an observer defines his or her
zenith
The apparent path of the Sun across the celestial sphere over the course of
a year is called the
ecliptic
At a latitude of +50°, how far above the horizon is the north celestial pole
located?
50°
at what latitude is the north celestial pole at your horizon?
0°
The meridian is defined as an imaginary circle on the sky on which lie the
zenith and the north and south celestial poles
If you go out at exactly 9 P.M. each evening over the course of 1 month,
the position of a given star will move westward by tens of degrees. What
causes this motion?
, the revolution of Earth around the Sun
The ecliptic is defined by the motion of _________ in the sky.
the Sun
When the northern hemisphere experiences fall, the southern hemisphere
experiences
spring
If Earth's axis were tilted by 5° instead of its actual tilt, how would the
seasons be different than they are currently?
winters would be warmer
For a person who lives at a latitude of +40°, when is the Sun directly
overhead at noon?
never
Earth is closest to the Sun when the Northern Hemisphere experiences
winter
You and a friend go outside to view the stars at midnight tonight. Six
months later, you go outside to find the stars in exactly the same position
in the sky as when you and your friend viewed them. What time is it?
Assume you can see the stars at any time, day or night.
noon
Choose the latitude on Earth this star trail picture was most likely taken at:
+5 degrees (near the equator)
If it is wintertime right now and it is just after the winter solstice, how does
the height of the Sun at noon change over the next several months?
increases
How would the number of hours of sunlight and the height of the Sun in
the sky at noon change (if at all) over the course of the year for locations
on the equator?
