ASTRONOMY 101 FINAL EXAM

At approx. what time would a full moon be on your meridian?

A) 6 P.M.

B) noon

C) 6 A.M.

D) Midnight

E) 9 A.M.

Midnight

In the Northern Hemisphere, the day that the Sun is up the longest in the sky is on the June solstice

A) true

B) false

True

Copernicus was the first person to suggest a Sun-centered solar system.

A) true

B) false

False

Why is it summer in the Northern Hemisphere is closer to the Sun than the Souther Hemisphere?

A) the northern hemisphere is tilted away from the sun and receives more indirect sunlight

B) due to earth's tilt, the northern hemisphere is closer to the sun than the Southern Hemisphere

C) the northern hemisphere is tilted toward the sun and receives more direct sunlight

D) it isn't; both hemispheres have the same seasons at the same time. summer comes where earth is nearest the sun

the northern hemisphere is tilted toward the sun and receives more direct sunlight

During the period each year when we see Mars undergoing apparent retrograde motion in our sky, what is really going on in space?

A) mars is moving around the sun in the opposite direction from which earth is moving around the sun

B) earth and mars are getting getting closer

C) earth is catching up with and passing by mars in their respective orbits

D) earth and mars are on opposite sides of the sun

earth is catching up with and passing by mars in their respective orbits

From Kepler's Second Law: Planetary orbits, when drawn with a line connecting the planet to the sun, show that this line sweeps out equal areas in equal times, no matter where the planet is in its orbit, we may conclude that...

A) planets move slower when they are closer to the sun

B) planets have circular orbits

C) planets have elliptical orbits

D) planets move faster when they are closer to the sun

planets move faster when they are closer to the sun

Which of the following statements about lunar phases is true?

A) the time between new moons is two weeks

B) only one quarter of the first-quarter moon is illuminated by the Sun

C) the full moon sometimes rises around midnight

D) it is possible to have two full moons during January, but not during February

E) it is possible to have two full moons during November, but not December

it is possible to have two full moons during January, but not during February

By locating the north celestial pole in the sky, how can you determine your latitude?

A) the altitude of the NCP is the same as your distance from the North Pole

B) the direction of the NCP is the angular distance from the North Pole

C) the altitude of the NCP is the same as your latitude

D) the direction of the NCP is the same as your latitude

E) the altitude of the NCP is your angular distance from the North Pole

the altitude of the NCP is the same as your latitude

If the moon is setting at 6 A.M., the phase of the Moon must be

A) third quarter

B) waning crescent

C) new

D) first

E) full

full

One light-year is the distance light travels in one year. The speed of light is about 300,000 km/s (3x10^5 km/s). How far is 1 light-year?

A) 1.8x10^7 km

B) 9.46x10^12 km

C) 3x10^5 km

D) 1.08x10^9

9.46x10^12 km

The universe is defined as

A) all material, space, and energy that exist: everything

B) all the objects we can see and the space between

C) all the stars and galaxies that we can see with telescopes

D) the entire milky way galaxy

all material, space, and energy that exist: everything

The moon rises in the east and sets in the west

A) earth rotates once each day

B) earth revolves around the sun each year

C) the direction of earth's axis in space precesses with a period of 26,000 years

D) the universe is expanding

earth rotates once each day

Planets show retrograde motion

A) earth rotates once each day

B) earth revolves around the sun each year

C) the direction of earth's axis in space precesses with a period of 26,000 years

D) the universe is expanding

earth revolves around the sun each year

In the year A.D. 15,000, Vega will be a better "North Star" than Polaris

A) earth rotates once each day

B) earth revolves around the sun each year

C) the direction of earth's axis in space precesses with a period of 26,000 years

D) the universe is expanding

the direction of earth's axis in space precesses with a period of 26,000 years

The stars of Orion's Belt rise in the east and set in the west

A) earth rotates once each day

B) earth revolves around the sun each year

C) the direction of earth's axis in space precesses with a period of 26,000 years

D) the universe is expanding

earth rotates once each day

The Greeks rejected the notion that the Earth orbits the Sun. Why?

A) they were not as smart as we are

B) they could not measure how big the earth was

C) they could not measure a change in stars' positions on the sky

D) they believed that the sun is a God

they could not measure a change in stars' positions on the sky

The number of official constellations is

A) 88

B) 123

C) 205

D) 56

88

The stars are present in the local sky during the daytime. We just can't see them.

A) true

B) false

true

The great contribution of Tycho Brahe was to

A) offer the first detailed model of a sun-centered solar system, thereby beginning the process of overturning the earth-centered model of the Greeks

B) observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion

C) discovered that planets orbit the sun in elliptical orbits with varying speed

D) discover four moons orbiting Jupiter, thereby lending strong support to the idea that the earth is not the center of the universe

observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion

Which of the following is NOT one of, nor a direct consequence of, Kepler's Laws?

A) more distant planets orbit the sun at slower speeds

B) as a planet moves around its orbit, it sweeps out equal areas in equal times

C) the orbit of each planet about the sun is an ellipse with the sun at one focus

D) the force of attraction between any two objects decreases with the square of the distance between their centers

the force of attraction between any two objects decreases with the square of the distance between their centers

If you lived on the Moon, you'd see full Earth when we see new moon.

A) true

B) false

true

Scientific thinking is _________

A) a difficult process that only a handful of people can do well

B) completely different from any other type of thinking

C) an ancient mode go thinking first invented in Egypt

D) based on everyday ideas of observation and trial-and-error experiments

based on everyday ideas of observation and trial-and-error experiments

Scientific theories can never be proved true beyond all doubt

A) true

B) false

true

You are standing on Earth's equator. Which way is Polaris, the North Star?

A) 30 degrees up, due west

B) on the northern horizon

C) directly overhead

D) the answer depends on whether it's winter or summer

E) the answer depends on what time of day (or night) it is

on the northern horizon

Why were ancient peoples unable to detect stellar parallax?

A) they did not observe for long enough periods of time

B) they did detect it, but they rejected the observations

C) they did not look for it

D) they could not see distant stars

E) they did not have the ability to measure very small angles

they did not have the ability to measure very small angles

What is a circumpolar star?

A) a star that is visible from the arctic or antarctic circles

B) a star that is close to the north celestial pole

C) a star that always remains above your horizon

D) a star that is close to the south celestial pole

E) a star that makes a daily circle around the celestial sphere

a star that always remains above your horizon

The ancient Greeks get a lot of attention for their contributions to science because _________.

A) the books of every other culture were lost in the destruction of the library of Alexandria

B) they were the first people to realize that earth is a planet orbiting the sun

C) they were the only ancient culture that kept written records of their astronomical observations

D) they were the first people known to try to explain nature with models based on reason and mathematics, without resort to the supernatural

they were the first people known to try to explain nature with models based on reason and mathematics, without resort to the supernatural

The stars stay in "fixed" positions on the celestial sphere because

A) they are all expanding away, so they have no transverse (sideways) motions

B) the stars on the sphere are all chosen to be approx. the same distance from earth

C) while they actually move through space, they are too far away for their motion to be seen

D) the sphere to which they are attached moves with them through space

while they actually move through space, they are too far away for their motion to be seen

The Ptolemaic model of the solar system was useless for predicting planetary positions

A) true

B) false

false

What conditions are required for a lunar eclipse?

A) the phase of the moon can be new or full, and the nodes of the moon's orbit must be nearly aligned with earth and the sun

B) the phase of the moon must be full, and the nodes of the moon's orbit must be nearly aligned with earth and the sun

C) the phase of the moon must be new, and the moon's orbital plane must lie in the ecliptic

D) the phase of the moon must be new, and the nodes of the moon's orbit must be nearly aligned with earth and the sun

the phase of the moon must be full, and the nodes of the moon's orbit must be nearly aligned with earth and the sun

Tycho failed to understand planetary motion because his data, taken before there were any telescopes, was simply too inaccurate

A) true

B) false

false

What conditions are required for a solar eclipse?

A) the phase of the moon must be full, and the nodes of the moon's orbit must be nearly aligned with earth and the sun

B) the phase of the moon must be new, and the moon's orbital plane must lie in the ecliptic

C) the phase of the moon can be new or full, and the nodes of the moon's orbit must be nearly aligned with the earth and the sun

D) the phase of the moon must be full, and the moon's orbital plane must like in the ecliptic

E) the phase of the moon must be new, and the nodes of the moon's orbit must be nearly aligned with earth and the sun

the phase of the moon must be new, and the nodes of the moon's orbit must be nearly aligned with earth and the sun

Sunlight takes 8.4 minutes to get from the Sun to Earth. When NASA's New Horizons Spacecraft passed Pluto in 2016, it was 33 AU from Earth. How long did it take for its transmitted images of Pluto to arrive at Earth?

A) 277.3 hours

B) 4.6 hours

C) one plutonian year

D) they arrived almost instantaneously. the transmitted signals were radio signals and therefore traveled at the speed of light

4.6 hours

Earth spins once on its axis in 23 hours and 56 minutes, not 24 hours

A) true

B) false

true

Why do the patterns of the stars in our sky look the same from year to year?

A) because the stars in constellations move so slowly- typically about the speed of a snail- that their motions are not noticeable

B) because the stars in the constellations all move at the same speeds and in the same directions, so they don't change their relative positions

C) because the stars in the constellations are so far away

D) because the star in the constellations are not moving

because the stars in the constellations are so far away

The Polynesian navigators of the South Pacific found their way primarily by observing the position of Polaris in the night sky

A) true

B) false

false

Which of the following has your "cosmic address" in the correct order?

A) you, earth, solar system, local group, Milky Way galaxy, local supercluster

B) you, earth, solar system, Milky Way galaxy, local group, local supercluster

C) you, earth, solar system, local group, local supercluster, Milky Way galaxy

you, earth, solar system, Milky Way galaxy, local group, local supercluster

If Earth's rotation axis was tilted by 45 degrees instead of 23.5 degrees, what are some of the implications, and why?

A) the seasons would be less extreme, because of the sun's rays would be less direct in summer, and more direct in winter

B) the seasons would be less extreme, because the surface of the earth would be farther from the Sun in the summer, and closer to the sun in the winter

C) the season would be more extreme, because the sun's rays would be more direct in summer and less direct in winter

D) the seasons would be more extreme, because the surface of the earth would be closer to the sun in the summer, and farther from the sun in the winter

the season would be more extreme, because the sun's rays would be more direct in summer and less direct in winter

A scientific model must take observational predictions

A) true

B) false

true

Today the sun is in the middle of the constellation Virgo. Therefore, tomorrow the Sun will be in the constellation

A) leo

B) sagittarius

C) libra

D) virgo

Virgo

Consider the elliptical orbit of a comet around the Sun. Where in its orbit is the comet moving the fastest?

A) it is always moving at the same speed

B) when it is closest to the sun

C) when it is farthest from the sun

when it is closest to the sun

How many arc seconds are in one degree?

A) 100

B) 60

C) 3,600

D) 10,000

E) 360

3,600

Which of the following statements about stellar parallax is true?

A) the amount of parallax we see depends on how fast a star is moving relative to us

B) stellar parallax was first observed by ancient Greek astronomers

C) the closer a star is to us, the more parallax it exhibits

D) we observe all stars to exit at least a slight amount of parallax

E) it takes at least 10 years of observation to measure a stars parallax

the closer a star is to us, the more parallax it exhibits

Which of the follow statements about the celestial equator is true at all latitudes?

A) it extends from your horizon due east, through your zenith, to your horizon due west

B) it extends from your horizon due north, through your zenith, to your horizon due south

C) it cuts the dome of your local sky exactly in half

D) it lies along the band of light we call the milky way

E) it represents an extension of earth's equator onto the celestial sphere

it represents an extension of earth's equator onto the celestial sphere

What is represented by the figure-eight analemma?

A) a composite snapshot of the sun taken from the same location at the same time of day over one year

B) an eight-fold intermediate analytical theorem (lemma) pertaining to all astronomical motions

C) the time-lapse photograph of a planet (e.g. mars) as it undergoes retrograde motion

D) a positional map of earth's wandering north celestial pole projected into the sky over the course of the next 10,000 years

a composite snapshot of the sun taken from the same location at the same time of day over one year

If the Moon is 3rd quarter phase, what shape does it have in the sky?

A) a quarter circle

B) a full circle

C) a half circle

D) nothing (it is impossible to view a 3rd quarter moon)

a half circle

Which of the following best describes the Milky Way Galaxy?

A) a spherically shaped collection of stars, including our solar system and about a dozen other solar systems, stretching about 4 light-years in diameter

B) a disk-shaped galaxy about 100,000 light-yers in diameter and containing between 100 million and 1 billion stars

C) a spherically shaped collection of about 1 million stars that is about 100 light-years in diameter

D) a disk-shaped galaxy about 50,000 light-years in diameter and containing between 100 million and 1 billion stars

E) a disk-shaped galaxy about 50,000 light-years in radius and containing between 100 billion and 1 trillion stars

a disk-shaped galaxy about 50,000 light-years in radius and containing between 100 billion and 1 trillion stars

Scientific thinking developed only in the past few decades

A) true

B) false

false

The moon and the sun are approx. the same angular size

A) true

B) false

true

When the Sun sets exactly in the West, it is at an azimuth of 90 degrees

A) true

B) false

false

Local sky

A) zenith

B) north celestial pole

C) south celestial pole

D) horizon

E) meridian

Superior Planets Elongation Configurations

A) quadrature (eastern or western)

B) opposition

C) conjunction

Suppose an object is moving in a straight line at 70 km/h. According to Newton's first law of motion, the object will

A) continue to move in the same way until it is acted upon by a force

B) continue to move in the same forever, no matter what happens

C) eventually slow down and come to a stop

D) continue to move in a straight line forever if it is in space, but fall to the ground if it is on earth

continue to move in the same way until it is acted upon by a force

Earth's tidal forces acting on the Moon have caused one side of the Moon to be constantly facing Earth

A) true

B) false

true

What percentage of the solar nebula's mass consisted of hydrogen and helium gases?

A) 50%

B) 100%

C) 0.5%

D) 5%

E) 98%

98%

What is the difference between a bound orbit and an unbound orbit around the Sun?

A) an object on a bound orbit follows the same path around the sun over and over, while an object on an unbound orbit approaches the sun just once and then never returns

B) a bound orbit is circular, while an unbound orbit is elliptical

C) an object on a bound orbit has a gravitational attraction to the sun, while an object on a unbound orbit does not

D) a bound orbit is an orbit allowed by the universal law of gravitation, and an unbound orbit is not

an object on a bound orbit follows the same path around the sun over and over, while an object on an unbound orbit approaches the sun just once and then never returns

When is energy converted form one form to another, a tiny amount is inevitably lost

A) true

B) false

false

Grass is green because it absorbs green light, reflecting all other colors

A) true

B) false

false

Which Jovian planet does not have rings?

A) mars

B) jupiter

C) neptune

D) uranus

E) all the Jovian planets have rings

all the Jovian planets have rings

Any object moving towards or away from the Earth will show a Doppler shift in its emitted or reflected light when observed from Earth

A) true

B) false

true

According to the universal law of gravitation, F=G(M1M2/d2), if you double the masses of both attracting objects, then the gravitational force between them will

A) increase by a factor of 2

B) not change at all

C) decrease by a factor of 2

D) increase by a factor of 4

E) decrease by a factor of 4

increase by a factor of 4

The force due to gravity between two objects can be described using the equation Fg=G(M1M2)/d2. In this equation what does d represent?

A) the distance between the two objects

B) the density of the smaller object

C) the universal gravitational constant

the distance between the two objects

In the formula E=mc^2, what does E represent?

A) the radiative energy carried by light

B) the gravitational potential energy

C) the mass-energy, or potential energy stored in an object's mass

D) the kinetic energy, also kabob as Einsteinium

E) the electric field produced by a charge

the mass-energy, or potential energy stored in an object's mss

Where does the energy come from that your body uses to keep you alive?

A) it is produced form the radiative energy of the Sun on your skin

B) it comes from the water you drink

C) it is in the air that you breathe

D) it comes from the foods you eat

E) it is created during the time that you rest or sleep

it comes from the foods you eat

If a spinning star suddenly gets bigger in diameter, what happens to its rotation rate?

A) increases

B) unaffected

C) decreases

decreases

At which lunar phase(s) are tides least pronounced (e.g., the lowest high tides)?

A) first quarter

B) full moon

C) new moon

D) both new and full moons

E) both first and third quarters

both first and third quarters

According to our theory of solar system formation, why do we find some exceptions to the general rules and patterns of the planets?

A) our theory is not quite correct because it cannot explain these exceptions

B) most of the exceptions are the result of giant impacts or close gravitational encounters

C) the exceptions probably represent objects that were captured by our solar system from interstellar space

D) the exceptions probably represent objects that formed recently, rather than early in the history of the solar system

E) the exceptions are probably the result of the Sun passing very close to another star billions of years ago

most of the exceptions are the result of giant impacts or close gravitational encounters

The age of the solar system can be established by radiometric dating of:

A) the oldest rocks on the Moon

B) the atmosphere of Mars

C) the oldest rocks on Earth

D) the oldest meteorites

E) it hasn't been done yet, but the age of the solar system could be obtained from a sample of lo's surface

the oldest meteorites

Considering Einstein's equation relating mass and energy, E = mc^2, which of the following statements is true?

A) mass can be turned into energy, but energy cannot be turned back into mass

B) a small amount of mass can be turned into a large amount of energy

C) one kilogram of mass represents 1 joule of energy

D) it takes a large amount of mass to produce a small amount of energy

E) you can make mass into energy if you can accelerate the mass to the speed of light

a small amount of mass can be turned into a large amount of energy

Which of the following shapes is NOT allowed trajectory of an undisturbed object around a star?

A) spiral

B) parabola

C) ellipse

D) hyperbola

spiral

Where are most of the known asteroids found?

A) in the Oort cloud

B) between the orbits of Mars and Jupiter

C) in the Kuiper belt

D) between the orbits of the jovian planets

E) between the orbits of the terrestrial planets

between the orbits of Mars and Jupiter

According to modern scientific dating techniques, approximately how old is the solar system?

A) 14 billion years

B) 10,000 years

C) 4.6 million years

D) 4.5 billion years

4.5 billion years

We can see each other in the classroom because we

A) emit visible light

B) emit infrared light

C) emit thermal radiation

D) reflect infrared light

E) reflect visible light

reflect visible light

We are measuring the spectra of two hydrogen gas clouds. The laboratory frame wavelength of one hydrogen line is 656.2 nm. Cloud A's emission line wavelength is 660.1 nm and Cloud B's emission line wavelength is 670.1 nm. What can we conclude about these clouds?

A) they are both receding from us, and cloud A is receding faster than cloud B

B) they are both receding from us, and cloud B is receding faster than cloud A

C) they are both approaching us, and cloud B is approaching faster than cloud A

D) they are approaching us, and cloud A is approaching faster than cloud B

they are both receding from us, and cloud B is receding faster than cloud A

The difference between speed and velocity is that:

A) they are expressed in different units

B) velocity is the same as acceleration but speed is different

C) velocity is calculated using a physics equation

D) velocity also includes a direction

velocity also includes a direction

Which of the following wavelengths regions cannot be studied at all with telescopes on the ground?

A) infrared waves

B) radio waves

C) x-rays

D) both A and C

D) both B and C

x-rays

The shorter the wavelength of light, the higher its frequency

A) true

B) false

true

The long-term energy source of energy that powers the Sun is

A) mass energy of hydrogen fusing into helium

B) kinetic energy of the orbital motion of the Sun

C) gravitational potential energy of the contraction of the gas cloud that formed the Sun

D) chemical potential energy of hydrogen burning into helium

E) thermal energy of the hydrogen atoms in the Sun

mass energy of hydrogen fusing into helium

What is the giant impact hypothesis for the origin of the Moon?

A) the moon originally was about the same size as Earth, but a giant impact blasted most of it away so that it ended up much smaller than earth

B) the moon formed from material blasted out of the earth's mantle and crest by the impact of a mars-size object

C) the moon formed just like the earth, from accretion in the solar nebula

D) the moon formed when two gigantic asteroids collided with one another

the moon formed from material blasted out of the earth's mantle and crest by the impact of a mars-size object

As a gas cloud in space shrinks, it

A) spins slower

B) spins faster

C) spins at the same rate as it did before it shrank

spins faster

Where does nuclear fusion occur in the Sun?

A) just above the visible surface

B) anywhere below the surface

C) on the surface

D) in its core

E) all of the above

in its core

Which of the following are relatively uncharged fragments from the early period of planet building in the solar system?

A) Oort Cloud comets

B) asteroids

C) Kuiper belts comets

D) all of the above

all of the above

How does a rocket launched into space take off?

A) its rocket engines push against the launch pad, propelling the rocket upwards

B) the hot rocket exhaust the air beneath the shuttle, propelling it forward

C) by converting mass-energy to potential energy

D) by achieving lift from its wings in the same way that airplanes do

E) hot gas shoots out form the rocket and, through the conversation of momentum, the rocket moves in the opposite direction

hot gas shoots out form the rocket and, through the conversation of momentum, the rocket moves in the opposite direction

Oceans cover more of Earth's surface than land

A) true

B) false

true

The force due to gravity between two objects can be described using the equation Fg=G(M1)(M2)/d^2. In this equation, what does G represent?

A) the distance between the two objects

B) the universal gravitational constant

C) the density of the smaller object

the universal gravitational constant

According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane?

A) we would expect that a very small fraction of all planetary systems would have planets orbiting in such a pattern, so ours turned out that way due to random chance

B) any planets that once orbited in the opposite direction or a different plane were ejected from the solar system

C) the original solar nebula happened to be disk-shaped

D) the sun formed first, and as it grew in size it spread into a disk, rather like the way a ball of dough can be flattened into a pizza by spinning it

E) the laws of conservation energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk

the laws of conservation energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk

Which of the following statements about our Sun is NOT true?

A) the sun is made mostly of hydrogen and helium

B) the sun is a star

C) the sun's diameter is about 5 times that of earth

D) the sun contains more than 99% of all the mass in our solar system

the sun's diameter is about 5 times that of earth

What is the acceleration of gravity at the surface of Earth?

A) 9.8 m/s downward

B) 9.8 m^2/s downward

C) 9.8 m/s^2 downward

D) 9.8 km/s downward

E) 9.8 km/s^2 downward

9.8 m/s^2 downward

Which of the following is furthest from the sun?

A) an asteroid in the asteroid belt

B) pluto

C) a comet in the Oort cloud

D) eris

E) a comet in the Kuiper

a comet in the Oort cloud

The moon is slowly moving away from Earth

A) true

B) false

true

What percent of the mass of the solar nebula consisted of elements other than hydrogen and helium?

A) 80%

B) 20%

C) 0%

D) 0.1%

E) 2%

2%

Which of the following objects would be most likely to produce an emission-line spectrum?

A) a light bulb

B) the earth

C) a star like our sun

D) a neon light

a neon light

In what part of the solar system is Pluto found?

A) the asteroid belt

B) the terrestrial planet region

C) the Kuiper belt

D) the Oort cloud

the Kuiper belt

The Jovian planets have no solid surface

A) true

B) false

true

We know the Sun is primarily made from hydrogen and helium on the basis of its

A) spectrum

B) luminosity

C) age

D) color

E) mass

spectrum

Which of two bowling balls accelerate faster during their fall from the same height? Assume the bowling balls are identical, except for their mass.

A) the heavier the bowling ball accelerates faster

B) they both fall with the same acceleration

C) the lighter bowling ball accelerates faster

they both fall with the same acceleration

X rays, because they have more energy, travel through space faster than visible light.

A) true

B) false

false

If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet?

A) the planet is rotating

B) the planet is actually two bodies, one moving toward us, the other far away from us

C) the planet is in the process of falling apart

D) the planet is in the process of formation

the planet is rotating

If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet?

A) the planet is rotating

B) the planet is actually two bodies, one moving toward us, the other away from us

C) the planet is in process of falling apart

D) the planet is in the process of formation

the planet is rotating

How can an electron in an atom lose energy to go from a higher energy level to a lower energy level?

A) it absorbs a photon equal in energy to its own energy drop

B) it loses gravitational potential energy

C) it releases a photon equal in energy to its own energy drop

D) it loses kinetic energy

E) it exchanges gravitational potential energy for kinetic energy

it releases a photon equal in energy to its own energy drop