AST101 Clicker Quizes UofT

What does the term "Solar System" mean?

The Sun, the planets, and all of their moons

What does the term "Universe" mean?

The totality of all space, time, energy, and matter

Earth is 1 AU from the Sun. What is the maximumpossible separation between Earth and Mars? (Hint: Mars is the next farthest planet from the Sun)

2.5 AU

A 'light year' is a measure of:

distance

Stars are...

balls of plasma which produce energy by nuclear fusion.

Planets are..

rocky, icy, or gassy, and they don't produce much energy.

Why is Pluto no longer considered a planet?

Its orbit is full of other stuff

Definition of the term "planet"

Planets must have cleared their orbits. That is, there can't be a lot of other stuff orbiting the parent star in orbits very similar to the planet.

A moon is ...

any large body which orbits a planet.

Titan is a rocky/icy object with an atmosphere and liquid on its surface. It is spherical in shape, has a clear orbit, and orbits Saturn. Titan is a ...

moon

Ceres orbits the Sun in the asteroid belt between Mars and Jupiter. It is large enough to be spherical. Ceres is a...

dwarf planet

A solar system consists of ...

a star orbited by planets, moons, and lots of debris (comets, asteroids, dust)

The Inner Solar System...

Mercury, Venus, Earth, Mars

The Outer Solar System...

:Jupiter, Saturn, Uranus, Neptune, many dwarf planets & comets

How many stars are there in our Solar System?

one, the sun

The terrestrial planets are called

Mercury, Venus, Earth, Mars

The terrestrial planets are

Rocky, relatively small, close to Sun

The jovian planets are called

Jupiter, Saturn, Uranus, Neptune

The Jovian planets are

gaseous, larger, and farther away from the Sun

Compared to planets in the inner Solar System, planets in the outer Solar System generally

are made of lighter elements

What is it like on Mercury

No atmosphere, highly cratered surface, Rocky exterior with a huge iron core

What is it like on Venus

Thick CO2 atmosphere, lots of (possibly) active volcanoes. About the same size as Earth, Runaway greenhouse effect makes it even hotter than Mercury, Rains acid, No moons

What is it like on Earth

Wet planet, Unusually big moon•Surface and atmosphere heavily modified by life

What is it like on Mars

Very thin CO2 atmosphere•Many huge, extinct volcanoes, Was probably warmer and wetter in the past, Many surface features probably carved by water, No life known to date

The planet with the highest average surface temperature is...

Venus

Scientists announce the discovery of a new planet in another solar system. The planet is the same size as Earth and orbits a star just like the Sun at a distance of 0.9 AU. Based on our own solar system, what can we conclude about this planet?

It will be made mainly of rock.

The asteroid belt is

A zone where rocky chunks orbit the sun between the orbits of Mars and Jupiter.

What is it like on Jupiter

Largest planet in the solar system, Thick gaseous atmosphere surrounds a giant ball of liquid hydrogen, and has very faint rings

What is it like on Saturn

Spectacular rings, More than 60 known moons

if you tried to land a space ship on a Jovian Planet, what would happen first?

You'd be crushed by the tremendous gas pressure.

What is it like on Uranus and Neptune

ice giants, Both about the same size, Both bluey/green, Both have many moons, Both have faint rings

The Kuiper Belt

A region of the solar system that is just beyond the orbit of Neptune and that contains small bodies made mostly of ice

The Oort cloud

A spherical region of comets that surrounds the solar system, Larger then the Kuiper belt

Milkyway Galaxy

The spiral galaxy in which Earth and our solar system reside.

Constellations are

arbitrary regions that cover the entire sky, which astronomers have named

Would the constellations look the same from Pluto as they do from Earth?

There are tiny (unnoticeable) differences

If you were at the north pole (at night) where wouldyou find Polaris on the sky?

Straight up

What causes Seasons

The tilt of the Earth's axis, The Sun is higher in the sky in June/July in the Northern Hemisphere (but lower in the Southern Hemisphere)

If the axis of the Earth's rotation was perpendicular to the orbital plane (and not tipped like it is now) what would seasons be like?

Almost no seasons at all.

If the axis of the Earth's rotation was parallel to the orbital plane (tipped on its side) what would seasons be like?

Much more severe

What is the apparent path of the sun on the sky on December 21 as viewed from the South Pole?

It travels around the sky about 23 degrees up

What is the apparent path of the sun on the sky on March 21 as viewed from the Equator?

It rises in the East, goes directly overhead, and sets in the West

Describes the motion of a full moon?

Rises near 6 PM, sets near 6 AM

A solar eclipse occurs

The moon blocks the Sun. At the new moon, but not always. When the moon passes directly between Earth and the sun, blocking sunlight from Earth

A lunar eclipse occurs

the earth casts a shadow on the moon. at a full moon when Earth is directly between the moon and the sun

What are the phases of the moon?

new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, waning crescent

Kepler's First law

Planets orbit the sun in an elliptical pattern, with the Sun at one focus

Kepler's Second Law

As a planet moves around its orbit, it sweeps out equal areas in equal times

Kepler's Third Law

A planet's orbital period depends on its distance from the sun. More distant planets orbit slower

Galileo Galilei

Showed that Jupiter has moons. Showed that the moon has craters. Observed the phases of Venus

Heliocentric

Based on the belief that the sun is the center of the universe

Geocentric

A model of the universe in which Earth is at the center of the revolving planets and stars.

At the time of Copernicus, why would one prefer Copernicus' Heliocentric model to Ptolemy's Geocentric model?

It wasn't clearly preferable at the time

According to Kepler's laws, when should a comet in a highly eccentric orbit be moving the fastest?

When it is closest to the sun

According to Kepler's laws, which planet moves the fastest

Mercury

Define speed

the rate of change of position. eg, the car is travelling 60km per hour

Define velocity

speed and direction. eg: the car is going due north at 60km/hour

Define Acceleration

the rate of change of velocity. eg, The car is changing speed from 0 km/hr to 100 km/hr in 9s. Or The car changed from going due north at 60 km/hr to going due east at 60km/hr in 20s.

Newton's first Law

An object in motion remains in motion unless acted upon by an outside force

Newton's second law

Acceleration is proportional to Force and inversely proportional to mass. F = ma

Newton's third law

For every force, there is always an equal and opposite reaction force.

Momentum

mass x velocity

Angular Momentum

Mass times velocity times distance. e.g a skater when she pulls her arms in makes her go faster, when they are out she goes slower.

Newton's Universal Law of Gravitation

There is a force between any two objects in the Universe. The force is proportional to the product of the masses of each object. The force is inversely proportional to the square of the distances

A car is traveling due north at 100 km/hr. How far will it go in a half of an hour?

50 km

According to Newton's laws...A ball on a flat surface rolls to a stop. Why?

A force (called friction) acts on the ball, causing it to stop.

An astronaut pushes herself away from her large spacecraft. What happens?

She and the spacecraft move apart

When, in the highly eccentric orbit of a comet, is the angular momentum of the comet the greatest?

It is always the same, because angular momentum is conserved.

Freefall

the motion of a body when only the force of gravity is acting on the body

When, in the highly eccentric orbit of a comet, is the force of gravity between the comet and the Sun the greatest?

When the comet is closest to the sun.

When might you feel freefall in a roller coaster, if the speed is just right?

At the top

If the moon were closer to the earth, then then tides would be

Larger, but the same frequency

When do you have the biggest tides?

Full and New moons

Explain how tides are caused

- Tides are caused by the gravitation pull between Earth and moon mainly. Tides are also caused by the gravitational pull by the sun and Earth.
- Moon's gravity pulls on the Earth, pulling the ocean waters toward the Moon.
- This pull creates a bulge of water on Earth.
- The bulge on the exact opposite side of the Earth is created by centrifugal forces as Earth rotates.
- These bulges create high tides and on side of Earth with no bulge is low tides.

escape speed

The speed that a projectile, space probe, or similar object must reach to escape the gravitational influence of Earth or of another celestial body to which it is attracted.

escape velocity

The velocity an object must reach to fly beyond a planet's or moon's gravitational pull.

Name the parts of the sun

Thermonuclear energy core, The Radiative zone, Convective zone, The Photosphere, The Corona,

Dwarf planet

a celestial body resembling a small planet but lacking certain technical criteria that are required for it to be classed as such.

Celestial sphere

An imaginary sphere surrounding Earth to which the stars are attached

Celestial pole

The north celestial pole: is the point directly over earth's north pole, The south celestial pole is the point directly over earth's south pole

Orbital period

The amount of time it takes to complete one orbit of a star, planet, or moon.

Orbital semimajor axis

is one half of the major axis, and thus runs from the centre, through a focus, and to the perimeter.

mass

is the actual amount of material contained in a body and is measured

weight

is the force exerted by the gravity on that object

kinetic energy

energy of motion

radiative energy

energy carried by light

potential energy

stored energy

Thermonuclear energy core

The core we cannot see

The Radiative zone

light & heat travel through the core

Convective zone

Lots of churning: hot gas rising, cool gas falling

The Photosphere

the visible surface of the sun

The Corona

the outermost layer of the sun's atmosphere, that we can see.

Chemical Reaction

Electrons in atoms or molecules change over new partners, Rearrangement often relates energy, Involve electrons. Example: photosynthesis, Fire, Battery power

Nuclear Reaction

Nuclei combine or split apart, Now electrons just observe, Example: atomic bombs, radioactivity, The involve nucia

The core of the Sun is

hottest place in the solar system.

Sunspots are

cooler, darker regions on the Sun's surface.

The corona is....

much hotter than the photosphere but is much harder to see.

Nuclear Fission

e.g. nuclear reactors, atomic bombs, requires heavy elements like uranium, plutonium

Nuclear Fusion

e.g. hydrogen bombs, uses light elements like hydrogen, helium

What is the difference between a chemical reaction and a nuclear reaction?

Chemical reactions involve electrons, while nuclear reactions involve atomic nuclei