Unit 5: Space

practice, practice, practice and really learn it! all the best! <3

ORIGIN AND EVOLUTION OF THE UNIVERSE:

ORIGIN AND EVOLUTION OF THE UNIVERSE:

• THE BIG BANG THEORY:

• THE BIG BANG THEORY:

• What is it ?

• The scientific explanation for the origin and expansion of the observable universe.

• When did it happen?

• Approximately 13.8 billion years ago.

• What theories / laws is it based on?

• Cosmic Microwave Background Radiation

• Hubble’s Law

• Einstein’s Theory of General Relativity

• Who discovered Cosmic Micorwave Background Radiation and when?

• Arno Allan Panzias & Robert Woodrow Wilson in 1964.

• What is the radiation remnant of?

• The extreme heat and energy released during the Big Bang.

• What theory states the universe is constantly expanding uniformly?

Hubble’s Law.

• What does Einstein’s Theory of General Relativity prove?

• The universe cannot be static. It must either be expanding or contracting.

• What is the catch with the Big Bang Theory?

• It does NOT fully explain the creation of the universe.

• THE EXPANSION OF THE UNIVERSE:

• THE EXPANSION OF THE UNIVERSE:

• What happens in expansion and how long does it last?

• Galaxies more farther apart, space itself is stretch, expansion still continues for billions of years (?)

• What direction does expansion occur in?

• Every direction.

• What is one of the most important discoveries of astronomy?

• The expansion of the universe.

• The farther two galaxies are, the faster they …?

• The faster they separate.

• Galaxies themselves do not expand. What does?

• The space between them does.

• Who studied distant galaxies, and when?

• Edwin Hubble, in 1929.

• What did Edwin Hubble observe about galaxies?

• That most galaxies showed red shift.

• He discovered that farther away a galaxy is, the …?

• The faster it moves away.

• What has this relationship been named?

• Hubble’s Law, and it proved (with strong evidence) that the universe is expanding.

• RED SHIFT:

• RED SHIFT:

• What does the Red Shift concept state?

• A core concept that occurs when an object in the universe (that emits light) moves away from us, causing it’s light to stretch out into a longer and “redder” wavelength.

• What does the Blue Shift concept state?

• When an object (that emits light) moves towards us, its light starts to become shorter, and getts more of a blue wavelength

• What is Red Shift caused by?

• The expansion of the universe.

• What has Red Shift been used as a tool for?

• To identify the speed and distance the universe is moving at.

• What did Christian Doppler discover, and when?

• That the pitch of a sound changes, as the source moves away from the observer; discovered in 1842.

• What was this effect named and what did it help discover?

• The Doppler effect; it helped discover Redshift.

• Which astronomer first measured and observed Redshift, and when?

• Vesto Slipher, in 1912.

• Which astronomer provided evidence for this phenomenon and when?

• Edwin Hubble, in 1929.

• What are the three different types of Redshift?

• Doppler Redshift.

• Cosmological Redshift

• Gravitational Redshift

• What is Doppler Redshift?

• When an object that emits light moves away from you, and the light starts to appear red.

• What is the Cosmological Redshift?

• Light becoming stretched out to make it more of a red wavelength.

• What is Gravitational Redshift?

• Proven with Einsetin’s General Law of Relativity, it also describes the wavelength stretching and shifting to become more red.

• DARK ENERGY:

• DARK ENERGY:

• What is dark energy?

• A mysterious form of energy, that no one can see directly, but causes the universe to expand faster over time.

• How much of the universe does dark energy make up?

• About 68%.

• When and how was it discovered?

• In1989, by astronomers who were studying distant exploding stars.

• Why is it important?

• Explains why the galaxies are moving faster away, and helps scientists understand the future of the universe.

• Why is it so hard to comprehend?

• Because scientists cannot see, touch or directly detect it. It does not give off radiation or light like planets or stars.

• Then how do we know it exists?

• Because scientists were able to observe its effects on the universe’s expansion.

• Why is it different than regular energy?

• Because it behaves different from normal matter or energy, making it hard to explain using current physics law. Even powerful telescopes cannot capture an image of dark energy.

• What evidence is there for Dark Energy?

• Expansion of the universe (which is accelerating).

• Observations of distant galaxies & supernovas, that support this idea.

• ACTIVITY: Do the practice Kahoot they sent!

• ACTIVITY: Do the practice Kahoot they sent!

GALAXIES & BLACK HOLES:

GALAXIES & BLACK HOLES:

• GALAXIES:

• GALAXIES:

• What is a galaxy?

• A vast, gravitationally bound system made up of stars, stellar remnants, interstellar gas, dust and dark matter.

• What are the different types of galaxy?

• Spiral

• Eplliptical

• Irregular

• What is a Spiral galaxy?

• Has a bright spiral central core of older stars, surronded by a rotating disk of young stars.

• What is an Elliptical galaxy?

• An ellipsoidal-shaped (egg-shaped) system of stars, dust and dark matter that lacks arms.

• What is an Irregular galaxy?

• A structureless, cosmic system.

• BLACK HOLES:

• BLACK HOLES:

• What is a black hole?

• A space object with an incredibly strong gravitational pull that traps everything in its vicinity.

• How is a black hole formed?

• Massive stars collpase into black holes when they exhaust their nuclear fuel, leading towards black holes.

• 3 MYTHS ABOUT BLACK HOLES:

• 3 MYTHS ABOUT BLACK HOLES:

• Black holes are cosmic vacuum cleaners.

• Myth. Only if matter is really close to the event horizon.

• All black holes are black.

• Myth. Black holes power quasars, which are really bright.

• All stars become black holes.

• Myth. A star needs to be 20 times our Sun to be a black hole.

• FUN FACTS / MISCALLEANOUS:

• FUN FACTS / MISCALLEANOUS:

• In how many years will the Milky Way galaxy collide with the Andromeda galaxy?

• 4.5 billion years!

• What is the word “Quasar” short for?

• Quasistellar radio source (and it means star-like emitters of radio waves!)

• WHAT IF …

• WHAT IF …

• You fell into a galaxy?

• You would just float until where the light can reach your eyes (?).

• You fell into a black hole?

• You would go through the process of spagettigication (a process in which the body is compressed from head to toe while being also stretched like spagehetti).

• AGNS:

• AGNS:

• What is the definition of AGN?

• Stands for Active Galactic Nucleus. It is the brightest object in the universe.

• What are quasars?

• Distant galaxies whose incredibly bright cores are powered by supermassive black holes; the most powerful type of AGN.

• ACTIVITY: Do the “What Am I?” activity on the handout!

• ACTIVITY: Do the “What Am I?” activity on the handout!

GRAVITY:

GRAVITY:

• WHO IS ISAAC NEWTON?

• WHO IS ISAAC NEWTON?

• What did Isaac Newton discover?

• The man who helped discover gravity, mass and distance (alongside Galileo Galilei!)

• What is Universal Gravitation?

• Every object with mass being attracted to every other object. Issac Newton also showed the same forces apply on Earth and in space.

• The same force that causes an apple to fall keeps the moon orbiting the Earth.

• What is Mass and Distance?

• The strength of gravity depends on the mass and distance, so when mass increase, gravitational force INCREASES but when distance increases, gravitational force DECREASES.

• Large objects exert a strong gravitation pull than smaller objects.

• WHAT IS GRAVITY?

• WHAT IS GRAVITY?

• What is gravity?

• It’s the force of attraction between two objects.

• It’s the force of attraction between two objects.

• It’s believed to exist as ripples.

• Is the force stronger between larger or smaller objects?

• Larger objects; bigger mass.

• Is the force stronger across shorter or longer distances?

• Shorter distances.

• What is the difference between weight and mass?

• Weight = how heavy something is in relation to gravity (i.e. a 10 kg box is 1.6 kg on the Moon, because of gravity differences).

• Mass = how many atoms are packed into an object; does not change across space.

• What is acceleration?

• When speed of a moving object changes (i.e. a car speeding up)

• What is the relationship between acceleration and gravity?

• Gravity (g) is the acceleration of falling objects. (g = -9.8 m/s^2) - [ the negative represents the downwards direction ]

• What does 9.8m/s represent? What does the m/s**2 represent?

• 9.8m/s is the velocity (speed). m/s**2 represents the speed changing at a rate of 9.8m/s every second (i.e. 9.8, 19.6, 2.4, etc.)

• What role does air (molecules) play in acceleration and gravity?

• In air, the weight/mass of objects affect how accelerated their descent is, due to gravity.

• Without air, both items fall at the same speed and rate.

• What is the role of gravity in space?

• It is the (weak) force that holds massive bodies together despite the acceleration of dark energy. Stars, solar systems, galaxies and anything is orbiting something else because of gravity.

• Why do astronauts float in space?

• Because space is a vaccum, meaning there is no air, and everything falls at the same rate.

• How do satellites stay in orbit?

• The momentum of speed pushes them around and around, but gravity keeps them in orbit. (This is more formally described as the counteracting forces of centripetal speed and gravity.") This is also called “zero G".

• HOW IS GRAVITY MEASURED?

• HOW IS GRAVITY MEASURED?

• How is gravity measured?

• Gravity (g) is the acceleration of falling objects. (g = -9.8 m/s^2)

• Can be measured using a pendulum or gravimeter.

• (IF NEED FORMULA, USE THE ONE PROVIDED ON HANDOUT!)

• CREATION OF THE SOLAR SYSTEM:

• CREATION OF THE SOLAR SYSTEM:

• When was the solar system formed?

• 4.6 billion years ago.

• How was it formed?

• A solar nebula (gas & dust cloud) collapsing under gravity; a supernova may have triggered the collapse. The collapsing nebula flattened into a spinning disc, forming the two main parts: the sun and the planets.

• How was the sun formed?

• Gravity pulled most (99.9%) of the material to the center. The cloud spun faster and formed a protostar. When it got hot enough, nuclear fusion began (hydrogen to helium), thus creating the sun.

• How were the planets formed?

• Dust and gas particles collided and stuck together, and over time they grew into full planets, thanks to gravity!

• RELATIONSHIP WITH OTHER SOLAR BODIES:

• RELATIONSHIP WITH OTHER SOLAR BODIES:

• What is the force that keeps the solar system together?

• Gravity.

• Objects with more mass have ___?

• Stronger gravity.

• What does the Sun’s gravity do?     

• Keeps all planets in orbit.

• What does Jupiter’s strong gravity do?

• Can affect asteroids and smaller objects passing by.

• What does the Moon’s gravity do on Earth?

• Causes tides.

• Without gravity, the solar system would _____?

• Not stay stable.

• WEIGHTLESSNESS AND FREEFALL:

• WEIGHTLESSNESS AND FREEFALL: