scince y10 1 universe Flashcards
define the universe
All of the matter and energy in space and time
common astronomical objects
-stars
-planets
-moons
list our cosmic address
Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, Universe
define what a scientific theory is
when a hypothisis is tested and evidnce shows that it works.
explain that scientific theories are sometimes rejected and change over time
because thye are put into place as an explaintion for sothing happing or how sothing works and not just a fact about life
explain what the big bang theory is
the theroy that the univese started when a big explosion hapoing this thery also says there is a limit of matter
compare and contrast the Big Bang and Steady State theories
**big bang **
matter cant be destyoyed or created
universe will end
steady state
matter can be created
the univese wont end
density consitant
list the scientific evidence that supports the Big Bang Theory
-Redshift
-Expansion Rate
- cosmic microwave background radiation
describe red shift
Distant galaxies’ light is redshifted—stretched wavelengths shifting towards red. This shows galaxies are moving away, faster the farther they are, proving the universe expands.
describe the cosmic microwave background radiation
The cosmic microwave background is faint radiation permeating the universe. It’s the afterglow of the Big Bang, supporting the idea of a hot, dense early universe.
define a star
A massive, luminous sphere of plasma held together by gravity, producing energy through nuclear fusion in its core.
low mass stars
Nebula
Protostar
Main Sequence
Red Gian
Planetary Nebula
White Dwarf
Black Dwarf
high mass stars
Nebula
Protostar
Main Sequence
Red Supergiant
Supernova
Neutron Star
recall that many different elements are created in stars (stellar nucleosynthesis)
Main Sequence Stars: Fuse hydrogen (H) into helium (He).
Red Giants: Fuse helium into carbon (C) and oxygen (O).
Massive Stars: Create heavier elements like neon (Ne), silicon (Si), and iron (Fe) through fusion.
Supernova Explosions: Form elements heavier than iron (Fe), including gold (Au) and uranium (U).
Neutron Star Mergers: Also produce heavy elements like gold and platinum.
describe the evolution of the Universe from the Big Bang to the present
1.cosmic inflation
2.first particles
3.first nuclie
4.first light
5.first stars
6.first galxies
7.dark enrgy
8.today
describe how the first elements formed (Big Bang nucleosynthesis)
10 sec – 20 min after Big Bang.
Formed Hydrogen, Helium, Lithium.
Fusion stopped as the universe cooled.
habitable zone
The region around a star where conditions allow liquid water to exist on a planet’s surface.
3 conditions to classify as a planet
Orbits the Sun – The object must revolve around the Sun and not be a moon of another body.
sufficient mass for a nearly round shape – The object must have enough gravity to pull itself into a spherical or nearly spherical shape.
Cleared its orbit – The object must have enough gravitational influence to clear its orbital path of other debris and smaller objects.
how do elliptical galaxys form
Elliptical Galaxies:
Form from galaxy mergers, disrupting star orbits.
Have little gas and dust, so new stars rarely form.
Contain mostly old, red stars in a random, oval shape.
how do spiral galaxys from
Spiral Galaxies:
Form from a rotating gas cloud collapsing under gravity.
Spiral arms form from density waves, triggering new star formation.
Have a central bulge with old stars and arms with young, bright stars.
what theroys does red shift support and why?
Big Bang Theory – Redshift suggests the universe started from a single point and has been expanding ever since. This matches the idea of a beginning (Big Bang).
Steady State Theory – This theory also accepts expansion but argues that new matter is continuously created, keeping the universe looking the same over time. Redshift alone does not prove or disprove this.
what theroys does miscrowave cosmic supoort and why
Big Bang Theory – CMB is leftover heat from the early universe, predicted by the Big Bang model. It shows that the universe was once hot and dense before expanding and cooling.
define a galaxy
large system of stars, gas, dust, and dark matter, bound together by gravity..
define an exo planet
A planet that orbits a star outside our solar system.
How does a high-mass star’s life cycle differ from a low-mass star’s?
Low-mass stars (like the Sun) become red giants, shed outer layers as a planetary nebula, and end as a white dwarf.
High-mass stars become red supergiants, explode in a supernova, and end as either a neutron star or a black hole.
What is cosmic microwave background (CMB) radiation, and how does it support the Big Bang Theory?
CMB is leftover heat from the early universe, spread evenly in all directions. It supports the Big Bang Theory by proving the universe was once hot and dense before expanding.
What is redshift, and how does it support the Big Bang Theory?
Redshift is the stretching of light from galaxies as they move away. It supports the Big Bang Theory by showing the universe is expanding, meaning it started from a single point.
What are the main stages that followed the Big Bang?
1️⃣ Inflation – Rapid expansion of the universe.
2️⃣ Formation of fundamental particles – Quarks, electrons, and other particles form.
3️⃣ Nucleosynthesis – Protons and neutrons combine to form light elements (hydrogen, helium).
4️⃣ Recombination – Atoms form, and cosmic microwave background (CMB) is released.
5️⃣ Dark Ages – No stars yet, just cooling gas.
6️⃣ First stars & galaxies – Gravity pulls gas together to form stars and galaxies.
7️⃣ Formation of planets & structures – Solar systems and galaxies evolve.
