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What is parallax effect
Definition: The apparent shift in the position of a nearby star against distant stars due to Earth’s movement around the Sun.
Key Concept: Measured from two points in Earth’s orbit (6 months apart).
Unit: 1 parsec = 3.26 light-years.
Limit: Effective for measuring distances to nearby stars (up to a few thousand light-years).
What is a parsec
a unit of distance used in astronomy, equal to about 3.26 light years (3.086 × 1013 kilometres). One parsec corresponds to the distance at which the mean radius of the earth’s orbit subtends an angle of one second of arc. It is the distance to an object whose parallax angle is one arcsecond (1/3600 of a degree)
What is cosmic microwave background radiation
The Cosmic Microwave Background (CMB) radiation is the remnant radiation from the early, hot, and dense universe. As the universe expanded, this radiation cooled and stretched to longer wavelengths, shifting from high-energy gamma rays and X-rays to lower-energy microwaves. Today, the CMB is observed at a temperature of about 2.7 K, consistent with predictions that it has cooled over billions of years due to the ongoing expansion of the universe.
How does cosmic microwave background radiation support the big bang theory
The Cosmic Microwave Background (CMB) supports the Big Bang theory because it is the predicted leftover heat from the universe’s hot, dense beginning, now stretched into microwaves by the universe’s expansion. Its uniformity and small temperature fluctuations match models of how the early universe evolved into the large-scale structures we see today.
What are black dwarfss and why are they important
A black dwarf is a theoretical stellar remnant formed when a white dwarf cools completely and stops emitting light. These objects do not exist yet because the universe (13.8 billion years old) is too young compared to the trillions of years required for a white dwarf to cool and become a black dwarf. Black dwarfs mark the final stage of small to medium-sized stars (less than 8 times the mass of the Sun) and represent the eventual “death” of such stars. After exhausting their nuclear fuel, these stars shed their outer layers and leave behind a dense white dwarf that slowly cools over time. Black dwarfs play a key role in the long-term fate of the universe, as they represent the ultimate end for stars that don’t undergo supernova explosions.
What do vector quantities NEED to have
direction associated e.g 50 m / s left
List 4 pieces of evidence that supports big bang theory
Red Shift
Cosmic microwave background radiation
hubbles law
Einsteins law
Amount of He present in universe
What are oceans in terms of carbon cycle
oceans act as a major carbon sink, absorbing large amounts of atmospheric CO₂ and storing it in both surface waters and deep ocean layers. However, their ability to continue to do so is threatened by climate change and increasing CO₂ concentrations.They are carbon sinks
what is a planetary nebula
A planetary nebula is a glowing shell of ionized gas that forms when a dying star sheds its outer layers.
What is a neutron star
A neutron star is the dense, collapsed core of a massive star that remains after the star has undergone a supernova explosion.
what size as a x is black holes it greater than our sun
Black holes are formed when a star with a mass greater than approximately 20 times that of the Sun collapses under its own gravity after a supernova explosion. If the core’s mass is high enough, it continues to collapse into an infinitely dense point known as a singularity, surrounded by an event horizon, beyond which nothing, not even light, can escape. Black holes can range in size from a few times the mass of the Sun to millions or even billions of solar masses, typically found at the centers of galaxies.
What are the layers of the atmopshere
Layer - Temperature - Trend - Key Features
Troposphere Decreases Weather, life, water vapor.
Stratosphere Increases Ozone layer, absorbs UV radiation.
Mesosphere Decreases Burns meteors, coldest layer.
Thermosphere Increases Auroras, satellites, ionosphere.
Exosphere N/A Transition to space, sparse particles.
What are some indicators of climate change
ocean and atmospheric temperatures,
sea levels, biodiversity, species distribution, permafrost and sea ice
What distance is the troposphere
0 - 10 km
What distance is the stratosphere
10 - 30 km
What distance is the mesosphere
30 - 50 km
What distance is the thermosphere
50 - 400km
What distance is the exosphere
> 400km
How did scientists first discover CMBR
The Cosmic Microwave Background Radiation (CMBR) was discovered in 1965 by Arno Penzias and Robert Wilson while working at Bell Labs, who detected an unexpected microwave signal coming from all directions in the sky. They initially struggled to explain the noise until they consulted cosmologists, who recognized it as the remnant radiation from the Big Bang. This discovery provided strong evidence for the Big Bang theory, earning Penzias and Wilson the Nobel Prize in Physics in 1978.
Why does a star become a red giant and what happens during this phase
Hydrogen Exhaustion in the Core:
Why it happens: The star has used up the hydrogen fuel in its core through nuclear fusion, so fusion slows down.
Key feature: The core contracts due to gravity, causing it to heat up, while the outer layers expand.
Expansion into a Red Giant:
Why it happens: As the core contracts and heats, the outer layers of the star are pushed outward and cool, making the star expand and redden.
Key feature: The star becomes much larger and cooler on the surface, turning it into a Red Giant.
Helium Fusion Begins:
Why it happens: When the core temperature becomes high enough, around 100 million K, helium fusion begins, turning helium into carbon and oxygen.
Key feature: The star enters the Red Giant phase, where fusion occurs in shells around the core, causing the outer layers to expand even further.
Why does a red giant become a planetary nebula and what happens during this phase
Planetary Nebula Formation:
Hydrogen and Helium Exhaustion:
Why it happens: The red giant exhausts its hydrogen and then helium fuel in the core, leading to the end of fusion.
Key feature: A star’s core contracts and heats up after it exhausts its nuclear fuel, while the outer layers expand due to the increased energy from the hotter core.
Expulsion of Outer Layers:
Why it happens: Without sufficient fusion to support it, the outer layers become unstable and are expelled into space.
Key feature: The outer layers form a glowing shell of ionized gas known as a planetary nebula.
The remaining core becomes a white dwarf, which will gradually cool over time.
This process occurs in stars with masses less than about 8 times the Sun’s mass.
Formation of white dwarf
Ionization by Hot Core:
“White dwarfs form from the core of small to medium-sized stars (less than 8 times the mass of the Sun) after they exhaust their nuclear fuel. The star sheds its outer layers, which are expelled as a planetary nebula. The remaining core becomes a dense, hot white dwarf, no longer undergoing fusion. The white dwarf remains extremely hot and emits ultraviolet radiation, ionizing the expelled gas and causing it to glow. Over time, the white dwarf slowly cools, and the planetary nebula disperses.”
Formation of red super giant
A red supergiant is a type of star that is in the later stages of its life cycle. These stars are much larger and more luminous than the Sun. They form when a star with at least 8 times the mass of the Sun exhausts the hydrogen in its core. Without fusion to support the core, gravity causes it to collapse, which heats up surrounding layers. This leads the outer layers to expand and cool, giving the star its red color.
Formation of super nova
This happens when a massive star (typically at least 8 times the mass of the Sun) exhausts its nuclear fuel. The core collapses under gravity, and when it becomes too dense, it rebounds, triggering a huge explosion. The outer layers of the star are blown away, while the core may become a neutron star or collapse further into a black hole.
Formation of black hole
A black hole forms when a star with a mass greater than about 20 times that of the Sun collapses under its own gravity after a supernova. The core becomes so dense that it creates a singularity, a point of infinite density, surrounded by an event horizon, beyond which nothing can escape, not even light. Black holes can grow to millions or even billions of times the mass of the Sun.
Formation of neutron star
A neutron star forms from the collapsed core of a massive star after a supernova explosion. When gravity causes the core to collapse, protons and electrons combine to form neutrons, creating an incredibly dense object, about 1.4 times the mass of the Sun but only 10-20 kilometers across. Neutron degeneracy pressure prevents further collapse, making neutron stars one of the densest objects in the universe.
What is the spectrum that light, x ray gamma etc are on
electromagnetic spectrum
What is the gulf stream
The Gulf Stream is a warm, fast-moving ocean current in the Atlantic Ocean that flows from the Gulf of Mexico, along the eastern U.S. coast, and across the Atlantic towards Europe, influencing climate and weather patterns. It moderates temperatures in coastal regions, keeping winters milder in Europe and the eastern U.S. It also impacts storm formation, strengthening hurricanes and distributing heat globally, affecting wind and precipitation patterns.
Why is the Gulf stream important
Regulates Climate: Transfers heat from the tropics to northern regions, moderating temperatures in North America and Europe.
Supports Marine Life: Provides a nutrient-rich environment for diverse ecosystems.
Influences Weather: Affects storms, hurricanes, and rainfall patterns.
Global Ocean Circulation: Drives the Atlantic Meridional Overturning Circulation (AMOC), essential for global heat and carbon exchange.
how do ocean currents influence our climate on land
Ocean currents influence climate on land by redistributing heat around the globe. Warm currents, like the Gulf Stream, transfer heat from the tropics to higher latitudes, warming nearby coastal areas. Cold currents, like the California Current, cool adjacent regions by bringing cold water from polar areas. These currents also affect wind patterns, precipitation, and the overall climate of continents.
What are the main greenhouse gas emissions
Carbon dioxide
Nitrous Oxide
Methane
Water Vapour
Main sources of Carbon Dioxide CO2
Burning fossil fuels (coal, oil, and natural gas), deforestation, industrial processes, and some chemical reactions (e.g., cement production).
Photosynthesis formula
6CO2 + 6H2O → C6H12O6 + 6O2.
Main source of Methane CH4
Agriculture (especially livestock digestion and manure management), landfills, coal mining, oil and natural gas production, and wetlands.
Main source of Nitrous Oxide
Agricultural activities (fertilizer use, manure management), fossil fuel combustion, industrial processes, and biomass burning.
Water Vapour
While not directly emitted by human activities, it is the most abundant greenhouse gas naturally present in the atmosphere (41 - 67%), amplifying warming as temperatures rise (a feedback loop).
Electromagnetic spectrum flow (incoming, absorption, release)
Incoming Solar Energy:
UV, visible, and some IR radiation.
Absorption and Re-emission:
Earth’s surface absorbs and re-emits energy as infrared radiation.
Trapping and Release:
Greenhouse gases trap some infrared radiation while the rest escapes into space.
What goes on in nuclear fusion
Deuterium (hydrogen-2) + Tritium (hydrogen-3) -> Neutrons, energy and helium
What is a pulsar
A pulsar is a type of neutron star, which is the dense remnant of a star that has exploded in a supernova. Pulsars are known for emitting beams of electromagnetic radiation, including radio waves, which are observed as periodic pulses. These pulses are emitted because the pulsar’s magnetic axis is not aligned with its rotational axis, so as it spins, the beams sweep across space like a lighthouse beacon. Pulsars are incredibly stable in their rotation, and some can spin hundreds of times per second. They are often used in astrophysics for precise measurements of time and distance due to their regularity.
