Week 3 Flashcards
What is the doppler effect
The Doppler effect is the change in the frequency (or pitch) of a sound or light wave as the source of the wave moves relative to the observer.
Here’s a simple way to think about it:
When the source of sound (like a car horn) moves towards you, the sound waves get compressed, which increases the frequency, and the pitch sounds higher.
When the source moves away from you, the sound waves stretch out, lowering the frequency, and the pitch sounds lower.
What is Hubble’s Law?
Hubble’s Law describes how galaxies are moving away from each other in the universe. It shows that the farther away a galaxy is, the faster it is moving away from us.
What is the formula for Hubble’s Law?
v=H₀⋅d
v is the speed at which the galaxy is receding (moving away) from us.
H₀ is the Hubble constant, which represents the rate of expansion of the universe.
d is the distance from the galaxy to us.
How can Hubble’s law be used to determine the age of the universe?
Hubble’s Law shows that the farther a galaxy is, the faster it moves away. If you think about it in reverse, this means that at some point in the past, all the galaxies would have been much closer together.
What is the formula to calculate the age of the universe?
Hubble’s Law is written as,
t ≈ 1/H₀
(For the proof, ask chatgpt)
What is the Big Bang Nucleosynthesis?
Big Bang Nucleosynthesis (BBN) refers to the process that occurred within the first few minutes of the universe, where temperatures and densities were extremely high. During this time, protons and neutrons and nucleuses combined to form the lightest elements, primarily hydrogen, helium, and trace amounts of lithium and beryllium.
How was gas clouds formed?
The universe began with the Big Bang, an explosion that created all matter and energy.
As the universe expanded, it cooled down, allowing simple atoms (mostly hydrogen and helium) to form.
Over time, Gravity began to pull gases together, forming gas clouds.
After the big bang, what was the universe mainly made out of?
Hydrogen and Helium
How are stars formed?
In a gas cloud, some areas naturally have a little more gas than others. These denser regions have stronger gravity, pulling more gas toward them.
As the gas particles get pulled inward, the region becomes denser and also heats up due to the compression. This process continues, concentrating matter into a smaller space. The core of the star reaches such high temperatures and pressures that nuclear fusion begins, releasing energy and stopping further collapse.
When a gas cloud collapses to form a star, the release of energy and light becomes so intense that the star becomes visible.
How are comets formed?
About 4.6 billion years ago, a rotating disk of gas and dust surrounded the young Sun, containing ices and rocky materials.
In the cold outer regions, ices condensed, and dust particles collided and stuck together to form larger icy bodies, known as comet nuclei.
Most comets originate from the Kuiper Belt (short-period comets) and the Oort Cloud (long-period comets).
Gravitational interactions can disturb the orbits of these icy nuclei, sending some toward the Sun.
As a comet approaches the Sun, heat causes the ice to sublimate, creating a glowing coma. Solar radiation and solar wind push this gas and dust away, forming a tail that always points away from the Sun.
How was the moon formed?
Mars-sized body named Theia collided with the early Earth approximately 4.5 billion years ago. This vent ejected debris into orbit around Earth, which eventually collied to form the Moon.
What is igneous Rocks?
Formed from the cooling and turning solid of molten rock (magma or lava).
What is Sedimentary Rocks?
Made from particles of other rocks and minerals that get pressed together over time.
What is Metamorphic Rock?
Metamorphic rocks form when existing rocks (igneous, sedimentary, or other metamorphic rocks) are changed by heat, pressure, or chemical processes over time.
How can these rocks be used to determine age?
Radiometric Dating: This is the most common method. It measures the decay of radioactive elements in the rocks.
Half-Life: Each radioactive element has a specific half-life, which is the time it takes for half of the original element to decay. By knowing the half-life and measuring the amounts, we can find the age of the rock.
