Astrophysics and Rocket Science Lectures

The distribution of energy among the particles in a fixed volume at a certain temperature. It's characterized by a peak emission wavelength that shifts towards shorter wavelengths as the temperature increases. The intensity of the radiation depends on the number of photons emitted per second.

Thermal Bremsstrahlung (TB) involves charged particles accelerating due to interactions with other charged particles. The acceleration rate determines the emitted frequency, with higher acceleration leading to higher frequencies. Synchrotron Radiation (SR) occurs when charged particles are accelerated in magnetic and electric fields, causing them to move in circles or straight lines.

The pressure exerted by electrons in degenerate matter, where electrons are packed so densely that quantum mechanical effects become significant. Unlike normal matter, degenerate matter resists compression due to the Pauli Exclusion Principle, which prevents electrons from occupying the same energy level.

Type II supernovae occur when massive stars (8 solar masses or more) exhaust their fuel and collapse due to gravity. The core collapses and forms a neutron star or a black hole. Type Ia supernovae are produced by the explosion of white dwarf stars that accrete matter from a companion star.

The amount of energy carried by a single photon, calculated as E = hf, where h is Planck's constant, and f is the frequency of light.

The minimum energy required to eject an electron from a material, measured in electron volts (eV).

The energy transferred to an electron when it absorbs a photon, calculated as the difference between the photon's energy and the work function.

The process where a photon interacts with an electron, resulting in the photon losing energy and changing direction.

The process where a photon is absorbed by an atom, causing an electron to be ejected.

A measure of the energy a photon carries, calculated as the product of Planck's constant and the speed of light divided by the wavelength of the photon.

The process where a high-energy photon interacts with a strong electromagnetic field, creating an electron-positron pair.

The minimum energy required for a photon to create an electron-positron pair, calculated as twice the rest mass energy of an electron.

A technique in particle physics that uses a scintillating material surrounding a target to identify and reject events where a photon deposits energy in both the target and the surrounding material, indicating potential contamination.

The discrepancy between the predicted number of solar neutrinos reaching Earth based on the Sun's energy production and the actual number observed by early neutrino detectors, largely due to neutrinos changing flavor during their journey.

The velocity of the hot gases exiting the rocket nozzle.

A more realistic measure of the effectiveness of a rocket engine, factoring in the effect of the rocket's mass and thrust direction on the overall performance.

The ratio of the kinetic energy of a smaller mass to the kinetic energy of a larger mass after an inelastic collision.

A system that uses gyroscopes connected to moving surfaces on fins or deflectors in the exhaust stream of a rocket engine to control the craft's orientation.

The principle stating that the total linear momentum of a closed system remains constant.

The use of turbopumps to pressurize liquid propellant in rocket engines, significantly increasing their efficiency and performance.

The escape velocity is the minimum speed an object needs to escape the gravitational pull of a planet or celestial body. It depends on the mass and radius of the celestial body.

The velocity required for an object to maintain a circular orbit around a celestial body is known as orbital velocity. It depends on the mass of the celestial body and the radius of the orbit.

The apoapsis is the point in an elliptical orbit where the satellite is farthest from the Earth. The periapsis is the point where it is closest to Earth. Both depend on the semi-major axis and eccentricity of the orbit.

Eccentricity is a measure of how elliptical an orbit is. It ranges from 0 for a perfectly circular orbit to 1 for a highly elliptical orbit.

The semi-major axis is half the longest diameter of an ellipse. It represents the average distance of the satellite from the Earth in its elliptical orbit.

Velocity at Apoapsis is the speed of the satellite at the point farthest from Earth in its elliptical orbit. Velocity at Periapsis is the speed at the point closest to Earth. Both depend on the gravitational forces and the speed of the satellite.

Gravitational force between two objects depends on their masses and the distance between them. This force is responsible for keeping satellites in orbit around Earth.

The specific impulse (ISP) is a measure of the efficiency of a rocket engine. It represents the thrust produced per unit of propellant consumed. Higher ISP values indicate greater efficiency.

The potential energy of a spacecraft in orbit is negative, indicating that it is bound to Earth's gravitational field.

The total energy of an object in orbit is a constant value, determined by the semi-major axis of the elliptical orbit. This implies that the object's kinetic and potential energy are constantly changing but their sum remains constant throughout the orbit.

A Hohmann Transfer orbit is an elliptical path between two circular orbits. It is the most efficient way to transfer a spacecraft from one circular orbit to another circular orbit.

The velocity the spacecraft needs to have to enter a specific orbit is called the orbital velocity, which is dependent on the mass of the central body and the radius of the orbit. It is calculated using the formula: v = √(GM/R).

The kinetic energy of a spacecraft is the energy it possesses due to its motion. It is calculated using the formula: KE = 1/2 * mv², where m is the mass of the spacecraft.

The difference in velocity required for maneuvering from one orbit to another is represented by ∆v, effectively the change in velocity needed to execute a maneuver.

The difference in velocity needed for a spacecraft to transition from one orbit to another.

The force exerted on a spacecraft by its engines, accelerating it.

It's the time duration for which the spacecraft's engines burn to achieve a specific ∆𝑣.

The total mass of the spacecraft, including the mass of its propellant.

A measure of how efficiently a rocket engine converts propellant mass into thrust.

The rate at which the spacecraft expels propellant from its engines.

A type of thruster that uses electric and magnetic fields to accelerate ions, producing much higher exhaust velocities than chemical rockets. They are particularly suitable for deep space missions.

The fundamental law in orbital mechanics that relates the orbital period of an object to the semi-major axis of its elliptical orbit. It states that the square of the orbital period is proportional to the cube of the semi-major axis of the orbit.